pr NVee's Pre-Idol Life Juggling Three Jobs! By world.kbs.co.kr Published On :: 2024-10-21 +09:00 Start your week off right with NVee and DJ Hyerim in another exciting episode of I Feel You! Today, they’re spilling stories about everything from their school days and being the coolest aunts...[more...] Full Article Economy&It
pr NVee Meets Xander, the Self-proclaimed "Kkondae" SBN By world.kbs.co.kr Published On :: 2024-11-11 +09:00 Get ready for an unforgettable first encounter! This week on I Feel You, our regular NVee meets special DJ Xander—the ultimate non-kkondae idol sbn! From hilarious icebreakers to shared stories...[more...] Full Article Economy&It
pr How to End an E-Mail: 21 Professional and Personal Sign-Offs By computer.howstuffworks.com Published On :: Mon, 17 Jun 2024 13:06:13 -0400 The perfect email deserves the perfect ending. But what is the right way to close an email? Well, that depends on who will be reading it. Full Article
pr Top Private Search Engines: Comparing 5 Competitors By computer.howstuffworks.com Published On :: Tue, 16 Jul 2024 11:44:29 -0400 In the realm of online privacy, private search engines provide a shield against intrusive tracking and data collection. Let's explore five prominent options. Full Article
pr 3 Essential Steps for Mobile Privacy With Startpage By computer.howstuffworks.com Published On :: Tue, 16 Jul 2024 11:44:33 -0400 In today's digital age, safeguarding your mobile privacy is vital. Here are three easy steps, powered by Startpage, to keep your digital life secure. Full Article
pr Top 6 Privacy and Security Apps to Safeguard Your Digital Life By computer.howstuffworks.com Published On :: Tue, 16 Jul 2024 11:44:37 -0400 In a world where digital privacy is increasingly important, finding the right tools to protect your data is essential. With mobile phones becoming central to our lives, it's crucial to choose apps that prioritize privacy. Full Article
pr What Does the 7th House Represent in Astrology? By entertainment.howstuffworks.com Published On :: Fri, 08 Nov 2024 05:00:03 -0500 Discover how the 7th House in astrology shapes love, partnerships, and marriage dynamics, revealing deep insights into relationship compatibility and commitment. Full Article
pr Is Virgo and Capricorn Compatibility Solid? Discover the Strengths and Challenges By entertainment.howstuffworks.com Published On :: Sun, 10 Nov 2024 05:15:02 -0500 s Virgo and Capricorn compatibility strong? Discover how these earth signs connect in love, friendship, and marriage with shared values, loyalty, and mutual support. Full Article
pr The Pros and Cons of Aries and Sagittarius Compatibility By entertainment.howstuffworks.com Published On :: Mon, 11 Nov 2024 05:30:04 -0500 Discover Aries and Sagittarius compatibility in love, friendship, and beyond. Learn how these two fire signs create a dynamic, passionate bond full of excitement and adventure. Full Article
pr Gemini vs. Capricorn: What Makes Their Relationship Unique? By entertainment.howstuffworks.com Published On :: Tue, 12 Nov 2024 05:15:03 -0500 Is Gemini and Capricorn compatibility strong? Discover the unique dynamics, strengths, and challenges that Gemini and Capricorn face in love, friendship, and beyond. Full Article
pr Import Prices Jump 2.2% in October, Largest Gain in 6 Months By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 09:13:48 +0900 [Economy] : The country’s import prices jumped more than two percent in October due to the won’s depreciation against the U.S. dollar and a rise in global oil prices. According to data from the Bank of Korea on Wednesday, the country’s import price index reached 137-point-61 in October, up two-point-two ...[more...] Full Article Economy
pr Minister Meets with Auto, Battery Industry Representatives ahead of Trump’s Second Term By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 16:54:38 +0900 [Economy] : The minister of trade, industry and energy has met with automotive and battery industry representatives ahead of Donald Trump’s return to power in the U.S. The ministry announced on Wednesday that the meeting took place earlier in the day, with participants highlighting the importance of South Korean ...[more...] Full Article Economy
pr Sino-US Decoupling Forecast to Intensify, Preference for US Interests to Expand under Trump Gov't By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 17:16:57 +0900 [Economy] : Sino-U.S. decoupling is forecast to intensify and preference for U.S. interests to expand under the incoming Donald Trump administration. This outlook was put forth Wednesday at a seminar hosted by the Korea International Trade Association(KITA). Kyung Hee University Professor Seo Jung-kun pointed to a ...[more...] Full Article Economy
pr Product development: properties and resources - British Geological Survey By news.google.com Published On :: Wed, 23 Sep 2020 13:28:59 GMT Product development: properties and resources British Geological Survey Full Article
pr BGS maps out priorities with five-year strategy - British Geological Survey By news.google.com Published On :: Thu, 11 May 2023 07:00:00 GMT BGS maps out priorities with five-year strategy British Geological Survey Full Article
pr Burrow-detecting devices could protect flood defences - British Geological Survey By news.google.com Published On :: Tue, 23 Jan 2024 08:00:00 GMT Burrow-detecting devices could protect flood defences British Geological Survey Full Article
pr Did you feel the earth move? Mini-earthquake recorded on Shropshire/Staffordshire border - Express & Star By news.google.com Published On :: Mon, 14 Oct 2024 07:00:00 GMT Did you feel the earth move? Mini-earthquake recorded on Shropshire/Staffordshire border Express & Star Full Article
pr BGS launches project to enhance value of ground investigation data - Ground Engineering By news.google.com Published On :: Fri, 05 Apr 2024 07:00:00 GMT BGS launches project to enhance value of ground investigation data Ground Engineering Full Article
pr Visit by Indonesian Embassy representatives to BGS - British Geological Survey By news.google.com Published On :: Tue, 27 Aug 2024 07:00:00 GMT Visit by Indonesian Embassy representatives to BGS British Geological Survey Full Article
pr BGS data product licence fees to rise - British Geological Survey By news.google.com Published On :: Fri, 01 Mar 2024 08:00:00 GMT BGS data product licence fees to rise British Geological Survey Full Article
pr The Common Ground project - British Geological Survey By news.google.com Published On :: Fri, 23 Feb 2024 14:43:19 GMT The Common Ground project British Geological Survey Full Article
pr Forty years and counting: new topsoil data provides most extensive snapshot of environmental pollution effects - British Geological Survey By news.google.com Published On :: Tue, 01 Oct 2024 07:00:00 GMT Forty years and counting: new topsoil data provides most extensive snapshot of environmental pollution effects British Geological Survey Full Article
pr World Mineral Production 2018 to 2022 is now available - British Geological Survey By news.google.com Published On :: Tue, 09 Apr 2024 14:26:00 GMT World Mineral Production 2018 to 2022 is now available British Geological Survey Full Article
pr Structural transformations and stability of benzo[a]pyrene under high pressure By journals.iucr.org Published On :: This study explores the high-pressure behavior of benzo[a]pyrene, revealing two previously unknown polymorphs at 4.8 and 7.1 GPa. These findings enhance our understanding of the structural dynamics and stability of polycyclic aromatic hydrocarbons under extreme conditions. Full Article text
pr The seventh blind test of crystal structure prediction: structure generation methods By journals.iucr.org Published On :: The results of the seventh blind test of crystal structure prediction are presented, focusing on structure generation methods. Full Article text
pr The seventh blind test of crystal structure prediction: structure ranking methods By journals.iucr.org Published On :: The results of the seventh blind test of crystal structure prediction are presented, focusing on structure ranking methods. Full Article text
pr Crystal structure of the incommensurate modulated high-pressure phase of the potassium guaninate monohydrate By journals.iucr.org Published On :: Incommensurate phase of potassium guaninate monohydrate is the first example of a modulation in purine derivatives and of a high-pressure incommensurate crystal structure to be solved for an organic compound. Full Article text
pr Crystal structure and compressibility of magnesium chloride heptahydrate found under high pressure By journals.iucr.org Published On :: In-situ diffraction measurements reveal that magnesium chloride forms a unique high-pressure phase, a heptahydrate, above 2 GPa. The hydrogen-bonding structure appears to contain orientational disorder. Full Article text
pr Symmetry, magnetic transitions and multiferroic properties of B-site-ordered A2MnB'O6 perovskites (B' = [Co, Ni]) By journals.iucr.org Published On :: A comparative description is presented of the symmetry and the magnetic structures found in the family of double perovskites A2MnB'O6 (mainly B' = Co and some Ni compounds for comparative purposes). Full Article text
pr Morphological control for hollow rod crystals of a photochromic diarylethene on spherulites by surface properties of substrates By journals.iucr.org Published On :: 1,2-Bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene formed its own spherulites by sublimation onto the hydrophilic surfaces of the (0001) planes of α-quartz and sapphire substrates. The formation of different morphologies of these spherulites was attributed to the surface properties of each substrate. Depending on the morphology of the spherulites, hollow rod crystals with cross sections of different sizes and shapes and branching structures were generated on the surfaces of the spherulites. Full Article text
pr Coordination geometry flexibility driving supramolecular isomerism of Cu/Mo pillared-layer hybrid networks By journals.iucr.org Published On :: The hydrothermal synthesis and structural characterization of four novel 3D pillared-layer metal–organic frameworks are studied, revealing how the malleability of copper coordination geometries drives diverse supramolecular isomerism. The findings provide new insights into designing advanced hybrid materials with tailored properties, emphasizing the significant role of reaction conditions and metal ion flexibility in determining network topologies. Full Article text
pr Crystal structure predictions for molecules with soft degrees of freedom using intermonomer force fields derived from first principles By journals.iucr.org Published On :: Full Article text
pr Morphological control for hollow rod crystals of a photochromic diarylethene on spherulites by surface properties of substrates By journals.iucr.org Published On :: 2024-10-31 Sublimation methods utilizing the surface properties of substrates can address the challenge of controlling hollow morphologies in rod crystals. Spherulites were formed on the hydrophilic surface of the (0001) planes of α-quartz and sapphire substrates by sublimation of 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1a). Various types of hollow morphologies, distinguished by the size and shape of their cross sections and by the presence or absence of branching structures, were formed separately on α-quartz and sapphire substrates. Such precise control of the hollow morphologies was attributed to the wettability of each substrate, leading to the formation of spherulites of 1a. In addition, it was indicated that the formation process of the surface morphologies of spherulites was associated with the hollow morphologies of rod crystals of 1a. Full Article text
pr Crystal structure and compressibility of magnesium chloride heptahydrate found under high pressure By journals.iucr.org Published On :: 2024-10-21 The odd hydration number has so far been missing in the water-rich magnesium chloride hydrate series (MgCl2·nH2O). In this study, magnesium chloride heptahydrate, MgCl2·7H2O (or MgCl2·7D2O), which forms at high pressures above 2 GPa and high temperatures above 300 K, has been identified. Its structure has been determined by a combination of in-situ single-crystal X-ray diffraction at 2.5 GPa and 298 K and powder neutron diffraction at 3.1 GPa and 300 K. The single-crystal specimen was grown by mixing alcohols to prevent nucleation of undesired crystalline phases. The results show orientational disorder of water molecules, which was also examined using density functional theory calculations. The disorder involves the reconnection of hydrogen bonds, which differs from those in water ice phases and known disordered salt hydrates. Shrinkage by compression occurs mainly in one direction. In the plane perpendicular to this most compressible direction, oxygen and chlorine atoms are in a hexagonal-like arrangement. Full Article text
pr Crystal structure of the incommensurate modulated high-pressure phase of the potassium guaninate monohydrate By journals.iucr.org Published On :: 2024-10-08 The crystal structure of the incommensurate modulated phase of potassium guaninate monohydrate has been solved on the basis of high-pressure single-crystal X-ray diffraction data. The modulated structure was described as a `mosaic' sequence of three different local configurations of two neighbouring guaninate rings. In contrast to known examples of incommensurate modulated organic compounds, the modulation functions of all atoms are discontinuous. This is the first example of the experimental detection of an incommensurate modulated crystal structure that can be modelled using the special `soliton mode' modulation function proposed by Aramburu et al. [(1995), J. Phys. Condens. Matter, 7, 6187–6196]. Full Article text
pr Contrasting conformational behaviors of molecules XXXI and XXXII in the seventh blind test of crystal structure prediction By journals.iucr.org Published On :: 2024-10-14 Accurate modeling of conformational energies is key to the crystal structure prediction of conformational polymorphs. Focusing on molecules XXXI and XXXII from the seventh blind test of crystal structure prediction, this study employs various electronic structure methods up to the level of domain-local pair natural orbital coupled cluster singles and doubles with perturbative triples [DLPNO-CCSD(T1)] to benchmark the conformational energies and to assess their impact on the crystal energy landscapes. Molecule XXXI proves to be a relatively straightforward case, with the conformational energies from generalized gradient approximation (GGA) functional B86bPBE-XDM changing only modestly when using more advanced density functionals such as PBE0-D4, ωB97M-V, and revDSD-PBEP86-D4, dispersion-corrected second-order Møller–Plesset perturbation theory (SCS-MP2D), or DLPNO-CCSD(T1). In contrast, the conformational energies of molecule XXXII prove difficult to determine reliably, and variations in the computed conformational energies appreciably impact the crystal energy landscape. Even high-level methods such as revDSD-PBEP86-D4 and SCS-MP2D exhibit significant disagreements with the DLPNO-CCSD(T1) benchmarks for molecule XXXII, highlighting the difficulty of predicting conformational energies for complex, drug-like molecules. The best-converged predicted crystal energy landscape obtained here for molecule XXXII disagrees significantly with what has been inferred about the solid-form landscape experimentally. The identified limitations of the calculations are probably insufficient to account for the discrepancies between theory and experiment on molecule XXXII, and further investigation of the experimental solid-form landscape would be valuable. Finally, assessment of several semi-empirical methods finds r2SCAN-3c to be the most promising, with conformational energy accuracy intermediate between the GGA and hybrid functionals and a low computational cost. Full Article text
pr Assessment of the exchange-hole dipole moment dispersion correction for the energy ranking stage of the seventh crystal structure prediction blind test By journals.iucr.org Published On :: 2024-10-15 The seventh blind test of crystal structure prediction (CSP) methods substantially increased the level of complexity of the target compounds relative to the previous tests organized by the Cambridge Crystallographic Data Centre. In this work, the performance of density-functional methods is assessed using numerical atomic orbitals and the exchange-hole dipole moment dispersion correction (XDM) for the energy-ranking phase of the seventh blind test. Overall, excellent performance was seen for the two rigid molecules (XXVII, XXVIII) and for the organic salt (XXXIII). However, for the agrochemical (XXXI) and pharmaceutical (XXXII) targets, the experimental polymorphs were ranked fairly high in energy amongst the provided candidate structures and inclusion of thermal free-energy corrections from the lattice vibrations was found to be essential for compound XXXI. Based on these results, it is proposed that the importance of vibrational free-energy corrections increases with the number of rotatable bonds. Full Article text
pr The seventh blind test of crystal structure prediction: structure ranking methods By journals.iucr.org Published On :: 2024-10-17 A seventh blind test of crystal structure prediction has been organized by the Cambridge Crystallographic Data Centre. The results are presented in two parts, with this second part focusing on methods for ranking crystal structures in order of stability. The exercise involved standardized sets of structures seeded from a range of structure generation methods. Participants from 22 groups applied several periodic DFT-D methods, machine learned potentials, force fields derived from empirical data or quantum chemical calculations, and various combinations of the above. In addition, one non-energy-based scoring function was used. Results showed that periodic DFT-D methods overall agreed with experimental data within expected error margins, while one machine learned model, applying system-specific AIMnet potentials, agreed with experiment in many cases demonstrating promise as an efficient alternative to DFT-based methods. For target XXXII, a consensus was reached across periodic DFT methods, with consistently high predicted energies of experimental forms relative to the global minimum (above 4 kJ mol−1 at both low and ambient temperatures) suggesting a more stable polymorph is likely not yet observed. The calculation of free energies at ambient temperatures offered improvement of predictions only in some cases (for targets XXVII and XXXI). Several avenues for future research have been suggested, highlighting the need for greater efficiency considering the vast amounts of resources utilized in many cases. Full Article text
pr The seventh blind test of crystal structure prediction: structure generation methods By journals.iucr.org Published On :: 2024-12-01 A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern. The use of CSP in the prediction of likely cocrystal stoichiometry was also explored, demonstrating multiple possible approaches. Crystallographic disorder emerged as an important theme throughout the test as both a challenge for analysis and a major achievement where two groups blindly predicted the existence of disorder for the first time. Additionally, large-scale comparisons of the sets of predicted crystal structures also showed that some methods yield sets that largely contain the same crystal structures. Full Article text
pr Analytical models representing X-ray form factors of ions By journals.iucr.org Published On :: 2024-01-01 Parameters in analytical models for X-ray form factors of ions f0(s), based on the inverse Mott–Bethe formula involving a variable number of Gaussians, are determined for a wide range of published data sets {s, f0(s)}. The models reproduce the calculated form-factor values close to what is expected from a uniform statistical distribution with limits determined by their precision. For different ions associated with the same atom, the number of Gaussians in the models decreases with increasing net positive charge. Full Article text
pr N-representable one-electron reduced density matrix reconstruction with frozen core electrons By journals.iucr.org Published On :: 2024-03-21 Recent advances in quantum crystallography have shown that, beyond conventional charge density refinement, a one-electron reduced density matrix (1-RDM) satisfying N-representability conditions can be reconstructed using jointly experimental X-ray structure factors and directional Compton profiles (DCP) through semidefinite programming. So far, such reconstruction methods for 1-RDM, not constrained to idempotency, have been tested only on a toy model system (CO2). In this work, a new method is assessed on crystalline urea [CO(NH2)2] using static (0 K) and dynamic (50 K) artificial experimental data. An improved model, including symmetry constraints and frozen core-electron contribution, is introduced to better handle the increasing system complexity. Reconstructed 1-RDMs, deformation densities and DCP anisotropy are analysed, and it is demonstrated that the changes in the model significantly improve the reconstruction quality, even when there is insufficient information and data corruption. The robustness of the model and the strategy are thus shown to be well adapted to address the reconstruction problem from actual experimental scattering data. Full Article text
pr GraphT–T (V1.0Beta), a program for embedding and visualizing periodic graphs in 3D Euclidean space By journals.iucr.org Published On :: 2024-04-29 Following the work of Day & Hawthorne [Acta Cryst. (2022), A78, 212–233] and Day et al. [Acta Cryst. (2024), A80, 258–281], the program GraphT–T has been developed to embed graphical representations of observed and hypothetical chains of (SiO4)4− tetrahedra into 2D and 3D Euclidean space. During embedding, the distance between linked vertices (T–T distances) and the distance between unlinked vertices (T⋯T separations) in the resultant unit-distance graph are restrained to the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is restrained to be equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. The notional interactions between vertices are described by a 3D spring-force algorithm in which the attractive forces between linked vertices behave according to Hooke's law and the repulsive forces between unlinked vertices behave according to Coulomb's law. Embedding parameters (i.e. spring coefficient, k, and Coulomb's constant, K) are iteratively refined during embedding to determine if it is possible to embed a given graph to produce a unit-distance graph with T–T distances and T⋯T separations that are compatible with the observed T–T distances and T⋯T separations in crystal structures. The resultant unit-distance graphs are denoted as compatible and may form crystal structures if and only if all distances between linked vertices (T–T distances) agree with the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. If the unit-distance graph does not satisfy these conditions, it is considered incompatible and the corresponding chain of tetrahedra is unlikely to form crystal structures. Using GraphT–T, Day et al. [Acta Cryst. (2024), A80, 258–281] have shown that several topological properties of chain graphs influence the flexibility (and rigidity) of the corresponding chains of Si tetrahedra and may explain why particular compatible chain arrangements (and the minerals in which they occur) are more common than others and/or why incompatible chain arrangements do not occur in crystals despite being topologically possible. Full Article text
pr Online carbohydrate 3D structure validation with the Privateer web app By journals.iucr.org Published On :: 2024-01-24 Owing to the difficulties associated with working with carbohydrates, validating glycan 3D structures prior to deposition into the Protein Data Bank has become a staple of the structure-solution pipeline. The Privateer software provides integrative methods for the validation, analysis, refinement and graphical representation of 3D atomic structures of glycans, both as ligands and as protein modifiers. While Privateer is free software, it requires users to install any of the structural biology software suites that support it or to build it from source code. Here, the Privateer web app is presented, which is always up to date and available to be used online (https://privateer.york.ac.uk) without installation. This self-updating tool, which runs locally on the user's machine, will allow structural biologists to simply and quickly analyse carbohydrate ligands and protein glycosylation from a web browser whilst retaining all confidential information on their devices. Full Article text
pr Expression, purification and crystallization of the photosensory module of phytochrome B (phyB) from Sorghum bicolor By journals.iucr.org Published On :: 2024-02-20 Sorghum, a short-day tropical plant, has been adapted for temperate grain production, in particular through the selection of variants at the MATURITY loci (Ma1–Ma6) that reduce photoperiod sensitivity. Ma3 encodes phytochrome B (phyB), a red/far-red photochromic biliprotein photoreceptor. The multi-domain gene product, comprising 1178 amino acids, autocatalytically binds the phytochromobilin chromophore to form the photoactive holophytochrome (Sb.phyB). This study describes the development of an efficient heterologous overproduction system which allows the production of large quantities of various holoprotein constructs, along with purification and crystallization procedures. Crystals of the Pr (red-light-absorbing) forms of NPGP, PGP and PG (residues 1–655, 114–655 and 114–458, respectively), each C-terminally tagged with His6, were successfully produced. While NPGP crystals did not diffract, those of PGP and PG diffracted to 6 and 2.1 Å resolution, respectively. Moving the tag to the N-terminus and replacing phytochromobilin with phycocyanobilin as the ligand produced PG crystals that diffracted to 1.8 Å resolution. These results demonstrate that the diffraction quality of challenging protein crystals can be improved by removing flexible regions, shifting fusion tags and altering small-molecule ligands. Full Article text
pr Preliminary X-ray diffraction and ligand-binding analyses of the N-terminal domain of hypothetical protein Rv1421 from Mycobacterium tuberculosis H37Rv By journals.iucr.org Published On :: 2024-06-27 Mycobacterium tuberculosis can reside and persist in deep tissues; latent tuberculosis can evade immune detection and has a unique mechanism to convert it into active disease through reactivation. M. tuberculosis Rv1421 (MtRv1421) is a hypothetical protein that has been proposed to be involved in nucleotide binding-related metabolism in cell-growth and cell-division processes. However, due to a lack of structural information, the detailed function of MtRv1421 remains unclear. In this study, a truncated N-terminal domain (NTD) of MtRv1421, which contains a Walker A/B-like motif, was purified and crystallized using PEG 400 as a precipitant. The crystal of MtRv1421-NTD diffracted to a resolution of 1.7 Å and was considered to belong to either the C-centered monoclinic space group C2 or the I-centered orthorhombic space group I222, with unit-cell parameters a = 124.01, b = 58.55, c = 84.87 Å, β = 133.12° or a = 58.53, b = 84.86, c = 90.52 Å, respectively. The asymmetric units of the C2 or I222 crystals contained two or one monomers, respectively. In terms of the binding ability of MtRv1421-NTD to various ligands, uridine diphosphate (UDP) and UDP-N-acetylglucosamine significantly increased the melting temperature of MtRv1421-NTD, which indicates structural stabilization through the binding of these ligands. Altogether, the results reveal that a UDP moiety may be required for the interaction of MtRv1421-NTD as a nucleotide-binding protein with its ligand. Full Article text
pr Preparing research samples for safe arrival at centers and facilities: recipes for successful experiments By journals.iucr.org Published On :: 2024-07-11 Preparation of biomacromolecules for structural biology studies is a complex and time-consuming process. The goal is to produce a highly concentrated, highly pure product that is often shipped to large facilities with tools to prepare the samples for crystallization trials or for measurements at synchrotrons and cryoEM centers. The aim of this article is to provide guidance and to discuss general considerations for shipping biomacromolecular samples. Details are also provided about shipping samples for specific experiment types, including solution- and cryogenic-based techniques. These guidelines are provided with the hope that the time and energy invested in sample preparation is not lost due to shipping logistics. Full Article text
pr Structures of Brucella ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein reveal a conformationally flexible peptide-binding cavity By journals.iucr.org Published On :: 2024-08-23 Brucella ovis is an etiologic agent of ovine epididymitis and brucellosis that causes global devastation in sheep, rams, goats, small ruminants and deer. There are no cost-effective methods for the worldwide eradication of ovine brucellosis. B. ovis and other protein targets from various Brucella species are currently in the pipeline for high-throughput structural analysis at the Seattle Structural Genomics Center for Infectious Disease (SSGCID), with the aim of identifying new therapeutic targets. Furthermore, the wealth of structures generated are effective tools for teaching scientific communication, structural science and biochemistry. One of these structures, B. ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein (BoLBP), is a putative periplasmic amino acid-binding protein. BoLBP shares less than 29% sequence identity with any other structure in the Protein Data Bank. The production, crystallization and high-resolution structures of BoLBP are reported. BoLBP is a prototypical bacterial periplasmic amino acid-binding protein with the characteristic Venus flytrap topology of two globular domains encapsulating a large central cavity containing the peptide-binding region. The central cavity contains small molecules usurped from the crystallization milieu. The reported structures reveal the conformational flexibility of the central cavity in the absence of bound peptides. The structural similarity to other LBPs can be exploited to accelerate drug repurposing. Full Article text
pr First crystal structure of the DUF2436 domain of virulence proteins from Porphyromonas gingivalis By journals.iucr.org Published On :: 2024-09-26 Porphyromonas gingivalis is a major pathogenic oral bacterium that is responsible for periodontal disease. It is linked to chronic periodontitis, gingivitis and aggressive periodontitis. P. gingivalis exerts its pathogenic effects through mechanisms such as immune evasion and tissue destruction, primarily by secreting various factors, including cysteine proteases such as gingipain K (Kgp), gingipain R (RgpA and RgpB) and PrtH (UniProtKB ID P46071). Virulence proteins comprise multiple domains, including the pro-peptide region, catalytic domain, K domain, R domain and DUF2436 domain. While there is a growing database of knowledge on virulence proteins and domains, there was no prior evidence or information regarding the structure and biological function of the well conserved DUF2436 domain. In this study, the DUF2436 domain of PrtH from P. gingivalis (PgDUF2436) was determined at 2.21 Å resolution, revealing a noncanonical β-jelly-roll sandwich topology with two antiparallel β-sheets and one short α-helix. Although the structure of PgDUF2436 was determined by the molecular-replacement method using an AlphaFold model structure as a template, there were significant differences in the positions of β1 between the AlphaFold model and the experimentally determined PgDUF2436 structure. The Basic Local Alignment Search Tool sequence-similarity search program showed no sequentially similar proteins in the Protein Data Bank. However, DaliLite search results using structure-based alignment revealed that the PgDUF2436 structure has structural similarity Z-scores of 5.9–5.4 with the C-terminal domain of AlgF, the D4 domain of cytolysin, IglE and the extracellular domain structure of PepT2. This study has elucidated the structure of the DUF2436 domain for the first time and a comparative analysis with similar structures has been performed. Full Article text
pr X-ray crystal structure of proliferating cell nuclear antigen 1 from Aeropyrum pernix By journals.iucr.org Published On :: 2024-10-09 Proliferating cell nuclear antigen (PCNA) plays a critical role in DNA replication by enhancing the activity of various proteins involved in replication. In this study, the crystal structure of ApePCNA1, one of three PCNAs from the thermophilic archaeon Aeropyrum pernix, was elucidated. ApePCNA1 was cloned and expressed in Escherichia coli and the protein was purified and crystallized. The resulting crystal structure determined at 2.00 Å resolution revealed that ApePCNA1 does not form a trimeric ring, unlike PCNAs from other domains of life. It has unique structural features, including a long interdomain-connecting loop and a PIP-box-like sequence at the N-terminus, indicating potential interactions with other proteins. These findings provide insights into the functional mechanisms of PCNAs in archaea and their evolutionary conservation across different domains of life. A modified medium and protocol were used to express recombinant protein containing the lac operon. The expression of the target protein increased and the total incubation time decreased when using this system compared with those of previous expression protocols. Full Article text
pr Optimizing crucible geometry to improve the quality of AlN crystals by the physical vapor transport method By journals.iucr.org Published On :: The growth quality of AlN single crystals was improved by optimizing the crucible structure for Al vapor transport with the help of finite element simulation. Full Article text