late Pakistan Violates Ceasefire, Shells Forward Areas Along LoC in J&K's Poonch By www.news18.com Published On :: Sat, 9 May 2020 08:42:06 +0530 The cross-border shelling is going on but there is no report of any casualty on the Indian side so far, a spokesman said. Full Article
late Latest TRP Ratings: Uttar Ramayan Tops The Chart; Doordarshan’s Mahabharat Occupies Second Place By www.filmibeat.com Published On :: Sat, 09 May 2020 17:55:32 +0530 The latest BARC/TRP ratings for the Week 17 (April 25-May 1, 2020) are here. The mythological shows are still ruling the TRP chart. Among the mythological shows, Doordarshan National's Uttar Ramayan is at the tops slot while DD Bharti's Mahabharat has Full Article
late Deepika Padukone Dedicates An Emotional Tribute To Late Actor Irrfan Khan As Piku Completes 5 Years By www.filmibeat.com Published On :: Fri, 08 May 2020 16:36:05 +0530 The news of Irrfan Khan's shocking demise is yet to sink in. The actor died of neuroendocrine tumour on April 29, 2020. One of his films Piku, co-starring Amitabh Bachchan and Deepika Padukone, completes 5 years today (May 8, 2020). Full Article
late Iulia Vantur Says Salman Khan Looks Like A 'Supermodel' In Latest Picture With Niketan Madhok By www.filmibeat.com Published On :: Fri, 08 May 2020 16:48:50 +0530 Salman Khan is currently living with his family at the Panvel farmhouse, from where everyone often shares their daily updates on social media. Recently, in one such Salman Khan's post, Iulia Vantur called him a supermodel. Salman, while at Full Article
late Russia buries latest priest to die from coronavirus By feeds.reuters.com Published On :: Sun, 10 May 2020 08:46:39 +0530 Father Andrei Molchanov, the latest Russian Orthodox priest to die from the novel coronavirus, was buried on Saturday by his heartbroken daughter who said she wished the Moscow church where he served had closed earlier. Full Article worldNews
late Latest TRP Ratings: Uttar Ramayan Tops The Chart; Doordarshan’s Mahabharat Occupies Second Place By www.filmibeat.com Published On :: Sat, 09 May 2020 17:55:32 +0530 The latest BARC/TRP ratings for the Week 17 (April 25-May 1, 2020) are here. The mythological shows are still ruling the TRP chart. Among the mythological shows, Doordarshan National's Uttar Ramayan is at the tops slot while DD Bharti's Mahabharat has Full Article
late Physical memoirs: selected and translated from foreign sources. / under the direction of the Physical society of London By library.mit.edu Published On :: Sun, 19 Jan 2014 06:34:31 EST Archives, Room Use Only - QC3.P49 1888 Full Article
late Submarine telegraphy: a practical manual / by Italio de Giuli ; translated from the Italian by J.J. McKichan, with a foreword by T.E. Herbert By library.mit.edu Published On :: Sun, 26 Jan 2014 06:36:43 EST Archives, Room Use Only - TK5621.G5313 1932 Full Article
late The telegraph / translated from the French of A.-L. Ternant by R. Routledge By library.mit.edu Published On :: Sun, 9 Feb 2014 06:34:19 EST Archives, Room Use Only - TK5115.T4713 1895 Full Article
late Elementary treatise on electric batteries / from the French of Alfred Niaudet ; translated by L.M. Fishback By library.mit.edu Published On :: Sun, 16 Feb 2014 06:33:42 EST Archives, Room Use Only - TK2941.N52313 1880 Full Article
late How to signal by many methods / by J. Gibson, late signalling instructor, R.A.M.C.(T.) .. By library.mit.edu Published On :: Sun, 2 Mar 2014 06:33:00 EST Archives, Room Use Only - HE9723.G53 1915 Full Article
late Signal tactics: assimilated to the tactics of artillery, cavalry and infantry, prepared for the use of officers and enlisted men of the military and naval forces of the United States and adapted for the use of the National Guards and military academies / By library.mit.edu Published On :: Sun, 23 Mar 2014 06:15:10 EDT Archives, Room Use Only - UG573.R44 1880 Full Article
late Genealogy of some of the Vail family descended from Thomas Vail at Salem, Massachusetts, 1640: together with collateral lines / by Wm. Penn Vail By library.mit.edu Published On :: Sun, 27 Apr 2014 06:17:16 EDT Archives, Room Use Only - CS71.V129 1937 Full Article
late Moses Vail of Huntington, L.I.: showing his descent from Joseph (2) Vail, son of Thomas Vail, at Salem, Massachusetts, 1640, together with collateral lines and with additions and corrections to both H.H. Vail's "Jeremiah Vail family" (pub. 1 By library.mit.edu Published On :: Sun, 22 Jun 2014 06:19:54 EDT Archives, Room Use Only - CS71.V129 1947 Full Article
late Chapman's principia, or, Nature's first principles: theory of universal electro-magnetism, simplified: explaining the elements of the important discovery of the laws of nature, which regulate the changes of the elements: exposing the numerous disc By library.mit.edu Published On :: Mon, 21 Jul 2014 13:55:30 EDT Archives, Room Use Only - QC670.C43 1855 Full Article
late A history of inventions, discoveries, and origins / by John Beckmann ; translated from the German by William Johnston By library.mit.edu Published On :: Sun, 27 Jul 2014 07:06:48 EDT Archives, Room Use Only - T15.B3813 1846 Full Article
late One hundred years: the story of Henley's / by Ernest Slater By library.mit.edu Published On :: Sun, 17 Aug 2014 07:36:28 EDT Archives, Room Use Only - TK5157.S53 1937 Full Article
late Elementary treatise on natural philosophy / by A. Privat Deschanel ; translated and edited, with extensive modifications, by J.D. Everett By library.mit.edu Published On :: Sun, 14 Sep 2014 08:09:40 EDT Archives, Room Use Only - QC23.P7513 1883 Full Article
late Coronavirus latest updates: Delhi govt asks DMs to release 2,446 Tablighi Jamaat members By timesofindia.indiatimes.com Published On :: Sun, 10 May 2020 10:03:12 IST Full Article
late NFL gives itself extra flexibility for late-season Saturday games By sports.yahoo.com Published On :: Sat, 09 May 2020 17:51:19 GMT The 2020 NFL schedule will feature football on two Saturdays in December, but we don't know specifically which games will be played. The league announced that there will be Saturday games in Weeks 15 and 16, but we don't know how many games, only that there can be "up to three" on each Saturday. The [more] Full Article article Sports
late Delhi results give Twitter its latest memes By www.rediff.com Published On :: Tue, 11 Feb 2020 11:39:37 +0530 As the Aam Aadmi Party is seen taking a big lead in Delhi election 2020, netizens are taking to social media with hilarious memes. The Arvind Kejriwal-led AAP has comfortably crossed the majority mark as per early trends, while the Bharatiya Janata Party has 15 seats. Full Article Aam Aadmi Party Bharatiya Janata Party Delhi
late Latest Bollywood News: Shehnaaz, Jassie's 'Keh Gayi Sorry' t... By Published On :: Latest Bollywood News: Shehnaaz, Jassie's 'Keh Gayi Sorry' t... Full Article
late No contacts, disposable plates: How Delhi hotels are hosting foreign evacuees By www.newkerala.com Published On :: Sun, 10 May 2020 07:24:01 +0530 Full Article
late COVID-19 pandemic is likely to reduce investment in construction related projects : KPMG By www.thehindu.com Published On :: Sat, 09 May 2020 22:36:46 +0530 COVID-19 pandemic is likely to reduce investment in construction related projects in the range of 13 to 30% which will have significant impact on Gros Full Article Business
late Co-morbidity, late hospitalization ailing Gujarat: AIIMS chief | Ahmedabad News - Times of India By Published On :: Co-morbidity, late hospitalization ailing Gujarat: AIIMS chief | Ahmedabad News - Times of India Full Article
late On the plate: Technology-aided dining and sparser eateries By Published On :: On the plate: Technology-aided dining and sparser eateries Full Article
late Coronavirus: 13 Italians isolated at Amritsar hotel By www.newkerala.com Published On :: Sat, 07 Mar 2020 09:12:01 +0530 Full Article
late 'Co-morbidity, late hospitalization ailing Guj' By timesofindia.indiatimes.com Published On :: Sun, 10 May 2020 06:34:10 IST Director of All India Institute of Medical Sciences, Delhi (AIIMS-D), Dr Randeep Guleria on Saturday said that late hospitalization of Covid-19 patients due to fear of stigma and higher prevalence of co-morbid conditions like diabetes, hypertension, heart and kidney disease were key reasons behind the high number of Civid-19 deaths in Gujarat. Full Article
late How to make eggless chocolate mousse By www.rediff.com Published On :: Sun, 10 May 2020 10:20:40 +0530 Recipes by chef Ashok Suyal, pastry chef at Jaypee Greens Golf and Spa Resort, Greater Noida. Full Article
late 'The virus will circulate for a very long time' By www.rediff.com Published On :: Sun, 10 May 2020 09:49:53 +0530 'Despite expanded testing the incidence remains low.' 'Therefore, the focus should be on specific districts where we need to improve the testing.' 'We should have a district-centric strategy.' Full Article
late Donald Trump congratulates UFC for restarting sports By indianexpress.com Published On :: Sun, 10 May 2020 04:49:54 +0000 Full Article Sport Others Sports
late 'The virus will circulate for a very long time' By www.rediff.com Published On :: 'Despite expanded testing the incidence remains low.' Full Article
late Correlated changes in structure and viscosity during gelatinization and gelation of tapioca starch granules By journals.iucr.org Published On :: Melting of the semicrystalline structure of native tapioca starch granules is correlated to solution viscosity for elucidating gelatinization and gelation processes. Full Article text
late Earth's North Magnetic Pole Keeps Drifting towards Siberia, Latest World Magnetic Model Shows | Geophysics, Geoscience - Sci-News.com By www.sci-news.com Published On :: Fri, 27 Dec 2019 08:00:00 GMT Earth's North Magnetic Pole Keeps Drifting towards Siberia, Latest World Magnetic Model Shows | Geophysics, Geoscience Sci-News.com Full Article
late Crystal and solution structures of fragments of the human leucocyte common antigen-related protein By journals.iucr.org Published On :: The crystal and solution SAXS structures of a fragment of human leucocyte common antigen-related protein show that it is less flexible than the homologous proteins tyrosine phosphatase receptors δ and σ. Full Article text
late Structure of Thermococcus litoralis Δ1-pyrroline-2-carboxylate reductase in complex with NADH and L-proline By journals.iucr.org Published On :: The paper reports the structure of a Δ1-pyrroline-2-carboxylate reductase from the archaeon Thermococcus litoralis, a key enzyme involved in the second step of trans-4-Hydroxy-L-proline metabolism, conserved in archaea, bacteria and humans. Full Article text
late Crystal structures of trans-diaqua(3-R-1,3,5,8,12-pentaazacyclotetradecane)copper(II) isophthalate hydrates (R = benzyl or pyridin-3-ylmethyl) By scripts.iucr.org Published On :: 2019-06-21 The asymmetric units of the title compounds, trans-diaqua(3-benzyl-1,3,5,8,12-pentaazacyclotetradecane-κ4N1,N5,N8,N12)copper(II) isophthalate monohydrate, [Cu(C16H29N5)(H2O)2](C8H4O4)·H2O, (I), and trans-diaqua[3-(pyridin-3-ylmethyl)-1,3,5,8,12-pentaazacyclotetradecane-κ4N1,N5,N8,N12]copper(II) isophthalate 0.9-hydrate, [Cu(C15H28N6)(H2O)2](C8H4O4)·0.9H2O, (II) consist of one diaqua macrocyclic cation, one dicarboxylate anion and uncoordinated water molecule(s). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand and the mutually trans O atoms of the water molecules in a tetragonally distorted octahedral geometry. The average equatorial Cu—N bond lengths are significantly shorter than the average axial Cu—O bond lengths [2.020 (9) versus 2.495 (12) Å and 2.015 (4) versus 2.507 (7) Å for (I) and (II), respectively]. The coordinated macrocyclic ligand in the cations of both compounds adopts the most energetically favorable trans-III conformation. In the crystals, the complex cations and counter-anions are connected via hydrogen-bonding interactions between the N—H groups of the macrocycles and the O—H groups of coordinated water molecules as the proton donors and the O atoms of the carboxylate as the proton acceptors. Additionally, as a result of O—H⋯O hydrogen bonding with the coordinated and water molecules of crystallization, the isophthalate dianions form layers lying parallel to the (overline{1}01) and (100) planes in (I) and (II), respectively. Full Article text
late (3,5-Dimethyladamantan-1-yl)ammonium methanesulfonate (memantinium mesylate): synthesis, structure and solid-state properties By scripts.iucr.org Published On :: 2019-07-26 The asymmetric unit of the title compound, C12H22N+·CH3O3S−, consists of three (3,5-dimethyladamantan-1-yl)ammonium cations, C12H22N+, and three methanesulfonate anions, CH3O3S−. In the crystal, the cations and anions associate via N—H⋯O hydrogen bonds into layers, parallel to the (001) plane, which include large supramolecular hydrogen-bonded rings. Full Article text
late Palladium(II) complexes of a bridging amine bis(phenolate) ligand featuring κ2 and κ3 coordination modes By scripts.iucr.org Published On :: 2019-07-26 Bidentate and tridentate coordination of a 2,4-di-tert-butyl-substituted bridging amine bis(phenolate) ligand to a palladium(II) center are observed within the same crystal structure, namely dichlorido({6,6'-[(ethane-1,2-diylbis(methylazanediyl)]bis(methylene)}bis(2,4-di-tert-butylphenol))palladium(II) chlorido(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hydroxyphenyl)methyl](methyl)amino}ethyl)(methyl)amino]methyl}phenolato)palladium(II) methanol 1.685-solvate 0.315-hydrate, [PdCl2(C34H56N2O2)][PdCl(C34H55N2O2)]·1.685CH3OH·0.315H2O. Both complexes exhibit a square-planar geometry, with unbound phenol moieties participating in intermolecular hydrogen bonding with co-crystallized water and methanol. The presence of both κ2 and κ3 coordination modes arising from the same solution suggest a dynamic process in which phenol donors may coordinate or dissociate from the metal center, and offers insight into catalyst speciation throughout Pd-mediated processes. The unit cell contains dichlorido({6,6'-[(ethane-1,2-diylbis(methylazanediyl)]bis(methylene)}bis(2,4-di-tert-butylphenol))palladium(II), {(L2)PdCl2}, and chlorido(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hydroxyphenyl)methyl](methyl)amino}ethyl)(methyl)amino]methyl}phenolato)palladium(II), {(L2X)PdCl}, molecules as well as fractional water and methanol solvent molecules. Full Article text
late Synthesis, characterization, crystal structure and supramolecularity of ethyl (E)-2-cyano-3-(3-methylthiophen-2-yl)acrylate and a new polymorph of ethyl (E)-2-cyano-3-(thiophen-2-yl)acrylate By scripts.iucr.org Published On :: 2019-08-23 The synthesis, crystal structure and structural motif of two thiophene-based cyanoacrylate derivatives, namely, ethyl (E)-2-cyano-3-(3-methylthiophen-2-yl)acrylate (1), C11H11NO2S, and ethyl (E)-2-cyano-3-(thiophen-2-yl)acrylate (2), C10H9NO2S, are reported. Derivative 1 crystallized with two independent molecules in the asymmetric unit, and derivative 2 represents a new monoclinic (C2/m) polymorph. The molecular conformations of 1 and the two polymorphs of 2 are very similar, as all non-H atoms are planar except for the methyl of the ethyl groups. The intermolecular interactions and crystal packing of 1 and 2 are described and compared with that of the reported monoclinic (C2/m) polymorph of derivative 2 [Castro Agudelo et al. (2017). Acta Cryst. E73, 1287–1289]. Full Article text
late The crystal structure of the zwitterionic co-crystal of 2,4-dichloro-6-{[(3-hydroxypropyl)azaniumyl]methyl}phenolate and 2,4-dichlorophenol By scripts.iucr.org Published On :: 2019-09-10 The title compound, C10H13Cl2NO2·C6H4Cl2O, was formed from the incomplete Mannich condensation reaction of 3-aminopropan-1-ol, formaldehyde and 2,4-dichlorophenol in methanol. This resulted in the formation of a co-crystal of the zwitterionic Mannich base, 2,4-dichloro-6-{[(3-hydroxypropyl)azaniumyl]methyl}phenolate and the unreacted 2,4-dichlorophenol. The compound crystallizes in the monoclinic crystal system (in space group Cc) and the asymmetric unit contains a molecule each of the 2,4-dichlorophenol and 2,4-dichloro-6-{[(3-hydroxypropyl)azaniumyl]methyl}phenolate. Examination of the crystal structure shows that the two components are clearly linked together by hydrogen bonds. The packing patterns are most interesting along the b and the c axes, where the co-crystal in the unit cell packs in a manner that shows alternating aromatic dichlorophenol fragments and polar hydrogen-bonded channels. The 2,4-dichlorophenol rings stack on top of one another, and these are held together by π–π interactions. The crystal studied was refined as an inversion twin. Full Article text
late Crystal structure and Hirshfeld surface analysis of 2-aminopyridinium hydrogen phthalate By scripts.iucr.org Published On :: 2019-10-08 Aminopyridine and phthalic acid are well known synthons for supramolecular architectures for the synthesis of new materials for optical applications. The 2-aminopyridinium hydrogen phthalate title salt, C5H7N2+·C8H5O4−, crystallizes in the non-centrosymmetric space group P21. The nitrogen atom of the –NH2 group in the cation deviates from the fitted pyridine plane by 0.035 (7) Å. The plane of the pyridinium ring and phenyl ring of the anion are oriented at an angle of 80.5 (3)° to each other in the asymmetric unit. The anion features a strong intramolecular O—H⋯O hydrogen bond, forming a self-associated S(7) ring motif. The crystal packing is dominated by intermolecular N—H⋯O hydrogen bonds leading to the formation of 21 helices, with a C(11) chain motif. They propagate along the b axis and enclose R22(8) ring motifs. The helices are linked by C—H⋯O hydrogen bonds, forming layers parallel to the ab plane. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to investigate and quantify the intermolecular interactions in the crystal. Full Article text
late Crystal structure and Hirshfeld surface analysis of 1,2,4-triazolium hydrogen oxalate By scripts.iucr.org Published On :: 2020-01-07 The asymmetric unit of the title 1:1 salt 1,2,4-triazolium hydrogen oxalate, C2H4N3+·C2HO4− (I), comprises one 1,2,4-triazolium cation and one hydrogen oxalate anion. In the crystal, the hydrogen oxalate anions are linked by O—H⋯O hydrogen bonds into chains running parallel to [100]. In turn, the anionic chains are linked through the 1,2,4-triazolium cations by charge-assisted +N—H⋯O− hydrogen bonds into sheets aligned parallel to (01overline{1}). The sheets are further stacked through π–π interactions between the 1,2,4-triazolium rings [centroid-to-centroid distance = 3.642 (3) Å, normal distance = 3.225 (3) Å, slippage 1.691 Å], resulting in the formation of a three-dimensional supramolecular network. Hirshfeld surface analysis of the title salt suggests that the most significant contributions to the crystal packing are by H⋯O/O⋯H and H⋯N/N⋯H contacts involving the hydrogen bonds. Full Article text
late Phosphorescent mono- and diiridium(III) complexes cyclometalated by fluorenyl- or phenyl-pyridino ligands with bulky substituents, as prospective OLED dopants By scripts.iucr.org Published On :: 2020-02-18 The crystal structures of tris[9,9-dihexyl-2-(5-methoxypyridin-2-yl-κN)-9H-fluoren-3-yl-κC3]iridium pentane monosolvate, [Ir(C31H38NO)3]·C5H12, (I), di-μ2-chlorido-bis{bis[2-(5-fluoropyridin-2-yl)-9,9-dihexyl-9H-fluoren-3-yl]iridium} pentane 0.3-solvate, [Ir2(C30H35FN)4Cl2]·0.3C5H12, (II), di-μ2-cyanato-bis{bis[9,9-dihexyl-2-(5-methoxypyridin-2-yl)-9H-fluoren-1-yl]iridium} pentane monosolvate, [Ir2(C31H38NO)4(NCO)2(NCO)2]·C5H12, (III), and {μ-N,N'-bis[3,5-bis(trifluoromethyl)phenyl]oxamidato}bis(bis{2-[4-(2,4,6-trimethylphenyl)pyridin-2-yl]phenyl-κ2C1,N'}iridium)–chlorobenzene–pentane (1/2.3/0.4), [Ir2(C20H19N)4(C18H6F12N2O2)]·2.3C6H5Cl·0.4C5H12, (IV), synthesized in the quest for organic light-emitting devices, were determined. The bis-μ2-chloro and bis-μ2-cyanato complexes have ΔΔ and ΛΛ configurations of the distorted octahedral Ir centres in racemic crystals, whereas the oxamido complex has a centrosymmetric (meso) structure with the ΔΛ configuration. The bridging oxamido moiety has a nearly planar anti geometry. All structures show substantial disorder of both host molecules and solvents of crystallization. Full Article text
late Cis versus trans arrangement of dithiocarbazate ligands in bis-chelated Ni and Cu complexes By scripts.iucr.org Published On :: 2020-04-21 The structures are described of two bis-chelated metal complexes of nickel(II) and copper(II) with S-n-hexyl 3-(1-phenylethylidene)dithiocarbazate Schiff bases in a cis configuration, namely, bis[S-n-hexyl 3-(1-phenylethylidene)dithiocarbazato-κ2N3,S]nickel(II), [Ni(C15H21N2S2)2], and bis[S-n-hexyl 3-(1-phenylethylidene)dithiocarbazato-κ2N3,S]copper(II), [Cu(C15H21N2S2)2]. In both complexes, the metals have distorted square-planar geometries. A search in the Cambridge Structural Database [Groom et al. (2016). Acta Cryst. B72, 171–179] for bis-chelated nickel(II) and copper(II) complexes with similar Schiff bases retrieved 55 and 36 hits for the two metals, respectively. An analysis of the geometrical parameters of complexes showing cis and trans configurations is reported and the values compared with those for the complexes described in this work. Full Article text
late Structures of three ependymin-related proteins suggest their function as a hydrophobic molecule binder By scripts.iucr.org Published On :: 2019-06-20 Ependymin was first discovered as a predominant protein in brain extracellular fluid in fish and was suggested to be involved in functions mostly related to learning and memory. Orthologous proteins to ependymin called ependymin-related proteins (EPDRs) have been found to exist in various tissues from sea urchins to humans, yet their functional role remains to be revealed. In this study, the structures of EPDR1 from frog, mouse and human were determined and analyzed. All of the EPDR1s fold into a dimer using a monomeric subunit that is mostly made up of two stacking antiparallel β-sheets with a curvature on one side, resulting in the formation of a deep hydrophobic pocket. All six of the cysteine residues in the monomeric subunit participate in the formation of three intramolecular disulfide bonds. Other interesting features of EPDR1 include two asparagine residues with glycosylation and a Ca2+-binding site. The EPDR1 fold is very similar to the folds of bacterial VioE and LolA/LolB, which also use a similar hydrophobic pocket for their respective functions as a hydrophobic substrate-binding enzyme and a lipoprotein carrier, respectively. A further fatty-acid binding assay using EPDR1 suggests that it indeed binds to fatty acids, presumably via this pocket. Additional interactome analysis of EPDR1 showed that EPDR1 interacts with insulin-like growth factor 2 receptor and flotillin proteins, which are known to be involved in protein and vesicle translocation. Full Article text
late A new small-angle X-ray scattering model for polymer spherulites with a limited lateral size of the lamellar crystals By scripts.iucr.org Published On :: 2019-08-31 As is well known, polymers commonly form lamellar crystals, and these assemble further into lamellar stacks and spherulites during quiescent crystallization. Fifty years ago, Vonk and Kortleve constructed the classical small-angle X-ray scattering theory (SAXS) for a lamellar system, in which it was assumed that the lamellar stack had an infinite lateral size [Vonk & Kortleve (1967), Kolloid Z. Z. Polym. 220, 19–24]. Under this assumption, only crystal planes satisfying the Bragg condition can form strong scattering, and the scattering from the lamellar stack arises from the difference between the scattering intensities in the amorphous and crystalline layers, induced by the incident X-ray beam. This assumption is now deemed unreasonable. In a real polymer spherulite, the lamellar crystal commonly has dimensions of only a few hundred nanometres. At such a limited lateral size, lamellar stacks in a broad orientation have similar scattering, so interference between these lamellar stacks must be considered. Scattering from lamellar stacks parallel to the incident X-ray beam also needs to be considered when total reflection occurs. In this study, various scattering contributions from lamellar stacks in a spherulite are determined. It is found that, for a limited lateral size, the scattering induced by the incident X-ray beam is not the main origin of SAXS. It forms double peaks, which are not observed in real scattering because of destructive interference between the lamellar stacks. The scattering induced by the evanescent wave is the main origin. It can form a similar interference pattern to that observed in a real SAXS measurement: a Guinier region in the small-q range, a signal region in the intermediate-q range and a Porod region in the high-q range. It is estimated that, to avoid destructive interference, the lateral size needs to be greater than 11 µm, which cannot be satisfied in a real lamellar system. Therefore, SAXS in a real polymer system arises largely from the scattering induced by the evanescent wave. Evidence for the existence of the evanescent wave was identified in the scattering of isotactic polypropylene. This study corrects a long-term misunderstanding of SAXS in a polymer lamellar system. Full Article text
late Structure-based mechanism of cysteine-switch latency and of catalysis by pappalysin-family metallopeptidases By scripts.iucr.org Published On :: 2020-01-01 Tannerella forsythia is an oral dysbiotic periodontopathogen involved in severe human periodontal disease. As part of its virulence factor armamentarium, at the site of colonization it secretes mirolysin, a metallopeptidase of the unicellular pappalysin family, as a zymogen that is proteolytically auto-activated extracellularly at the Ser54–Arg55 bond. Crystal structures of the catalytically impaired promirolysin point mutant E225A at 1.4 and 1.6 Å revealed that latency is exerted by an N-terminal 34-residue pro-segment that shields the front surface of the 274-residue catalytic domain, thus preventing substrate access. The catalytic domain conforms to the metzincin clan of metallopeptidases and contains a double calcium site, which acts as a calcium switch for activity. The pro-segment traverses the active-site cleft in the opposite direction to the substrate, which precludes its cleavage. It is anchored to the mature enzyme through residue Arg21, which intrudes into the specificity pocket in cleft sub-site S1'. Moreover, residue Cys23 within a conserved cysteine–glycine motif blocks the catalytic zinc ion by a cysteine-switch mechanism, first described for mammalian matrix metallopeptidases. In addition, a 1.5 Å structure was obtained for a complex of mature mirolysin and a tetradecapeptide, which filled the cleft from sub-site S1' to S6'. A citrate molecule in S1 completed a product-complex mimic that unveiled the mechanism of substrate binding and cleavage by mirolysin, the catalytic domain of which was already preformed in the zymogen. These results, including a preference for cleavage before basic residues, are likely to be valid for other unicellular pappalysins derived from archaea, bacteria, cyanobacteria, algae and fungi, including archetypal ulilysin from Methanosarcina acetivorans. They may further apply, at least in part, to the multi-domain orthologues of higher organisms. Full Article text
late Structural insights into conformational switching in latency-associated peptide between transforming growth factor β-1 bound and unbound states By scripts.iucr.org Published On :: 2020-02-06 Transforming growth factor β-1 (TGFβ-1) is a secreted signalling protein that directs many cellular processes and is an attractive target for the treatment of several diseases. The primary endogenous activity regulatory mechanism for TGFβ-1 is sequestration by its pro-peptide, latency-associated peptide (LAP), which sterically prohibits receptor binding by caging TGFβ-1. As such, recombinant LAP is promising as a protein-based therapeutic for modulating TGFβ-1 activity; however, the mechanism of binding is incompletely understood. Comparison of the crystal structure of unbound LAP (solved here to 3.5 Å resolution) with that of the bound complex shows that LAP is in a more open and extended conformation when unbound to TGFβ-1. Analysis suggests a mechanism of binding TGFβ-1 through a large-scale conformational change that includes contraction of the inter-monomer interface and caging by the `straight-jacket' domain that may occur in partnership through a loop-to-helix transition in the core jelly-roll fold. This conformational change does not appear to include a repositioning of the integrin-binding motif as previously proposed. X-ray scattering-based modelling supports this mechanism and reveals possible orientations and ensembles in solution. Although native LAP is heavily glycosylated, solution scattering experiments show that the overall folding and flexibility of unbound LAP are not influenced by glycan modification. The combination of crystallography, solution scattering and biochemical experiments reported here provide insight into the mechanism of LAP sequestration of TGFβ-1 that is of fundamental importance for therapeutic development. Full Article text
late New zeolite-like RUB-5 and its related hydrous layer silicate RUB-6 structurally characterized by electron microscopy By scripts.iucr.org Published On :: 2020-04-21 This study made use of a recently developed combination of advanced methods to reveal the atomic structure of a disordered nanocrystalline zeolite using exit wave reconstruction, automated diffraction tomography, disorder modelling and diffraction pattern simulation. By applying these methods, it was possible to determine the so far unknown structures of the hydrous layer silicate RUB-6 and the related zeolite-like material RUB-5. The structures of RUB-5 and RUB-6 contain the same dense layer-like building units (LLBUs). In the case of RUB-5, these building units are interconnected via additional SiO4/2 tetrahedra, giving rise to a framework structure with a 2D pore system consisting of intersecting 8-ring channels. In contrast, RUB-6 contains these LLBUs as separate silicate layers terminated by silanol/siloxy groups. Both RUB-6 and RUB-5 show stacking disorder with intergrowths of different polymorphs. The unique structure of RUB-6, together with the possibility for an interlayer expansion reaction to form RUB-5, make it a promising candidate for interlayer expansion with various metal sources to include catalytically active reaction centres. Full Article text