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Crystallographic snapshots of the EF-hand protein MCFD2 complexed with the intracellular lectin ERGIC-53 involved in glycoprotein transport

The transmembrane intracellular lectin ER–Golgi intermediate compartment protein 53 (ERGIC-53) and the soluble EF-hand multiple coagulation factor deficiency protein 2 (MCFD2) form a complex that functions as a cargo receptor, trafficking various glycoproteins between the endoplasmic reticulum (ER) and the Golgi apparatus. It has been demonstrated that the carbohydrate-recognition domain (CRD) of ERGIC-53 (ERGIC-53CRD) interacts with N-linked glycans on cargo glycoproteins, whereas MCFD2 recognizes polypeptide segments of cargo glycoproteins. Crystal structures of ERGIC-53CRD complexed with MCFD2 and mannosyl oligosaccharides have revealed protein–protein and protein–sugar binding modes. In contrast, the polypeptide-recognition mechanism of MCFD2 remains largely unknown. Here, a 1.60 Å resolution crystal structure of the ERGIC-53CRD–MCFD2 complex is reported, along with three other crystal forms. Comparison of these structures with those previously reported reveal that MCFD2, but not ERGIC-53–CRD, exhibits significant conformational plasticity that may be relevant to its accommodation of various polypeptide ligands.




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Crystal structure of hexa-μ-chlorido-μ4-oxido-tetra­kis­{[1-(2-hy­droxy­eth­yl)-2-methyl-5-nitro-1H-imidazole-κN3]copper(II)} containing short NO2⋯NO2 contacts

The title tetra­nuclear copper complex, [Cu4Cl6O(C6H9N3O3)4] or [Cu4Cl6O­(MET)4] [MET is 1-(2-hy­droxy­eth­yl)-2-methyl-5-nitro-1H-imidazole or metronidazole], contains a tetra­hedral arrangement of copper(II) ions. Each copper atom is also linked to the other three copper atoms in the tetra­hedron via bridging chloride ions. A fifth coordination position on each metal atom is occupied by a nitro­gen atom of the monodentate MET ligand. The result is a distorted CuCl3NO trigonal–bipyramidal coordination polyhedron with the axial positions occupied by oxygen and nitro­gen atoms. The extended structure displays O—H⋯O hydrogen bonding, as well as unusual short O⋯N inter­actions [2.775 (4) Å] between the nitro groups of adjacent clusters that are oriented perpendicular to each other. The scattering contribution of disordered water and methanol solvent mol­ecules was removed using the SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–16] in PLATON [Spek (2009). Acta Cryst. D65, 148–155].




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Synthesis and crystal structure of catena-poly[[bis[(2,2';6',2''-terpyridine)­manganese(II)]-μ4-penta­thio­dianti­monato] tetra­hydrate] showing a 1D MnSbS network

The asymmetric unit of the title compound, {[Mn2Sb2S5(C15H11N3)2]·4H2O}n, consists of two crystallographically independent MnII ions, two unique terpyridine ligands, one [Sb2S5]4− anion and four solvent water mol­ecules, all of which are located in general positions. The [Sb2S5]4− anion consists of two SbS3 units that share common corners. Each of the MnII ions is fivefold coordinated by two symmetry-related S atoms of [Sb2S5]4− anions and three N atoms of a terpyridine ligand within an irregular coordination. Each two anions are linked by two [Mn(terpyridine)]2+ cations into chains along the c-axis direction that consist of eight-membered Mn2Sb2S4 rings. These chains are further connected into a three-dimensional network by inter­molecular O—H⋯O and O—H⋯S hydrogen bonds. The crystal investigated was twinned and therefore, a twin refinement using data in HKLF-5 [Sheldrick (2015). Acta Cryst. C71, 3–8] format was performed.




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An unusually short inter­molecular N—H⋯N hydrogen bond in crystals of the hemi-hydro­chloride salt of 1-exo-acetamido­pyrrolizidine

The title compound [systematic name: (1R*, 8S)-2-acetamidoocta­hydro­pyrrol­izin-4-ium chloride–N-[(1R, 8S)-hexa­hydro-1H-pyrrolizin-2-yl)acetamide (1/1)], 2(C9H16N2O)·HCl or C9H17N2O+·Cl−·C9H16N2O, arose as an unexpected product when 1-exo-acetamido­pyrrolizidine (AcAP; C9H16N2O) was dissolved in CHCl3. Within the AcAP pyrrolizidine group, the unsubstituted five-membered ring is disordered over two orientations in a 0.897 (5):0.103 (5) ratio. Two AcAP mol­ecules related by a crystallographic twofold axis link to H+ and Cl− ions lying on the rotation axis, thereby forming N—H⋯N and N—H⋯Cl⋯H—N hydrogen bonds. The first of these has an unusually short N⋯N separation of 2.616 (2) Å: refinement of different models against the present data set could not distinguish between a symmetrical hydrogen bond (H atom lying on the twofold axis and equidistant from the N atoms) or static or dynamic disorder models (i.e. N—H⋯N + N⋯H—N). Computational studies suggest that the disorder model is slightly more stable, but the energy difference is very small.




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Refinement for single-nanoparticle structure determination from low-quality single-shot coherent diffraction data

With the emergence of X-ray free-electron lasers, it is possible to investigate the structure of nanoscale samples by employing coherent diffractive imaging in the X-ray spectral regime. In this work, we developed a refinement method for structure reconstruction applicable to low-quality coherent diffraction data. The method is based on the gradient search method and considers the missing region of a diffraction pattern and the small number of detected photons. We introduced an initial estimate of the structure in the method to improve the convergence. The present method is applied to an experimental diffraction pattern of an Xe cluster obtained in an X-ray scattering experiment at the SPring-8 Angstrom Compact free-electron LAser (SACLA) facility. It is found that the electron density is successfully reconstructed from the diffraction pattern with a large missing region, with a good initial estimate of the structure. The diffraction pattern calculated from the reconstructed electron density reproduced the observed diffraction pattern well, including the characteristic intensity modulation in each ring. Our refinement method enables structure reconstruction from diffraction patterns under difficulties such as missing areas and low diffraction intensity, and it is potentially applicable to the structure determination of samples that have low scattering power.




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Characterizing crystalline defects in single nanoparticles from angular correlations of single-shot diffracted X-rays

Characterizing and controlling the uniformity of nanoparticles is crucial for their application in science and technology because crystalline defects in the nanoparticles strongly affect their unique properties. Recently, ultra-short and ultra-bright X-ray pulses provided by X-ray free-electron lasers (XFELs) opened up the possibility of structure determination of nanometre-scale matter with Å spatial resolution. However, it is often difficult to reconstruct the 3D structural information from single-shot X-ray diffraction patterns owing to the random orientation of the particles. This report proposes an analysis approach for characterizing defects in nanoparticles using wide-angle X-ray scattering (WAXS) data from free-flying single nanoparticles. The analysis method is based on the concept of correlated X-ray scattering, in which correlations of scattered X-ray are used to recover detailed structural information. WAXS experiments of xenon nanoparticles, or clusters, were conducted at an XFEL facility in Japan by using the SPring-8 Ångstrom compact free-electron laser (SACLA). Bragg spots in the recorded single-shot X-ray diffraction patterns showed clear angular correlations, which offered significant structural information on the nanoparticles. The experimental angular correlations were reproduced by numerical simulation in which kinematical theory of diffraction was combined with geometric calculations. We also explain the diffuse scattering intensity as being due to the stacking faults in the xenon clusters.




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Structure of the MICU1–MICU2 heterodimer provides insights into the gatekeeping threshold shift

Mitochondrial calcium uptake proteins 1 and 2 (MICU1 and MICU2) mediate mitochondrial Ca2+ influx via the mitochondrial calcium uniporter (MCU). Its molecular action for Ca2+ uptake is tightly controlled by the MICU1–MICU2 heterodimer, which comprises Ca2+ sensing proteins which act as gatekeepers at low [Ca2+] or facilitators at high [Ca2+]. However, the mechanism underlying the regulation of the Ca2+ gatekeeping threshold for mitochondrial Ca2+ uptake through the MCU by the MICU1–MICU2 heterodimer remains unclear. In this study, we determined the crystal structure of the apo form of the human MICU1–MICU2 heterodimer that functions as the MCU gatekeeper. MICU1 and MICU2 assemble in the face-to-face heterodimer with salt bridges and me­thio­nine knobs stabilizing the heterodimer in an apo state. Structural analysis suggests how the heterodimer sets a higher Ca2+ threshold than the MICU1 homodimer. The structure of the heterodimer in the apo state provides a framework for understanding the gatekeeping role of the MICU1–MICU2 heterodimer.




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First synthesis of a unique icosahedral phase from the Khatyrka meteorite by shock-recovery experiment

Icosahedral quasicrystals (i-phases) in the Al–Cu–Fe system are of great interest because of their perfect quasicrystalline structure and natural occurrences in the Khatyrka meteorite. The natural quasicrystal of composition Al62Cu31Fe7, referred to as i-phase II, is unique because it deviates significantly from the stability field of i-phase and has not been synthesized in a laboratory setting to date. Synthetic i-phases formed in shock-recovery experiments present a novel strategy for exploring the stability of new quasicrystal compositions and prove the impact origin of natural quasicrystals. In this study, an Al–Cu–W graded density impactor (GDI, originally manufactured as a ramp-generating impactor but here used as a target) disk was shocked to sample a full range of Al/Cu starting ratios in an Fe-bearing 304 stainless-steel target chamber. In a strongly deformed region of the recovered sample, reactions between the GDI and the steel produced an assemblage of co-existing Al61.5Cu30.3Fe6.8Cr1.4 i-phase II + stolperite (β, AlCu) + khatyrkite (θ, Al2Cu), an exact match to the natural i-phase II assemblage in the meteorite. In a second experiment, the continuous interface between the GDI and steel formed another more Fe-rich quinary i-phase (Al68.6Fe14.5Cu11.2Cr4Ni1.8), together with stolperite and hollisterite (λ, Al13Fe4), which is the expected assemblage at phase equilibrium. This study is the first laboratory reproduction of i-phase II with its natural assemblage. It suggests that the field of thermodynamically stable icosahedrite (Al63Cu24Fe13) could separate into two disconnected fields under shock pressure above 20 GPa, leading to the co-existence of Fe-rich and Fe-poor i-phases like the case in Khatyrka. In light of this, shock-recovery experiments do indeed offer an efficient method of constraining the impact conditions recorded by quasicrystal-bearing meteorite, and exploring formation conditions and mechanisms leading to quasicrystals.




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Crystallographic snapshots of the EF-hand protein MCFD2 complexed with the intracellular lectin ERGIC-53 involved in glycoprotein transport

This article reports conformational polymorphisms of the EF-hand protein MCFD2 which is involved in glycoprotein transport..




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Which Online Unitveristy for Cyber should I choose ?




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Fossils Show Prehistoric Global Warming

For those who think that global warming is a 21st-century phenomenon, Scott Wing, a scientist at the Smithsonian’s National Museum of Natural History, has news about the past.

The post Fossils Show Prehistoric Global Warming appeared first on Smithsonian Insider.




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Smithsonian to lead study on degradation of nearshore coastal habitats of the Chesapeake

Invasive species, contaminants, excessive nutrient's and sediment are just some of the many factors threatening sensitive wetlands and seagrass beds.

The post Smithsonian to lead study on degradation of nearshore coastal habitats of the Chesapeake appeared first on Smithsonian Insider.




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Smithsonian and MIT to launch online mystery game for middle-shool children

On April 4 the Smithsonian and the Massachusetts Institute of Technology will launch VANISHED, an 8-week online/offline environmental disaster mystery game for middle-school children, meant […]

The post Smithsonian and MIT to launch online mystery game for middle-shool children appeared first on Smithsonian Insider.




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Hormone tests show Mei Xiang, the National Zoo’s female giant panda, may be pregnant

Scientists at the Smithsonian’s National Zoo detected a secondary rise in urinary progesterone levels in the Zoo’s female giant panda Mei Xiang (may-SHONG). This hormone rise indicates that it should be 40 to 50 days before Mei Xiang either gives birth to a cub or comes to the end of a pseudopregnancy, or false pregnancy, which is common in giant pandas.

The post Hormone tests show Mei Xiang, the National Zoo’s female giant panda, may be pregnant appeared first on Smithsonian Insider.




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Slideshow: Species discovered by Smithsonian researchers the past decade

Smithsonian scientists have discovered hundreds of new species around the world. To mark this year’s International Day for Biological Diversity, May 22, here is a […]

The post Slideshow: Species discovered by Smithsonian researchers the past decade appeared first on Smithsonian Insider.




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Bone fragment is only Ice Age artwork from America to show a “proboscidean”

Researchers from the Smithsonian Institution and the University of Florida have announced the discovery of a bone fragment, approximately 13,000 years old, in Florida with an incised image of a mammoth or mastodon.

The post Bone fragment is only Ice Age artwork from America to show a “proboscidean” appeared first on Smithsonian Insider.




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Scientists show that modern humans never co-existed with Homo erectus

New excavations in Indonesia and dating analyses by scientists at the Smithsonian and their colleagues show that modern humans never co-existed with Homo erectus.

The post Scientists show that modern humans never co-existed with <em>Homo erectus</em> appeared first on Smithsonian Insider.




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Females can place limits on evolution of attractive features in males, research shows

In a new paper appearing this week in Science, a group of biologists have shown that females themselves can also limit the evolution of increased elaboration.

The post Females can place limits on evolution of attractive features in males, research shows appeared first on Smithsonian Insider.




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A first: National Zoo elephant shows insightful problem solving

Kandula, an 8-year-old male Asian elephant at the Smithsonian’s National Zoo, recently demonstrated to researchers for the first time that elephants are capable of insightful problem solving.

The post A first: National Zoo elephant shows insightful problem solving appeared first on Smithsonian Insider.






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First fish App from the Smithsonian free on iTunes. “The Smithsonian Guide to the Shore Fishes of the Tropical Eastern Pacific”

The Smithsonian Tropical Research Institute has released the first completely portable bilingual species identification guide for the shore fishes of the tropical Eastern Pacific as a free iPhone application.

The post First fish App from the Smithsonian free on iTunes. “The Smithsonian Guide to the Shore Fishes of the Tropical Eastern Pacific” appeared first on Smithsonian Insider.




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New mapping of Mars shows Medusae Fossae Formation older than once thought

Recent geologic mapping of the Medusae Fossae Formation on Mars—an intensely eroded deposit near the northern edge of the cratered highlands—has revealed a wider distribution of its western component than was previously recognized.

The post New mapping of Mars shows Medusae Fossae Formation older than once thought appeared first on Smithsonian Insider.




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Aircraft bird-strike reports can save lives. New video shows how to report, collect and ship evidence

A new video to help aviators identify the cause of bird strikes has been posted on YouTube by the U.S. Department of Agriculture's Wildlife Services Airport Wildlife Hazard Program and the Smithsonian's National Museum of Natural History.

The post Aircraft bird-strike reports can save lives. New video shows how to report, collect and ship evidence appeared first on Smithsonian Insider.






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Mississippi State borrows grasshopper collection from Smithsonian

JoVonn Hill, a research associate with the Mississippi Agricultural and Forestry Experiment Station at Mississippi State University, recently borrowed 32,000 grasshoppers from the Smithsonian’s National […]

The post Mississippi State borrows grasshopper collection from Smithsonian appeared first on Smithsonian Insider.




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Chandra X-ray Observatory shows Milky Way is surrounded by halo of hot gas

stronomers have used NASA's Chandra X-ray Observatory to find evidence our Milky Way Galaxy is embedded in an enormous halo of hot gas that extends for hundreds of thousands of light years.

The post Chandra X-ray Observatory shows Milky Way is surrounded by halo of hot gas appeared first on Smithsonian Insider.





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Powerful computer simulations show how spiral galaxies get their arms

Spiral galaxies are some of the most beautiful and photogenic residents of the universe. Our own Milky Way is a spiral. Our solar system and […]

The post Powerful computer simulations show how spiral galaxies get their arms appeared first on Smithsonian Insider.




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Obese marmosets are more developmentally advanced as infants, study shows

Marmosets on track for obesity appeared to be more efficient in their feeding behavior. “Although all animals consumed the same amount of liquid, the ones […]

The post Obese marmosets are more developmentally advanced as infants, study shows appeared first on Smithsonian Insider.





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These mites should make birds quiver right down to their quills

The black-headed paradise-flycatcher of western and central Africa is a small colorful forest bird that thrives on the flying insects it chases down by swooping, […]

The post These mites should make birds quiver right down to their quills appeared first on Smithsonian Insider.




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American Indians, colonists had healthy appetite for crabs, study shows

Native Americans and America’s early colonists ate many more blue crabs than modern researchers previously thought, according to a team of scientists studying crab remains […]

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Corn entered Southwest U.S. first along highland route, DNA shows

A new DNA study of ancient corn kernels and cobs from archaeological sites across North America has settled a long debate as to exactly where […]

The post Corn entered Southwest U.S. first along highland route, DNA shows appeared first on Smithsonian Insider.




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Fossil shows Prehistoric Reptile Gave Birth in Open Ocean

A case of mistaken identity turned out to be the key for proving that a prehistoric aquatic reptile did not lay eggs, but rather gave […]

The post Fossil shows Prehistoric Reptile Gave Birth in Open Ocean appeared first on Smithsonian Insider.




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This simple trick helped fix a wildlife water shortage in Cambodia

It is a simple solution to a wildlife water shortage. During the annual dry season [November through April] in a protected forest in eastern Cambodia, […]

The post This simple trick helped fix a wildlife water shortage in Cambodia appeared first on Smithsonian Insider.




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Research shows same growth rate for farming, non-farming societies

Prehistoric human populations of hunter-gatherers in a region of North America grew at the same rate as farming societies in Europe, according to a new […]

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Ghost octopod shows how little we know about deep-sea life

A social media celebrity was born last week when the bright lights and camera of NOAA’s remotely operated vehicle Deep Discoverer zoomed in on a […]

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Planet 9: A world that should not exist

Earlier this year scientists presented evidence for Planet Nine, a Neptune-mass planet in an elliptical orbit 10 times farther from our Sun than Pluto. Since […]

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Smithsonian Study shows relocated desert tortoises reproduce at lower rate

Four years after conservationists relocated 570 desert tortoises (Gopherus agassizii) in California from a threatened habitat to a new nearby location, the tortoises outwardly appeared […]

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  • Animals
  • Research News
  • Science & Nature
  • Smithsonian Conservation Biology Institute
  • Smithsonian's National Zoo

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Study shows ancient California Indians risked toxins from bitumen-coated bottles

Finding clean ways to store water is a challenge that humans have faced for millennia. In a new paper in Environmental Health, anthropologist Sabrina Sholts […]

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Astronomers see light show associated with gravitational waves

This animation shows how binary neutron stars warp space-time to create gravitational waves, then collide and explode into a visible kilonova, which can be detected […]

The post Astronomers see light show associated with gravitational waves appeared first on Smithsonian Insider.



  • Research News
  • Science & Nature
  • Space
  • Center for Astrophysics | Harvard & Smithsonian
  • Center for Earth and Planetary Studies
  • Smithsonian Astrophysical Observatory

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A new stellar X-ray “reality” show debuts

A new project using data from NASA’s Chandra X-ray Observatory and other telescopes allows people to navigate through real data of the remains of an […]

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  • Science & Nature
  • Space
  • Center for Astrophysics | Harvard & Smithsonian
  • Chandra X-Ray Observatory