scholarly journals The crystal structure of PD1, aHaemophilussurface fibril domain

2017 ◽  
Vol 73 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Jack Wright ◽  
Maren Thomsen ◽  
Robert Kolodziejczyk ◽  
Joshua Ridley ◽  
Jessica Sinclair ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Electron Micrographs ◽  
In Silico ◽  
Structural Data ◽  
Domain Annotation ◽  
Virulent Strains ◽  
Trimeric Autotransporter Adhesin ◽  
Putative Domain

TheHaemophilussurface fibril (Hsf) is an unusually large trimeric autotransporter adhesin (TAA) expressed by the most virulent strains ofH. influenzae. Hsf is known to mediate adhesion between pathogen and host, allowing the establishment of potentially deadly diseases such as epiglottitis, meningitis and pneumonia. While recent research has suggested that this TAA might adopt a novel `hairpin-like' architecture, the characterization of Hsf has been limited toin silicomodelling and electron micrographs, with no high-resolution structural data available. Here, the crystal structure of Hsf putative domain 1 (PD1) is reported at 3.3 Å resolution. The structure corrects the previous domain annotation by revealing the presence of an unexpected N-terminal TrpRing domain. PD1 represents the first Hsf domain to be solved, and thus paves the way for further research on the `hairpin-like' hypothesis.

scholarly journals The High Resolution Crystal Structure of the Human Tumor Suppressor Maspin Reveals a Novel Conformational Switch in the G-helix

2005 ◽  
Vol 280 (23) ◽  
pp. 22356-22364 ◽  
Author(s):  
Ruby H. P. Law ◽  
James A. Irving ◽  
Ashley M. Buckle ◽  
Katya Ruzyla ◽  
Marguerite Buzza ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Tumor Suppressor ◽  
Physiological Role ◽  
Human Tumor ◽  
Salt Bridge ◽  
Structural Data ◽  
Crystal Forms ◽  
Reactive Center ◽  
Α Helix

Maspin is a serpin that acts as a tumor suppressor in a range of human cancers, including tumors of the breast and lung. Maspin is crucial for development, because homozygous loss of the gene is lethal; however, the precise physiological role of the molecule is unclear. To gain insight into the function of human maspin, we have determined its crystal structure in two similar, but non-isomorphous crystal forms, to 2.1- and 2.8-Å resolution, respectively. The structure reveals that maspin adopts the native serpin fold in which the reactive center loop is expelled fully from the A β-sheet, makes minimal contacts with the core of the molecule, and exhibits a high degree of flexibility. A buried salt bridge unique to maspin orthologues causes an unusual bulge in the region around the D and E α-helices, an area of the molecule demonstrated in other serpins to be important for cofactor recognition. Strikingly, the structural data reveal that maspin is able to undergo conformational change in and around the G α-helix, switching between an open and a closed form. This change dictates the electrostatic character of a putative cofactor binding surface and highlights this region as a likely determinant of maspin function. The high resolution crystal structure of maspin provides a detailed molecular framework to elucidate the mechanism of function of this important tumor suppressor.

Synthesis and Characterization of N-Methyl-Substituted Germocanes. Crystal Structure of MeN(CH2CH2O)2GeBr2

2003 ◽  
Vol 58 (12) ◽  
pp. 1165-1170 ◽  
Author(s):  
Sergey S. Karlov ◽  
Elmira Kh. Yakubova ◽  
Ekaterina V. Gauchenova ◽  
Anastasia A. Selina ◽  
Andrei V. Churakov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structural Data ◽  
Closed Shell ◽  
Bond Critical Point ◽  
Composition And Structure ◽  
Elemental Analyses ◽  
Laplacian Of Charge Density ◽  
Good Agreement ◽  
C Nmr

The reaction of GeHal4 with MeN(CH2CH2OSiMe3)2 affords dihalogermocanes MeN(CH2 CH2O)2GeHal2 (1, Hal = Br; 2, Hal = Cl). Treatment of Me2Ge(NMe2)2 with MeN(CH2CH2OH)2 leads to dimethylgermocane MeN(CH2CH2O)2GeMe2 (3). The composition and structure of 1-3 were established by elemental analyses, 1H, 13C NMR spectroscopy, and mass spectrometry. The crystal structure of 1 is reported; structural data obtained from geometry DFT optimization on 1 are in good agreement with experimental results. Values of the electron density in the N→Ge bond critical point and the Laplacian of charge density for 1-3 indicate a closed-shell interaction between the Ge and N atoms.

scholarly journals High-Resolution Crystal Structure of Chloroplastic Ribose-5-Phosphate Isomerase from Chlamydomonas reinhardtii—An Enzyme Involved in the Photosynthetic Calvin-Benson Cycle

2020 ◽  
Vol 21 (20) ◽  
pp. 7787
Author(s):  
Théo Le Moigne ◽  
Pierre Crozet ◽  
Stéphane D. Lemaire ◽  
Julien Henri
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Metabolic Pathway ◽  
Carbon Fixation ◽  
Electron Flow ◽  
Structural Data ◽  
Post Translational Modifications ◽  
Photosynthetic Electron Flow ◽  
Biochemical Modeling ◽  
Experimental Structure

The Calvin–Benson cycle is the key metabolic pathway of photosynthesis responsible for carbon fixation and relies on eleven conserved enzymes. Ribose-5-phosphate isomerase (RPI) isomerizes ribose-5-phosphate into ribulose-5-phosphate and contributes to the regeneration of the Rubisco substrate. Plant RPI is the target of diverse post-translational modifications including phosphorylation and thiol-based modifications to presumably adjust its activity to the photosynthetic electron flow. Here, we describe the first experimental structure of a photosynthetic RPI at 1.4 Å resolution. Our structure confirms the composition of the catalytic pocket of the enzyme. We describe the homo-dimeric state of the protein that we observed in the crystal and in solution. We also map the positions of previously reported post-translational modifications and propose mechanisms by which they may impact the catalytic parameters. The structural data will inform the biochemical modeling of photosynthesis.

scholarly journals Crystal Structure of a Novel Conformational State of the Flavivirus NS3 Protein: Implications for Polyprotein Processing and Viral Replication

2009 ◽  
Vol 83 (24) ◽  
pp. 12895-12906 ◽  
Author(s):  
René Assenberg ◽  
Eloise Mastrangelo ◽  
Thomas S. Walter ◽  
Anil Verma ◽  
Mario Milani ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Serine Protease ◽  
Biochemical Characterization ◽  
Nonstructural Protein ◽  
Structural Data ◽  
Murray Valley Encephalitis Virus ◽  
Ns3 Protein ◽  
Single Protein ◽  
Protease Activation

ABSTRACT The flavivirus genome comprises a single strand of positive-sense RNA, which is translated into a polyprotein and cleaved by a combination of viral and host proteases to yield functional proteins. One of these, nonstructural protein 3 (NS3), is an enzyme with both serine protease and NTPase/helicase activities. NS3 plays a central role in the flavivirus life cycle: the NS3 N-terminal serine protease together with its essential cofactor NS2B is involved in the processing of the polyprotein, whereas the NS3 C-terminal NTPase/helicase is responsible for ATP-dependent RNA strand separation during replication. An unresolved question remains regarding why NS3 appears to encode two apparently disconnected functionalities within one protein. Here we report the 2.75-Å-resolution crystal structure of full-length Murray Valley encephalitis virus NS3 fused with the protease activation peptide of NS2B. The biochemical characterization of this construct suggests that the protease has little influence on the helicase activity and vice versa. This finding is in agreement with the structural data, revealing a single protein with two essentially segregated globular domains. Comparison of the structure with that of dengue virus type 4 NS2B-NS3 reveals a relative orientation of the two domains that is radically different between the two structures. Our analysis suggests that the relative domain-domain orientation in NS3 is highly variable and dictated by a flexible interdomain linker. The possible implications of this conformational flexibility for the function of NS3 are discussed.

scholarly journals High-resolution structure of AKR1a4 in the apo form and its interaction with ligands

2012 ◽  
Vol 68 (11) ◽  
pp. 1271-1274 ◽  
Author(s):  
Frédérick Faucher ◽  
Zongchao Jia
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Aldehyde Reductase ◽  
Founding Member ◽  
High Resolution Structure ◽  
Ascorbate Biosynthesis ◽  
Resolution Structure

Aldo-keto reductase 1a4 (AKR1a4; EC 1.1.1.2) is the mouse orthologue of human aldehyde reductase (AKR1a1), the founding member of the AKR family. As an NADPH-dependent enzyme, AKR1a4 catalyses the conversion of D-glucuronate to L-gulonate. AKR1a4 is involved in ascorbate biosynthesis in mice, but has also recently been found to interact with SMAR1, providing a novel mechanism of ROS regulation by ATM. Here, the crystal structure of AKR1a4 in its apo form at 1.64 Å resolution as well as the characterization of the binding of AKR1a4 to NADPH and P44, a peptide derived from SMAR1, is presented.

A Rich Man, Poor Man Story ofS-Adenosylmethionine and Cobalamin Revisited

2018 ◽  
Vol 87 (1) ◽  
pp. 555-584 ◽  
Author(s):  
Jennifer Bridwell-Rabb ◽  
Tsehai A.J. Grell ◽  
Catherine L. Drennan
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Structural Data ◽  
Biosynthetic Enzyme ◽  
Structural Motifs ◽  
Compare And Contrast ◽  
Radical Enzymes

S-adenosylmethionine (AdoMet) has been referred to as both “a poor man's adenosylcobalamin (AdoCbl)” and “a rich man's AdoCbl,” but today, with the ever-increasing number of functions attributed to each cofactor, both appear equally rich and surprising. The recent characterization of an organometallic species in an AdoMet radical enzyme suggests that the line that differentiates them in nature will be constantly challenged. Here, we compare and contrast AdoMet and cobalamin (Cbl) and consider why Cbl-dependent AdoMet radical enzymes require two cofactors that are so similar in their reactivity. We further carry out structural comparisons employing the recently determined crystal structure of oxetanocin-A biosynthetic enzyme OxsB, the first three-dimensional structural data on a Cbl-dependent AdoMet radical enzyme. We find that the structural motifs responsible for housing the AdoMet radical machinery are largely conserved, whereas the motifs responsible for binding additional cofactors are much more varied.

scholarly journals Crystal structure and spectroscopic analysis of a new oxalate-bridged MnIIcompound:catena-poly[guanidinium [[aquachloridomanganese(II)]-μ2-oxalato-κ4O1,O2:O1′,O2′] monohydrate]

2016 ◽  
Vol 72 (5) ◽  
pp. 724-729 ◽  
Author(s):  
Hiba Sehimi ◽  
Ichraf Chérif ◽  
Mohamed Faouzi Zid
Keyword(s):  
Crystal Structure ◽  
Metal Ion ◽  
Spectroscopic Analysis ◽  
Structural Data ◽  
Compound A ◽  
Distorted Octahedral Coordination ◽  
Hydrogen Bonding Interactions ◽  
Distorted Octahedral ◽  
Uv Visible

As part of our studies on the synthesis and the characterization of oxalate-bridged compoundsM–ox–M(ox = oxalate dianion andM= transition metal ion), we report the crystal structure of a new oxalate-bridged MnIIphase, {(CH6N3)[Mn(C2O4)Cl(H2O)]·H2O}n. In the compound, a succession of MnIIions (situated on inversion centers) adopting a distorted octahedral coordination and bridged by oxalate ligands forms parallel zigzag chains running along thecaxis. These chains are interconnected through O—H...O hydrogen-bonding interactions to form anionic layers parallel to (010). Individual layers are held togetherviastrong hydrogen bonds involving the guanidinium cations (N—H...O and N—H...Cl) and the disordered non-coordinating water molecule (O—H...O and O—H...Cl), as well as by guanidinium π–π stacking. The structural data were confirmed by IR and UV–Visible spectroscopic analysis.

scholarly journals Micrarchaeota are covered by a proteinaceous S-Layer

2021 ◽  
Author(s):  
Sabrina Gfrerer ◽  
Dennis Winkler ◽  
Julia Novion Ducassou ◽  
Yohann Couté ◽  
Reinhard Rachel ◽  
...  
Keyword(s):  
Surface Structure ◽  
Cell Size ◽  
Electron Micrographs ◽  
Primary Structure ◽  
In Silico ◽  
Cytoplasmic Membrane ◽  
Host Organism ◽  
Membrane Systems ◽  
Cultivation Conditions

AbstractIn previous publications, it was hypothesized that Micrarchaeota cells are covered by two individual membrane systems. This study proofs that at least the recently cultivated “Candidatus Micrarchaeum harzensis A_DKE” possesses an S-layer covering its cytoplasmic membrane. The potential S-layer protein was found to be among the proteins with the highest abundance in A_DKE and in silico characterization of its primary structure indicated homologies to other known S-layer proteins. Homologs of this protein were found in other Micrarchaeota genomes, which raises the question, whether the ability to form an S-layer is a common trait within this phylum. The S-layer protein seems to be glycosylated and the Micrarchaeum expresses genes for N-glycosylation under cultivation conditions, despite not being able to synthesize carbohydrates. Electron micrographs of freeze-etched samples of a previously described co-culture, containing Micrarchaeum A_DKE and a Thermoplasmatales member as its host organism, verified the hypothesis of an S-layer on the surface of A_DKE. Both organisms are clearly distinguishable by cell size, shape and surface structure.

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