scholarly journals Crystal structure of maize serine racemase with pyridoxal 5′-phosphate

2016 ◽  
Vol 72 (3) ◽  
pp. 165-171 ◽  
Author(s):  
Lingling Zou ◽  
Yang Song ◽  
Chengliang Wang ◽  
Jiaqi Sun ◽  
Leilei Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Absorption Spectrometry ◽  
Serine Racemase ◽  
Type Ii ◽  
Active Site Residues ◽  
Structural Comparison ◽  
X Ray ◽  
Vancomycin Resistant ◽  
Serine Biosynthesis

Serine racemase (SR) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that is responsible for D-serine biosynthesisin vivo. The first X-ray crystal structure of maize SR was determined to 2.1 Å resolution and PLP binding was confirmed in solution by UV–Vis absorption spectrometry. Maize SR belongs to the type II PLP-dependent enzymes and differs from the SR of a vancomycin-resistant bacterium. The PLP is bound to each monomer by forming a Schiff base with Lys67. Structural comparison with rat and fission yeast SRs reveals a similar arrangement of active-site residues but a different orientation of the C-terminal helix.

scholarly journals Crystal structure of a pyridoxal 5′-phosphate-dependent aspartate racemase derived from the bivalve mollusc Scapharca broughtonii

2017 ◽  
Vol 73 (12) ◽  
pp. 651-656 ◽  
Author(s):  
Taichi Mizobuchi ◽  
Risako Nonaka ◽  
Motoki Yoshimura ◽  
Katsumasa Abe ◽  
Shouji Takahashi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Binding Site ◽  
Active Site ◽  
Metal Binding ◽  
Bivalve Mollusc ◽  
Active Site Residues ◽  
X Ray ◽  
Aspartate Racemase ◽  
Scapharca Broughtonii

Aspartate racemase (AspR) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that is responsible for D-aspartate biosynthesis in vivo. To the best of our knowledge, this is the first study to report an X-ray crystal structure of a PLP-dependent AspR, which was resolved at 1.90 Å resolution. The AspR derived from the bivalve mollusc Scapharca broughtonii (SbAspR) is a type II PLP-dependent enzyme that is similar to serine racemase (SR) in that SbAspR catalyzes both racemization and dehydration. Structural comparison of SbAspR and SR shows a similar arrangement of the active-site residues and nucleotide-binding site, but a different orientation of the metal-binding site. Superposition of the structures of SbAspR and of rat SR bound to the inhibitor malonate reveals that Arg140 recognizes the β-carboxyl group of the substrate aspartate in SbAspR. It is hypothesized that the aromatic proline interaction between the domains, which favours the closed form of SbAspR, influences the arrangement of Arg140 at the active site.

Effects of dietary alteration of bicarbonate and magnesium on rat bone

1986 ◽  
Vol 250 (2) ◽  
pp. F302-F307 ◽  
Author(s):  
J. M. Burnell ◽  
C. Liu ◽  
A. G. Miller ◽  
E. Teubner
Keyword(s):  
Crystal Structure ◽  
Bone Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growing Rats ◽  
Final Composition ◽  
Rat Bone

To study the effects of bicarbonate and magnesium on bone, mild acidosis and/or hypermagnesemia were produced in growing rats by feeding ammonium chloride and/or magnesium sulfate. Bone composition, quantitative histomorphometry, and mineral x-ray diffraction (XRD) characteristics were measured after 6 wk of treatment. The results demonstrated that both acidosis (decreased HCO3) and hypermagnesemia inhibited periosteal bone formation, and, when combined, results were summative; and the previously observed in vitro role of HCO3- and Mg2+ as inhibitors of crystal growth were confirmed in vivo. XRD measurements demonstrated that decreased plasma HCO3 resulted in larger crystals and increased Mg resulted in smaller crystals. However, the combined XRD effects of acidosis and hypermagnesemia resembled acidosis alone. It is postulated that the final composition and crystal structure of bone are strongly influenced by HCO3- and Mg2+, and the effects are mediated by the combined influence on both osteoblastic bone formation and the growth of hydroxyapatite.

scholarly journals High-resolution structure of the alcohol dehydrogenase domain of the bifunctional bacterial enzyme AdhE

2020 ◽  
Vol 76 (9) ◽  
pp. 414-421
Author(s):  
Liyana Azmi ◽  
Eilis C. Bragginton ◽  
Ian T. Cadby ◽  
Olwyn Byron ◽  
Andrew J. Roe ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Escherichia Coli ◽  
Alcohol Dehydrogenase ◽  
Aldehyde Dehydrogenase ◽  
X Ray ◽  
X Ray Scattering ◽  
Bacterial Enzyme ◽  
High Resolution Structure ◽  
Resolution Structure

The bifunctional alcohol/aldehyde dehydrogenase (AdhE) comprises both an N-terminal aldehyde dehydrogenase (AldDH) and a C-terminal alcohol dehydrogenase (ADH). In vivo, full-length AdhE oligomerizes into long oligomers known as spirosomes. However, structural analysis of AdhE is challenging owing to the heterogeneity of the spirosomes. Therefore, the domains of AdhE are best characterized separately. Here, the structure of ADH from the pathogenic Escherichia coli O157:H7 was determined to 1.65 Å resolution. The dimeric crystal structure was confirmed in solution by small-angle X-ray scattering.

Notizen: The Crystal Structure of N3P3C15(NPPh3) — a Novel Conformation in Phosphazenylcyclophosphazene Chemistry

1976 ◽  
Vol 31 (7) ◽  
pp. 999-1000 ◽  
Author(s):  
Y. Sudhakara Babu ◽  
T. Stanley Cameron ◽  
S. S. Krishnamurthy ◽  
H. Manohar ◽  
Robert A. Shaw
Keyword(s):  
Crystal Structure ◽  
Crystallographic Structure ◽  
Type I ◽  
Type Ii ◽  
Structure Investigation ◽  
X Ray ◽  
Ring Segment

An X-ray crystallographic structure investigation of pentachloro(triphenylphosphazenyl)cyclotriphosphazatriene, N3P3C15(NPPh3), reveals a novel conformation (type I) of the triphenylphosphazenyl group with respect to the adjacent ring segment. This is contrasted with the structure of gem. –N3P3CI4Ph(NPPh3), where a type II conformation is observed.

Isolation and in Vitro Antiplasmodial Activities of Alkaloids fromTecleatrichocarpa:  In Vivo Antimalarial Activity and X-ray Crystal Structure of Normelicopicine

2002 ◽  
Vol 65 (7) ◽  
pp. 956-959 ◽  
Author(s):  
Mary W. Muriithi ◽  
W.-R. Abraham ◽  
Jonathan Addae-Kyereme ◽  
Ian Scowen ◽  
Simon L. Croft ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Antimalarial Activity ◽  
X Ray

scholarly journals Crystal structure of the toxin Msmeg_6760, the structural homolog ofMycobacterium tuberculosisRv2035, a novel type II toxin involved in the hypoxic response

2016 ◽  
Vol 72 (12) ◽  
pp. 863-869 ◽  
Author(s):  
R. Alexandra Bajaj ◽  
Mark A. Arbing ◽  
Annie Shin ◽  
Duilio Cascio ◽  
Linda Miallau
Keyword(s):  
Crystal Structure ◽  
Mycobacterium Tuberculosis ◽  
Structural Features ◽  
Bacterial Toxins ◽  
Type Ii ◽  
Structural Comparison ◽  
Macrophage Infection ◽  
Bioinformatics Analyses ◽  
Hydrophobic Residues ◽  
Hydrophobic Ligand

The structure of Msmeg_6760, a protein of unknown function, has been determined. Biochemical and bioinformatics analyses determined that Msmeg_6760 interacts with a protein encoded in the same operon, Msmeg_6762, and predicted that the operon is a toxin–antitoxin (TA) system. Structural comparison of Msmeg_6760 with proteins of known function suggests that Msmeg_6760 binds a hydrophobic ligand in a buried cavity lined by large hydrophobic residues. Access to this cavity could be controlled by a gate–latch mechanism. The function of the Msmeg_6760 toxin is unknown, but structure-based predictions revealed that Msmeg_6760 and Msmeg_6762 are homologous to Rv2034 and Rv2035, a predicted novel TA system involved inMycobacterium tuberculosislatency during macrophage infection. The Msmeg_6760 toxin fold has not been previously described for bacterial toxins and its unique structural features suggest that toxin activation is likely to be mediated by a novel mechanism.

scholarly journals Structural Characterization of the Rhenium(V) Oxo Complex of Mercaptoacetyltriglyclne in its Dianionic Form

1995 ◽  
Vol 2 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Lory Hansen ◽  
Andrew Taylor ◽  
Luigi G. Marzilli
Keyword(s):  
Crystal Structure ◽  
Nuclear Medicine ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
X Ray ◽  
Oxo Ligand ◽  
Solid State Structures ◽  
Dianionic Form

Dianionic [MO(MAG3)]2−(MAG3= penta-anionic form of mercaptoacetyltriglycine, M = R186e,T99mc ) complexes have important applications in nuclear medicine. In vivo the complexes have a deprotonated carboxyl group that is important to their biodistribution. The solid-state structures of T99c and Re complexes with mercaptoacetyltriglycine reported previously are monoanions with protonated carboxyl groups. In the present work, we report the preparation and X-ray crystal structure of Na2[ReO(MAG3)]·5H2O(1), which contains the physiologically relevant dianion. The dianion is a distorted square pyramid with the nitrogen and sulphur donor atoms forming the base and the oxo ligand at the apex. The terminal carboxyl group is deprotonated, uncoordinated and has a syn orientation with respect to the oxo ligand. The syn conformation of the dianion in 1 differs in conformation from the anti-monoanion in [Bu4N][ReO(MAG3H)] but is similar to the syn-monoanion in [Ph4P][T99cO(MAG3H)] .

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