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Biomedical subjects

B H Rubin

Publications and source records attributed to B H Rubin.

7 recordsLinked to original sources
PubMed1984

X-ray crystal structure of D-xylose isomerase at 4-A resolution.

The structure of D-xylose isomerase from Streptomyces rubiginosus has been determined at 4-A resolution using multiple isomorphous phasing techniques. The folding of the polypeptide chain has been established and consists of two structural domains. The larger domain consists of eight beta-strand alpha-helix (beta alpha) units arranged in a configuration similar to that found for triose phosphate isomerase, 2-keto-3-deoxy-6-phosphogluconate aldolase, and pyruvate kinase. The smaller domain forms a loop away from the larger domain but overlapping the larger domain of another subunit so that a tightly bound dimer is formed. The tetramer then consists of two such dimers. The location of the active site in the enzyme has been tentatively identified from studies using a crystal grown from a solution containing the inhibitor xylitol.

Aldose-Ketose Isomerases↗
PubMed1983

Crystallographic studies of Escherichia coli citrate synthase.

The citrate synthase from Escherichia coli B has been crystallized in a cubic space group with a unit cell spacing of 220 A. X-ray diffraction, electron microscopy, symmetry considerations, and low resolution projection Patterson syntheses are consistent with a model proposed in which 24 tetrameric molecules of Mr = 188,000 +/- 12,000 occupy the unit cell. The space group is apparently P23, although at low resolution the observed systematic absences in reflections are consistent with the space group P43n, a space group not allowed for asymmetric molecules. Estimates of VM suggest that in the true space group, P23, two tetrameric molecules occupy the asymmetric unit.

Chemical Phenomena↗
PubMed1982

Crystal structure and anti herpes simplex virus activity of 2,2'-anhydro-1-beta-D-arabinofuranosylthymine.

1-beta-D-Arabinofuranosylthymine (aThy; ara-T) is a potent selective anti herpes simplex virus drug. Its anhydro analogue, 2,2'-anhydro-aThy, was shown to be 9-fold less active and at least 3-fold less toxic than aThy. This compound was relatively stable at physiological pH and in strong acid but was rapidly hydrolyzed in base with a half-life of 18.3 min. The three-dimensional crystal structure of 2,2'-anhydro-aThy revealed a rigid structure with the arabinose ring in the unusual O1' endo, pucker, conformation. The trans-gauche conformation along the C4'-C5' bond permits only intermolecular hydrogen bonding of the 5'-hydroxy and O3'.

Antiviral Agents↗
PubMed1975

Crystal structure of bovine Cu,Zn superoxide dismutase at 3 A resolution: chain tracing and metal ligands.

An electron density map at 3 angstrom resolution has been calculated for Cu2+, Zn2+ superoxide dismutase from bovine erythrocytes, and the course of the main chain has been traced. The dominant structural feature is an 8-stranded barrel of antiparallel beta-pleated sheet. There is one very short helical section and two long loops of non-repetitive structure. The Cu and Zn are bound between the loops and one side of the beta barrel and are about 6 Angstrom apart, with a common histidine ligand. The Cu has four histidine ligands in a somewhat distorted square plane, and the Zn has three histidines and an aspartate in approximately tetrahedral arrangement. The two coppers of a dimer are about 34 Angstrom apart. The two subunits have essentially the same conformation and have an extensive contact area that mainly involves hydrophobic side chain interactions. The overall folding pattern of the polypeptide chain is very similar to that of an immunoglobulin domain.

Animals↗