Biomedical subjects

S Vijay-Kumar

Publications and source records attributed to S Vijay-Kumar.

22 records · Page 2Linked to original sources

PubMed1987

Crystallization and preliminary X-ray investigation of a recombinant form of human gamma-interferon.

A genetically engineered human gamma-interferon has been crystallized from solutions of ammonium sulfate. The crystals are trigonal, space group R32, with hexagonal axes of a = 114.0(1) A and c = 314.9(2) A. The crystals are moderately stable to x-rays and diffract to 2.85-A resolution. Density measurements indicate that the crystallographic asymmetric volume contains four interferon molecules.

Cloning, Molecular↗

PubMed1985

Three-dimensional structure of ubiquitin at 2.8 A resolution.

The three-dimensional structure of ubiquitin has been determined at 2.8 A resolution. X-ray diffraction data for the native protein and derivatives were collected with an automated diffractometer. Phases were obtained by use of a single isomorphous mercuric acetate derivative. The molecule contains a pronounced hydrophobic core. Prominent secondary structural features include three and one-half turns of alpha-helix, a mixed beta-sheet that contains four strands, and seven reverse turns. The histidine, tyrosine, and two phenylalanine residues are located on the surface of the molecule.

Amino Acid Sequence↗

PubMed1984

A crystalline end product produced by the hydrolytic cleavage of an RNA-like fragment by an organometallointercalator: 1,10-phenanthroline-platinum(II)-ethylenediamine-cytidine 3' monophosphate.

1,10-Phenanthroline-platinum(II)-ethylenediamine ( PEPt ) forms a crystalline complex with cytidine-3'-phosphate (3'-CMP) and its structure has been determined by X-ray crystallography. 3'-CMP molecules are hemiprotonated and form hydrogen-bonded pairs that stack above and below the phenanthroline-platinum(II) drug molecule. Sugar residues are in the C2' endo conformation, with glycosidic torsional angles intermediate between the high and low anti forms. The structure is of particular interest since it forms as an end product of the hydrolytic cleavage of the dinucleoside monophosphate, CpG, by the platinum organometallointercalator ( PEPt ). This hydrolytic activity appears to be specific for the RNA dinucleoside monophosphate fragment, since deoxycytidylyl (3'-5')deoxyguanosine (d-CpG) and other deoxyribooligonucleotides are not cleaved under similar conditions.

Cytidine Monophosphate↗

PubMed1984

Structure of a novel drug-nucleic acid crystalline complex: 1, 10-phenanthroline-platinum (II) ethylenediamine--5'-phosphoryl-thymidylyl(3'-5') deoxyadenosine.

1,10-Phenanthroline-platinum (II) ethylenediamine (PEPt) forms a 1:2 crystalline complex with 5'-phosphorylthymidylyl (3'-5') deoxyadeno sine (d-pTpA). Crystals are monoclinic, P2, with a = 10.204 A, b = 24.743 A, c = 21.064 A, Beta = 94.6 degrees. The structure has been determined by Patterson and Fourier methods, and refined by least squares to a residual of 0.128 on 2,367 observed reflections. PEPt molecules form sandwich-like stacks with adenine-thymine hydrogen-bonded pairs along the alpha axis. Intercalation in the classic sense is not observed in this structure. Instead, d-pTpA molecules form an open chain structure in which adenine-thymine residues hydrogenbond together with the reversed Hoogsteen type base-pairing configuration. Deoxyadenosine residues exist in the syn conformation and are C3' endo and C1' exo. Thymidine residues are in the high anti conformation with C2' endo puckers. The structure is heavily hydrated, forming a channel-like water network along the alpha axis. Other features of the structure are described.

Intercalating Agents↗