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Biomedical subjects

O Kennard

Publications and source records attributed to O Kennard.

At least 55 records · Page 3Linked to original sources
PubMed1980

Interactions of tris buffer with nucleotides: the crystal structure of tris(hydroxymethyl)methylammonium adenosine 5'-diphosphate dihydrate.

The crystal and molecular structures of the Tris salt of adenosine 5'-diphosphate were determined from X-ray diffraction data. The crystals are monoclinic, space P21, and Z = 2 with a=9.198 (2) A, b=6.894 (1) A, c=18.440 (4) A, and beta = 92.55 (2) degrees. Intensity data were collected on an automated diffractometer. The structure was solved by the heavy-atom technique and refined by least squares to R = 0.047. The ADP molecule adopts a folded conformation. The conformation about the glycosidic bond is anti. The conformation of the ribose ring is close to a perfect C(2')-endo-C-(3')-exo puckering. The conformation about C(4')-C(5') is gauche-gauche, similar to other nucleotide structures. The pyrophosphate chain displays a nearly eclipsed geometry when viewed down the P-P vector, unlike the staggered conformation observed in crystal structures of other pyrophosphates. The less favorable eclipsed conformation probably results from the observed association of Tris molecules with the polar diphosphate chain through electrostatic interactions and hydrogen bonds. Such interactions may play an important role in Tris-buffered aqueous solutions of nucleotides and metal ions.

Adenosine Diphosphate↗
PubMed1978

Structure of vancomycin and its complex with acetyl-D-alanyl-D-alanine.

Vancomycin, a broad-spectrum antibiotic, inhibits the growth of cell walls by complex formation with peptides terminating in D-alanyl-D-alanine. The structure of vancomycin was determined by X-ray analysis of the degradation product CDP-I. A model of the complex is proposed based on this study and spectroscopic data.

Dipeptides↗
PubMed1977

The Protein Data Bank. A computer-based archival file for macromolecular structures.

The Protein Data Bank is a computer-based archival file for macromolecular structures. The Bank stores in a uniform format atomic co-ordinates and partial bond connectivities, as derived from crystallographic studies. Text included in each data entry gives pertinent information for the structure at hand (e.g. species from which the molecule has been obtained, resolution of diffraction data, literature citations and specifications of secondary structure). In addition to atomic co-ordinates and connectivities, the Protein Data Bank stores structure factors and phases, although these latter data are not placed in any uniform format. Input of data to the Bank and general maintenance functions are carried out at Brookhaven National Laboratory. All data stored in the Bank are available on magnetic tape for public distribution, from Brookhaven (to laboratories in the Americas), Tokyo (Japan), and Cambridge (Europe and worldwide). A master file is maintained at Brookhaven and duplicate copies are stored in Cambridge and Tokyo. In the future, it is hoped to expand the scope of the Protein Data Bank to make available co-ordinates for standard structural types (e.g. alpha-helix, RNA double-stranded helix) and representative computer programs of utility in the study and interpretation of macromolecular structures.

Computers↗
PubMed1975

Molecular structures of cytidine-5'-diphosphate and cytidine-5'-diphospho-choline, and their role in intermidiary metabolism.

The nucleotide coenzyme cytidine-5'-diphospho-choline is highly folded. The CMP-5' parts of the molecules in the crystal structure are strongly linked by metal ligation and hydrogen bonds leaving the phosphoryl-choline residues relatively free. Cytidine-5'-diphosphoric acid exists as a zwitterion with N31 protonated. The P-O bond lengths from the anhydride bridging oxygen in the pyrophosphate are significantly different.

Choline↗
PubMed1975

A crystallographic and theoretical study of the conformation of DOET and its significance for the hallucinogenic amphetamines.

The crystal and molecular structure of 2, 5-dimethoxy-4-ethyl-alpha-methyl-phenylethylamine (DOET) has been determined by X-ray crystallography and the conformation of the side chain has been examined theoretically by the use of a potential energy calculation. There is no indication in the solid state of any intra or inter-molecular hydrogen bonding. The isopropylamine side chain is staggered to the plane of the benzene ring. The alpha-methyl group is fully extended (antiplanar) whereas the amino group is orientated back towards the ring (synclinal). The potential energy calculations show the existence of 6 minima, one of which corresponds to the crystal position. The calculations also show that the energy differences between the various minima of the side chain are very small. The relationship of these data to the conformations of the hallucinogens, mescaline and 2, 4, 5,-trimethoxyamphetamine is discussed.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1975

Dopamine receptor blockade and the neuroleptics, a crystallographic study.

The X-ray structures of 12 drugs of the tricyclic class having varying pharmacological profiles have been examined in detail in an attempt to rationalize the known structure-activity relations of neuroleptic drugs with respect to their ability to block dopamine receptors in the brain. Further evidence is presented in support of the theory that the neuroleptics are able to block dopamine receptors because of a conformational complementarity between certain portions of these drugs and dopamine.

Chlorpromazine↗