William L. Duax

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BACKGROUND Bacterial 3 alpha,20 beta-hydroxysteroid dehydrogenase reversibly oxidizes the 3 alpha and 20 beta hydroxyl groups of steroids derived from androstanes and pregnanes. It was the first short-chain dehydrogenase to be studied by X-ray crystallography. The previous description of the structure of this enzyme, at 2.6 A resolution, did not permit(More)
Porcine testicular carbonyl reductase (PTCR) belongs to the short chain dehydrogenases/reductases (SDR) superfamily and catalyzes the NADPH-dependent reduction of ketones on steroids and prostaglandins. The enzyme shares nearly 85% sequence identity with the NADPH-dependent human 15-hydroxyprostaglandin dehydrogenase/carbonyl reductase. The tertiary(More)
The short-chain oxidoreductase (SCOR) family of enzymes includes over 2000 members identified in sequenced genomes. Of these enzymes, approximately 200 have been characterized functionally, and the three-dimensional crystal structures of approximately 40 have been reported. Since some SCOR enzymes are involved in hypertension, diabetes, breast cancer, and(More)
The x-ray structure of a short-chain dehydrogenase, the bacterial holo 3 alpha,20 beta-hydroxysteroid dehydrogenase (EC, is described at 2.6 A resolution. This enzyme is active as a tetramer and crystallizes with four identical subunits in the asymmetric unit. It has the alpha/beta fold characteristic of the dinucleotide binding region. The fold(More)
Cholesterol esterase from Candida cylindracea was separated into two fractions, corresponding to a dimeric and a monomeric form. Fingerprint analysis after lysine cleavages shows identical patterns, suggesting lack of primary differences. Crystals obtained from the two proteins differ and suggest the possibility of an equilibrium between the two forms,(More)
BACKGROUND The principal human estrogen, 17 beta-estradiol, is a potent stimulator of certain endocrine-dependent forms of breast cancer. Because human estrogenic 17 beta-hydroxysteroid dehydrogenase (type I 17 beta-HSD) catalyzes the last step in the biosynthesis of 17 beta-estradiol from the less potent estrogen, estrone, it is an attractive target for(More)
BACKGROUND Candida cylindracea cholesterol esterase (CE) reversibly hydrolyzes cholesteryl linoleate and oleate. CE belongs to the same alpha/beta hydrolase superfamily as triacylglycerol acyl hydrolases and cholinesterases. Other members of the family that have been studied by X-ray crystallography include Torpedo californica acetylcholinesterase,(More)
The linear pentadecapeptide antibiotic, gramicidin D, is a naturally occurring product of Bacillus brevis known to form ion channels in synthetic and natural membranes. The x-ray crystal structures of the right-handed double-stranded double-helical dimers (DSDH) reported here agree with 15N-NMR and CD data on the functional gramicidin D channel in lipid(More)
beta-ketoacyl (acyl carrier protein) reductase (beta-k-ACPR) enzymes are essential to fatty acid synthesis in bacteria. The analyses revealed the most primitive member of the beta-k-ACPRs family was a NADP reductase where NADP was recognised by a Thr residue in the beta2alpha3 turn. Aromatic residue stacking at the dimer interface and a previously(More)