David N Greeley

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Structures have been determined for a potent analogue of vasoactive intestinal peptide (VIP), Ac-[Lys12, Lys14, Nle17, Val26, Thr28]VIP (VIP'), in methanol/water solutions. In CD studies, both VIP and VIP' were helical in methanol/water, with the percentage of alpha-helix increasing with percentage methanol. The pH had little effect on the structure.(More)
Solution structures were determined for a linear analogue of growth hormone releasing factor (GRF), and cyclic and dicyclic analogues in which the side chains of aspartyl and lysyl residues spaced at positions i-(i + 4) were joined to form a lactam. The four analogues were [Ala15]-GRF-(1-29)-NH2 and its cyclo8-12, cyclo21-25, and dicyclo8-12;21-25(More)
Nuclear magnetic resonance (NMR) methods were employed to study the interaction of the cytokine Interleukin-2 (IL-2) with the alpha-subunit of its receptor (IL-2Ralpha), and to help understand the behavior of small molecule inhibitors of this interaction. Heteronuclear (1)H-(15)N HSQC experiments were used to identify the interaction surface of(More)
Using nuclear magnetic resonance (NMR) spectroscopy, we have determined the solution structures for a series of potent agonists for the human melanocortin-4 receptor (hMC4R), based on the cyclic peptide MT-II [Ac-Nle-cyclo-(Asp-Lys) (Asp-His-(D)Phe-Arg-Trp-Lys)-NH2]. Members of this series were designed to improve selectivity for MC4R versus the other(More)
This study was designed to examine whether 13C nuclear magnetic resonance (NMR) spectroscopy can be used to differentiate between the 25R and 25S diastereoisomers of 5 beta-cholestane-3 alpha, 7 alpha, 26-triol, a key intermiediate in the biosynthetic pathway of chenodeoxycholic acid. Chemical shift values were assigned to the individual carbon atoms with(More)
This paper describes the synthesis of 5 beta-cholestane-3 beta, 7 alpha,25-triol and 5 beta-cholestane-3 beta, 7 alpha, 12 alpha, 25-tetrol from their corresponding 3 alpha-analogs. The method consists of refluxing a mixture of a steroid alcohol, triphenylphosphine, and diethyl azodicarboxylate in benzene solution with an acid such as formic acid. The(More)
In vertebrate rod cells, the activated alpha-subunit of rod transducin interacts with the gamma (regulatory) subunits of phosphodiesterase to disinhibit the catalytic subunits. A 22-amino acid long region of rod transducin involved in phosphodiesterase activation has recently been identified. We have used peptides from this region of rod transducin and from(More)
An unrecognized pentahydroxy bile alcohol has been isolated from the bile and feces of patients with cerebrotendinous xanthomatosis (CTX). Its structure, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25, 26-pentol has been deduced by spectroscopic methods and confirmed by comparison with a synthetic analog.
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