Development of bioapplicable collagen peptides and crosslinked dimerization inhibitors of HIV -1 protease
Abstract
Collagen is an essential protein that gives support and structure to bone, cartilage, skin, and tendons. We have successfully designed a collagen peptide that folds in a pH-dependent manner using a carboxylate-modified hydroxyproline scaffold. While our designed peptide showed a significant thermal transition at acidic pH, a linear decrease in ellipticity was observed at neutral pH, indicating the formation of a monomeric polyproline type II helix. These data demonstrate that it is difficult to form a stable triple helix due to interhelical electrostatic repulsion between the negatively charged carboxylate groups. HIV-1 protease (PR), a central enzyme in viral replication, has been a prime target for the treatment of AIDS. Due to viral drug resistance, however, it is imperative to develop new classes of inhibitors. One strategy to overcome viral resistance is to target the dimerization interface of HIV-1 PR, which is highly conserved. Our initial strategy began with crosslinked peptides derived from the dimerization interface of HIV-1 PR. In the work described within, focused libraries of single and double amino acid mutations of PR dimerization inhibitors were synthesized and evaluated for potency. With the single mutation study, a number of smaller molecular weight agents demonstrated better inhibitory efficacy than the full length, crosslinked interfacial peptides. For the double mutation study, a 54 component library was designed using a rapid synthesis and in situ screening method in microtiter plates. This strategy identified some of the most potent dimerization inhibitors of PR to date, and the free energy of binding for the combined modifications was generally found to be additive, demonstrating the predictive value of earlier libraries. Finally, in an effort to develop protease-resistant HIV-1 PR dimerization inhibitors, a small library of peptoid based agents was designed and tested. Through this study, a number of potent peptoid dimerization inhibitors of HIV PR were generated.
Degree
Ph.D.
Advisors
Chmielewski, Purdue University.
Subject Area
Organic chemistry
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