The Specific Aims: 1) comparison of 2-disulfide analogs of insulin and IGF-1, 2) characterization of a 1-disulfide IGF-1 folding intermediate and a minimalist peptide model, 3) comparative 15N relaxation studies on IGF-1 analogs, 4) mutagenesis studies aimed at producing molecules that fold with the characteristics of either insulin or IGF-1, and 5) characterization of the in vivo folding pathway. The overall experimental plan is based on the observation that two proteins, insulin and IGF-1, that are highly similar to each other in their native, folded, disulfide-bonded states, exhibit significantly different folding properties. In particular, oxidative refolding under thermodynamic control yields a single (native) product for insulin, but yields two products (native, and one in which two of the three disulfides have swapped pairings) for IGF-1. This differential property is the basis on which Dr. Weiss proposes to identify factors responsible for on-pathway and off-pathway oxidative folding.
| Hua, Qing-xin; Weiss, Michael A (2004) Mechanism of insulin fibrillation: the structure of insulin under amyloidogenic conditions resembles a protein-folding intermediate. J Biol Chem 279:21449-60 |
| Dong, Jian; Wan, Zhuli; Popov, Maxim et al. (2003) Insulin assembly damps conformational fluctuations: Raman analysis of amide I linewidths in native states and fibrils. J Mol Biol 330:431-42 |
| Hua, Qing-Xin; Jia, Wenhua; Frank, Bruce H et al. (2002) A protein caught in a kinetic trap: structures and stabilities of insulin disulfide isomers. Biochemistry 41:14700-15 |
| Dong, J; Wan, Z L; Chu, Y C et al. (2001) Isotope-edited Raman spectroscopy of proteins: a general strategy to probe individual peptide bonds with application to insulin. J Am Chem Soc 123:7919-20 |
