Probing the bottom of a folding funnel using conformationally gated electron transfer reactions

Swati Bandi, Bruce E. Bowler

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of global stability on the kinetics of interconversion between the native (N) and a compact, partially unfolded form (I) of iso-1-cytochrome c stabilized by His73-heme ligation is investigated using a novel conformationally gated ET method. For the K73H variant and the 2-fold less stable AcH73 variant, the N and I conformers are of nearly equal stability at pH 7.5. The pH jump kinetic data yield kobs = kNI + kIN of 35-40 s-1 at final pH values from 6 to 8 for the AcH73 variant, about 3-fold faster than for the more stable K73H variant. Gated ET measurements give kNI = 28 s-1 and kIN = 13 s-1 for the AcH73 variant, 10- and 2-fold greater than that for the more stable K73H variant. Thus, funneled landscapes have evolved such that loss of global stability lowers barriers at the bottom of a folding funnel, still allowing for efficient folding.

Original languageEnglish
Pages (from-to)7540-7541
Number of pages2
JournalJournal of the American Chemical Society
Volume130
Issue number24
DOIs
StatePublished - Jun 18 2008

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