Betaalpha-hairpin clamps brace betaalphabeta modules and can make substantive contributions to the stability of TIM barrel proteins.

ABSTRACT: Non-local hydrogen bonding interactions between main chain amide hydrogen atoms and polar side chain acceptors that bracket consecutive betaalpha or alphabeta elements of secondary structure in alphaTS from E. coli, a TIM barrel protein, have previously been found to contribute 4-6 kcal mol(-1) to the stability of the native conformation. Experimental analysis of similar betaalpha-hairpin clamps in a homologous pair of TIM barrel proteins of low sequence identity, IGPS from S. solfataricus and E. coli, reveals that this dramatic enhancement of stability is not unique to alphaTS. A survey of 71 TIM barrel proteins demonstrates a 4-fold symmetry for the placement of betaalpha-hairpin clamps, bracing the fundamental betaalphabeta building block and defining its register in the (betaalpha)(8)

SUBMITTER: Yang X 

PROVIDER: S-EPMC2747017 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature