NMR analysis of the conformational properties of the trapped on-pathway folding intermediate of the bacterial immunity protein Im7.

ABSTRACT: Previous work shows that the transiently populated, on-pathway intermediate in Im7 folding contains three of the four native alpha-helices docked around a core stabilised by native and non-native interactions. To determine the structure and dynamic properties of this species in more detail, we have used protein engineering to trap the intermediate at equilibrium and analysed the resulting proteins using NMR spectroscopy and small angle X-ray scattering. Four variants were created. In L53AI54A, two hydrophobic residues within helix III are truncated, preventing helix III from docking stably onto the developing hydrophobic core. In two other variants, the six residues encompassing the native helix III were replaced with three (H3G3) or six (H3G6) glycine residues. In the fourth variant, YY,

SUBMITTER: Whittaker SB 

PROVIDER: S-EPMC2706327 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature