Role of conserved local motifs in folding and stability of hGSTP1-1

We investigated, by site directed mutagenesis, the role played by a conserv ed N-capping box and hydrophobic staple motif in the folding and stability of human GSTPl-1. The corresponding mutants, I149A, S150A, D153A and Y154A, in which these motifs have been removed were significantly more thermolabi le than wild-type GSTP1-1. Reactivation experiments in vitro indicate that both these local signals are essential for refolding. The results suggest t hat these buried and conserved local motifs, making a definite set of nativ e-like contacts, determines the formation of a specific folding nucleus tha t probably represents a transition state of the folding process. (C) 2001 E lsevier Science Ireland Ltd. All rights reserved.