The Rubredoxin from Clostridium pasteurianum: Mutation of the Conserved Glycine Residues 10 and 43 to Alanine and Valine

Abstract

Conserved glycine residues at positions 10 and 43 in the electron transfer protein rubredoxin (active site: Fe-(Cys-S)4) from Clostridium pasteurianum are related by a pseudo-2-fold symmetry. They have been mutated to alanine and valine and four single and two double mutant (G10V/G43A and G10V/G43V) proteins expressed in stable form in Escherichia coli. Physical properties were modified by steric interactions between the β- and γ-carbon substituents of the new side chains and the CO functions of C9 and C42 and other adjacent groups. These interactions perturb the chelate loops formed by residues 5-11 and 38-44. 1H NMR results for Cd(II) forms indicate that the Pr side chain of V10 in the G10..