Histidine residue mediates radical-induced hinge cleavage of human IgG1.

ABSTRACT: Hydroxyl radicals induce hinge cleavage in a human IgG1 molecule via initial radical formation at the first hinge Cys(231) followed by electron transfer to the upper hinge residues. To enable engineering of a stable monoclonal antibody hinge, we investigated the role of the hinge His(229) residue using structure modeling and site-directed mutagenesis. Direct involvement of His(229) in the reaction mechanism is suggested by a 75-85% reduction of the hinge cleavage for variants in which His(229) was substituted with either Gln, Ser, or Ala. In contrast, mutation of Lys(227) to Gln, Ser, or Ala increased hinge cleavage. However, the H229S/K227S double mutant shows hinge cleavage levels similar to that of the single H229S variant, further revealing the importance of His(229). Examination of th

SUBMITTER: Yates Z 

PROVIDER: S-EPMC2881791 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature