Functional consequences of the open distal pocket of dehaloperoxidase-hemoglobin observed by time-resolved X-ray crystallography.

ABSTRACT: Using time-resolved X-ray crystallography, we contrast a bifunctional dehaloperoxidase-hemoglobin (DHP) with previously studied examples of myoglobin and hemoglobin to understand the functional role of the distal pocket of globins. One key functional difference between DHP and other globins is the requirement that H2O2 enter the distal pocket of oxyferrous DHP to displace O2 from the heme Fe atom and thereby activate the heme for the peroxidase function. The open architecture of DHP permits more than one molecule to simultaneously enter the distal pocket of the protein above the heme to facilitate the unique peroxidase cycle starting from the oxyferrous state. The time-resolved X-ray data show that the distal pocket of DHP lacks a protein valve found in the two other globins that have been

SUBMITTER: Zhao J 

PROVIDER: S-EPMC3983922 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature