A model for the flexibility of the distal histidine in dehaloperoxidase-hemoglobin A based on X-ray crystal structures of the carbon monoxide adduct.

ABSTRACT: Dehaloperoxidase hemoglobin A (DHP A) is a multifunctional hemoglobin that appears to have evolved oxidative pathways for the degradation of xenobiotics as a protective function that complements the oxygen transport function. DHP A possesses at least two internal binding sites, one for substrates and one for inhibitors, which include various halogenated phenols and indoles. Herein, we report the X-ray crystallographic structure of the carbonmonoxy complex (DHPCO). Unlike other DHP structures with 6-coordinated heme, the conformation of the distal histidine (H55) in DHPCO is primarily external or solvent exposed, despite the fact that the heme Fe is 6-coordinated. As observed generally in globins, DHP exhibits two distal histidine conformations (one internal and one external). In previous s

SUBMITTER: Zhao J 

PROVIDER: S-EPMC4203366 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature