Covalent heme attachment in Synechocystis hemoglobin is required to prevent ferrous heme dissociation.

ABSTRACT: Synechocystis hemoglobin contains an unprecedented covalent bond between a nonaxial histidine side chain (H117) and the heme 2-vinyl. This bond has been previously shown to stabilize the ferric protein against denaturation, and also to affect the kinetics of cyanide association. However, it is unclear why Synechocystis hemoglobin would require the additional degree of stabilization accompanying the His117-heme 2-vinyl bond because it also displays endogenous bis-histidyl axial heme coordination, which should greatly assist heme retention. Furthermore, the mechanism by which the His117-heme 2-vinyl bond affects ligand binding has not been reported, nor has any investigation of the role of this bond on the structure and function of the protein in the ferrous oxidation state. Here we report a

SUBMITTER: Hoy JA 

PROVIDER: S-EPMC2203299 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature