Coupling of the distal hydrogen bond network to the exogenous ligand in substrate-bound, resting state human heme oxygenase.

ABSTRACT: Mammalian heme oxygenase (HO) possesses catalytically implicated distal ordered water molecules within an extended H-bond network, with one of the ordered water molecules (#1) providing a bridge between the iron-coordinated ligand and the catalytically critical Asp140, that, in turn, serves as an acceptor for the Tyr58 OH H-bond. The degree of H-bonding by the ligated water molecule and the coupling of this water molecule to the H-bond network are of current interest and are herein investigated by (1)H NMR. Two-dimensional NMR allowed sufficient assignments to provide both the H-bond strength and hyperfine shifts, the latter of which were used to quantify the magnetic anisotropy in both the ferric high-spin aquo and low-spin hydroxo complexes. The anisotropy in the aquo complex indicates t

SUBMITTER: Peng D 

PROVIDER: S-EPMC3008551 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature