Determinants of the heme-CO vibrational modes in the H-NOX family.

ABSTRACT: The Heme Nitric oxide/OXygen binding (H-NOX) family of proteins have important functions in gaseous ligand signaling in organisms from bacteria to humans, including nitric oxide (NO) sensing in mammals, and provide a model system for probing ligand selectivity in hemoproteins. A unique vibrational feature that is ubiquitous throughout the H-NOX family is the presence of a high C-O stretching frequency. To investigate the cause of this spectroscopic characteristic, the Fe-CO and C-O stretching frequencies were probed in the H-NOX domain from Thermoanaerobacter tengcongensis (Tt H-NOX) using resonance Raman (RR) spectroscopy. Four classes of heme pocket mutants were generated to assess the changes in stretching frequency: (i) the distal H-bonding network, (ii) the proximal histidine ligand,

SUBMITTER: Tran R 

PROVIDER: S-EPMC3148809 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature