Biological responses to the gaseous molecules CO, NO and O2 are mediated by the heme prosthetic group, which binds these p acceptor XO ligands through Fe(II)-XO backbonding.  Subsequent signaling or ligand activation is controlled by distal interactions with the protein, or by modulation of the trans proximal ligand.  These interactions affect the positions of the ligand vibrational frequencies, which can be monitored via resonance Raman spectroscopy.  The electrostatic field of the distal residues influences the extent of backbonding and produces anti-correlated shifts in ?FeX and ?XO.1 However, the antibonding electrons in NO and O2 permit specific interactions with distal H-bond or lone pair donors that determine activation patterns and produce distinctive deviations from vibrational backbonding patterns.2-4 These effects can be accurately modeled vial DFT computation.3-5References1. Spiro, T. G.; Ibrahim, M.; Wasbotten, I. H., CO, NO and O2 as vibrational probes of heme protein active sites. In The Smallest Biomolecules: Diatomics and their Interactions with Heme Proteins; Ghosh, A., Ed.; Elsevier: Amsterdam, 2008; pp 95-123.2. Coyle, C. M.; Vogel, K. M.; Rush III, T. S.; Kozlowski, P. M.; Williams, R.; Spiro, T. G.; Dou, Y.; Ikeda-Saito, M.; Olson, J. S.; Zgierski, M. Z. Biochemistry 2003, 42, 4896-4903.3. Vogel, K. M.; Kozlowski, P. M.; Zgierski, M. Z.; Spiro, T. G. J. Am. Chem. Soc. 1999, 121, 9915-9921.4. Soldatova, A. V.; Ibrahim, M.; Olson, J. S.; Czernuszewicz, R. S.; Spiro, T. G. 2009, submitted.5. Xu, C.; Spiro, T. G. J. Biol. Inorg. Chem. 2008, 13, 613-621.

Protein control and sensing of CO, NO and O<sub>2</sub> binding to heme

239th National Meeting (2010)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Protein control and sensing of CO, NO and O2 binding to heme

Protein control and sensing of CO, NO and O₂ binding to heme