CrossRef enabled

PAC Archives

Archive →

Pure Appl. Chem., 2008, Vol. 80, No. 12, pp. 2667-2678

Structural chemistry involved in information detection and transmission by gas sensor heme proteins: Resonance Raman investigation

Samir F. El-Mashtoly1 and Teizo Kitagawa2

1 Department of Chemistry, Faculty of Science, King Khalid University, Abha 9004, Saudi Arabia
2 Toyota Physical and Chemical Research Institute, Nagakute, Aichi 480-1192, Japan

Abstract: A variety of heme-containing gas sensor proteins have been discovered by gene analysis from bacteria to mammals. In general, these proteins are composed of an N-terminal heme-containing sensor domain and a C-terminal catalytic domain. Binding of O2, CO, or NO to the heme causes a change in the structure of heme, which alters the protein conformation in the vicinity of the heme, and the conformational change is propagated to the catalytic domain, leading to regulation of the protein activity. This mini-review summarizes the recent resonance Raman studies obtained with both visible and UV excitation sources for two O2 sensor proteins, EcDOS and HemAT-Bs. These investigations have shown the role of heme propionate hydrogen-bonding interactions in communicating the heme structural changes, which occur upon ligand binding, from heme to the protein moiety. Furthermore, it is deduced that the contact interactions between the heme 2-vinyl group and the surrounding residues are also important for signal transmission from heme to protein in EcDOS.