Physical Sciences and Mathematics Commons^™

Linking Conformation Change To Hemoglobin Activation Via Chain-Selective Time-Resolved Resonance Raman Spectroscopy On Protoheme/Mesoheme Hybrids, Gurusamy Balakrishnan, Mohammed Ibrahim, Piotr J. Mak, Jessica Hata, James R. Kincaid, Thomas G. Spiro

Chemistry Faculty Research and Publications

Time-resolved Resonance Raman spectra are reported for Hb tetramers, in which the αand β chains are selectively substituted with mesoheme. The Soret absorption band shift in meso- relative to protoheme permits chain-selective excitation of heme RR spectra. The evolution of these spectra following HbCO photolysis show that geminate recombination rates and yields are the same for the two chains, consistent with recent results on 15N-heme isotopomer hybrids. The spectra also reveal systematic shifts in the deoxy-heme ν4 and νFe-His) RR bands, which are anti-correlated. These shifts are resolved for the successive intermediates in the protein structure, which have previously been …