Structural analysis of cytochromes P450 shows differences in flexibility of heme 2- and 4-vinyls

• Published in: Biochimica et biophysica acta 2007-03, Vol.1770 (3), p.413-419
• Main Authors: Hudeček, Jiří, Hodek, Petr, Anzenbacherová, Eva, Anzenbacher, Pavel
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - chemistry; Camphor 5-Monooxygenase - chemistry; Cytochrome P-450 Enzyme System - chemistry; Cytochromes P450; Enzyme structural flexibility; Heme - chemistry; Heme vinyls; Isoenzymes - chemistry; Mixed Function Oxygenases - chemistry; NADPH-Ferrihemoprotein Reductase; Protein Conformation; Resonance Raman spectra; Spectrum Analysis, Raman
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2006.10.008

Structural analysis of the orientations of heme vinyl side chains was carried out using the published crystallographic data for different cytochromes P450. Torsional angles ( τ, C αC β–C aC b) show different distributions for the vinyls in positions 2 and 4. Whereas the orientation of 2-vinyls is rather restricted ( τ between − 120° and − 180°), the 4-vinyls have a much higher mobility over almost the entire conformational space. On the basis of the empirical correlation recently reported for peroxidases (M.P. Marzocchi, G. Smulevich, Relationship between heme vinyl conformation and the protein matrix in peroxidases, J. Raman Spectrosc. 34 (2003), 725–736), an attempt has been made to compare the observed vinyl orientations with the experimental frequencies of the vinyl stretching vibrational modes. The data for P450 proteins do not exactly match the peroxidase-derived function, although a qualitatively similar relationship is likely to exist. Differences between P450 forms suggest a variability in heme-region flexibility and in communication with the rest of enzyme.