Download MendeleyStructural insight into the altered substrate specificity of human cytochrome P450 2A6 mutants.
Sansen, S., Hsu, M.H., Stout, C.D., Johnson, E.F.(2007) Arch Biochem Biophys 464: 197-206
- PubMed: 17540336
- DOI: https://doi.org/10.1016/j.abb.2007.04.028
- Primary Citation of Related Structures:
2PG5, 2PG6, 2PG7 - PubMed Abstract:
Human P450 2A6 displays a small active site that is well adapted for the oxidation of small planar substrates. Mutagenesis of CYP2A6 resulted in an increased catalytic efficiency for indole biotransformation to pigments and conferred a capacity to oxidize substituted indoles (Wu, Z.-L., Podust, L.M., Guengerich, F.P. J. Biol. Chem. 49 (2005) 41090-41100.). Here, we describe the structural basis that underlies the altered metabolic profile of three mutant enzymes, P450 2A6 N297Q, L240C/N297Q and N297Q/I300V. The Asn297 substitution abolishes a potential hydrogen bonding interaction with substrates in the active site, and replaces a structural water molecule between the helix B'-C region and helix I while maintaining structural hydrogen bonding interactions. The structures of the P450 2A6 N297Q/L240C and N297Q/I300V mutants provide clues as to how the protein can adapt to fit the larger substituted indoles in the active site, and enable a comparison with other P450 family 2 enzymes for which the residue at the equivalent position was seen to function in isozyme specificity, structural integrity and protein flexibility.
Organizational Affiliation:
Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, MEM-255, La Jolla, CA 92037, USA.
