Premium
Crystal Structure of a Cytochrome P450 2B6 Genetic Variant in Complex with the Inhibitor 4‐(4‐Chlorophenyl)imidazole at 2.0 Å Resolution
Author(s) -
Gay Sean C.,
Shah Manish B.,
Talakad Jyothi C.,
Maekawa Keiko,
Roberts Arthur G.,
Wilderman P. Ross,
Sun Ling,
Yang Jane Y.,
Huelga Stephanie C.,
Zhang Qinghai,
Stout C. David,
Halpert James R.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.967.16
Subject(s) - chemistry , crystal structure , active site , crystallography , imidazole , protein structure , stereochemistry , enzyme , biochemistry
The structure of the K262R genetic variant of human cytochrome P450 2B6 in complex with the inhibitor 4‐(4‐chlorophenyl)imidazole has been determined using x‐ray crystallography to 2.0 Å resolution. Production of diffraction quality crystals was enabled through a combination of protein engineering, chaperone coexpression, modifications to the purification protocol, and the use of unique facial amphiphiles during crystallization. The 2B6‐4‐CPI complex is virtually identical to the rabbit 2B4 structure bound to the same inhibitor with respect to the arrangement of secondary structural elements and the placement of active site residues. Based on the new P450 2B6 crystal structure and previous 2B4 structures, substitutions at residue 262 affect a hydrogen‐bonding network connecting the G and H helices, where subtle differences could be transduced to the active site. Docking experiments indicate that the closed protein conformation allows smaller ligands such as ticlopidine and clopidogrel to bind to the 2B6 active site in the expected orientation. However, the inability to dock the larger ligands raloxifene and itraconazole in favorable conformations suggests that 2B6 undergoes some degree of structural reorganization to accommodate bulkier molecules, as previously inferred from multiple P450 2B4 crystal structures. NIH grants ES003619, ES006676