Synthetic peptide mimics of a predicted topographical interaction surface: the cytochrome P450 2B1 recognition domain for NADPH-cytochrome P450 reductase.
In order to identify the cytochrome P450-binding domain for NADPH-cytochrome P450 reductase, synthetic peptide mimics of predicted surface regions of rat cytochrome P450 2B 1 were constructed and evaluated for inhibition of the P450-reductase interaction. A peptide corresponding to residues 116-134, which includes the C helix, completely inhibited reductase-mediated benzphetamine demethylation by purified P450 2B1. Replacement of Arg-125 by Glu yielded a noninhibitory peptide, suggesting that this residue significantly contributes to the reductase-P450 interaction. Additional P450 peptides were prepared which correspond to combinations of regions distant in primary sequence, but predicted to be spatially proximate. A peptide derived from segments of the C and L helices was a more potent inhibitor than peptides derived from either segment alone. This topographically designed peptide not only inhibited P450 2B1 in its purified form, but also when membrane-bound in rat liver microsomes. The peptide also inhibited microsomal aryl hydrocarbon hydroxylase, aniline hydroxylase, and erythromycin demethylase activities derived from other P450s. These results indicate that the C and L helices contribute to a reductase-binding site common to multiple P450s, and present a peptide mimic for this region that is useful for inhibition of P450-mediated microsomal activities.
Omata
Y
Y
Laboratory of Molecular Carcinogenesis, National Cancer Institute, Bethesda, Maryland 20892, USA.
Dai
R
R
Smith
S V
SV
Robinson
R C
RC
Friedman
F K
FK
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019362:Cytochrome P-450 CYP2B1 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013501:Surface-Active Agents / Q000494:pharmacology
D003902:Detergents; D010455:Peptides; D013501:Surface-Active Agents; D019362:Cytochrome P-450 CYP2B1; D009251:NADPH-Ferrihemoprotein Reductase