title: Distance between lysine 384 and heme of cytochrome P-450 LM2 (P-450 IIB4) studied by fluorescence energy transfer measurements.
abstract: The distance between FITC-modified lysine 384 of cytochrome P-450 LM2 and the active site, heme, was estimated by fluorescence energy transfer measurements. To avoid differential labelling of P-450 LM2 for protection of the alpha-amino group from FITC modification, deconvolution of measured fluorescence decay curves using a double exponential model was performed. A value of 2.7 nm was obtained for the distance FITC (lysine 384) - heme. This distance is too large to account for a direct electron tunneling from prosthetic group to prosthetic group at this interaction site between reductase and P-450 LM2.
authors.affiliation: Academy of Sciences of the GDR, Department of Biocatalysis, Berlin-Buch.
authors.forename: R
authors.initials: R
authors.lastname: Bernhardt
authors.forename: H
authors.initials: H
authors.lastname: Stiel
authors.forename: K
authors.initials: K
authors.lastname: Ruckpaul
mesh_terms: D000818:Animals; D001665:Binding Sites; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins / Q000494:pharmacology; D005456:Fluorescent Dyes; D006418:Heme / Q000032:analysis*; D008239:Lysine / Q000032:analysis*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D011487:Protein Conformation; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D013861:Thiocyanates / Q000494:pharmacology
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D013861:Thiocyanates; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; D016650:Fluorescein-5-isothiocyanate; D008239:Lysine; D010634:Phenobarbital