An active site substitution, F87V, converts cytochrome P450 BM-3 into a regio- and stereoselective (14S,15R)-arachidonic acid epoxygenase

Sandra Graham-Lorence, Gilles Truant, Julian A. Peterson, J R Falck, Shouzuo Wei, Christian Helvig, Jorge H. Capdevila

Research output: Contribution to journalArticle

155 Citations (Scopus)

Abstract

Cytochrome P450 BM-3 catalyzes the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids. To map structural determinants of productive active site fatty acid binding, we mutated two amino acid residues, arginine 47 and phenylalanine 87, which flank the surface and heme ends of the enzyme's substrate access channel, respectively. Replacement of arginine 47 with glutamic acid resulted in a catalytically inactive mutant. Replacement of arginine 47 with alanine yielded a protein with reduced substrate binding affinity and arachidonate sp3 carbon hydroxylation activity (72% of control wild type). On the other hand, arachidonic and eicosapentaenoic acid epoxidation was significantly enhanced (154 and 137%, of control wild type, respectively). As with wild type, the alanine 47 mutant generated (18R)-hydroxyeicosatetraenoic, (14S,15R)-epoxyeicosatrienoic, and (17S,18R)-epoxyeicosatetraenoic acids nearly enantiomerically pure. Replacement of phenylalanine 87 with valine converted cytochrome P450 BM-3 into a regio- and stereoselective arachidonic acid epoxygenase ((14S,15R)-epoxyeicosatrienoic acid, 99% of total products). Conversely, metabolism of eicosapentaenoic acid by the valine 87 mutant yielded a mixture of (14S,15R)- and (17S,18R)-epoxyeicosatetraenoic acids (26 and 69% of total, 94 and 96% optical purity, respectively). Finally, replacement of phenylalanine 87 with tyrosine yielded an inactive protein. We propose that: (a) fatty acid oxidation by P450 BM-3 is incompatible with the presence of residues with negatively charged side chains at the surface opening of the substrate access channel or a polar aromatic side chain in the vicinity of the heme iron; (b) the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids involves charge- dependent anchoring of the fatty acids at the mouth of the access channel by arginine 47, as well as steric gating of the heme-bound oxidant by phenylalanine 87; and (c) substrate binding coordinates, as opposed to oxygen chemistries, are the determining factors responsible for reaction rates, product chemistry, and, thus, catalytic outcome.

Original languageEnglish (US)
Pages (from-to)1127-1135
Number of pages9
JournalJournal of Biological Chemistry
Volume272
Issue number2
DOIs
StatePublished - 1997

Fingerprint

Eicosapentaenoic Acid
Phenylalanine
Cytochrome P-450 Enzyme System
Arginine
Catalytic Domain
Substitution reactions
Heme
Metabolism
Arachidonic Acids
Fatty Acids
Valine
Substrates
Alanine
Acids
Hydroxylation
Epoxidation
Arachidonic Acid
Oxidants
Reaction rates
Tyrosine

ASJC Scopus subject areas

  • Biochemistry

Cite this

An active site substitution, F87V, converts cytochrome P450 BM-3 into a regio- and stereoselective (14S,15R)-arachidonic acid epoxygenase. / Graham-Lorence, Sandra; Truant, Gilles; Peterson, Julian A.; Falck, J R; Wei, Shouzuo; Helvig, Christian; Capdevila, Jorge H.

In: Journal of Biological Chemistry, Vol. 272, No. 2, 1997, p. 1127-1135.

Research output: Contribution to journalArticle

Graham-Lorence, Sandra ; Truant, Gilles ; Peterson, Julian A. ; Falck, J R ; Wei, Shouzuo ; Helvig, Christian ; Capdevila, Jorge H. / An active site substitution, F87V, converts cytochrome P450 BM-3 into a regio- and stereoselective (14S,15R)-arachidonic acid epoxygenase. In: Journal of Biological Chemistry. 1997 ; Vol. 272, No. 2. pp. 1127-1135.
@article{76873245d8cb44339c513478d63aa42c,
title = "An active site substitution, F87V, converts cytochrome P450 BM-3 into a regio- and stereoselective (14S,15R)-arachidonic acid epoxygenase",
abstract = "Cytochrome P450 BM-3 catalyzes the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids. To map structural determinants of productive active site fatty acid binding, we mutated two amino acid residues, arginine 47 and phenylalanine 87, which flank the surface and heme ends of the enzyme's substrate access channel, respectively. Replacement of arginine 47 with glutamic acid resulted in a catalytically inactive mutant. Replacement of arginine 47 with alanine yielded a protein with reduced substrate binding affinity and arachidonate sp3 carbon hydroxylation activity (72{\%} of control wild type). On the other hand, arachidonic and eicosapentaenoic acid epoxidation was significantly enhanced (154 and 137{\%}, of control wild type, respectively). As with wild type, the alanine 47 mutant generated (18R)-hydroxyeicosatetraenoic, (14S,15R)-epoxyeicosatrienoic, and (17S,18R)-epoxyeicosatetraenoic acids nearly enantiomerically pure. Replacement of phenylalanine 87 with valine converted cytochrome P450 BM-3 into a regio- and stereoselective arachidonic acid epoxygenase ((14S,15R)-epoxyeicosatrienoic acid, 99{\%} of total products). Conversely, metabolism of eicosapentaenoic acid by the valine 87 mutant yielded a mixture of (14S,15R)- and (17S,18R)-epoxyeicosatetraenoic acids (26 and 69{\%} of total, 94 and 96{\%} optical purity, respectively). Finally, replacement of phenylalanine 87 with tyrosine yielded an inactive protein. We propose that: (a) fatty acid oxidation by P450 BM-3 is incompatible with the presence of residues with negatively charged side chains at the surface opening of the substrate access channel or a polar aromatic side chain in the vicinity of the heme iron; (b) the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids involves charge- dependent anchoring of the fatty acids at the mouth of the access channel by arginine 47, as well as steric gating of the heme-bound oxidant by phenylalanine 87; and (c) substrate binding coordinates, as opposed to oxygen chemistries, are the determining factors responsible for reaction rates, product chemistry, and, thus, catalytic outcome.",
author = "Sandra Graham-Lorence and Gilles Truant and Peterson, {Julian A.} and Falck, {J R} and Shouzuo Wei and Christian Helvig and Capdevila, {Jorge H.}",
year = "1997",
doi = "10.1074/jbc.272.2.1127",
language = "English (US)",
volume = "272",
pages = "1127--1135",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "2",

}

TY - JOUR

T1 - An active site substitution, F87V, converts cytochrome P450 BM-3 into a regio- and stereoselective (14S,15R)-arachidonic acid epoxygenase

AU - Graham-Lorence, Sandra

AU - Truant, Gilles

AU - Peterson, Julian A.

AU - Falck, J R

AU - Wei, Shouzuo

AU - Helvig, Christian

AU - Capdevila, Jorge H.

PY - 1997

Y1 - 1997

N2 - Cytochrome P450 BM-3 catalyzes the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids. To map structural determinants of productive active site fatty acid binding, we mutated two amino acid residues, arginine 47 and phenylalanine 87, which flank the surface and heme ends of the enzyme's substrate access channel, respectively. Replacement of arginine 47 with glutamic acid resulted in a catalytically inactive mutant. Replacement of arginine 47 with alanine yielded a protein with reduced substrate binding affinity and arachidonate sp3 carbon hydroxylation activity (72% of control wild type). On the other hand, arachidonic and eicosapentaenoic acid epoxidation was significantly enhanced (154 and 137%, of control wild type, respectively). As with wild type, the alanine 47 mutant generated (18R)-hydroxyeicosatetraenoic, (14S,15R)-epoxyeicosatrienoic, and (17S,18R)-epoxyeicosatetraenoic acids nearly enantiomerically pure. Replacement of phenylalanine 87 with valine converted cytochrome P450 BM-3 into a regio- and stereoselective arachidonic acid epoxygenase ((14S,15R)-epoxyeicosatrienoic acid, 99% of total products). Conversely, metabolism of eicosapentaenoic acid by the valine 87 mutant yielded a mixture of (14S,15R)- and (17S,18R)-epoxyeicosatetraenoic acids (26 and 69% of total, 94 and 96% optical purity, respectively). Finally, replacement of phenylalanine 87 with tyrosine yielded an inactive protein. We propose that: (a) fatty acid oxidation by P450 BM-3 is incompatible with the presence of residues with negatively charged side chains at the surface opening of the substrate access channel or a polar aromatic side chain in the vicinity of the heme iron; (b) the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids involves charge- dependent anchoring of the fatty acids at the mouth of the access channel by arginine 47, as well as steric gating of the heme-bound oxidant by phenylalanine 87; and (c) substrate binding coordinates, as opposed to oxygen chemistries, are the determining factors responsible for reaction rates, product chemistry, and, thus, catalytic outcome.

AB - Cytochrome P450 BM-3 catalyzes the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids. To map structural determinants of productive active site fatty acid binding, we mutated two amino acid residues, arginine 47 and phenylalanine 87, which flank the surface and heme ends of the enzyme's substrate access channel, respectively. Replacement of arginine 47 with glutamic acid resulted in a catalytically inactive mutant. Replacement of arginine 47 with alanine yielded a protein with reduced substrate binding affinity and arachidonate sp3 carbon hydroxylation activity (72% of control wild type). On the other hand, arachidonic and eicosapentaenoic acid epoxidation was significantly enhanced (154 and 137%, of control wild type, respectively). As with wild type, the alanine 47 mutant generated (18R)-hydroxyeicosatetraenoic, (14S,15R)-epoxyeicosatrienoic, and (17S,18R)-epoxyeicosatetraenoic acids nearly enantiomerically pure. Replacement of phenylalanine 87 with valine converted cytochrome P450 BM-3 into a regio- and stereoselective arachidonic acid epoxygenase ((14S,15R)-epoxyeicosatrienoic acid, 99% of total products). Conversely, metabolism of eicosapentaenoic acid by the valine 87 mutant yielded a mixture of (14S,15R)- and (17S,18R)-epoxyeicosatetraenoic acids (26 and 69% of total, 94 and 96% optical purity, respectively). Finally, replacement of phenylalanine 87 with tyrosine yielded an inactive protein. We propose that: (a) fatty acid oxidation by P450 BM-3 is incompatible with the presence of residues with negatively charged side chains at the surface opening of the substrate access channel or a polar aromatic side chain in the vicinity of the heme iron; (b) the high turnover regio- and stereoselective metabolism of arachidonic and eicosapentaenoic acids involves charge- dependent anchoring of the fatty acids at the mouth of the access channel by arginine 47, as well as steric gating of the heme-bound oxidant by phenylalanine 87; and (c) substrate binding coordinates, as opposed to oxygen chemistries, are the determining factors responsible for reaction rates, product chemistry, and, thus, catalytic outcome.

UR - http://www.scopus.com/inward/record.url?scp=0031021585&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031021585&partnerID=8YFLogxK

U2 - 10.1074/jbc.272.2.1127

DO - 10.1074/jbc.272.2.1127

M3 - Article

C2 - 8995412

AN - SCOPUS:0031021585

VL - 272

SP - 1127

EP - 1135

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 2

ER -