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Titolo:
Crystal structures of ligand complexes of P450eryF exhibiting homotropic cooperativity
Autore:
Cupp-Vickery, J; Anderson, R; Hatziris, Z;
Indirizzi:
Calif State Univ Fullerton, Dept Chem & Biochem, Fullerton, CA 92834 USA Calif State Univ Fullerton Fullerton CA USA 92834 Fullerton, CA 92834 USA
Titolo Testata:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
fascicolo: 7, volume: 97, anno: 2000,
pagine: 3050 - 3055
SICI:
0027-8424(20000328)97:7<3050:CSOLCO>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN CYTOCHROME-P450 3A4; ERYTHROMYCIN BIOSYNTHESIS; ALPHA-NAPHTHOFLAVONE; ACTIVE-SITE; SUBSTRATE; HYDROXYLASE; ACTIVATION; MUTAGENESIS; RESIDUES; ENZYMES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Cupp-Vickery, J Calif State Univ Fullerton, Dept Chem & Biochem, 800 N State Coll Blvd, Fullerton, CA 92834 USA Calif State Univ Fullerton 800 N State Coll Blvd Fullerton CA USA 92834
Citazione:
J. Cupp-Vickery et al., "Crystal structures of ligand complexes of P450eryF exhibiting homotropic cooperativity", P NAS US, 97(7), 2000, pp. 3050-3055

Abstract

Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic cooperativity with a number of substrates, including steroids and polycyclicaromatic hydrocarbons. To identify structural factors contributing to steroid and polycyclic aromatic hydrocarbon binding to P450 enzymes and to determine the location of the allosteric site, we investigated interactions of the macrolide hydroxylase P450eryF from Saccharopolyspora erythraea with androstenedione and 9-aminophenanthrene. Spectroscopic binding assays indicate that P450eryF binds androstenedione with an affinity of 365 mu M and a Hill coefficient of 1.31 +/- 0.6 and coordinates with 9-aminophenanthrene with an affinity of 91 mu M and a Hill coefficient of 1.38 +/- 0.2. Crystals of complexes of androstenedione and 9-aminophenanthrene with P450eryF were grown and diffracted to 2.1 Angstrom and 2.35 Angstrom, respectively. Electron density maps indicate that for both complexes two ligand molecules are simultaneously present in the active site. The P450eryF/ androstenedione model was refined to an r = 18.9%, and the two androstenedione molecules have similar conformations. The proximal androstenedione is positioned such thatthe alpha-face of carbon-6 is closest to the heme iron, and the second steroid molecule is positioned 5.5 Angstrom distal in the active site, The P450eryF/9-aminophenanthrene model was refined to an r = 19.7% with the proximal 9-aminophenanthrene coordinated with the heme iron through the 9-amino group and the second ligand positioned approximate to 6 Angstrom distal in the active site. These results establish that homotropic cooperativity in ligand binding can result from binding of two substrate molecules within the active site pocket without major conformational changes in the protein.

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Documento generato il 25/01/20 alle ore 18:27:38