title: [Structural organization and localization of cytochromes P450 in the membrane].
abstract: The secondary structure prediction of 19 microsomal cytochrome P-450s from two different families was made based on their amino acid sequences. It was shown that there is a structural similarity between the heme-binding sites of these enzymes and the bacterial P-450cam. An average predicted secondary structure of cytochrome P-450 proteins with 70% accuracy contains about 46% alpha-helices, 12% beta-strands, 9% beta-turns and 33% random coil. In the region of the 35-120 residues in microsomal P-450s two adjacent beta alpha beta-units (the Rossmann domain) were recognized, which may interact with the NADPH-cytochrome P-450 reductase. Using the procedure of identification of hydrophobic and membrane-associated alpha-helical segments of 23 cytochromes, only one N-terminal transmembrane anchor was predicted. Also the heme-binding site perhaps includes surface-bound helix. A model of vertebrate microsomal P-450s is proposed. That is an amphypathic membrane protein located on the cytoplasmic face of the endoplasmic reticulum, their active center lies out/on the bilayer border.
authors.forename: V E
authors.initials: VE
authors.lastname: Tret'iakov
authors.forename: K N
authors.initials: KN
authors.lastname: Degtiarenko
authors.forename: V Iu
authors.initials: VIu
authors.lastname: Uvarov
authors.forename: A I
authors.initials: AI
authors.lastname: Archakov
authors.forename: L Z
authors.initials: LZ
authors.lastname: Tret'iakova
authors.forename: A I
authors.initials: AI
authors.lastname: Varenitsa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000235:genetics*; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology*; D007527:Isoenzymes / Q000032:analysis / Q000235:genetics; D008861:Microsomes / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D051381:Rats; D012689:Sequence Homology, Nucleic Acid
chemical_list: D007527:Isoenzymes; D003577:Cytochrome P-450 Enzyme System
vernacular_title: Strukturnaia organizatsiia i raspolozhenie tsitokhromov P450 v membrane.