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Titolo:
Saccharomyces cerevisiae leukotriene A(4) hydrolase: Formation of leukotriene B-4 and identification of catalytic residues
Autore:
Kull, F; Ohlson, E; Lind, B; Haeggstrom, JZ;
Indirizzi:
Karolinska Inst, Dept Med Biochem & Biophys, Div Chem 2, S-17177 Stockholm, Sweden Karolinska Inst Stockholm Sweden S-17177 em 2, S-17177 Stockholm, Sweden Karolinska Inst, Inst Environm Med, Div Met & Hlth, S-17177 Stockholm, Sweden Karolinska Inst Stockholm Sweden S-17177 Hlth, S-17177 Stockholm, Sweden
Titolo Testata:
BIOCHEMISTRY
fascicolo: 42, volume: 40, anno: 2001,
pagine: 12695 - 12703
SICI:
0006-2960(20011023)40:42<12695:SCLAHF>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
MECHANISM-BASED INACTIVATION; CYTOSOLIC EPOXIDE HYDROLASE; SITE-DIRECTED MUTAGENESIS; AMINO-ACID SEQUENCE; HUMAN-ERYTHROCYTES; MOLECULAR-CLONING; XENOPUS-LAEVIS; ONCORHYNCHUS-MYKISS; ZINC METALLOENZYME; PEPTIDASE ACTIVITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Haeggstrom, JZ Karolinska Inst, Dept Med Biochem & Biophys, Div Chem 2, S-17177 Stockholm, Sweden Karolinska Inst Stockholm Sweden S-17177 tockholm, Sweden
Citazione:
F. Kull et al., "Saccharomyces cerevisiae leukotriene A(4) hydrolase: Formation of leukotriene B-4 and identification of catalytic residues", BIOCHEM, 40(42), 2001, pp. 12695-12703

Abstract

Leukotriene A(4) hydrolase in mammals is a bifunctional zinc metalloenzymethat catalyzes the hydrolysis of leukotriene A(4) into the proinflammatorymediator leukotriene B-4, and also possesses an aminopeptidase activity. Recently we cloned and characterized an leukotriene A(4) hydrolase from Saccharomyces cerevisiae as a leucyl aminopeptidase with an epoxide hydrolase activity. Here we show that S. cerevisiae leukotriene A(4) hydrolase is a metalloenzyme containing one zinc atom complexed to His-340, His-344, and Glu-363. Mutagenetic analysis indicates that the aminopeptidase activity follows a general base mechanism with Glu-341 and Tyr-429 as the base and protondonor, respectively. Furthermore, the yeast enzyme hydrolyzes leukotriene A(4) into three compounds, viz., 5S,6S-dihydroxy-7,9-trans-11, 14-cis-eicosatetraenoic acid, leukotriene B-4, and Delta (6)-trans-Delta (8)-cis-leukotriene B-4, with a relative formation of 1:0.2:0.1. In addition, exposure ofS. cerevisiae leukotriene A(4) hydrolase to leukotriene A(4) selectively inactivates the epoxide hydrolase activity with a simultaneous stimulation of the aminopeptidase activity. Moreover, kinetic analyses of wild-type and mutated S. cerevisiae leukotriene A(4) hydrolase suggest that leukotriene A(4) binds in one catalytic mode and one tight-binding, regulatory mode. Exchange of a Phe-424 in S. cerevisiae leukotriene A(4) hydrolase for a Tyr, the corresponding residue in human leukotriene A(4) hydrolase, results in a protein that converts leukotriene A(4) into leukotriene B-4 with an improved efficiency and specificity. Hence, by a single point mutation, we could make the active site better suited to bind and turn over the substrate leukotriene. A(4), thus mimicking a distinct step in the molecular evolution of S. cerevisiae leukotriene A(4) hydrolase toward its mammalian counterparts.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 21:18:05