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Kristan, K.* ; Adamski, J. ; Lanisnik Rizner, T.* ; Stojan, J.*

His164 regulates accessibility to the active site in fungal 17β-hydroxysteroid dehydrogenase.

Biochimie 89, 63-71 (2007)
DOI PMC
Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
17ß-Hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17ß-HSDcl) is an NADPH-dependent member of the short-chain dehydrogenase/ reductase superfamily. To study the catalytic properties of this enzyme, we prepared several specific mutations of 17ß-HSDcl (Tyr167Phe, His164Trp/Gly, Tyr212Ala). Wild-type 17ß-HSDcl and the 17ß-HSDcl mutants were evaluated by chromatographic, kinetic and thermodynamic means. The Tyr167Phe mutation resulted in a complete loss of enzyme activity, while substitution of His164 with Trp and Gly both resulted in higher specificity number (V/K) for the steroid substrates, which are mainly a consequence of easier accessibility of steroid substrates to the active-site hollow under optimized conditions. The Tyr212Ala mutant showed increased activity in the oxidative direction, which appears to be a consequence of increased NADPH dissociation. The kinetic characterizations and thermodynamic analyses also suggest that His164 and Tyr212 in 17ß-HSDcl have a role in the opening and closing of the active site of this enzyme and in the discrimination between oxidized and reduced coenzyme.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter 17ß-Hydroxysteroid dehydrogenase; Short-chain dehydrogenase/reductase; Site-directed mutagenesis; Kinetic characterization; Thermodynamic analysis
ISSN (print) / ISBN 0300-9084
e-ISSN 1638-6183
Zeitschrift Biochimie
Quellenangaben Band: 89, Heft: 1, Seiten: 63-71 Artikelnummer: , Supplement: ,
Verlag Elsevier
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Molekulare Endokrinologie und Metabolismus (MEM)