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

Rational design of novel mutants of fungal 17β-hydroxysteroid dehydrogenase.

J. Biotechnol. 129, 123-130 (2007)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Reduction of 17-ketosteroids is a biocatalytic process of economic significance for the production of steroid drugs. This reaction can be catalyzed by different microbial 17ß-hydroxysteroid dehydrogenases (17ß-HSD), like the 17ß-HSD activity of Saccharomyces cerevisiae, Pichia faranosa and Mycobacterium sp., and by purified 3ß,17ß-HSD from Pseudomonas testosteroni. In addition to the bacterial 3ß,17ß-HSD the 17ß-HSD of the filamentous fungus Cochliobolus lunatus is the only microbial 17ß-HSD that has been expressed as a recombinant protein and fully characterized. On the basis of its modeled 3D structure, we selected several positions for the replacement of amino acids by site-directed mutagenesis to change substrate specificity, alter coenzyme requirements, and improve overall catalytic activity. Replacement of Val161 and Tyr212 in the substrate-binding region by Gly and Ala, respectively, increased the initial rates for the conversion of androstenedione to testosterone. Replacement of Tyr49 within the coenzyme binding site by Asp changed the coenzyme specificity of the enzyme. This latter mutant can convert the steroids not only in the presence of NADP+ and NADPH, but also in the presence of NADH and NAD+. The replacement of His164, located in the non-flexible part of the ‘lid’ covering the active center resulted in a conformation of the enzyme that possessed a higher catalytic activity.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Biotransformation of steroids; 17ß-Hydroxysteroid dehydrogenase; Fungi; Cochliobolus lunatus; Site-directed mutagenesis; Enzyme engineering
ISSN (print) / ISBN 0168-1656
e-ISSN 1873-4863
Journal Journal of Biotechnology
Quellenangaben Volume: 129, Issue: 1, Pages: 123-130 Article Number: , Supplement: ,
Publisher Elsevier
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Molekulare Endokrinologie und Metabolismus (MEM)