Author/Editor     Brunskole, Mojca; Kristan, Katja; Stojan, Jure; Lanišnik-Rižner, Tea
Title     Mutations that affect coenzyme binding and dimer formation of fungal 17beta-hydroxysteroid dehydrogenase
Type     članek
Source     Mol Cell Endocrinol
Vol. and No.     Letnik 301, št. 1-2
Publication year     2009
Volume     str. 47-50
Language     eng
Abstract     The 17â-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17â-HSDcl) is an NADPH-dependent member of the short-chain dehydrogenase/reductase superfamily, and it functions as a dimer that is composed of two identical subunits. By constructing the appropriate mutants, we have examined the M204 residue that is situated in the coenzyme binding pocket, for its role in the binding of the coenzyme NADP(H). We have also studied the importance of hydrophobic interactions through F124, F132, F133 and F177 for 17â-HSDcl dimer formation. The M204G substitution decreased the catalytic efficiency of 17â-HSDcl, suggesting that M204 sterically coerces the nicotinamide moiety of the coenzyme into the appropriate position for further hydride transfer. Phenylalanine substitutions introduced at the dimer interface produced inactive aggregates and oligomers with high molecular masses, suggesting that these hydrophobic interactions have important roles in the formation of the active dimer.
Descriptors     ASCOMYCETES
17-HYDROXYSTEROID DEHYDROGENASES
MUTAGENESIS, SITE-DIRECTED
COENZYMES
DIMERIZATION
BINDING SITES