6ffb
17beta-hydroxysteroid dehydrogenase 14 variant S205 - mutant Q148A - in complex with a nonsteroidal inhibitor
Structural highlights
Function[DHB14_HUMAN] Has NAD-dependent 17-beta-hydroxysteroid dehydrogenase activity. Converts oestradiol to oestrone. The physiological substrate is not known. Acts on oestradiol and 5-androstene-3-beta,17-beta-diol (in vitro).[1] Publication Abstract from PubMed17beta-Hydroxysteroid dehydrogenase type 14 (17beta-HSD14) catalyzes the conversion of highly active estrogens and androgens into their less active oxidized forms in presence of NAD(+) as cofactor. The crystal structure of 17beta-HSD14 has been determined, however, the role of individual amino acids likely involved in the enzymatic function remains poorly understood. Objective of this study was to further characterize the enzyme by site-directed mutagenesis considering five amino acids next to the catalytic center. The tools used for the characterization of the enzyme variants are X-ray crystallography and enzyme kinetics. Lys158 was confirmed to belong to the catalytic triad. Tyr253', located on the C-terminal loop of the adjacent monomer, enters into the active site of the neighboring monomer and interacts with the catalytic Tyr154. Therefore, Tyr253' helps to tie the two monomers together. Cys255, located at the interface between both monomers, can form a disulfide bridge with the Cys255' from the adjacent monomer. In contrast to the contact provided by Tyr253, the latter interaction is not crucial for dimer formation. His93 and Gln148 are located at the rim of the substrate binding pocket. His93 does not interact directly with the ligand in the active site. However, it influences the turnover of the enzyme. The Gln148 restricts in size the access tunnel of the substrate to the binding pocket. Mutational and structural studies uncover crucial amino acids determining activity and stability of 17beta-HSD14.,Badran MJ, Bertoletti N, Keils A, Heine A, Klebe G, Marchais-Oberwinkler S J Steroid Biochem Mol Biol. 2019 May;189:135-144. doi:, 10.1016/j.jsbmb.2019.02.009. Epub 2019 Mar 2. PMID:30836176[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
