Linked Life Data

12899831

Source:http://linkedlifedata.com/resource/pubmed/id/12899831

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-8-5
pubmed:abstractText
Human 20alpha-hydroxysteroid dehydrogenase (h20alpha-HSD; AKR1C1) catalyzes the transformation of progesterone (Prog) into 20alpha-hydroxy-progesterone (20alpha-OHProg). Although h20alpha-HSD shares 98% sequence identity with human type 3 3alpha-HSD (h3alpha-HSD3, AKR1C2), these two enzymes differ greatly in their activities. In order to explain these differences, we have solved the crystal structure of h20alpha-HSD in a ternary complex with NADP(+) and 20alpha-OHProg at 1.59A resolution. The steroid is stabilized by numerous hydrophobic interactions and a hydrogen bond between its O20 and the N(epsilon ) atom of His222. This new interaction prevents the formation of a hydrogen bond with the cofactor, as seen in h3alpha-HSD3 ternary complexes. By combining structural, direct mutagenesis and kinetic studies, we found that the H(222)I substitution decreases the K(m) value for the cofactor 95-fold. With these results, we hypothesize that the rotation of the lateral chain of His222 could be a mediating step between the transformation of Prog and the release of the cofactor. Moreover, crystal structure analysis and direct mutagenesis experiments lead us to identify a new residue involved in the binding of Prog. Indeed, the R(304)L substitution leads to a 65-fold decrease in the K(m) value for Prog reduction. We thus propose that Prog is maintained in a new steroid-binding site composed mainly of residues found in the carboxy-terminal region of the protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
331
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
593-604
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:12899831-20-Hydroxysteroid Dehydrogenases, pubmed-meshheading:12899831-20-alpha-Hydroxysteroid Dehydrogenase, pubmed-meshheading:12899831-Arginine, pubmed-meshheading:12899831-Binding Sites, pubmed-meshheading:12899831-Crystallization, pubmed-meshheading:12899831-Histidine, pubmed-meshheading:12899831-Humans, pubmed-meshheading:12899831-Hydrogen Bonding, pubmed-meshheading:12899831-Hydrophobic and Hydrophilic Interactions, pubmed-meshheading:12899831-Kinetics, pubmed-meshheading:12899831-Leucine, pubmed-meshheading:12899831-Ligands, pubmed-meshheading:12899831-Models, Molecular, pubmed-meshheading:12899831-Mutagenesis, Site-Directed, pubmed-meshheading:12899831-NADP, pubmed-meshheading:12899831-Progesterone, pubmed-meshheading:12899831-Protein Conformation, pubmed-meshheading:12899831-Rotation, pubmed-meshheading:12899831-Stereoisomerism, pubmed-meshheading:12899831-Steroids, pubmed-meshheading:12899831-Substrate Specificity, pubmed-meshheading:12899831-X-Ray Diffraction
pubmed:year
2003
pubmed:articleTitle
Human 20alpha-hydroxysteroid dehydrogenase: crystallographic and site-directed mutagenesis studies lead to the identification of an alternative binding site for C21-steroids.
pubmed:affiliation
Oncology and Molecular Endocrinology Research Center, Laval University Medical Center (CHUL) 2705 boul. Laurier, Ste-Foy, Qc., Canada G1V 4G2.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't