This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


2ipj

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:2ipj.gif|left|200px]]
+
{{Seed}}
 +
[[Image:2ipj.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_2ipj| PDB=2ipj | SCENE= }}
{{STRUCTURE_2ipj| PDB=2ipj | SCENE= }}
-
'''Crystal structure of h3alpha-hydroxysteroid dehydrogenase type 3 mutant Y24A in complex with NADP+ and epi-testosterone'''
+
===Crystal structure of h3alpha-hydroxysteroid dehydrogenase type 3 mutant Y24A in complex with NADP+ and epi-testosterone===
-
==Overview==
+
<!--
-
The mouse 17alpha-hydroxysteroid dehydrogenase (m17alpha-HSD) is the unique known member of the aldo-keto reductase (AKR) superfamily able to catalyze efficiently and in a stereospecific manner the conversion of androstenedione (Delta4) into epi-testosterone (epi-T), the 17alpha-epimer of testosterone. Structural and mutagenic studies had already identified one of the residues delineating the steroid-binding cavity, A24, as the major molecular determinant for the stereospecificity of m17alpha-HSD. We report here a ternary complex crystal structure (m17alpha-HSD:NADP(+):epi-T) determined at 1.85 A resolution that confirms this and reveals a unique steroid-binding mode for an AKR enzyme. Indeed, in addition to the interactions found in all other AKRs (van der Waals contacts stabilizing the core of the steroid and the hydrogen bonds established at the catalytic site by the Y55 and H117 residues with the oxygen atom of the ketone group to be reduced), m17alpha-HSD establishes with the other extremity of the steroid nucleus an additional interaction involving K31. By combining direct mutagenesis and kinetic studies, we found that the elimination of this hydrogen bond did not affect the affinity of the enzyme for its steroid substrate but led to a slight but significant increase of its catalytic efficiency (k(cat)/K(m)), suggesting a role for K31 in the release of the steroidal product at the end of the reaction. This previously unobserved steroid-binding mode for an AKR is similar to that adopted by other steroid-binding proteins, the hydroxysteroid dehydrogenases of the short-chain dehydrogenases/reductases (SDR) family and the steroid hormone nuclear receptors. Mutagenesis and structural studies made on the human type 3 3alpha-HSD, a closely related enzyme that shares 73% amino acids identity with the m17alpha-HSD, also revealed that the residue at position 24 of these two enzymes directly affects the binding and/or the release of NADPH, in addition to its role in their 17alpha/17beta stereospecificity.
+
The line below this paragraph, {{ABSTRACT_PUBMED_17442338}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 17442338 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_17442338}}
==Disease==
==Disease==
Line 39: Line 43:
[[Category: Hydroxysteroid dehydrogenase]]
[[Category: Hydroxysteroid dehydrogenase]]
[[Category: Open conformation]]
[[Category: Open conformation]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:44:55 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 14:05:13 2008''

Revision as of 11:05, 29 July 2008

Image:2ipj.png

Template:STRUCTURE 2ipj

Contents

Crystal structure of h3alpha-hydroxysteroid dehydrogenase type 3 mutant Y24A in complex with NADP+ and epi-testosterone

Template:ABSTRACT PUBMED 17442338

Disease

Known disease associated with this structure: Obesity, hyperphagia, and developmental delay OMIM:[600450]

About this Structure

2IPJ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Mouse 17alpha-hydroxysteroid dehydrogenase (AKR1C21) binds steroids differently from other aldo-keto reductases: identification and characterization of amino acid residues critical for substrate binding., Faucher F, Cantin L, Pereira de Jesus-Tran K, Lemieux M, Luu-The V, Labrie F, Breton R, J Mol Biol. 2007 Jun 1;369(2):525-40. Epub 2007 Mar 27. PMID:17442338

Page seeded by OCA on Tue Jul 29 14:05:13 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/2ipj"
Personal tools