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1mrq
From Proteopedia
(New page: 200px<br /> <applet load="1mrq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mrq, resolution 1.59Å" /> '''Crystal structure o...) |
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| - | [[Image:1mrq.gif|left|200px]]<br /> | + | [[Image:1mrq.gif|left|200px]]<br /><applet load="1mrq" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1mrq" size=" | + | |
caption="1mrq, resolution 1.59Å" /> | caption="1mrq, resolution 1.59Å" /> | ||
'''Crystal structure of human 20alpha-HSD in ternary complex with NADP and 20alpha-hydroxy-progesterone'''<br /> | '''Crystal structure of human 20alpha-HSD in ternary complex with NADP and 20alpha-hydroxy-progesterone'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Human 20alpha-hydroxysteroid dehydrogenase (h20alpha-HSD; AKR1C1) | + | 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. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1MRQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with NAP, STR and BME as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/20-alpha-hydroxysteroid_dehydrogenase 20-alpha-hydroxysteroid dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.149 1.1.1.149] Full crystallographic information is available from [http:// | + | 1MRQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=NAP:'>NAP</scene>, <scene name='pdbligand=STR:'>STR</scene> and <scene name='pdbligand=BME:'>BME</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/20-alpha-hydroxysteroid_dehydrogenase 20-alpha-hydroxysteroid dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.149 1.1.1.149] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MRQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Breton, R.]] | [[Category: Breton, R.]] | ||
[[Category: Cantin, L.]] | [[Category: Cantin, L.]] | ||
| - | [[Category: Couture, J | + | [[Category: Couture, J F.]] |
[[Category: Labrie, F.]] | [[Category: Labrie, F.]] | ||
[[Category: Legrand, P.]] | [[Category: Legrand, P.]] | ||
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[[Category: ternary complex]] | [[Category: ternary complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:58:22 2008'' |
Revision as of 11:58, 21 February 2008
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Crystal structure of human 20alpha-HSD in ternary complex with NADP and 20alpha-hydroxy-progesterone
Contents |
Overview
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.
Disease
Known disease associated with this structure: Obesity, hyperphagia, and developmental delay OMIM:[600450]
About this Structure
1MRQ is a Single protein structure of sequence from Homo sapiens with , and as ligands. Active as 20-alpha-hydroxysteroid dehydrogenase, with EC number 1.1.1.149 Full crystallographic information is available from OCA.
Reference
Human 20alpha-hydroxysteroid dehydrogenase: crystallographic and site-directed mutagenesis studies lead to the identification of an alternative binding site for C21-steroids., Couture JF, Legrand P, Cantin L, Luu-The V, Labrie F, Breton R, J Mol Biol. 2003 Aug 15;331(3):593-604. PMID:12899831
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