1qjg: Difference between revisions

Revision as of 10:21, 29 July 2008

This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.

File:1qjg.png

Template:STRUCTURE 1qjg

CRYSTAL STRUCTURE OF DELTA5-3-KETOSTEROID ISOMERASE FROM PSEUDOMONAS TESTOSTERONI IN COMPLEX WITH EQUILENINCRYSTAL STRUCTURE OF DELTA5-3-KETOSTEROID ISOMERASE FROM PSEUDOMONAS TESTOSTERONI IN COMPLEX WITH EQUILENIN

Template:ABSTRACT PUBMED 10551849

About this StructureAbout this Structure

1QJG is a Single protein structure of sequence from Comamonas testosteroni. Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure of delta(5)-3-ketosteroid isomerase from Pseudomonas testosteroni in complex with equilenin settles the correct hydrogen bonding scheme for transition state stabilization., Cho HS, Ha NC, Choi G, Kim HJ, Lee D, Oh KS, Kim KS, Lee W, Choi KY, Oh BH, J Biol Chem. 1999 Nov 12;274(46):32863-8. PMID:10551849

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Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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-'''CRYSTAL STRUCTURE OF DELTA5-3-KETOSTEROID ISOMERASE FROM PSEUDOMONAS TESTOSTERONI IN COMPLEX WITH EQUILENIN'''
+===CRYSTAL STRUCTURE OF DELTA5-3-KETOSTEROID ISOMERASE FROM PSEUDOMONAS TESTOSTERONI IN COMPLEX WITH EQUILENIN===
-==Overview==
+<!--
-Delta(5)-3-Ketosteroid isomerase from Pseudomonas testosteroni has been intensively studied as a prototype to understand an enzyme-catalyzed allylic isomerization. Asp(38) (pK(a) approximately 4.7) was identified as the general base abstracting the steroid C4beta proton (pK(a) approximately 12.7) to form a dienolate intermediate. A key and common enigmatic issue involved in the proton abstraction is the question of how the energy required for the unfavorable proton transfer can be provided at the active site of the enzyme and/or how the thermodynamic barrier can be drastically reduced. Answering this question has been hindered by the existence of two differently proposed enzyme reaction mechanisms. The 2.26 A crystal structure of the enzyme in complex with a reaction intermediate analogue equilenin reveals clearly that both the Tyr(14) OH and Asp(99) COOH provide direct hydrogen bonds to the oxyanion of equilenin. The result negates the catalytic dyad mechanism in which Asp(99) donates the hydrogen bond to Tyr(14), which in turn is hydrogen bonded to the steroid. A theoretical calculation also favors the doubly hydrogen-bonded system over the dyad system. Proton nuclear magnetic resonance analyses of several mutant enzymes indicate that the Tyr(14) OH forms a low barrier hydrogen bond with the dienolic oxyanion of the intermediate.
+The line below this paragraph, {{ABSTRACT_PUBMED_10551849}}, adds the Publication Abstract to the page
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+{{ABSTRACT_PUBMED_10551849}}
 ==About this Structure==
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 [[Category: Ksi]]
 [[Category: Steroid isomeration]]
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