1qq5
From Proteopedia
(New page: 200px<br /><applet load="1qq5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qq5, resolution 1.52Å" /> '''STRUCTURE OF L-2-HAL...) |
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| - | [[Image:1qq5.gif|left|200px]]<br /><applet load="1qq5" size=" | + | [[Image:1qq5.gif|left|200px]]<br /><applet load="1qq5" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qq5, resolution 1.52Å" /> | caption="1qq5, resolution 1.52Å" /> | ||
'''STRUCTURE OF L-2-HALOACID DEHALOGENASE FROM XANTHOBACTER AUTOTROPHICUS'''<br /> | '''STRUCTURE OF L-2-HALOACID DEHALOGENASE FROM XANTHOBACTER AUTOTROPHICUS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The L-2-haloacid dehalogenase from the 1,2-dichloroethane-degrading | + | The L-2-haloacid dehalogenase from the 1,2-dichloroethane-degrading bacterium Xanthobacter autotrophicus GJ10 catalyzes the hydrolytic dehalogenation of small L-2-haloalkanoates to their corresponding D-2-hydroxyalkanoates, with inversion of the configuration at the C(2) atom. The structure of the apoenzyme at pH 8 was refined at 1.5-A resolution. By lowering the pH, the catalytic activity of the enzyme was considerably reduced, allowing the crystal structure determination of the complexes with L-2-monochloropropionate and monochloroacetate at 1.7 and 2.1 A resolution, respectively. Both complexes showed unambiguous electron density extending from the nucleophile Asp(8) to the C(2) atom of the dechlorinated substrates corresponding to a covalent enzyme-ester reaction intermediate. The halide ion that is cleaved off is found in line with the Asp(8) Odelta1-C(2) bond in a halide-stabilizing cradle made up of Arg(39), Asn(115), and Phe(175). In both complexes, the Asp(8) Odelta2 carbonyl oxygen atom interacts with Thr(12), Ser(171), and Asn(173), which possibly constitute the oxyanion hole in the hydrolysis of the ester bond. The carboxyl moiety of the substrate is held in position by interactions with Ser(114), Lys(147), and main chain NH groups. The L-2-monochloropropionate CH(3) group is located in a small pocket formed by side chain atoms of Lys(147), Asn(173), Phe(175), and Asp(176). The size and position of the pocket explain the stereospecificity and the limited substrate specificity of the enzyme. These crystallographic results demonstrate that the reaction of the enzyme proceeds via the formation of a covalent enzyme-ester intermediate at the nucleophile Asp(8). |
==About this Structure== | ==About this Structure== | ||
| - | 1QQ5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Xanthobacter_autotrophicus Xanthobacter autotrophicus] with FMT as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/(S)-2-haloacid_dehalogenase (S)-2-haloacid dehalogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.8.1.2 3.8.1.2] Full crystallographic information is available from [http:// | + | 1QQ5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Xanthobacter_autotrophicus Xanthobacter autotrophicus] with <scene name='pdbligand=FMT:'>FMT</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/(S)-2-haloacid_dehalogenase (S)-2-haloacid dehalogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.8.1.2 3.8.1.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QQ5 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Xanthobacter autotrophicus]] | [[Category: Xanthobacter autotrophicus]] | ||
| - | [[Category: Dijkstra, B | + | [[Category: Dijkstra, B W.]] |
| - | [[Category: Kalk, K | + | [[Category: Kalk, K H.]] |
| - | [[Category: Ridder, I | + | [[Category: Ridder, I S.]] |
| - | [[Category: Rozeboom, H | + | [[Category: Rozeboom, H J.]] |
[[Category: FMT]] | [[Category: FMT]] | ||
[[Category: hydrolase]] | [[Category: hydrolase]] | ||
[[Category: l-2-haloacid dehalogenase]] | [[Category: l-2-haloacid dehalogenase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:42:35 2008'' |
Revision as of 12:42, 21 February 2008
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STRUCTURE OF L-2-HALOACID DEHALOGENASE FROM XANTHOBACTER AUTOTROPHICUS
Overview
The L-2-haloacid dehalogenase from the 1,2-dichloroethane-degrading bacterium Xanthobacter autotrophicus GJ10 catalyzes the hydrolytic dehalogenation of small L-2-haloalkanoates to their corresponding D-2-hydroxyalkanoates, with inversion of the configuration at the C(2) atom. The structure of the apoenzyme at pH 8 was refined at 1.5-A resolution. By lowering the pH, the catalytic activity of the enzyme was considerably reduced, allowing the crystal structure determination of the complexes with L-2-monochloropropionate and monochloroacetate at 1.7 and 2.1 A resolution, respectively. Both complexes showed unambiguous electron density extending from the nucleophile Asp(8) to the C(2) atom of the dechlorinated substrates corresponding to a covalent enzyme-ester reaction intermediate. The halide ion that is cleaved off is found in line with the Asp(8) Odelta1-C(2) bond in a halide-stabilizing cradle made up of Arg(39), Asn(115), and Phe(175). In both complexes, the Asp(8) Odelta2 carbonyl oxygen atom interacts with Thr(12), Ser(171), and Asn(173), which possibly constitute the oxyanion hole in the hydrolysis of the ester bond. The carboxyl moiety of the substrate is held in position by interactions with Ser(114), Lys(147), and main chain NH groups. The L-2-monochloropropionate CH(3) group is located in a small pocket formed by side chain atoms of Lys(147), Asn(173), Phe(175), and Asp(176). The size and position of the pocket explain the stereospecificity and the limited substrate specificity of the enzyme. These crystallographic results demonstrate that the reaction of the enzyme proceeds via the formation of a covalent enzyme-ester intermediate at the nucleophile Asp(8).
About this Structure
1QQ5 is a Single protein structure of sequence from Xanthobacter autotrophicus with as ligand. Active as (S)-2-haloacid dehalogenase, with EC number 3.8.1.2 Full crystallographic information is available from OCA.
Reference
Crystal structures of intermediates in the dehalogenation of haloalkanoates by L-2-haloacid dehalogenase., Ridder IS, Rozeboom HJ, Kalk KH, Dijkstra BW, J Biol Chem. 1999 Oct 22;274(43):30672-8. PMID:10521454
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