1s46
From Proteopedia
(New page: 200px<br /><applet load="1s46" size="450" color="white" frame="true" align="right" spinBox="true" caption="1s46, resolution 2.20Å" /> '''Covalent intermediat...) |
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| - | [[Image:1s46.jpg|left|200px]]<br /><applet load="1s46" size=" | + | [[Image:1s46.jpg|left|200px]]<br /><applet load="1s46" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1s46, resolution 2.20Å" /> | caption="1s46, resolution 2.20Å" /> | ||
'''Covalent intermediate of the E328Q amylosucrase mutant'''<br /> | '''Covalent intermediate of the E328Q amylosucrase mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The alpha-retaining amylosucrase from the glycoside hydrolase family 13 | + | The alpha-retaining amylosucrase from the glycoside hydrolase family 13 performs a transfer reaction of a glucosyl moiety from sucrose to an acceptor molecule. Amylosucrase has previously been shown to be able to use alpha-D-glucopyranosyl fluoride as a substrate, which suggested that it could also be used for trapping the reaction intermediate for crystallographic studies. In this paper, the crystal structure of the acid/base catalyst mutant, E328Q, with a covalently bound glucopyranosyl moiety is presented. Sucrose cocrystallized crystals were soaked with alpha-D-glucopyranosyl fluoride, which resulted in the trapping of a covalent intermediate in the active site of the enzyme. The structure is refined to a resolution of 2.2 A and showed that binding of the covalent intermediate resulted in a backbone movement of 1 A around the location of the nucleophile, Asp286. This structure reveals the first covalent intermediate of an alpha-retaining glycoside hydrolase where the glucosyl moiety is identical to the expected biologically relevant entity. Comparison to other enzymes with anticipated glucosylic covalent intermediates suggests that this structure is a representative model for such intermediates. Analysis of the active site shows how oligosaccharide binding disrupts the putative nucleophilic water binding site found in the hydrolases of the GH family 13. This reveals important parts of the structural background for the shift in function from hydrolase to transglycosidase seen in amylosucrase. |
==About this Structure== | ==About this Structure== | ||
| - | 1S46 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Neisseria_polysaccharea Neisseria polysaccharea] with BGC as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Amylosucrase Amylosucrase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.4 2.4.1.4] Full crystallographic information is available from [http:// | + | 1S46 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Neisseria_polysaccharea Neisseria polysaccharea] with <scene name='pdbligand=BGC:'>BGC</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Amylosucrase Amylosucrase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.4 2.4.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1S46 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Albenne, C.]] | [[Category: Albenne, C.]] | ||
[[Category: Gajhede, M.]] | [[Category: Gajhede, M.]] | ||
| - | [[Category: Jensen, M | + | [[Category: Jensen, M H.]] |
[[Category: Mirza, O.]] | [[Category: Mirza, O.]] | ||
[[Category: Monsan, P.]] | [[Category: Monsan, P.]] | ||
[[Category: Remaud-Simeon, M.]] | [[Category: Remaud-Simeon, M.]] | ||
| - | [[Category: Skov, L | + | [[Category: Skov, L K.]] |
[[Category: BGC]] | [[Category: BGC]] | ||
[[Category: (beta/alpha)8-barrel]] | [[Category: (beta/alpha)8-barrel]] | ||
[[Category: protein-glucopyranosyl covalent intermediate]] | [[Category: protein-glucopyranosyl covalent intermediate]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:57:48 2008'' |
Revision as of 12:57, 21 February 2008
|
Covalent intermediate of the E328Q amylosucrase mutant
Overview
The alpha-retaining amylosucrase from the glycoside hydrolase family 13 performs a transfer reaction of a glucosyl moiety from sucrose to an acceptor molecule. Amylosucrase has previously been shown to be able to use alpha-D-glucopyranosyl fluoride as a substrate, which suggested that it could also be used for trapping the reaction intermediate for crystallographic studies. In this paper, the crystal structure of the acid/base catalyst mutant, E328Q, with a covalently bound glucopyranosyl moiety is presented. Sucrose cocrystallized crystals were soaked with alpha-D-glucopyranosyl fluoride, which resulted in the trapping of a covalent intermediate in the active site of the enzyme. The structure is refined to a resolution of 2.2 A and showed that binding of the covalent intermediate resulted in a backbone movement of 1 A around the location of the nucleophile, Asp286. This structure reveals the first covalent intermediate of an alpha-retaining glycoside hydrolase where the glucosyl moiety is identical to the expected biologically relevant entity. Comparison to other enzymes with anticipated glucosylic covalent intermediates suggests that this structure is a representative model for such intermediates. Analysis of the active site shows how oligosaccharide binding disrupts the putative nucleophilic water binding site found in the hydrolases of the GH family 13. This reveals important parts of the structural background for the shift in function from hydrolase to transglycosidase seen in amylosucrase.
About this Structure
1S46 is a Single protein structure of sequence from Neisseria polysaccharea with as ligand. Active as Amylosucrase, with EC number 2.4.1.4 Full crystallographic information is available from OCA.
Reference
Crystal structure of the covalent intermediate of amylosucrase from Neisseria polysaccharea., Jensen MH, Mirza O, Albenne C, Remaud-Simeon M, Monsan P, Gajhede M, Skov LK, Biochemistry. 2004 Mar 23;43(11):3104-10. PMID:15023061
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