1dyp
From Proteopedia
(New page: 200px<br /><applet load="1dyp" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dyp, resolution 1.54Å" /> '''1,3-ALPHA-1,4-BETA-D...) |
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- | [[Image:1dyp.gif|left|200px]]<br /><applet load="1dyp" size=" | + | [[Image:1dyp.gif|left|200px]]<br /><applet load="1dyp" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1dyp, resolution 1.54Å" /> | caption="1dyp, resolution 1.54Å" /> | ||
'''1,3-ALPHA-1,4-BETA-D-GALACTOSE-4-SULFATE-3,6-ANHYDRO-D-GALACTOSE 4 GALACTOHYDROLASE'''<br /> | '''1,3-ALPHA-1,4-BETA-D-GALACTOSE-4-SULFATE-3,6-ANHYDRO-D-GALACTOSE 4 GALACTOHYDROLASE'''<br /> | ||
==Overview== | ==Overview== | ||
- | BACKGROUND: kappa-carrageenans are gel-forming, sulfated | + | BACKGROUND: kappa-carrageenans are gel-forming, sulfated 1,3-alpha-1,4-beta-galactans from the cell walls of marine red algae. The kappa-carrageenase from the marine, gram-negative bacterium Pseudoalteromonas carrageenovora degrades kappa-carrageenan both in solution and in solid state by an endoprocessive mechanism. This beta-galactanase belongs to the clan-B of glycoside hydrolases. RESULTS: The structure of P. carrageenovora kappa-carrageenase has been solved to 1.54 A resolution by the multiwavelength anomalous diffraction (MAD) method, using a seleno-methionine-substituted form of the enzyme. The enzyme folds into a curved beta sandwich, with a tunnel-like active site cavity. Another remarkable characteristic is the presence of an arginine residue at subsite -1. CONCLUSIONS: The crystal structure of P. carrageenovora kappa-carrageenase is the first three-dimensional structure of a carrageenase. Its tunnel-shaped active site, the first to be reported for enzymes other than cellulases, suggests that such tunnels are associated with the degradation of solid polysaccharides. Clan-B glycoside hydrolases fall into two subgroups, one with catalytic machinery held by an ancestral beta bulge, and the other in which it is held by a regular beta strand. At subsite -1, all of these hydrolases exhibit an aromatic amino acid that interacts with the hexopyranose ring of the monosaccharide undergoing catalysis. In addition, in kappa-carrageenases, an arginine residue recognizes the sulfate-ester substituents of the beta-linked kappa-carrageenan monomers. It also appears that, in addition to the nucleophile and acid/base catalysts, two other amino acids are involved with the catalytic cycle, accelerating the deglycosylation step. |
==About this Structure== | ==About this Structure== | ||
- | 1DYP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudoalteromonas_carrageenovora Pseudoalteromonas carrageenovora] with CD and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Kappa-carrageenase Kappa-carrageenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.83 3.2.1.83] Full crystallographic information is available from [http:// | + | 1DYP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudoalteromonas_carrageenovora Pseudoalteromonas carrageenovora] with <scene name='pdbligand=CD:'>CD</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Kappa-carrageenase Kappa-carrageenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.83 3.2.1.83] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DYP OCA]. |
==Reference== | ==Reference== | ||
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[[Category: kappa-carrageenan double helix degradation]] | [[Category: kappa-carrageenan double helix degradation]] | ||
- | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:21:57 2008'' |
Revision as of 10:21, 21 February 2008
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1,3-ALPHA-1,4-BETA-D-GALACTOSE-4-SULFATE-3,6-ANHYDRO-D-GALACTOSE 4 GALACTOHYDROLASE
Overview
BACKGROUND: kappa-carrageenans are gel-forming, sulfated 1,3-alpha-1,4-beta-galactans from the cell walls of marine red algae. The kappa-carrageenase from the marine, gram-negative bacterium Pseudoalteromonas carrageenovora degrades kappa-carrageenan both in solution and in solid state by an endoprocessive mechanism. This beta-galactanase belongs to the clan-B of glycoside hydrolases. RESULTS: The structure of P. carrageenovora kappa-carrageenase has been solved to 1.54 A resolution by the multiwavelength anomalous diffraction (MAD) method, using a seleno-methionine-substituted form of the enzyme. The enzyme folds into a curved beta sandwich, with a tunnel-like active site cavity. Another remarkable characteristic is the presence of an arginine residue at subsite -1. CONCLUSIONS: The crystal structure of P. carrageenovora kappa-carrageenase is the first three-dimensional structure of a carrageenase. Its tunnel-shaped active site, the first to be reported for enzymes other than cellulases, suggests that such tunnels are associated with the degradation of solid polysaccharides. Clan-B glycoside hydrolases fall into two subgroups, one with catalytic machinery held by an ancestral beta bulge, and the other in which it is held by a regular beta strand. At subsite -1, all of these hydrolases exhibit an aromatic amino acid that interacts with the hexopyranose ring of the monosaccharide undergoing catalysis. In addition, in kappa-carrageenases, an arginine residue recognizes the sulfate-ester substituents of the beta-linked kappa-carrageenan monomers. It also appears that, in addition to the nucleophile and acid/base catalysts, two other amino acids are involved with the catalytic cycle, accelerating the deglycosylation step.
About this Structure
1DYP is a Single protein structure of sequence from Pseudoalteromonas carrageenovora with and as ligands. Active as Kappa-carrageenase, with EC number 3.2.1.83 Full crystallographic information is available from OCA.
Reference
The kappa-carrageenase of P. carrageenovora features a tunnel-shaped active site: a novel insight in the evolution of Clan-B glycoside hydrolases., Michel G, Chantalat L, Duee E, Barbeyron T, Henrissat B, Kloareg B, Dideberg O, Structure. 2001 Jun;9(6):513-25. PMID:11435116
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