1ktw
From Proteopedia
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|PDB= 1ktw |SIZE=350|CAPTION= <scene name='initialview01'>1ktw</scene>, resolution 2.00Å | |PDB= 1ktw |SIZE=350|CAPTION= <scene name='initialview01'>1ktw</scene>, resolution 2.00Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=DGS:3,6-ANHYDRO-D-GALACTOSE-2-SULFATE'>DGS</scene>, <scene name='pdbligand=G4S:D-GALACTOSE-4-SULFATE+GROUP'>G4S</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Iota-carrageenase Iota-carrageenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.157 3.2.1.157] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Iota-carrageenase Iota-carrageenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.157 3.2.1.157] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1h80|1H80]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ktw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ktw OCA], [http://www.ebi.ac.uk/pdbsum/1ktw PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1ktw RCSB]</span> | ||
}} | }} | ||
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[[Category: Kahn, R.]] | [[Category: Kahn, R.]] | ||
[[Category: Michel, G.]] | [[Category: Michel, G.]] | ||
| - | [[Category: CA]] | ||
| - | [[Category: CL]] | ||
| - | [[Category: NA]] | ||
[[Category: hydrolase]] | [[Category: hydrolase]] | ||
[[Category: iota-carrageenan double helix degradation]] | [[Category: iota-carrageenan double helix degradation]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:53:32 2008'' |
Revision as of 18:53, 30 March 2008
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| , resolution 2.00Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , , , | ||||||
| Activity: | Iota-carrageenase, with EC number 3.2.1.157 | ||||||
| Related: | 1H80
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
IOTA-CARRAGEENASE COMPLEXED TO IOTA-CARRAGEENAN FRAGMENTS
Overview
iota-Carrageenans are sulfated 1,3-alpha-1,4-beta-galactans from the cell walls of red algae, which auto-associate into crystalline fibers made of aggregates of double-stranded helices. iota-Carrageenases, which constitute family 82 of glycoside hydrolases, fold into a right-handed beta-helix. Here, the structure of Alteromonas fortis iota-carrageenase bound to iota-carrageenan fragments was solved at 2.0A resolution (PDB 1KTW). The enzyme holds a iota-carrageenan tetrasaccharide (subsites +1 to +4) and a disaccharide (subsites -3, -4), thus providing the first direct determination of a 3D structure of iota-carrageenan. Electrostatic interactions between basic protein residues and the sulfate substituents of the polysaccharide chain dominate iota-carrageenan recognition. Glu245 and Asp247 are the proton donor and the base catalyst, respectively. C-terminal domain A, which was highly flexible in the native enzyme structure, adopts a alpha/beta-fold, also found in DNA/RNA-binding domains. In the substrate-enzyme complex, this polyanion-binding module shifts toward the beta-helix groove, forming a tunnel. Thus, from an open conformation which allows for the initial endo-attack of iota-carrageenan chains, the enzyme switches to a closed-tunnel form, consistent with its highly processive character, as seen from the electron-microscopy analysis of the degradation of iota-carrageenan fibers.
About this Structure
1KTW is a Single protein structure of sequence from Alteromonas sp. atcc 43554. Full crystallographic information is available from OCA.
Reference
The structural bases of the processive degradation of iota-carrageenan, a main cell wall polysaccharide of red algae., Michel G, Helbert W, Kahn R, Dideberg O, Kloareg B, J Mol Biol. 2003 Nov 28;334(3):421-33. PMID:14623184
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