This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1ktw
From Proteopedia
(Difference between revisions)
| (14 intermediate revisions not shown.) | |||
| Line 1: | Line 1: | ||
| - | [[Image:1ktw.gif|left|200px]]<br /><applet load="1ktw" size="350" color="white" frame="true" align="right" spinBox="true" | ||
| - | caption="1ktw, resolution 2.00Å" /> | ||
| - | '''IOTA-CARRAGEENASE COMPLEXED TO IOTA-CARRAGEENAN FRAGMENTS'''<br /> | ||
| - | == | + | ==IOTA-CARRAGEENASE COMPLEXED TO IOTA-CARRAGEENAN FRAGMENTS== |
| + | <StructureSection load='1ktw' size='340' side='right'caption='[[1ktw]], [[Resolution|resolution]] 2.00Å' scene=''> | ||
| + | == Structural highlights == | ||
| + | <table><tr><td colspan='2'>[[1ktw]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Alteromonas_macleodii Alteromonas macleodii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KTW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KTW FirstGlance]. <br> | ||
| + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2Å</td></tr> | ||
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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:4-O-SULFO-BETA-D-GALACTOPYRANOSE'>G4S</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr> | ||
| + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1ktw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ktw OCA], [https://pdbe.org/1ktw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ktw RCSB], [https://www.ebi.ac.uk/pdbsum/1ktw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ktw ProSAT]</span></td></tr> | ||
| + | </table> | ||
| + | == Function == | ||
| + | [https://www.uniprot.org/uniprot/CGIA_ALTMA CGIA_ALTMA] Hydrolyzes iota-carrageenans, sulfated 1,3-alpha-1,4-beta galactans from red algal cell walls, with an inversion of anomeric configuration. Also active against hybrid iota-/nu-carrageenan, not active against kappa- or lambda-carrageenans.[UniProtKB:Q9F284]<ref>PMID:10934194</ref> <ref>PMID:20227066</ref> | ||
| + | == Evolutionary Conservation == | ||
| + | [[Image:Consurf_key_small.gif|200px|right]] | ||
| + | Check<jmol> | ||
| + | <jmolCheckbox> | ||
| + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/kt/1ktw_consurf.spt"</scriptWhenChecked> | ||
| + | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | ||
| + | <text>to colour the structure by Evolutionary Conservation</text> | ||
| + | </jmolCheckbox> | ||
| + | </jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1ktw ConSurf]. | ||
| + | <div style="clear:both"></div> | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
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. | 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. | ||
| - | + | 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<ref>PMID:14623184</ref> | |
| - | + | ||
| - | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |
| - | + | </div> | |
| - | [[Category: Alteromonas | + | <div class="pdbe-citations 1ktw" style="background-color:#fffaf0;"></div> |
| - | [[Category: | + | == References == |
| - | + | <references/> | |
| - | [[Category: Dideberg | + | __TOC__ |
| - | [[Category: Kahn | + | </StructureSection> |
| - | [[Category: Michel | + | [[Category: Alteromonas macleodii]] |
| - | + | [[Category: Large Structures]] | |
| - | + | [[Category: Dideberg O]] | |
| - | + | [[Category: Kahn R]] | |
| - | + | [[Category: Michel G]] | |
| - | + | ||
| - | + | ||
| - | + | ||
Current revision
IOTA-CARRAGEENASE COMPLEXED TO IOTA-CARRAGEENAN FRAGMENTS
| |||||||||||
