1byf: Difference between revisions
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==STRUCTURE OF TC14; A C-TYPE LECTIN FROM THE TUNICATE POLYANDROCARPA MISAKIENSIS== | ==STRUCTURE OF TC14; A C-TYPE LECTIN FROM THE TUNICATE POLYANDROCARPA MISAKIENSIS== | ||
<StructureSection load='1byf' size='340' side='right' caption='[[1byf]], [[Resolution|resolution]] 2.00Å' scene=''> | <StructureSection load='1byf' size='340' side='right' caption='[[1byf]], [[Resolution|resolution]] 2.00Å' scene=''> | ||
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<table><tr><td colspan='2'>[[1byf]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Polmi Polmi]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BYF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1BYF FirstGlance]. <br> | <table><tr><td colspan='2'>[[1byf]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Polmi Polmi]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BYF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1BYF FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1byf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1byf OCA], [http://pdbe.org/1byf PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1byf RCSB], [http://www.ebi.ac.uk/pdbsum/1byf PDBsum]</span></td></tr> | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1byf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1byf OCA], [http://pdbe.org/1byf PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1byf RCSB], [http://www.ebi.ac.uk/pdbsum/1byf PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1byf ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == Function == | ||
Revision as of 11:16, 29 November 2017
STRUCTURE OF TC14; A C-TYPE LECTIN FROM THE TUNICATE POLYANDROCARPA MISAKIENSISSTRUCTURE OF TC14; A C-TYPE LECTIN FROM THE TUNICATE POLYANDROCARPA MISAKIENSIS
Structural highlights
Function[LECC_POLMI] Role in the defense system of the organism against microorganisms. This calcium-binding lectin binds galactose. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedC-type lectins are calcium-dependent carbohydrate-recognising proteins. Isothermal titration calorimetry of the C-type Polyandrocarpa lectin (TC14) from the tunicate Polyandrocarpa misakiensis revealed the presence of a single calcium atom per monomer with a dissociation constant of 2.6 microM, and confirmed the specificity of TC14 for D -galactose and related monosaccharides. We have determined the 2.2 A X-ray crystal structure of Polyandrocarpa lectin complexed with D -galactose. Analytical ultracentrifugation revealed that TC14 behaves as a dimer in solution. This is reflected by the presence of two molecules in the asymmetric unit with the dimeric interface formed by antiparallel pairing of the two N-terminal beta-strands and hydrophobic interactions. TC14 adopts a typical C-type lectin fold with differences in structure from other C-type lectins mainly in the diverse loop regions and in the second alpha-helix, which is involved in the formation of the dimeric interface. The D -galactose is bound through coordination of the 3 and 4-hydroxyl oxygen atoms with a bound calcium atom. Additional hydrogen bonds are formed directly between serine, aspartate and glutamate side-chains of the protein and the sugar 3 and 4-hydroxyl groups. Comparison of the galactose binding by TC14 with the mannose binding by rat mannose-binding protein reveals how monosaccharide specificity is achieved in this lectin. A tryptophan side-chain close to the binding site and the distribution of hydrogen-bond acceptors and donors around the 3 and 4-hydroxyl groups of the sugar are essential determinants of specificity. These elements are, however, arranged in a very different way than in an engineered galactose-specific mutant of MBPA. Possible biological functions can more easily be understood from the fact that TC14 is a dimer under physiological conditions. The structure of a tunicate C-type lectin from Polyandrocarpa misakiensis complexed with D -galactose.,Poget SF, Legge GB, Proctor MR, Butler PJ, Bycroft M, Williams RL J Mol Biol. 1999 Jul 23;290(4):867-79. PMID:10398588[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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