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| [[Image:1lnd.jpg|left|200px]]<br /><applet load="1lnd" size="350" color="white" frame="true" align="right" spinBox="true"
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| caption="1lnd, resolution 1.70Å" />
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| '''A STRUCTURAL ANALYSIS OF METAL SUBSTITUTIONS IN THERMOLYSIN'''<br />
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| ==Overview== | | ==A STRUCTURAL ANALYSIS OF METAL SUBSTITUTIONS IN THERMOLYSIN== |
| Native thermolysin binds a single catalytically essential zinc ion that is tetrahedrally coordinated by three protein ligands and a water molecule. During catalysis the zinc ligation is thought to change from fourfold to fivefold. Substitution of the active-site zinc with Cd2+, Mn2+, Fe2+, and Co2+ alters the catalytic activity (Holmquist B, Vallee BL, 1974, J Biol Chem 249:4601-4607). Excess zinc inhibits the enzyme. To investigate the structural basis of these changes in activity, we have determined the structures of a series of metal-substituted thermolysins at 1.7-1.9 A resolution. The structure of the Co(2+)-substituted enzyme is shown to be very similar to that of wild type except that two solvent molecules are liganded to the metal at positions that are thought to be occupied by the two oxygens of the hydrated scissile peptide in the transition state. Thus, the enhanced activity toward some substrates of the cobalt-relative to the zinc-substituted enzyme may be due to enhanced stabilization of the transition state. The ability of Zn2+ and Co2+ to accept tetrahedral coordination in the Michaelis complex, as well as fivefold coordination in the transition state, may also contribute to their effectiveness in catalysis. The Cd(2+)- and Mn(2+)-substituted thermolysins display conformational changes that disrupt the active site to varying degrees and could explain the associated reduction of activity. The conformational changes involve not only the essential catalytic residue, Glu 143, but also concerted side-chain rotations in the adjacent residues Met 120 and Leu 144. Some of these side-chain movements are similar to adjustments that have been observed previously in association with the "hinge-bending" motion that is presumed to occur during catalysis by the zinc endoproteases. In the presence of excess zinc, a second zinc ion is observed to bind at His 231 within 3.2 A of the zinc bound to native thermolysin, explaining the inhibitory effect.
| | <StructureSection load='1lnd' size='340' side='right'caption='[[1lnd]], [[Resolution|resolution]] 1.70Å' scene=''> |
| | == Structural highlights == |
| | <table><tr><td colspan='2'>[[1lnd]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_thermoproteolyticus Bacillus thermoproteolyticus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LND OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LND 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]] 1.7Å</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=DMS:DIMETHYL+SULFOXIDE'>DMS</scene>, <scene name='pdbligand=LYS:LYSINE'>LYS</scene>, <scene name='pdbligand=VAL:VALINE'>VAL</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'>[https://proteopedia.org/fgij/fg.htm?mol=1lnd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lnd OCA], [https://pdbe.org/1lnd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1lnd RCSB], [https://www.ebi.ac.uk/pdbsum/1lnd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1lnd ProSAT]</span></td></tr> |
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/THER_BACTH THER_BACTH] Extracellular zinc metalloprotease. |
| | == 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/ln/1lnd_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=1lnd ConSurf]. |
| | <div style="clear:both"></div> |
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| ==About this Structure== | | ==See Also== |
| 1LND is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=DMS:'>DMS</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Thermolysin Thermolysin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.24.27 3.4.24.27] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LND OCA].
| | *[[Thermolysin 3D structures|Thermolysin 3D structures]] |
| | | __TOC__ |
| ==Reference==
| | </StructureSection> |
| Structural analysis of zinc substitutions in the active site of thermolysin., Holland DR, Hausrath AC, Juers D, Matthews BW, Protein Sci. 1995 Oct;4(10):1955-65. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8535232 8535232]
| | [[Category: Bacillus thermoproteolyticus]] |
| [[Category: Single protein]] | | [[Category: Large Structures]] |
| [[Category: Thermolysin]] | | [[Category: Hausrath AC]] |
| [[Category: Hausrath, A C.]] | | [[Category: Holland DR]] |
| [[Category: Holland, D R.]] | | [[Category: Juers D]] |
| [[Category: Juers, D.]] | | [[Category: Matthews BW]] |
| [[Category: Matthews, B W.]] | |
| [[Category: CA]]
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| [[Category: DMS]]
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| [[Category: ZN]]
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| [[Category: hydrolase (metalloprotease)]]
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| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:46:31 2008''
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