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| - | [[Image:1vjs.gif|left|200px]]<br /><applet load="1vjs" size="350" color="white" frame="true" align="right" spinBox="true" | |
| - | caption="1vjs, resolution 1.7Å" /> | |
| - | '''STRUCTURE OF ALPHA-AMYLASE PRECURSOR'''<br /> | |
| | | | |
| - | ==Overview== | + | ==STRUCTURE OF ALPHA-AMYLASE PRECURSOR== |
| - | alpha-Amylases (alpha-1,4-glucan-4-glucanohydrolase, E.C.3.2.1.1) catalyze the cleavage of alpha-1, 4-glucosidic linkages of starch components, glycogen, and various oligosaccharides. Thermostable alpha-amylases from Bacillus species are of great industrial importance in the production of corn syrup or dextrose. Thermostable alpha-amylase from Bacillus licheniformis, a monomeric enzyme with molecular mass of 55,200 Da (483 amino acid residues), shows a remarkable heat stability. This enzyme provides an attractive model for investigating the structural basis for thermostability of proteins. The three-dimensional structure of thermostable alpha-amylase from Bacillus licheniformis has been determined by the multiple isomorphous replacement method of X-ray crystallography. The structure has been refined to a crystallographic R-factor of 19.9% for 58,601 independent reflections with F0 > 2 sigma F0 between 8.0 and 1.7 A resolution, with root mean square deviations of 0.013 A from ideal bond lengths and 1.72 degrees from ideal bond angles. The final model consists of 469 amino acid residues and 294 water molecules. Missing from the model are the N- and C-termini and the segment between Trp182 and Asn192. Like other alpha-amylases, the polypeptide chain folds into three distinct domains. The first domain (domain A), consisting of 291 residues (from residue 3 to 103 and 207 to 396), forms a (beta/alpha)8-barrel structure. The second domain (domain B), consisting of residues 104 to 206, is inserted between the third beta-strand and the third alpha-helix of domain A. The third C-terminal domain (domain C), consisting of residues 397 to 482, folds into an eight-stranded antiparallel beta-barrel. Neither calcium ion nor chloride ion is located near the active site. This study reveals the architecture of the thermostable alpha-amylase from Bacillus licheniformis. By homology with other alpha-amylases, important active site residues can be identified as Asp231, Glu261, and Asp328, which are all located at the C-terminal end of the central (beta/alpha)8-barrel. Since many of the stabilizing and destabilizing mutations obtained so far fall in domain B or at its border, this region of the enzyme appears to be important for thermostability. The factors responsible for the remarkable thermostability of this enzyme may be increased ionic interactions, reduced surface area, and increased packing interactions in the interior.
| + | <StructureSection load='1vjs' size='340' side='right'caption='[[1vjs]], [[Resolution|resolution]] 1.70Å' scene=''> |
| | + | == Structural highlights == |
| | + | <table><tr><td colspan='2'>[[1vjs]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VJS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1VJS 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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1vjs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1vjs OCA], [https://pdbe.org/1vjs PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1vjs RCSB], [https://www.ebi.ac.uk/pdbsum/1vjs PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1vjs ProSAT]</span></td></tr> |
| | + | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/AMY_BACLI AMY_BACLI] |
| | + | == 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/vj/1vjs_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=1vjs ConSurf]. |
| | + | <div style="clear:both"></div> |
| | | | |
| - | ==About this Structure== | + | ==See Also== |
| - | 1VJS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VJS OCA].
| + | *[[Amylase 3D structures|Amylase 3D structures]] |
| - | | + | __TOC__ |
| - | ==Reference==
| + | </StructureSection> |
| - | Crystal structure of thermostable alpha-amylase from Bacillus licheniformis refined at 1.7 A resolution., Hwang KY, Song HK, Chang C, Lee J, Lee SY, Kim KK, Choe S, Sweet RM, Suh SW, Mol Cells. 1997 Apr 30;7(2):251-8. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9163741 9163741]
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| - | [[Category: Alpha-amylase]]
| + | |
| | [[Category: Bacillus licheniformis]] | | [[Category: Bacillus licheniformis]] |
| - | [[Category: Single protein]] | + | [[Category: Large Structures]] |
| - | [[Category: Chang, C.]] | + | [[Category: Chang C]] |
| - | [[Category: Hwang, K Y.]] | + | [[Category: Hwang KY]] |
| - | [[Category: Song, H K.]] | + | [[Category: Song HK]] |
| - | [[Category: Suh, S W.]] | + | [[Category: Suh SW]] |
| - | [[Category: carbohydrate metabolism]]
| + | |
| - | [[Category: glycosidase]]
| + | |
| - | [[Category: hydrolase]]
| + | |
| - | | + | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:36:03 2008''
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