1tcm
From Proteopedia
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| - | [[Image:1tcm.jpg|left|200px]]<br /><applet load="1tcm" size=" | + | [[Image:1tcm.jpg|left|200px]]<br /><applet load="1tcm" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1tcm, resolution 2.2Å" /> | caption="1tcm, resolution 2.2Å" /> | ||
'''CYCLODEXTRIN GLYCOSYLTRANSFERASE W616A MUTANT FROM BACILLUS CIRCULANS STRAIN 251'''<br /> | '''CYCLODEXTRIN GLYCOSYLTRANSFERASE W616A MUTANT FROM BACILLUS CIRCULANS STRAIN 251'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1TCM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cyclomaltodextrin_glucanotransferase Cyclomaltodextrin glucanotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.19 2.4.1.19] Known structural/functional Sites: <scene name='pdbsite=CA1:1st Ca Binding Site'>CA1</scene>, <scene name='pdbsite=CA2:2nd Ca Binding Site'>CA2</scene>, <scene name='pdbsite=CA3:1st Ca Binding Site'>CA3</scene>, <scene name='pdbsite=CA4:2nd Ca Binding Site'>CA4</scene>, <scene name='pdbsite=CT1:Catalytic Site'>CT1</scene>, <scene name='pdbsite=CT2:Catalytic Site'>CT2</scene>, <scene name='pdbsite=MB1:1st Maltose Binding Site. Site Mb1 Also Includes Residue ...'>MB1</scene>, <scene name='pdbsite=MB2:2nd Maltose Binding Site'>MB2</scene>, <scene name='pdbsite=MB3:3rd Maltose Binding Site. Site Mb3 Also Includes Residue ...'>MB3</scene>, <scene name='pdbsite=MB4:1st Maltose Binding Site'>MB4</scene>, <scene name='pdbsite=MB5:2nd Maltose Binding Site'>MB5</scene> and <scene name='pdbsite=MB6:3rd Maltose Binding Site, # - Denotes Symmetry-Related M ...'>MB6</scene>. Full crystallographic information is available from [http:// | + | 1TCM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cyclomaltodextrin_glucanotransferase Cyclomaltodextrin glucanotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.19 2.4.1.19] Known structural/functional Sites: <scene name='pdbsite=CA1:1st+Ca+Binding+Site'>CA1</scene>, <scene name='pdbsite=CA2:2nd+Ca+Binding+Site'>CA2</scene>, <scene name='pdbsite=CA3:1st+Ca+Binding+Site'>CA3</scene>, <scene name='pdbsite=CA4:2nd+Ca+Binding+Site'>CA4</scene>, <scene name='pdbsite=CT1:Catalytic+Site'>CT1</scene>, <scene name='pdbsite=CT2:Catalytic+Site'>CT2</scene>, <scene name='pdbsite=MB1:1st+Maltose+Binding+Site.+Site+Mb1+Also+Includes+Residue+...'>MB1</scene>, <scene name='pdbsite=MB2:2nd+Maltose+Binding+Site'>MB2</scene>, <scene name='pdbsite=MB3:3rd+Maltose+Binding+Site.+Site+Mb3+Also+Includes+Residue+...'>MB3</scene>, <scene name='pdbsite=MB4:1st+Maltose+Binding+Site'>MB4</scene>, <scene name='pdbsite=MB5:2nd+Maltose+Binding+Site'>MB5</scene> and <scene name='pdbsite=MB6:3rd+Maltose+Binding+Site,+#+-+Denotes+Symmetry-Related+M+...'>MB6</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TCM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 10:02:22 2008'' |
Revision as of 08:02, 3 February 2008
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CYCLODEXTRIN GLYCOSYLTRANSFERASE W616A MUTANT FROM BACILLUS CIRCULANS STRAIN 251
Overview
The E-domain of cyclodextrin glycosyltransferase (CGTase) (EC 2.4.1.19), from Bacillus circulans strain 251 is a putative raw starch binding, domain. Analysis of the maltose-dependent CGTase crystal structure, revealed that each enzyme molecule contained three maltose molecules, situated at contact points between protein molecules. Two of these, maltoses were bound to specific sites in the E-domain, the third maltose, was bound at the C-domain. To delineate the roles in raw starch binding, and cyclization reaction kinetics of the two maltose binding sites in the, E-domain, we replaced Trp-616 and Trp-662 of maltose binding site 1 and, Tyr-633 of maltose binding site 2 by alanines using site-directed, mutagenesis. Purified mutant CGTases were characterized with respect to, raw starch binding and cyclization reaction kinetics on both soluble and, raw starch. The results show that maltose binding site 1 is most important, for raw starch binding, whereas maltose binding site 2 is involved in, guiding linear starch chains into the active site. beta-Cyclodextrin, causes product inhibition by interfering with catalysis in the active site, and the function of maltose binding site 2 in the E-domain. CGTase mutants, in the E-domain maltose binding site 1 could no longer be crystallized as, maltose-dependent monomers. Instead, the W616A mutant CGTase protein was, successfully crystallized as a carbohydrate-independent dimer; its, structure has been refined to 2.2 A resolution. The three-dimensional, structure shows that, within the error limits, neither the absence of, carbohydrates nor the W616A mutation caused significant further, conformational changes. The modified starch binding and cyclization, kinetic properties observed with the mutant CGTase proteins thus can be, directly related to the amino acid replacements.
About this Structure
1TCM is a Single protein structure of sequence from Bacillus circulans with as ligand. Active as Cyclomaltodextrin glucanotransferase, with EC number 2.4.1.19 Known structural/functional Sites: , , , , , , , , , , and . Full crystallographic information is available from OCA.
Reference
The raw starch binding domain of cyclodextrin glycosyltransferase from Bacillus circulans strain 251., Penninga D, van der Veen BA, Knegtel RM, van Hijum SA, Rozeboom HJ, Kalk KH, Dijkstra BW, Dijkhuizen L, J Biol Chem. 1996 Dec 20;271(51):32777-84. PMID:8955113
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