1wp6: Difference between revisions
New page: left|200px<br /><applet load="1wp6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1wp6, resolution 2.1Å" /> '''Crystal structure of ... |
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[[Image:1wp6.jpg|left|200px]]<br /><applet load="1wp6" size=" | [[Image:1wp6.jpg|left|200px]]<br /><applet load="1wp6" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1wp6, resolution 2.1Å" /> | caption="1wp6, resolution 2.1Å" /> | ||
'''Crystal structure of maltohexaose-producing amylase from alkalophilic Bacillus sp.707.'''<br /> | '''Crystal structure of maltohexaose-producing amylase from alkalophilic Bacillus sp.707.'''<br /> | ||
==Overview== | ==Overview== | ||
Maltohexaose-producing amylase, called G6-amylase (EC 3.2.1.98), from | Maltohexaose-producing amylase, called G6-amylase (EC 3.2.1.98), from alkalophilic Bacillus sp.707 predominantly produces maltohexaose (G6) from starch and related alpha-1,4-glucans. To elucidate the reaction mechanism of G6-amylase, the enzyme activities were evaluated and crystal structures were determined for the native enzyme and its complex with pseudo-maltononaose at 2.1 and 1.9 A resolutions, respectively. The optimal condition for starch-degrading reaction activity was found at 45 degrees C and pH 8.8, and the enzyme produced G6 in a yield of more than 30% of the total products from short-chain amylose (DP = 17). The crystal structures revealed that Asp236 is a nucleophilic catalyst and Glu266 is a proton donor/acceptor. Pseudo-maltononaose occupies subsites -6 to +3 and induces the conformational change of Glu266 and Asp333 to form a salt linkage with the N-glycosidic amino group and a hydrogen bond with secondary hydroxyl groups of the cyclitol residue bound to subsite -1, respectively. The indole moiety of Trp140 is stacked on the cyclitol and 4-amino-6-deoxyglucose residues located at subsites -6 and -5 within a 4 A distance. Such a face-to-face short contact may regulate the disposition of the glucosyl residue at subsite -6 and would govern the product specificity for G6 production. | ||
==About this Structure== | ==About this Structure== | ||
1WP6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_sp. Bacillus sp.] with CA, NA, PO4 and TRS as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glucan_1,4-alpha-maltohexaosidase Glucan 1,4-alpha-maltohexaosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.98 3.2.1.98] Full crystallographic information is available from [http:// | 1WP6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_sp. Bacillus sp.] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=TRS:'>TRS</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glucan_1,4-alpha-maltohexaosidase Glucan 1,4-alpha-maltohexaosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.98 3.2.1.98] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WP6 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: maltohexaose]] | [[Category: maltohexaose]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:46:45 2008'' | ||
Revision as of 16:46, 21 February 2008
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Crystal structure of maltohexaose-producing amylase from alkalophilic Bacillus sp.707.
OverviewOverview
Maltohexaose-producing amylase, called G6-amylase (EC 3.2.1.98), from alkalophilic Bacillus sp.707 predominantly produces maltohexaose (G6) from starch and related alpha-1,4-glucans. To elucidate the reaction mechanism of G6-amylase, the enzyme activities were evaluated and crystal structures were determined for the native enzyme and its complex with pseudo-maltononaose at 2.1 and 1.9 A resolutions, respectively. The optimal condition for starch-degrading reaction activity was found at 45 degrees C and pH 8.8, and the enzyme produced G6 in a yield of more than 30% of the total products from short-chain amylose (DP = 17). The crystal structures revealed that Asp236 is a nucleophilic catalyst and Glu266 is a proton donor/acceptor. Pseudo-maltononaose occupies subsites -6 to +3 and induces the conformational change of Glu266 and Asp333 to form a salt linkage with the N-glycosidic amino group and a hydrogen bond with secondary hydroxyl groups of the cyclitol residue bound to subsite -1, respectively. The indole moiety of Trp140 is stacked on the cyclitol and 4-amino-6-deoxyglucose residues located at subsites -6 and -5 within a 4 A distance. Such a face-to-face short contact may regulate the disposition of the glucosyl residue at subsite -6 and would govern the product specificity for G6 production.
About this StructureAbout this Structure
1WP6 is a Single protein structure of sequence from Bacillus sp. with , , and as ligands. Active as Glucan 1,4-alpha-maltohexaosidase, with EC number 3.2.1.98 Full crystallographic information is available from OCA.
ReferenceReference
Biochemical and crystallographic analyses of maltohexaose-producing amylase from alkalophilic Bacillus sp. 707., Kanai R, Haga K, Akiba T, Yamane K, Harata K, Biochemistry. 2004 Nov 9;43(44):14047-56. PMID:15518553
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