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| [[Image:1qho.jpg|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1qho| PDB=1qho | SCENE= }} | | {{STRUCTURE_1qho| PDB=1qho | SCENE= }} |
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| '''FIVE-DOMAIN ALPHA-AMYLASE FROM BACILLUS STEAROTHERMOPHILUS, MALTOSE/ACARBOSE COMPLEX'''
| | ===FIVE-DOMAIN ALPHA-AMYLASE FROM BACILLUS STEAROTHERMOPHILUS, MALTOSE/ACARBOSE COMPLEX=== |
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| ==Overview==
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| The three-dimensional structure of the Bacillus stearothermophilus "maltogenic" alpha-amylase, Novamyl, has been determined by X-ray crystallography at a resolution of 1.7 A. Unlike conventional alpha-amylases from glycoside hydrolase family 13, Novamyl exhibits the five-domain structure more usually associated with cyclodextrin glycosyltransferase. Complexes of the enzyme with both maltose and the inhibitor acarbose have been characterized. In the maltose complex, two molecules of maltose are found in the -1 to -2 and +2 to +3 subsites of the active site, with two more on the C and E domains. The C-domain maltose occupies a position identical to one previously observed in the Bacillus circulans CGTase structure [Lawson, C. L., et al. (1994) J. Mol. Biol. 236, 590-600], suggesting that the C-domain plays a genuine biological role in saccharide binding. In the acarbose-maltose complex, the tetrasaccharide inhibitor acarbose is found as an extended hexasaccharide species, bound in the -3 to +3 subsites. The transition state mimicking pseudosaccharide is bound in the -1 subsite of the enzyme in a 2H3 half-chair conformation, as expected. The active site of Novamyl lies in an open gully, fully consistent with its ability to perform internal cleavage via an endo as opposed to an exo activity. | | The line below this paragraph, {{ABSTRACT_PUBMED_10387084}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10387084 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10387084}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Glycoside hydrolase]] | | [[Category: Glycoside hydrolase]] |
| [[Category: Starch degradation]] | | [[Category: Starch degradation]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:17:06 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 19:38:00 2008'' |
