1qhp
From Proteopedia
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| , resolution 1.7Å | |||||||
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| Ligands: | , , | ||||||
| Activity: | Glucan 1,4-alpha-maltohydrolase, with EC number 3.2.1.133 | ||||||
| Related: | 1QHO
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
FIVE-DOMAIN ALPHA-AMYLASE FROM BACILLUS STEAROTHERMOPHILUS, MALTOSE COMPLEX
Overview
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.
About this Structure
1QHP is a Single protein structure of sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA.
Reference
X-ray structure of Novamyl, the five-domain "maltogenic" alpha-amylase from Bacillus stearothermophilus: maltose and acarbose complexes at 1.7A resolution., Dauter Z, Dauter M, Brzozowski AM, Christensen S, Borchert TV, Beier L, Wilson KS, Davies GJ, Biochemistry. 1999 Jun 29;38(26):8385-92. PMID:10387084
Page seeded by OCA on Sun Mar 30 23:13:44 2008
