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2d3l
From Proteopedia
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| , resolution 2.30Å | |||||||
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| Ligands: | , and | ||||||
| Activity: | Glucan 1,4-alpha-maltohexaosidase, with EC number 3.2.1.98 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of maltohexaose-producing amylase from Bacillus sp.707 complexed with maltopentaose.
Overview
Maltohexaose-producing amylase (G6-amylase) from alkalophilic Bacillus sp.707 predominantly produces maltohexaose (G6) in the yield of >30% of the total products from short-chain amylose (DP=17). Our previous crystallographic study showed that G6-amylase has nine subsites, from -6 to +3, and pointed out the importance of the indole moiety of Trp140 in G6 production. G6-amylase has very low levels of hydrolytic activities for oligosaccharides shorter than maltoheptaose. To elucidate the mechanism underlying G6 production, we determined the crystal structures of the G6-amylase complexes with G6 and maltopentaose (G5). In the active site of the G6-amylase/G5 complex, G5 is bound to subsites -6 to -2, while G1 and G6 are found at subsites +2 and -7 to -2, respectively, in the G6-amylase/G6 complex. In both structures, the glucosyl residue located at subsite -6 is stacked to the indole moiety of Trp140 within a distance of 4A. The measurement of the activities of the mutant enzymes when Trp140 was replaced by leucine (W140L) or by tyrosine (W140Y) showed that the G6 production from short-chain amylose by W140L is lower than that by W140Y or wild-type enzyme. The face-to-face short contact between Trp140 and substrate sugars is suggested to regulate the disposition of the glucosyl residue at subsite -6 and to govern product specificity for G6 production.
About this Structure
2D3L is a Single protein structure of sequence from Bacillus sp.. Full crystallographic information is available from OCA.
Reference
Role of Trp140 at subsite -6 on the maltohexaose production of maltohexaose-producing amylase from alkalophilic Bacillus sp.707., Kanai R, Haga K, Akiba T, Yamane K, Harata K, Protein Sci. 2006 Mar;15(3):468-77. Epub 2006 Feb 1. PMID:16452622
Page seeded by OCA on Thu Mar 20 16:22:56 2008
