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| {{STRUCTURE_2d0f| PDB=2d0f | SCENE= }} | | {{STRUCTURE_2d0f| PDB=2d0f | SCENE= }} |
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| '''Crystal Structure of Thermoactinomyces vulgaris R-47 Alpha-Amylase 1 (TVAI) Mutant D356N complexed with P2, a pullulan model oligosaccharide'''
| | ===Crystal Structure of Thermoactinomyces vulgaris R-47 Alpha-Amylase 1 (TVAI) Mutant D356N complexed with P2, a pullulan model oligosaccharide=== |
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| ==Overview==
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| Thermoactinomyces vulgaris R-47 alpha-amylase 1 (TVAI) has unique hydrolyzing activities for pullulan with sequence repeats of alpha-(1,4), alpha-(1,4), and alpha-(1,6) glycosidic linkages, as well as for starch. TVAI mainly hydrolyzes alpha-(1,4) glycosidic linkages to produce a panose, but it also hydrolyzes alpha-(1,6) glycosidic linkages with a lesser efficiency. X-ray structures of three complexes comprising an inactive mutant TVAI (D356N or D356N/E396Q) and a pullulan model oligosaccharide (P2; [Glc-alpha-(1,6)-Glc-alpha-(1,4)-Glc-alpha-(1,4)]2 or P5; [Glc-alpha-(1,6)-Glc-alpha-(1,4)-Glc-alpha-(1,4)]5) were determined. The complex D356N/P2 is a mimic of the enzyme/product complex in the main catalytic reaction of TVAI, and a structural comparison with Aspergillus oryzaealpha-amylase showed that the (-) subsites of TVAI are responsible for recognizing both starch and pullulan. D356N/E396Q/P2 and D356N/E396Q/P5 provided models of the enzyme/substrate complex recognizing the alpha-(1,6) glycosidic linkage at the hydrolyzing site. They showed that only subsites -1 and -2 at the nonreducing end of TVAI are effective in the hydrolysis of alpha-(1,6) glycosidic linkages, leading to weak interactions between substrates and the enzyme. Domain N of TVAI is a starch-binding domain acting as an anchor in the catalytic reaction of the enzyme. In this study, additional substrates were also found to bind to domain N, suggesting that domain N also functions as a pullulan-binding domain.
| | The line below this paragraph, {{ABSTRACT_PUBMED_16302977}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16302977 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_16302977}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Yoshida, H.]] | | [[Category: Yoshida, H.]] |
| [[Category: Alpha-amylase]] | | [[Category: Alpha-amylase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 23:28:15 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 11:52:24 2008'' |