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Article Dans Une Revue FEBS Letters Année : 2008

Multi-site substrate binding and interplay in barley alpha-amylase 1.

Résumé

Certain starch hydrolases possess secondary carbohydrate binding sites outside of the active site, suggesting that multi-site substrate interactions are functionally significant. In barley alpha-amylase both Tyr(380), situated on a remote non-catalytic domain, and Tyr(105) in subsite -6 of the active site cleft are principal carbohydrate binding residues. The dual active site/secondary site mutants Y105A/Y380A and Y105A/Y380M show that each of Tyr(380) and Tyr(105) is important, albeit not essential for binding, degradation, and multiple attack on polysaccharides, while Tyr(105) predominates in oligosaccharide hydrolysis. Additional delicate structure/function relationships of the secondary site are uncovered using Y380A/H395A, Y380A, and H395A AMY1 mutants.Certain starch hydrolases possess secondary carbohydrate binding sites outside of the active site, suggesting that multi-site substrate interactions are functionally significant. In barley alpha-amylase both Tyr(380), situated on a remote non-catalytic domain, and Tyr(105) in subsite -6 of the active site cleft are principal carbohydrate binding residues. The dual active site/secondary site mutants Y105A/Y380A and Y105A/Y380M show that each of Tyr(380) and Tyr(105) is important, albeit not essential for binding, degradation, and multiple attack on polysaccharides, while Tyr(105) predominates in oligosaccharide hydrolysis. Additional delicate structure/function relationships of the secondary site are uncovered using Y380A/H395A, Y380A, and H395A AMY1 mutants.
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Dates et versions

hal-00315255 , version 1 (27-08-2008)

Identifiants

  • HAL Id : hal-00315255 , version 1
  • PUBMED : 18588886

Citer

Mm Nielsen, Es Seo, Sophie Bozonnet, N. Aghajari, X. Robert, et al.. Multi-site substrate binding and interplay in barley alpha-amylase 1.. FEBS Letters, 2008, 582, pp.2567-2571. ⟨hal-00315255⟩
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