VARIANT ALPHA AMYLASES WITH ENHANCED ACTIVITY ON STARCH POLYMERS

摘要

Described are variants of alpha-amylase enzymes for use in industrial processes, such as liquefaction of starch. The alpha-amylase variants have increased specific activity allowing the more rapidly reduction of peak viscosity during liquefaction processes. The alpha-amylase is modified by introducing into the amino sequence of a parent Family 13 alpha-amylase polypeptide a mutation at an amino acid residue in the starch-binding groove; wherein the starch-binding groove is formed by amino acid residues in the alpha-helix preceding the first beta-strand in the A domain, the loop between the sixth alpha-helix and the seventh beta-strand in the A domain, the loop between the seventh alpha-helix and the eighth beta-strand in the A domain, and the loop connecting the A domain and the C domain; and wherein the mutation alters the binding of starch to the variant alpha amylase polypeptide compared to the parental alpha amylase polypeptide.

主权项

1. A method for producing a variant α-amylase polypeptide, comprising:
introducing into the amino sequence of a parent Family 13 α-amylase polypeptide a mutation at an amino acid residue in the starch-binding groove; wherein the starch-binding groove is formed by amino acid residues in the α-helix preceding the first β-stand in the A domain, the loop between the sixth α-helix and the seventh β-strand in the A domain, the loop between the seventh α-helix and the eighth β-strand in the A domain, and the loop connecting the A domain and the C domain; and wherein the mutation alters the binding of starch to the variant α-amylase polypeptide compared to the parental α-amylase polypeptide.