Glucoamylase variants

摘要

The present invention relates to glucoamylase variants. In particular, the invention relates to variants in the starch binding domain (SBD) of a glucoamylase. The invention also relates to variants having altered properties (e.g., improved thermostability and/or increased specific activity) as compared to a corresponding parent glucoamylase. The present invention also provides enzyme compositions comprising the variant glucoamylases; DNA constructs comprising polynucleotides encoding the variants; and methods of producing the glucoamylase variants in host cells.

主权项

1. An isolated glucoamylase variant comprising a catalytic domain and a starch binding domain (SBD), a) said catalytic domain comprising at least 90% sequence identity to the amino acid sequence of SEQ ID NO:3 and b) said SBD comprising one or more amino acid substitutions at a position corresponding to position: 3, 4, 5, 11, 12, 13, 18, 21, 27, 28, 29, 30, 35, 37, 41, 43, 45, 46, 47, 48, 49, 50, 55, 56, 57, 59, 61, 71, 73, 77, 79, 87, 89, and 93 of SEQ ID NO: 11 or said SBD comprising one or more amino acid substitutions in an equivalent position to SEQ ID NO: 11 of a parent glucoamylase SBD; wherein the equivalent position in a parent glucoamylase is determined by sequence identity and said parent glucoamylase has at least 80% amino acid sequence identity and less than 100% amino acid sequence identity with SEQ ID NO: 11.