Variants of the enzyme, cellulase and EGV of humicola insolens processes and reduces Æo the thermostability of a cellulase of supply of properties of an enzyme to improve the activity speciKeep a cell

摘要

A method for improving the properties of a cellulolytic enzyme by amino acid substitution, deletion or insertion, the method comprising the steps of: a. constructing a multiple alignment of at least two amino acid sequences known to have three-dimensional structures similar to endoglucanase V (EGV) from Humicola insolens known from Protein Data Bank entry 4ENG; b. constructing a homology-built three-dimensional structure of the cellulolytic enzyme based on the structure of the EGV; c. identifying amino acid residue positions present in a distance from the substrate binding cleft of not more than 5Å; d. identifying surface-exposed amino acid residues of the enzyme; e. identifying all charged or potentially charged amino acid residue positions of the enzyme; f. choosing one or more positions wherein the amino acid residue is to be substituted, deleted or where an insertion is to be provided; g. carrying out the substition, deletion or insertion by using conventional protein engineering techniques; and cellulase variants obtained by the method.