| 摘要 |
<p>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 5 Å; 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 substitution, deletion or insertion by using conventional protein engineering techniques; and cellulase variants obtained by the method.</p> |
