Variant humicola grisea CBH1.1
Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.
1. An isolated polynucleotide encoding a polypeptide having cellobiohydrolase I activity, wherein said polypeptide has a sequence homology of at least 90% with SEQ ID NO:10 and comprises a substitution selected from the group consisting of: T55E, T55K, S58T, Q101Y, Q101H, N250D, N250E, P265A, P265S and L288I.
2. A nucleic acid construct comprising the isolated polynucleotide of claim 1 , operably linked to one or more control sequences.
3. A recombinant expression vector comprising the nucleic acid construct of claim 2 .
4. A recombinant host cell comprising the nucleic acid construct of claim 2 or the recombinant expression vector of claim 3 .
5. A method of producing a polypeptide having cellobiohydrolase I activity, said method comprising:
a) transforming a host cell with a nucleic acid comprising the isolated polynucleotide of claim 1 ;
b) culturing the host cell under conditions suitable for producing the polypeptide; and
c) recovering the polypeptide.
6. The isolated polynucleotide of claim 1 , wherein said polypeptide has a sequence homology of at least 95% with SEQ ID NO:10.