CBH1 homologs and varian CBH1 cellulase
Disclosed are a number of homologs and variants of Hypocrea jecorina Cel7A (formerly Trichoderma reesei cellobiohydrolase I or CBH1), nucleic acids encoding the same and methods for producing the same. The homologs and variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted and/or deleted.
1. A variant CBH I cellulase polypeptide, wherein the full length of said polypeptide has at least 97% sequence identity to SEQ ID NO:2, and wherein said polypeptide comprises a substitution or deletion at a position corresponding to one or more of residues L6, P13, T24, Q27, S47, T59, T66, G88, T160, Q186, S195, T232, E236, E239, G242, N250, T281, F311, N327, D329, A336, K354, V407, P412, T417 or F418 of SEQ ID NO:2.
2. The variant CBH I cellulase polypeptide of claim 1 , wherein said polypeptide comprises a substitution selected from the group consisting of Q186E, S195(A/F), E239S, G242(H/Y/N/S/T/D/A) and P412(T/S/A).
3. An isolated nucleic acid sequence encoding the polypeptide of claim 1 .
4. An isolated nucleic acid sequence encoding the polypeptide of claim 2 .
5. A vector comprising the nucleic acid according to claim 3 .
6. A vector comprising the nucleic acid according to claim 4 .
7. An isolated host cell transformed with the vector of claim 5 .
8. An isolated host cell transformed with the vector of claim 6 .
9. A method of producing a CBH I cellulase polypeptide, comprising the steps of:
(a) culturing the isolated host cell of claim 7 or 8 in a suitable culture medium under suitable conditions to produce the variant CBH I cellulase polypeptide;
(b) obtaining said variant CBH I cellulase polypeptide.
10. A detergent composition comprising a surfactant and the variant CBH I polypeptide according to claim 1 .
11. The detergent composition of claim 10 , wherein the detergent is a laundry detergent or a dish detergent.
12. A feed additive composition comprising the variant CBH I polypeptide according to claim 1 .
13. A cellulase composition comprising the variant CBH I polypeptide according to claim 1 .
14. A method of treating wood pulp comprising contacting said wood pulp with the variant CBH I polypeptide of claim 1 .
15. A method of converting biomass to sugars comprising contacting the biomass with the variant CBH I polypeptide according to claim 1 .