COMPOSITIONS AND METHODS COMPRISING A XYLANASE ENZYME VARIANT

摘要

The present invention provides hemicellulytic enzyme variants. Specifically, the present invention provides xylanase variants having one or more modifications as compared to a parent xylanase enzyme resulting in at least one improved property. In addition, the present invention provides compositions comprising a xylanase variant of the invention. The present invention also provides methods of degrading hemicellulotic material, including arabino-xylan using compositions comprising a xylanase variant of the invention.

主权项

1. A xylanase polypeptide variant which comprises a substitution at a productive amino acid position compared to a parent GH10 xylanase, wherein said substitution increases the thermostability of the polypeptide without significantly reducing the specific activity, pepsin resistance and expression of the polypeptide, and wherein at least 2 out of 20 possible amino acid substitutions at the productive position makes the xylanase variant able to meet at least one of the following criteria:
a. Relative performance (Performance Index, PI) for specific activity in at least one of the two activity assays I and II is greater than 0.8, PI for pepsin resistance is greater than 0.9, PI for expression (unstressed activity assay 1) is greater than 0.057, and PI for thermostability assay 1 is greater than 1.2 or PI for thermostability assay 2 is greater than 1.5; b. Relative performance (Performance Index, PI) for specific activity in at least one of the two activity assays I and II is greater than 0.5, PI for pepsin resistance is greater than 0.8, PI for expression (unstressed activity assay 1) is greater than 0.057, and PI for Thermostability assay 1 is greater than 1.2 or PI for thermostability assay 2 is greater than 1.3; or c. Relative performance (Performance Index, PI) for specific activity in at least one of the two activity assays I and II is greater than 0.9, PI for pepsin resistance is greater than 0.9, PI for expression (unstressed activity assay 1) is greater than 0.057, and PI for Thermostability assay 1 is greater than 1.0 or PI for thermostability assay 2 is greater than 1.0;wherein the productive position is selected from the group consisting of 135, 28, 57, 62, 70, 79, 89, 102, 105, 118, 151, 153, 160, 181, 184, 200, 220, 232, 262, 298, 4, 21, 25, 30, 56, 59, 64, 65, 71, 74, 77, 98, 99, 100, 103, 104, 106, 113, 115, 117, 120, 134, 141, 142, 148, 150, 152, 156, 161, 163, 167, 176, 180, 193, 198, 199, 201, 202, 215, 217, 227, 229, 230, 233, 3, 6, 7, 11, 12, 16, 18, 29, 32, 33, 37, 38, 52, 53, 58, 67, 72, 75, 92, 93, 94, 96, 97, 107, 109, 110, 112, 114, 116, 125, 129, 132, 133, 136, 138, 139, 146, 147, 149, 155, 159, 162, 164, 168, 169, 182, 183, 188, 190, 191, 194, 196, 206, 209, 211, 219, 221, 231, 235, 236, 238, 244, 249, 260, 266, 268, 269, 274, 296, 300, 302 and 304, and wherein the polypeptide set forth in SEQ ID NO:2 is used for numbering.