HER MAJESTY THE QUEEN IN RIGHT OF CANADA, AS REPRESENTED BY THE MINISTER OF AGRICULTURE AND AGRIFOOD
发明人:
LAROCHE ANDRE J.,HUANG TIMOTHY YIKAI,FRICK MICHELE M.,LU ZHEN-XIANG,HUANG HUNG CHANG,CHENG KUO JOAN
申请号：
US20000733643
公开号：
US6734344(B2)
申请日:
2000.12.08
申请国别(地区):
美国
年份:
2004
代理人:
摘要：
The invention provides the nucleotide sequence of a novel beta-(1,3) exoglucanase gene denoted as cbeg1 of the soil-borne fungus Coniothyrium minitans. The deduced amino acid sequence of the encoded beta-(1,3) exoglucanase enzyme, denoted Cbeg1, is also provided. Encoded beta-(1,3) exoglucanase Cbeg1 is specific for the substrate laminarin, in that results showed no activity with other substrates tested, such as carboxymethylcellulose, barley beta-glucan, lichenan, oat spelt xylan and birchwood xylan. The pH and temperature optima for beta-(1,3) exoglucanase Cbeg1 are 6.0 and 57° C., respectively. Cbeg1 contains 784 amino acids, and has a predicted isoelectric point (pI) of 6.0 and molecular weight of 83,646 Daltons. The invention further provides vectors and cells comprising a nucleic acid molecule encoding the cbeg1 gene, and methods for producing beta-(1,3) exoglucanase Cbeg1. The cbeg1 gene is compatible with a eukaryotic heterologous expression system, making it particularly useful for a wide range of industrial applications, such as improvement of plant resistance to fungal phytopathogens or use in ruminant microbial transgenic strategies to improve feed digestion and nutritive carbohydrate availability from forage feed. In addition, the high activity of Cbeg1 over broad pH and temperature ranges may be beneficial for use in high temperature industrial applications, such as bleaching of pulp, which require temperatures greater than 37° C. Further, Cbeg1 may complement degradation initiated by endoglucanases which release oligoglucans, in that beta-(1,3) exoglucanase sequentially hydrolyzes beta-(1,3) glucan fragments and is required to hydrolyze oligoglucan fragments completely to obtain D-glucose, which can be assimilated.
