A gene library of Cellulomonas pachnodae was constructed in Escherichia coli and was screened for endoglucanase activity. Five endoglucanase-positive clones were isolated that carried identical DNA fragments. The gene, designated cel6A, encoding an endoglucanase enzyme, belongs to the glycosyl hydrolase family 6 (cellulase family B). The recombinant Cel6A had a molecular mass of 53 kDa, a pH optimum of 5.5, and a temperature optimum of 50-55 degrees C. The recombinant endoglucanase Cel6A bound to crystalline cellulose and beech litter. Based on amino acid sequence similarity, a clear cellulose-binding domain was not distinguished. However, the regions in the Cel6A amino acid sequence at the positions 262-319 and 448-473, which did not show similarity to any of the known family-6 glycosyl hydrolases, may be involved in substrate binding.
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http://dx.doi.org/10.1007/s002530051514 | DOI Listing |
FEMS Microbiol Lett
May 2008
Microbial Genetics Division, National Institute of Agricultural Biotechnology, Rural Development Administration, Suwon, Korea.
To detect cellulases encoded by uncultured microorganisms, we constructed metagenomic libraries from Korean soil DNAs. Screenings of the libraries revealed a clone pCM2 that uses carboxymethyl cellulose (CMC) as a sole carbon source. Further analysis of the insert showed two consecutive ORFs (celM2 and xynM2) encoding proteins of 226 and 662 amino acids, respectively.
View Article and Find Full Text PDFA novel cellulolytic and xylanolytic bacterium, strain MX5T, was isolated from the hindgut contents of the Australian termite Mastotermes darwiniensis (Froggatt). The isolate was a facultative anaerobe and had a Gram-positive cell-wall profile. The rod-shaped bacterium formed irregular coryneform and coccoid cells during growth.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
August 1999
Department of Microbiology and Evolutionary Biology, Faculty of Science, University of Nijmegen, The Netherlands.
A gene library of Cellulomonas pachnodae was constructed in Escherichia coli and was screened for endoglucanase activity. Five endoglucanase-positive clones were isolated that carried identical DNA fragments. The gene, designated cel6A, encoding an endoglucanase enzyme, belongs to the glycosyl hydrolase family 6 (cellulase family B).
View Article and Find Full Text PDFAppl Environ Microbiol
September 1999
Department of Microbiology and Evolutionary Biology, Faculty of Science, University of Nijmegen, NL-6525 ED Nijmegen, The Netherlands.
Two xylanase-encoding genes, named xyn11A and xyn10B, were isolated from a genomic library of Cellulomonas pachnodae by expression in Escherichia coli. The deduced polypeptide, Xyn11A, consists of 335 amino acids with a calculated molecular mass of 34,383 Da. Different domains could be identified in the Xyn11A protein on the basis of homology searches.
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