Nucleotide sequence of the endoglucanase C gene ( cenC ) of Cellulomonas fimi , its high‐level expression in Escherichia coli , and characterization of its products
1991; Wiley; Volume: 5; Issue: 5 Linguagem: Inglês
10.1111/j.1365-2958.1991.tb01896.x
ISSN1365-2958
AutoresJohn B. Coutinho, Bernhard Moser, Douglas G. Kilburn, R. A. J. Warren, Robert C. Miller,
Tópico(s)Enzyme Catalysis and Immobilization
ResumoSummary The cenC gene of Cellulomonas fimi , encoding endoglucanase CenC, has an open reading frame of 1101 codons closely followed by a 9bp inverted repeat. The predicted amino acid sequence of mature CenC, which is 1069 amino acids long, is very unusual in that it has a 150‐amino‐acid tandem repeat at the N ‐terminus and an unrelated 100‐amino‐acid tandem repeat at the C ‐terminus. CenC belongs to subfamily E 1 of the β‐1,4‐glycanases. High‐level expression in Escherichia coli of cenC from a 3.6kbp fragment of C. fimi DNA leads to levels of CenC which exceed 10% of total cell protein. Most of the CenC is in the cytoplasm in an inactive form. About 60% of the active fraction of CenC is in the periplasm. The catalytic properties of the active CenC are indistinguishable from those of native CenC from C. fimi. The M r of CenC from E. coli and C. fimi is approximately 130 kDa. E. coli and C. fimi also produce an endoglucanase, CenC', of approximate M r , 120kDa and with the same N ‐terminal amino acid sequence and catalytic properties as CenC. CenC’appears to be a proteolytic product of CenC. CenC and CenC’can bind to cellulose and to Sephadex. CenC is the most active component of the C. fimi cellulase system isolated to date.
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