Clostridium thermocellum cellulase CelT, a family 9 endoglucanase without an Ig-like domain or family 3c carbohydrate-binding module

被引：33

作者：

Kurokawa, J ^{[1
]}

Hemjinda, E ^{[1
]}

Arai, T ^{[1
]}

Kimura, T ^{[1
]}

Sakka, K ^{[1
]}

Ohmiya, K ^{[1
]}

机构：

[1] Mie Univ, Fac Bioresources, Tsu, Mie 5148507, Japan

来源：

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY | 2002年 / 59卷 / 4-5期

关键词：

D O I：

10.1007/s00253-002-1048-y

中图分类号：

Q81 [生物工程学（生物技术）]; Q93 [微生物学];

学科分类号：

071005 ; 0836 ; 090102 ; 100705 ;

摘要：

The celT gene of Clostridium thermocellum strain F1 was found downstream of the mannanase gene man26B [Kurokawa J et al. (2001) Biosci Biotechnol Biochem 65:548-554] in pKS305. The open reading frame of celT consists of 1,833 nucleotides encoding a protein of 611 amino acids with a predicted molecular weight of 68,510. The mature form of CelT consists of a family 9 cellulase domain and a dockerin domain responsible for cellulosome assembly, but lacks a family 3c carbohydrate-binding module (CBM) and an immunoglobulin (Ig)-like domain, which are often found with family 9 catalytic domains. CelT devoid of the dockerin domain (CelTDeltadoc) was constructed and purified from a recombinant Escherichia coli, and its enzyme properties were examined. CelTDeltadoc showed strong activity toward carboxymethylcellulose (CMC) and barley beta-glucan, and low activity toward xylan. The V-max and K-m values were 137 mumol min(-1) mg(-1) and 16.7 mg/ml, respectively, for CMC. Immunological analysis indicated that CelT is a catalytic component of the C. thermocellum F1 cellulosome. This is the first report describing the characterization of a family 9 cellulase without an Ig-like domain or family 3c CBM.

引用

页码：455 / 461

页数：7

共 36 条

[1] Cloning, DNA sequencing, and expression of the gene encoding Clostridium thermocellum cellulase CelJ, the largest catalytic component of the cellulosome [J].