嗜纤维梭菌非纤维素体内切葡聚糖酶基因engF的特性分析

Characterization of engF, a gene for a non-cellulosomal Clostridium cellulovorans endoglucanase.

作者信息

Sheweita S A, Ichi-ishi A, Park J S, Liu C, Malburg L M, Doi R H

机构信息

Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.

出版信息

Gene. 1996 Dec 5;182(1-2):163-7. doi: 10.1016/s0378-1119(96)00544-6.

DOI:10.1016/s0378-1119(96)00544-6

PMID:8982083

Abstract

A new Clostridium cellulovorans (strain ATCC 35296) endoglucanase gene engF has been isolated and sequenced. The gene contains 1671 bp and codes for a protein containing 557 amino acids and a mass of 60.1 kDa. A putative signal peptide of 29 amino acids is present and the mature protein has a mass of 57.1 kDa. EngF does not have amino acid sequence homology to previously isolated EngB and EngD, but does show sequence homology to family 5 glycosyl hydrolases from Bacillus, Erwinia carotovora, and C. acetobutylicum species. EngF is not a component of the cellulosome and does not contain a duplicated sequence (DS) at its C-terminal region. EngF is capable of binding to cellulose and hydrolyzing carboxymethylcellulose but not xylan. The cellulose binding domain (CBD) differs from types I, II and III CBDs and no obvious homology has been found to other CBD types. The maximum activity of EngF occurs at pH 5.5 and at 47 degrees C. Its properties suggest that EngF plays an ancillary role in the degradation of cellulosic materials.

摘要

一种新的嗜纤维梭菌（菌株ATCC 35296）内切葡聚糖酶基因engF已被分离和测序。该基因包含1671个碱基对，编码一种含有557个氨基酸、质量为60.1 kDa的蛋白质。存在一个由29个氨基酸组成的假定信号肽，成熟蛋白的质量为57.1 kDa。EngF与先前分离的EngB和EngD没有氨基酸序列同源性，但与芽孢杆菌、胡萝卜软腐欧文氏菌和丙酮丁醇梭菌属的5家族糖基水解酶具有序列同源性。EngF不是纤维小体的组成成分，其C末端区域也不包含重复序列（DS）。EngF能够结合纤维素并水解羧甲基纤维素，但不能水解木聚糖。纤维素结合结构域（CBD）不同于I型、II型和III型CBD，未发现与其他CBD类型有明显同源性。EngF的最大活性出现在pH 5.5和47℃。其特性表明EngF在纤维素材料的降解中起辅助作用。