Ahmadian G, Degrassi G, Venturi V, Zeigler D R, Soudi M, Zanguinejad P
Department of Molecular Genetic, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran.
J Appl Microbiol. 2007 Oct;103(4):1081-9. doi: 10.1111/j.1365-2672.2007.03340.x.
Isolation and characterization of chitinases from a halotolerant Bacillus pumilus.
Bacillus pumilus strain SG2 was isolated from saline conditions. It is able to produce chitinase activity at high salt concentration. SDS-PAGE analysis of the B. pumilus SG2 culture supernatant showed two major bands that were induced by chitin. The amino acid sequence of the two proteins, designated ChiS and ChiL, showed a high homology with the chitinase of B. subtilis CHU26, and chitinase A of B. licheniformis, respectively. N-terminal signal peptide of both proteins was also determined. The molecular weight and isoelectric point of the chitinases were determined to be 63 and 74 kDa, and 4.5 and 5.1, for ChiS and ChiL respectively. The genes encoding for both chitinases were isolated and their sequence determined. The regulation of the chitinase genes is under the control of the catabolite repression system.
Secreted chitinase genes and their flanking region on the genome of B. pumilus SG2 have been identified and sequenced.
This is the first report of a multiple chitinases-producing B. pumilus halotolerant strain. We have identified two chitinases by using a reverse genetics approach. The chitinases show resistance to salt.
从耐盐短小芽孢杆菌中分离并鉴定几丁质酶。
从盐环境中分离出短小芽孢杆菌菌株SG2。它能够在高盐浓度下产生几丁质酶活性。对短小芽孢杆菌SG2培养上清液进行SDS-PAGE分析，显示出两条由几丁质诱导产生的主要条带。这两种分别命名为ChiS和ChiL的蛋白质的氨基酸序列，分别与枯草芽孢杆菌CHU26的几丁质酶和地衣芽孢杆菌的几丁质酶A具有高度同源性。还确定了这两种蛋白质的N端信号肽。对于ChiS和ChiL，几丁质酶的分子量和等电点分别测定为63和74 kDa，以及4.5和5.1。分离出编码这两种几丁质酶的基因并确定其序列。几丁质酶基因的调控受分解代谢物阻遏系统控制。
已鉴定并测序了短小芽孢杆菌SG2基因组上分泌的几丁质酶基因及其侧翼区域。
这是关于一株能产生多种几丁质酶的耐盐短小芽孢杆菌的首次报道。我们通过反向遗传学方法鉴定了两种几丁质酶。这些几丁质酶表现出耐盐性。
