Driss F, Kallassy-Awad M, Zouari N, Jaoua S
Laboratory of Biopesticides, Centre of Biotechnology of Sfax, Sfax, Tunisia.
J Appl Microbiol. 2005;99(4):945-53. doi: 10.1111/j.1365-2672.2005.02639.x.
The present work aims to study a new chitinase from Bacillus thuringiensis subsp. kurstaki.
BUPM255 is a chitinase-producing strain of B. thuringiensis, characterized by its high chitinolytic and antifungal activities. The cloning and sequencing of the corresponding gene named chi255 showed an open reading frame of 2031 bp, encoding a 676 amino acid residue protein. Both nucleotide and amino acid sequences similarity analyses revealed that the chi255 is a new chitinase gene, presenting several differences from the published chi genes of B. thuringiensis. The identification of chitin hydrolysis products resulting from the activity, exhibited by Chi255 through heterologous expression in Escherichia coli revealed that this enzyme is a chitobiosidase.
Another chitinase named Chi255 belonging to chitobiosidase class was evidenced in B. thuringiensis subsp. kurstaki and was shown to present several differences in its amino acid sequence with those of published ones. The functionality of Chi255 was proved by the heterologous expression of chi255 in E. coli.
The addition of the sequence of chi255 to the few sequenced B. thuringiensis chi genes might contribute to a better investigation of the chitinase 'structure-function' relation.
本研究旨在对苏云金芽孢杆菌库尔斯塔克亚种中的一种新型几丁质酶进行研究。
BUPM255是苏云金芽孢杆菌的一株产几丁质酶菌株，具有高几丁质分解活性和抗真菌活性。对名为chi255的相应基因进行克隆和测序，结果显示其开放阅读框为2031 bp，编码一个含有676个氨基酸残基的蛋白质。核苷酸和氨基酸序列相似性分析均表明，chi255是一个新的几丁质酶基因，与已发表的苏云金芽孢杆菌chi基因存在多处差异。通过在大肠杆菌中异源表达Chi255所表现出的活性对几丁质水解产物进行鉴定，结果表明该酶是一种壳二糖酶。
在苏云金芽孢杆菌库尔斯塔克亚种中发现了另一种属于壳二糖酶类的几丁质酶Chi255，其氨基酸序列与已发表的几丁质酶存在多处差异。chi255在大肠杆菌中的异源表达证明了Chi255的功能。
将chi255的序列添加到已测序的少数苏云金芽孢杆菌chi基因中，可能有助于更好地研究几丁质酶的“结构-功能”关系。
