García I, Lora J M, de la Cruz J, Benítez T, Llobell A, Pintor-Toro J A
Instituto de Recursos Naturales y Agrobiología, Sevilla, Spain.
Curr Genet. 1994 Dec;27(1):83-9. doi: 10.1007/BF00326583.
A cDNA of Trichoderma harzianum (chit42), coding for an endochitinase of 42 kDa, has been cloned using synthetic oligonucleotides corresponding to amino-acid sequences of the purified chitinase. The cDNA codes for a protein of 423 amino acids. Analysis of the N-terminal amino-acid sequence of the chitinase, and comparison with that deduced from the nucleotide sequence, revealed post-translational processing of a putative signal peptide of 22 amino acids and a second peptide of 12 amino acids. The chit42 sequence presents overall similarities with filamentous fungal and bacterial chitinases and to a lesser extent with yeast and plant chitinases. The deduced amino-acid sequence has putative catalytic, phosphorylation and glycosylation domains. Expression of chit42 mRNA is strongly induced by chitin and chitin-containing cell walls and is subjected to catabolite repression. Southern analysis shows that it is present as a single-copy gene in T. harzianum. chit42 is also detected in several tested mycoparasitic and non-mycoparasitic fungal strains.
利用与纯化的几丁质酶氨基酸序列对应的合成寡核苷酸，克隆了哈茨木霉（Trichoderma harzianum）的一个编码42 kDa内切几丁质酶的cDNA（chit42）。该cDNA编码一个由423个氨基酸组成的蛋白质。对几丁质酶的N端氨基酸序列进行分析，并与从核苷酸序列推导的序列进行比较，发现一个由22个氨基酸组成的假定信号肽和一个由12个氨基酸组成的第二个肽段存在翻译后加工。chit42序列与丝状真菌和细菌的几丁质酶总体相似，与酵母和植物几丁质酶的相似程度较低。推导的氨基酸序列具有假定的催化、磷酸化和糖基化结构域。几丁质和含几丁质的细胞壁强烈诱导chit42 mRNA的表达，且该表达受分解代谢物阻遏。Southern分析表明，它在哈茨木霉中以单拷贝基因形式存在。在几种测试的真菌寄生和非真菌寄生真菌菌株中也检测到了chit42。
