Cloning and characterization of a chitinase (CHIT42) cDNA from the mycoparasitic fungusTrichoderma harzianum

✍ Scribed by Irene García; José M. Lora; Jesús Cruz; Tahía Benítez; Antonio Llobell; José A. Pintor-Toro

• Publisher: Springer-Verlag
• Year: 1994
• Tongue: English
• Weight: 969 KB
• Volume: 27
• Category: Article
• ISSN: 0172-8083
• DOI: 10.1007/bf00326583

✦ Synopsis

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.