Cloning and characterization of a cyanide hydratase gene from Metarhizium acridum
蝗绿僵菌氰化物水合酶基因MaChy的克隆及表达分析

By screening a cDNA library, the full length cDNA sequence and DNA sequence of a cyanide hydratase gene was isolated from Metarhizium acridum. Sequence analysis showed that the MaChy gene had no intron and the open reading frame was 1,074bp which encodes a protein with 357 amino acid residues with a calculated Mr of 39.78kDa and pI of 5.53. The characters of this putative protein were analyzed by several online bioinformatics tools, including signal peptide sequence, transmembrane segment, and secondary structure. The results indicated that this protein was neither a secreted protein nor a membrane protein. The putative amino acid sequence of MaChy shared high identities with the Chy proteins from other fungi. The highly conserved catalytic triad constituted by Glu-Lys-Cys could be found in the protein. A quantative RT-PCR analysis showed that the gene expression level was highly up-regulated at the appressorium formation stage, and it was about 2.5 times over the colonization of host hemolymph stage.