The morecular cloning, gene structure, expression and enzyme activity of a serine-like proteas frome Laccotrephes Japonensis were examined.
In this study, RT-PCR was used to amplify cDNA fragments for serine-like proteases from total RNA the hole body of Laccotrephes japonensis. The flanking sequences of the 5'- and 3'- end of the this gene were characterized by RACE-PCR. Sequence analysis showed that this gene contained an 963bp ORF encoding 321 amino acids. The deduced amino acid sequence of this protease showed 62% identity to the serine protease of Creontiades dilutus, 58% to Lygus loneolaris trypsin precuror LlsgP4, 54% to Triatonatoma infestans salivary trypsin.
To generate Laccotrephes japonensis serine-like protease, the DNA fragment coding for serine protease is cloning into suttle vector pBACⅠ, named pBAC1-JG and infected to Spodoptera frugiperda (sf9) insect cell. The cDNA encoding JG was expressed as a 32-kDa polypeptide in baculovirus infected insect cells and the recombinant JG showed activity in the protease enzyme assay using gelatin as a substrate.