Cathepsin B-like protease from chili pepper revealed by in silico approach

摘要

The cathepsin B-like proteases of higher plants are mostly related to stress / damage. The expression of cathepsin B-like transcript in the plant system is regarded the response towards abiotic stimuli, wounding of tissues, organ abscission. We isolated a putative cathepsin B-like proteases partial cDNA from chili pepper (Capsicum frutescens). A cDNA library of wound induced placental tissue transcripts was constructed in the phage vector system. Partial sequencing and in silico analysis revealed high levels of sequence homology to cathepsin B-like cysteine protease from the plants of solanaceae family, but much lower levels with other plant cysteine proteinases. Sequence alignment using ClustalW revealed the consensus sequences of the family solanaceae for cathepsin B-like proteases. Further, translated amino acid sequences by BLASTx revealed the conserved domains among the unrelated families. Name assignment to this cDNA as cathepsin B-like protease was based on nucleotide and translated amino acid sequence similarity which is of 91% and 97% respectively with cathepsin B-like cysteine proteinase of Nicotiana rustica. Our current hypothesis towards the function of this cDNA is that it encodes cathepsin B-like proteases in response to mechanical wounding in plant tissues.