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Received August 7, 2007; Revision received September 18, 2007
A full-length cDNA encoding ribosome-inactivating/antiviral protein from the leaves of Bougainvillea xbuttiana was recently isolated. The coding region of cDNA was cloned and expressed in Escherichia coli, and the protein product was designated as BBAP1 (Bougainvillea xbuttiana antiviral protein 1). BBAP1 showed ribonuclease activity against Torula yeast RNA. It also exhibited depurination activity against supercoiled pBlueScript SK+ plasmid DNA in a concentration dependent manner, and was found to convert nicked circular DNA into linear form only at higher concentration. On bioassay, BBAP1 exhibited antiviral activity against sunnhemp rosette virus infecting Cyamopsis tetragonoloba leaves in which 95% inhibition of local lesion formation was observed.
KEY WORDS: Bougainvillea xbuttiana, antiviral protein, BBAP1, RNase activity, DNase activity, antiviral activity