Purification and characterization of a novel antifungal protein with antiproliferation and anti-HIV-1 reverse transcriptase activities from Peganum harmala seeds

摘要

A novel antifungal protein,designated as PHP,was isolated from the seeds of Peganum harmala,by cationic exchange chromatography on Resource S column and gel filtration on Sephadex 75 10/300 GL column.PHP was found to form a homodimer of about 16 kDa.Isoelectric focusing polyacrylamide gel electrophoresis analysis showed that the isoelectrie point of PHP was ～8.4.The N-terminal 20-amino acid sequence of PHP,ITCPQVTQSLAPCVPYLISG,resembles the non-specific lipid transfer proteins in certain plants.PHP exhibited lipid-binding activity.Furthermore,PHP exerted antifungal activity against Alternaria alternate,Penicillium degitatum,Rhizopus stuolonifer,and Magnaporthe grisea,and its antifungal activity was stable in the temperature range 4-60℃,and in the pH range 4-10.It inhibited the mycelial growth in A.alternate,P.degitatum,R.stuolonifer,and M.grisea with 50％ inhibitory concentration (ICso) of 1.5,37.5,8.44,and 12.19 μM,respectively.PHP was also able to inhibit the proliferation of esophagus carcinoma (Eca-109),cervical carcinoma (HeLa),gastric carcinoma (MGC-7),and melanoma (B16) cells with IC50 of 0.7,2.74,3.13,and 1.47 μM,respectively.Moreover,PHP significantly inhibited HIV-1 reverse transcriptase (RT) with an ICso of 1.26 μM.It did not have hemagglutinating and antibacterial activities.In conclusion,a novel antifungal protein with antiproliferation and anti-HIV-1 RT activities was obtained from P.harmala seeds.