1. Limenin, a defensin-like peptide with multiple exploitable activities from shelf beans
Jack H Wong, T B Ng J Pept Sci. 2006 May;12(5):341-6. doi: 10.1002/psc.732.
From the seeds of the shelf bean, an antifungal peptide with a molecular mass of 6.5 kDa was isolated. The isolation procedure comprised affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono S, and gel filtration on Superdex 75. The peptide was adsorbed on Affi-gel blue gel and Mono S. It potently suppressed mycelial growth in Botrytis cinerea, Fusarium oxysporum, and Mycosphaerella arachidicola with an IC(50) of 2.9, 2.1, and 0.34 microM, respectively. It exerted antibacterial activity toward several bacterial species with an IC(50) approximating 100 microM. [Methyl-(3)H]-thymidine incorporation into isolated mouse splenocytes was stimulated. [Methyl-(3)H]-thymidine incorporation into M1 (myeloma) and L1210 (leukemia) cells was inhibited. The peptide reduced the activity of HIV-1 reverse transcriptase and also inhibited translation in a cell-free rabbit reticulocyte lysate system.
2. Phaseococcin, an antifungal protein with antiproliferative and anti-HIV-1 reverse transcriptase activities from small scarlet runner beans
Patrick H K Ngai, T B Ng Biochem Cell Biol. 2005 Apr;83(2):212-20. doi: 10.1139/o05-037.
From the seeds of small scarlet runner beans (Phaseolus coccineus 'Minor'), an antifungal protein with an N-terminal sequence homologous to those of defensins was isolated. The antifungal protein bound to Affi-gel blue gel and Mono S but it did not bind to DEAE-cellulose. It was further purified by gel filtration on a Superdex peptide column. It exhibited a molecular mass of 5422 Da as determined by mass spectrometry. The protein, designated as phaseococcin, suppressed mycelial growth in a number of fungi including Botrytis cinerea, Coprinus comatus, Fusarium oxysporum, Mycosphaerella arachidicola, Physalospora piricola, and Rhizoctonia solani. It also inhibited proliferation in several Bacillus species and the leukemia cell lines HL60 and L1210 and curtailed the activity of HIV-1 reverse transcriptase. It did not affect proliferation of mouse splenocytes and neither did it inhibit protein synthesis in a cell-free rabbit reticulocyte lysate system.
3. Lunatusin, a trypsin-stable antimicrobial peptide from lima beans (Phaseolus lunatus L.)
Jack Ho Wong, Tzi Bun Ng Peptides. 2005 Nov;26(11):2086-92. doi: 10.1016/j.peptides.2005.03.004. Epub 2005 Apr 25.
An anti-fungal peptide designated as lunatusin, with a molecular mass around 7kDa, was purified from the seeds of Chinese lima bean (Phaseolus lunatus L.). The peptide was isolated using a simple protocol consisting of affinity chromatography on Affi-gel blue gel and gel filtration on Superdex 75. Lunatusin exerted an anti-fungal activity toward fungal species such as Fusarium oxysporum, Mycosphaerella arachidicola and Botrytis cinerea, and an antibacterial action on, Bacillus megaterium, Bacillus subtilis, Proteus vulgaris and Mycobacterium phlei. It also inhibited proliferation in the breast cancer cell line MCF-7. Lunatusin reduced the activity of HIV-1 reverse transcriptase and it also inhibited translation in a cell-free rabbit reticulocyte lysate system. Its anti-fungal activity was retained after incubation with trypsin. Lunatusin elicited a mitogenic response from mouse splenocytes.
