An antifungal defensin from Phaseolus vulgaris cv. ‘Cloud Bean’

Wu, Xiangli; Sun, Jian; Zhang, Guoqing; Wang, Hexiang; Ng, Tzi Bun

doi:10.1016/j.phymed.2010.06.010

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Volume 18, Issue 2 , Pages 104-109, 15 January 2011

An antifungal defensin from Phaseolus vulgaris cv. ‘Cloud Bean’

Xiangli Wu
- State Key Laboratory for Agrobiotechnology, Department of Microbiology, China Agricultural University, Beijing 100193, China
Jian Sun
- State Key Laboratory for Agrobiotechnology, Department of Microbiology, China Agricultural University, Beijing 100193, China
Guoqing Zhang
- State Key Laboratory for Agrobiotechnology, Department of Microbiology, China Agricultural University, Beijing 100193, China
Hexiang Wang
- State Key Laboratory for Agrobiotechnology, Department of Microbiology, China Agricultural University, Beijing 100193, China
- Corresponding authors. Tel.: +852 2609 8031; fax: +852 2603 5123.
Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Corresponding authors. Tel.: +852 2609 8031; fax: +852 2603 5123.

published online 23 August 2010.

Abstract

An antifungal peptide with a defensin-like sequence and exhibiting a molecular mass of 7.3kDa was purified from dried seeds of Phaseolus vulgaris ‘Cloud Bean’. The isolation procedure entailed anion exchange chromatography on DEAE-cellulose, affinity chromatography an Affi-gel blue gel, cation exchange chromatography on SP-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. Although the antifungal peptide was unadsorbed on DEAE-cellulose, it was adsorbed on both Affi-gel blue gel and SP-Sepharose. The antifungal peptide exerted antifungal activity against Mycosphaerella arachidicola with an IC₅₀ value of 1.8μM. It was also active against Fusarium oxysporum with an IC₅₀ value of 2.2μM. It had no inhibitory effect on HIV-1 reverse transcriptase when tested up to 100μM. Proliferation of L1210 mouse leukemia cells and MBL2 lymphoma cells was inhibited by the antifungal peptide with an IC₅₀ of 10μM and 40μM, respectively.