Isolation and characterization of juncin, an antifungal protein from seeds of Japanese Takana (Brassica juncea Var. integrifolia).
An 18.9 kDa antifungal protein designated juncin was isolated from seeds of the Japanese takana (Brassica juncea var. integrifolia). The purification protocol employed comprised anion-exchange chromatography on Q-Sepharose, affinity chromatography on Affi-gel blue gel, cation exchange chromatography on SP-Sepharose, and gel filtration on Superdex 75. Juncin was adsorbed on Affi-gel blue gel and SP-Sepharose but unadsorbed on Q-Sepharose. The protein exhibited antifungal activity toward the phytopathogens Fusarium oxysporum, Helminthosporium maydis, and Mycosphaerella arachidicola with IC(50) values of 13.5, 27, and 10 μM, respectively. It was devoid of mitogenic activity toward splenocytes and nitric oxide inducing activity toward macrophages. It inhibited the proliferation of hepatoma (HepG2) and breast cancer (MCF7) cells with IC(50) values of 5.6 and 6.4 μM, respecitvely, and the activity of HIV-1 reverse transcriptase with an IC(50) of 4.5 μM. Its N-terminal sequence differed from those of antifungal proteins that have been reported to date. Compared with Brassica campestris and Brassica alboglabra antifungal peptides, juncin exhibits a different molecular mass and N-terminal amino acid sequence but similar biological activities.
Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
Xiujuan
X
Ye
Tzi Bun
TB
Ng
D000595:Amino Acid Sequence; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D005659:Fungicides, Industrial; D006801:Humans; D051379:Mice; D003904:Mitosporic Fungi / Q000187:drug effects; D008969:Molecular Sequence Data; D009149:Mustard Plant / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry*; D013154:Spleen / Q000166:cytology
D000972:Antineoplastic Agents, Phytogenic; D005659:Fungicides, Industrial; D010940:Plant Proteins; C558315:juncin