Purification and Structural Analysis of the Effective Anti-TMV Compound ε-Poly-<span style="font-variant: small-caps">l</span>-lysine Produced by <i>Streptomyces ahygroscopicus</i>

• Main Authors: Jianguang Chen, He Liu, Zihao Xia, Xiuxiang Zhao, Yuanhua Wu, Mengnan An
• Format: Article
• Language: English
• Published: MDPI AG 2019-03-01
• Series: Molecules
• Subjects: <i>Streptomyces ahygroscopicus</i>; anti-TMV activity; isolation and purification; structural determination; ε-poly-<span style="font-variant: small-caps">l</span>-lysine
• Online Access: https://www.mdpi.com/1420-3049/24/6/1156

Microbial secondary metabolites produced by actinomycetes are important natural products widely applied to control plant diseases. A variety of actinomycetes were isolated from soil samples collected from Tianzhu Mountain in Shenyang, China. A <i>Streptomyces</i> strain Shenyang Tianzhu (STZ) exhibits effective antiviral activity against Tobacco mosaic virus (TMV). The isolate was identified as <i>Streptomyces ahygroscopicus</i> based on its cultural, morphological, physiological, biochemical characteristics as well as the phylogenetic analysis using 16S rRNA sequences. To obtain the pure anti-TMV compound from <i>Streptomyces</i> STZ, the culture broth was subjected to Amberlite IRC-50 ion-exchange resin, SX-8 macroporous adsorption resin and Sephadex G-25 gel column chromatography. The purified active compound was confirmed to be &#949;-poly-<span style="font-variant: small-caps;">l</span>-lysine (&#949;-PL), with molecular mass in the range of 3454&#8211;4352 Da by structural analysis with infrared (IR), matrix-assisted laser desorption ionization-time-of-flight MS (MALDI-TOF), thin-layer chromatography (TLC) and high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR). The protective and curative effects of the purified compound &#949;-PL were tested and the results showed that the compound exhibited significant protective and curative activity against TMV. The potential application of &#949;-PL as an efficient anti-plant virus agent was expected.