近日，南京农业大学植保学院刘凤权教授领导的研究团队在《Journal of the American Chemistry Society》（影响因子8.58）上发表了题为《Biosynthesis of HSAF, a Tetramic Acid-containing Macrolactam from Lysobacter enzymogenes》的研究论文。该论文以钱国良博士为并列第一作者，刘凤权教授为第一通讯作者，首次报道了新型生防细菌——产酶溶杆菌的全基因组信息，在对该菌产生的一种热稳定抗菌物质（HSAF）进行分离和结构鉴定的基础上，明确了HSAF在该菌体内合成的关键基因，揭示了HSAF独特的生物合成机制，研究结果为利用基因工程和发酵工程实现该抗菌物质的产业化及生产应用奠定了基础。
此外，刘凤权教授领导的研究团队2010年在《Biosensors & Bioelectronics》（影响因子5.429）上先后发表了两篇题为《Development of an immunochromatographic assay for the rapid detection of chlorpyrifos-methyl in water samples》和《A novel immunochromatographic electrochemical biosensor for highly sensitive and selective detection of trichloropyridinol, a biomarker of exposure to chlorpyrifos》的研究论文。这两篇论文分别以博士生华修德和王利民为第一作者，刘凤权教授为第一通讯作者。详细研究了基于单克隆抗体和免疫传感器的农药（代谢物）残留快速检测技术，开发了农药及代谢产物免疫检测试纸条，可用于农产品和环境中农药残留的在线检测。（生物谷Bioon.com）
doi:10.1021/ja105732c
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Biosynthesis of HSAF, a Tetramic Acid-Containing Macrolactam from Lysobacter enzymogenes
Lili Lou†, Guoliang Qian‡, Yunxuan Xie†, Jiliang Hang†, Haotong Chen†, Kathia Zaleta-Rivera†, Yaoyao Li†§, Yuemao Shen§, Patrick H. Dussault†, Fengquan Liu*‡, and Liangcheng Du*†
HSAF was isolated from Lysobacter enzymogenes, a bacterium used in the biological control of fungal diseases of plants. Structurally, it is a tetramic acid-containing macrolactam fused to a tricyclic system. HSAF exhibits a novel mode of action by disrupting sphingolipids important to the polarized growth of filamentous fungi. Here we describe the HSAF biosynthetic gene cluster, which contains only a single-module polyketide synthase/nonribosomal peptide synthetase (PKS/NRPS), although the biosynthesis of HSAF apparently requires two separate polyketide chains that are linked together by one amino acid (ornithine) via two amide bonds. Flanking the PKS/NRPS are six genes that encoding a cascade of four tightly clustered redox enzymes on one side and a sterol desaturase/fatty acid hydroxylase and a ferredoxin reductase on the other side. The genetic data demonstrate that the four redox genes, in addition to the PKS/NRPS gene and the sterol desaturase/fatty acid hydroxylase gene, are required for HSAF production. The biochemical data show that the adenylation domain of the NRPS specifically activates l-ornithine and that the four-domain NRPS is able to catalyze the formation of a tetramic acid-containing product from acyl-S-ACP and ornithinyl-S-NRPS. These results reveal a previously unrecognized biosynthetic mechanism for hybrid PK/NRP in prokaryotic organisms.
