文献类型： 外文期刊

作者： Yu, Lingjun ¹ ; Li, Hui ² ; Zhou, Zaichun ² ; Liu, Fengquan ¹ ; Du, Liangcheng ² ;

作者机构： 1.Jiangsu Acad Agr Sci, Inst Plant Protect, Nanjing, Peoples R China

2.Univ Nebraska, Dept Chem, Lincoln, NE 68588 USA

3.Univ Nebraska, Nebraska Ctr Mat & Nanosci, Lincoln, NE USA

4.Univ Nebraska, Ctr Integrated Biomol Commun, Lincoln, NE USA

5.Hunan Univ Sci & Technol, Sch Chem & Chem Engn, Key Lab Theoret Organ Chem & Funct Mol, Minist Educ, Xiangtan, Peoples R China

关键词： natural products; polycyclic tetramate macrolactams; Lysobacter enzymogenes; oxidative damage; iron binding

期刊名称：APPLIED AND ENVIRONMENTAL MICROBIOLOGY （ 影响因子：4.016； 五年影响因子：4.597 ）

ISSN： 0099-2240

年卷期： 2021 年 87 卷 10 期

页码：

收录情况： SCI

摘要： Polycyclic tetramate macrolactams (PoTeMs) are a fast-growing family of antibiotic natural products found in phylogenetically diverse microorganisms. Surprisingly, none of the PoTeMs have been investigated for potential physiological functions in their producers. Here, we used heat-stable antifungal factor (HSAF), an antifungal PoTeM from Lysobacter enzymogenes, as a model to show that PoTeMs form complexes with iron ions, with an association constant (K-a) of 2.71 x 10(6) M-1. The in vivo and in vitro data showed formation of 2:1 and 3:1 complexes between HSAF and iron ions, which were confirmed by molecular mechanical and quantum mechanical calculations. HSAF protected DNA from degradation in high concentrations of iron and H2O2 or under UV radiation. HSAF mutants of L. enzymogenes barely survived under oxidative stress and exhibited markedly increased production of reactive oxygen species (ROS). Exogenous addition of HSAF into the mutants significantly prevented ROS production and restored normal growth in the mutants under the oxidative stress. The results reveal that the function of HSAF is to protect the producer microorganism from oxidative damage rather than as an iron-acquisition siderophore. The characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. The study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells. IMPORTANCE PoTeMs are a family of structurally distinct metabolites that have been found in a large number of bacteria. Although PoTeMs exhibit diverse therapeutic properties, the physiological function of PoTeMs in the producer microorganisms had not been investigated. HSAF from Lysobacter enzymogenes is an antifungal PoTeM that has been subjected to extensive studies for mechanisms of biosynthesis, regulation, and antifungal activity. Using HSAF as a model system, we here showed that the characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. In L. enzymogenes, HSAF functions as a small-molecule modulator for oxidative damage caused by iron, H2O2, and UV light. Together, the study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells. HSAF represents the first member of the fast-growing PoTeM family of microbial metabolites whose potential biological function has been studied.