Susman Melanie, Makris Christina, Butler Alison
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States.
ACS Chem Biol. 2025 Sep 19;20(9):2318-2327. doi: 10.1021/acschembio.5c00484. Epub 2025 Sep 2.
-diazeniumdiolate siderophores are a small class of photoactive bacterial Fe(III) chelators. Driven by genome mining, we discovered a new -type diazeniumdiolate siderophore, pandorachelin, produced by the rhizospheric bacterium, DSM 11628. The biosynthetic gene cluster encoding the production of pandorachelin is conserved across several species. are environmentally widespread and are increasingly prevalent clinical pathogens, spurring new interest in their metabolites. UV irradiation photolytically cleaves the N-N bonds within the diazeniumdiolate-containing graminine constituents of pandorachelin. With EPR spin trapping, we directly detect nitric oxide released from the two -diazeniumdiolate ligands of pandorachelin upon UV irradiation. Additionally, we show that nitric oxide can react with the intermediates during the photoreaction to reconstruct the diazeniumdiolate groups via exchange of the distal nitric oxide (NO) and thereby recover Fe(III)-binding capacity. The photochemistry of this class of siderophores points to a broader biological role, both in their propensity to release the biological signaling molecule, nitric oxide, and in their ability to undergo photoinduced NO exchange.
重氮二醇盐类铁载体是一类小型的光活性细菌铁(III)螯合剂。在基因组挖掘的推动下,我们发现了一种新型重氮二醇盐类铁载体——潘多拉菌素,它由根际细菌DSM 11628产生。编码潘多拉菌素产生的生物合成基因簇在多个物种中是保守的。这些细菌在环境中广泛存在,并且是日益普遍的临床病原体,这激发了人们对其代谢产物的新兴趣。紫外线照射能光解潘多拉菌素中含重氮二醇盐的禾胺成分中的N-N键。通过电子顺磁共振自旋捕获技术,我们直接检测到紫外线照射下潘多拉菌素的两个重氮二醇盐配体释放出的一氧化氮。此外,我们还表明,一氧化氮可以在光反应过程中与中间体反应,通过远端一氧化氮(NO)的交换来重建重氮二醇盐基团,从而恢复铁(III)结合能力。这类铁载体的光化学表明其具有更广泛的生物学作用,既体现在它们释放生物信号分子一氧化氮的倾向,也体现在它们进行光诱导的NO交换的能力上。