CAREER: Iron-sulfur cluster assembly in Bacillus subtilis

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All forms of life require that many of their proteins have non-protein parts known as cofactors added to them so that they can function properly. Many of these cofactors are built from vitamins and minerals that are important in the diet. One such cofactor is the iron-sulfur (Fe-S) cluster, which allows proteins to perform many important types of chemistry. Because free Fe and S are toxic to cells, elaborate protein systems are used to build these cofactors. Once they are built, the Fe-S clusters must be trafficked to, and inserted into, proteins that require them. Cells that cannot properly build Fe-S clusters or maturate Fe-S proteins have chronic complications, which often results in cell death. The nature of this cellular machinery, however, is not well understood, and many questions remain about how organisms build Fe-S clusters and deliver them to proteins that require them for function. Novel Fe-S protein maturation proteins continue to be discovered, highlighting the fact that a global understanding of this process is lacking. The studies to be conducted in this project will impact the understanding of iron-dependent processes from bacteria to humans. The project will also provide unique educational opportunities for two postdoctoral scholars and up to ten undergraduate students. These trainees will be technically and intellectually trained and will receive the necessary guidance and resources to aid their transition into the next phases of their careers. The trainees will focus on enhancing their communication skills, technical skills, teaching skills, and personnel management skills.The Gram-positive bacterium Bacillus subtilis utilizes the SufCDSUB Fe-S cluster biosynthetic system and at least two Fe-S cluster carriers. Additional factors have been identified that have roles in Fe-S protein maturation, including SufT and YlaN; however, the functions of these molecules are unknown. Moreover, the Fe and electron donors for Suf-directed Fe-S cluster synthesis, as well as additional carrier molecules, are unknown. To properly understand how Fe-S proteins are maturated, the components involved must be identified and their functions defined. This project combines classic genetics and biochemistry with state-of-the-art, next-generation technologies and computational biology to 1) determine the physical interactions between SufT, YlaN, and Fe-S cluster synthesis, assembly, and target proteins, 2) quantify the necessity of SufT and alternate Fe-S cluster assembly factors for the function of specific metabolic pathways that require Fe-S enzymes, 3) assign biochemical functions to SufT and YlaN, and 4) model and predict the effect of faulty Fe-S protein maturation and validate the effects in vivo.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.