Iron–sulphur cluster biogenesisviathe SUF pathway

Abstract

Iron-sulphur (Fe-S) clusters are versatile cofactors, which are essential for key metabolic processes in cells, such as respiration and photosynthesis, and which may have also played a crucial role in establishing life on Earth. They can be found in almost all living organisms, from unicellular prokaryotes and archaea to multicellular animals and plants, and exist in diverse forms. This review focuses on the most ancient Fe-S cluster assembly system, the sulphur utilization factor (SUF) mechanism, which is crucial in bacteria for cell survival under stress conditions such as oxidation and iron starvation, and which is also present in the chloroplasts of green microalgae and plants, where it is responsible for plastidial Fe-S protein maturation. We explain the SUF Fe-S cluster assembly process, the proteins involved, their regulation and provide evolutionary insights. We specifically focus on examples from Fe-S cluster synthesis in the model organisms Escherichia coli and Arabidopsis thaliana and discuss in an in vivo context the assembly of the [FeFe]-hydrogenase H-cluster from Chlamydomonas reinhardtii.

Iron–Sulfur Cluster Biogenesis and Iron Homeostasis in Cyanobacteria

“…The newly assembled Fe-S cluster is transferred to the carrier protein, which delivers the Fe-S cluster to recipient Apo and converts recipient Apo into holo-protein (Holo). Nishio and Nakai, 2000;Seidler et al, 2001;Balasubramanian et al, 2006 In the cyanobacterial genome, the sufB, sufC, sufD, and sufS (sufBCDS operon) are arranged with the same transcriptional direction; sufA is not included in the sufBCDS operon, and sufR is located at upstream of sufB with an opposite transcriptional direction (Wang et al, 2004;Seki et al, 2006;Shen et al, 2007;Bai et al, 2018). Cyanobacterial SufR can coordinate two [4Fe-4S] 2+,1+ clusters and functions as a transcriptional repressor of the sufBCDS operon and an autoregulator itself (Shen et al, 2007).…”

Monitoring H-cluster assembly using a semi-synthetic HydF protein

“…The Fe ions of the [2Fe] subsite are bridged by an aza-dithiolate ligand (–SCH 2 NHCH 2 S–, adt), and further coordinated by carbonyl and cyanide ligands 3–6. The assembly of the H-cluster is a two-step process, where the biosynthesis of the [2Fe] subsite and its insertion into apo-hydrogenase7 requires at least three hydrogenase specific auxiliary proteins or maturation enzymes 8–12. Two of these enzymes (HydG and HydE) belong to the radical S -adenosyl- l -methionine (SAM) enzyme family.…”

The maturase HydF enables [FeFe] hydrogenase assembly via transient, cofactor-dependent interactions

“…The latter complex is coordinated by carbonyl and cyanide ligands, as well as a bridging dithiolate ligand (adt = − SCH 2 NHCH 2 S − ). The biosynthesis of the H-cluster is a complex, multistep process, during which the [4Fe-4S] H -cluster is first assembled by the standard house-keeping FeS cluster machinery ( 3 – 5 ). The active hydrogenase is then generated through the combined activities of at least three [FeFe] hydrogenase-specific maturation enzymes, denoted HydE, HydG, and HydF, responsible for the synthesis and insertion of the [2Fe] subsite ( Fig.…”