Abstract
In Escherichia coli, three cysteine desulfurases (IscS, SufS, and CsdA) initiate the delivery of sulfur for various biological processes such as the biogenesis of Fe-S clusters. The sulfur generated as persulfide on a cysteine residue of cysteine desulfurases is further transferred to Fe-S scaffolds (e.g. IscU) or to intermediate cysteine-containing sulfur acceptors (e.g. TusA, SufE, and CsdE) prior to its utilization. Here, we report the structures of CsdA and the CsdA-CsdE complex, which provide insight into the sulfur transfer mediated by the trans-persulfuration reaction. Analysis of the structures indicates that the conformational flexibility of the active cysteine loop in CsdE is essential for accepting the persulfide from the cysteine of CsdA. Additionally, CsdA and CsdE invoke a different binding mode than those of previously reported cysteine desulfurase (IscS) and sulfur acceptors (TusA and IscU). Moreover, the conservation of interaction-mediating residues between CsdA/SufS and CsdE/SufE further suggests that the SufS-SufE interface likely resembles that of CsdA and CsdE.
Highlights
Cysteine desulfurases deliver sulfur from cysteine to sulfur acceptors for sulfur utilization in various biological processes
Structure Determination and Refinement—The positions of three E. coli CsdAs in the free CsdA crystal asymmetric units were determined by molecular replacement using E. coli SufS as a search model (PDB code 1C0N) against data from all the resolution shells
The positions of two E. coli CsdAs in the CsdA-CsdE complex crystal were determined by molecular replacement using the CsdA structure as a search model against data from all the resolution shells in PHASER
Summary
Cysteine desulfurases deliver sulfur from cysteine to sulfur acceptors for sulfur utilization in various biological processes. Structure Determination and Refinement—The positions of three E. coli CsdAs in the free CsdA crystal asymmetric units were determined by molecular replacement using E. coli SufS as a search model (PDB code 1C0N) against data from all the resolution shells. The positions of two E. coli CsdAs in the CsdA-CsdE complex crystal were determined by molecular replacement using the CsdA structure as a search model against data from all the resolution shells in PHASER.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
