Functional Dynamics Revealed by the Structure of the SufBCD Complex, a Novel ATP-binding Cassette (ABC) Protein That Serves as a Scaffold for Iron-Sulfur Cluster Biogenesis

Abstract

ATP-binding cassette (ABC)-typeATPases are chemomechanical engines involved in diverse biological pathways. Recent genomic information reveals that ABC ATPase domains/subunits act not only in ABC transporters and structural maintenance of chromosome proteins, but also in iron-sulfur (Fe-S) cluster biogenesis. A novel type of ABC protein, the SufBCD complex, functions in the biosynthesis of nascent Fe-S clusters in almost all Eubacteria and Archaea, as well as eukaryotic chloroplasts. In this study, we determined the first crystal structure of the Escherichia coli SufBCD complex, which exhibits the common architecture of ABC proteins: two ABC ATPase components (SufC) with function-specific components (SufB-SufD protomers). Biochemical and physiological analyses based on this structure provided critical insights into Fe-S cluster assembly and revealed a dynamic conformational change driven by ABC ATPase activity. We propose a molecular mechanism for the biogenesis of the Fe-S cluster in the SufBCD complex.

Combing Chromosomal DNA Mediated by the SMC Complex: Structure and Mechanisms

“…The model also suggests that the two arms force the head domains into a non‐engaged position (Figure A), and argues that their subsequent engagement mechanically opens the inter‐arm space. This resting mode is also observed in complexes containing the ABC‐type ATPase domain . The two arms probably constantly search for suitable contacts within the restricted range to avoid repulsion between residues having the same electropotential charge.…”

Biological and Chemical Adaptation to Endogenous Hydrogen Peroxide Production in Streptococcus pneumoniae D39

“…The SufBCD complex (76) is highly abundant in our cells (Fig. 5A; Table S2A and B) in contrast to the cysteine desulfurase SufS and the putative Fe-S scaffold protein SufU; furthermore, SufB and SufD are sulfenylated or sulfonylated (SufD) in cells (Fig.…”

[Fe–S] cluster assembly in the apicoplast and its indispensability in mosquito stages of the malaria parasite

“…5B) are in proximity to the PfSufC-PfSufD interaction pocket suggesting that conformational changes imposed by interaction with PfSufD enhance ATP hydrolysis by PfSufC. As in E. coli, PfSufB-PfSufD are likely to provide the scaffold in the PfSufB-C 2 -D complex [38,46]; the presence of conserved residues (Cys 379 in PfSufB and His 1396 in PfSufD) that position at the PfSufB-PfSufD interface (Fig. 5C) and have recently been shown to be indispensable for [Fe-S] assembly [38] supports this view.…”

“…As in E. coli , Pf SufB– Pf SufD are likely to provide the scaffold in the Pf SufB‐C 2 ‐D complex ; the presence of conserved residues (Cys 379 in Pf SufB and His 1396 in Pf SufD) that position at the Pf SufB– Pf SufD interface (Fig. C) and have recently been shown to be indispensable for [Fe–S] assembly supports this view. A critical role of SufD for in vivo iron acquisition has been proposed and the protein has been shown to be dispensable for in vivo sulfur transfer in bacteria , suggesting involvement of Pf SufD in channeling iron from the source to the scaffold.…”

“…These results suggest that PfSufB-C 2 -D is likely to function as a scaffold in the apicoplast capable of assembling [4Fe-4S] clusters. The level of cluster formation on the P. falciparum complex is lower than that observed for E. coli SufB-C 2 -D [36,38]. This could be because recombinant PfSufB int represents only an internal region of P. falciparum SufB [17]; although PfSufB int interacts with both PfSufD and PfSufC, efficiency of cluster formation might be compromised.…”