PMID:24958725

Citation	Yamashita, M, Shepherd, M, Booth, WI, Xie, H, Postis, V, Nyathi, Y, Tzokov, SB, Poole, RK, Baldwin, SA and Bullough, PA (2014) Structure and function of the bacterial heterodimeric ABC transporter CydDC: stimulation of ATPase activity by thiol and heme compounds. J. Biol. Chem. 289:23177-88
Abstract	In Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ATP-binding cassette-type cysteine/GSH transporter, CydDC. Recombinant CydDC was purified as a heterodimer and found to be an active ATPase both in soluble form with detergent and when reconstituted into a lipid environment. Two-dimensional crystals of CydDC were analyzed by electron cryomicroscopy, and the protein was shown to be made up of two non-identical domains corresponding to the putative CydD and CydC subunits, with dimensions characteristic of other ATP-binding cassette transporters. CydDC binds heme b. Detergent-solubilized CydDC appears to adopt at least two structural states, each associated with a characteristic level of bound heme. The purified protein in detergent showed a weak basal ATPase activity (approximately 100 nmol Pi/min/mg) that was stimulated ∼3-fold by various thiol compounds, suggesting that CydDC could act as a thiol transporter. The presence of heme (either intrinsic or added in the form of hemin) led to a further enhancement of thiol-stimulated ATPase activity, although a large excess of heme inhibited activity. Similar responses of the ATPase activity were observed with CydDC reconstituted into E. coli lipids. These results suggest that heme may have a regulatory role in CydDC-mediated transmembrane thiol transport.
Links	PubMed PMC4132815 Online version:10.1074/jbc.M114.590414
Keywords	ATP-Binding Cassette Transporters/chemistry; ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism; Adenosine Triphosphatases/chemistry; Adenosine Triphosphatases/genetics; Adenosine Triphosphatases/metabolism; Biological Transport, Active/physiology; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Heme/chemistry; Heme/genetics; Heme/metabolism; Protein Multimerization; Protein Structure, Quaternary; Structure-Activity Relationship
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:CYDD	enables	GO:0016887: ATPase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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