4mrr
Structure of a bacterial Atm1-family ABC transporter
Structural highlights
FunctionATM1_NOVAD Mediates the ATP-dependent export of glutathione-conjugated substrates, such as heavy metal-glutathione conjugates. ATP hydrolysis is stimulated by glutathione binding. Protects cells against toxic heavy metal ions, such as silver and mercury ions. May also mediate the transport of glutathione-conjugated aromatic hydrocarbons, such as dinitrobenzene.[1] Publication Abstract from PubMedAlthough substantial progress has been achieved in the structural analysis of exporters from the superfamily of adenosine triphosphate (ATP)-binding cassette (ABC) transporters, much less is known about how they selectively recognize substrates and how substrate binding is coupled to ATP hydrolysis. We have addressed these questions through crystallographic analysis of the Atm1/ABCB7/HMT1/ABCB6 ortholog from Novosphingobium aromaticivorans DSM 12444, NaAtm1, at 2.4 angstrom resolution. Consistent with a physiological role in cellular detoxification processes, functional studies showed that glutathione derivatives can serve as substrates for NaAtm1 and that its overexpression in Escherichia coli confers protection against silver and mercury toxicity. The glutathione binding site highlights the articulated design of ABC exporters, with ligands and nucleotides spanning structurally conserved elements to create adaptable interfaces accommodating conformational rearrangements during the transport cycle. Structural basis for heavy metal detoxification by an Atm1-type ABC exporter.,Lee JY, Yang JG, Zhitnitsky D, Lewinson O, Rees DC Science. 2014 Mar 7;343(6175):1133-6. doi: 10.1126/science.1246489. PMID:24604198[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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