6PAR
Structure of a bacterial Atm1-family ABC exporter with MgAMPPNP bound
Summary for 6PAR
| Entry DOI | 10.2210/pdb6par/pdb |
| Related | 6PAM 6PAN 6PAO 6PAQ |
| Descriptor | ATM1-type heavy metal exporter, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, MAGNESIUM ION (3 entities in total) |
| Functional Keywords | abc transporter, abc exporter, atpase, membrane protein, transport protein |
| Biological source | Novosphingobium aromaticivorans (strain ATCC 700278 / DSM 12444 / CIP 105152 / NBRC 16084 / F199) |
| Total number of polymer chains | 6 |
| Total formula weight | 409812.62 |
| Authors | Fan, C.,Kaiser, J.T.,Rees, D.C. (deposition date: 2019-06-11, release date: 2020-06-24, Last modification date: 2023-10-11) |
| Primary citation | Fan, C.,Kaiser, J.T.,Rees, D.C. A structural framework for unidirectional transport by a bacterial ABC exporter. Proc.Natl.Acad.Sci.USA, 117:19228-19236, 2020 Cited by PubMed Abstract: The ATP-binding cassette (ABC) transporter of mitochondria (Atm1) mediates iron homeostasis in eukaryotes, while the prokaryotic homolog from (Atm1) can export glutathione derivatives and confer protection against heavy-metal toxicity. To establish the structural framework underlying the Atm1 transport mechanism, we determined eight structures by X-ray crystallography and single-particle cryo-electron microscopy in distinct conformational states, stabilized by individual disulfide crosslinks and nucleotides. As Atm1 progresses through the transport cycle, conformational changes in transmembrane helix 6 (TM6) alter the glutathione-binding site and the associated substrate-binding cavity. Significantly, kinking of TM6 in the post-ATP hydrolysis state stabilized by MgADPVO eliminates this cavity, precluding uptake of glutathione derivatives. The presence of this cavity during the transition from the inward-facing to outward-facing conformational states, and its absence in the reverse direction, thereby provide an elegant and conceptually simple mechanism for enforcing the export directionality of transport by Atm1. One of the disulfide crosslinked Atm1 variants characterized in this work retains significant glutathione transport activity, suggesting that ATP hydrolysis and substrate transport by Atm1 may involve a limited set of conformational states with minimal separation of the nucleotide-binding domains in the inward-facing conformation. PubMed: 32703810DOI: 10.1073/pnas.2006526117 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.35 Å) |
Structure validation
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