9RVXSummary for 9RVX
| Entry DOI | 10.2210/pdb9rvx/pdb |
| Related | 9RVQ |
| Descriptor | TonB-dependent receptor, CITRATE ANION (3 entities in total) |
| Functional Keywords | tbdt, tonb dependet transporter, copper, transport protein |
| Biological source | Bordetella pertussis |
| Total number of polymer chains | 2 |
| Total formula weight | 159298.47 |
| Authors | |
| Primary citation | Hachmi, M.,Mirgaux, M.,Wintjens, R.,Carassus, C.,Arnoux, P.,Roy, G.,Rivera-Millot, A.,Slupek, S.,Debrie, A.S.,Alaimo, V.,Billon, G.,Coutte, L.,Antoine, R.,Jacob-Dubuisson, F. A new family of TonB-dependent copper transporters linked to respiratory oxidase function. J.Biol.Chem., 302:111180-111180, 2026 Cited by PubMed Abstract: Copper is an essential metal notably found in respiration complexes for its redox properties. It is also toxic hence its cellular trafficking is tightly controlled. Bacteria have developed a number of defense systems against copper excess, but its acquisition pathways remain poorly characterized. Ubiquitous in Gram-negative bacteria, TonB-dependent transporters (TBDTs) are outer membrane β-barrel proteins that mediate the proton motive force-dependent import of various nutrients to the periplasm. Here, we characterized a TBDT that imports copper in the whooping cough agent Bordetella pertussis, CrtA (formerly BfrG), which is a prototype of a new subfamily of TBDTs. Our data indicate that CrtA is dedicated to the import of copper for heme-copper respiratory oxidoreductases. We revealed that CrtA imports chelated rather than free copper, solved the crystal structure of CrtA and identified a conserved ligand binding site. By combining bacterial growth experiments, biophysical approaches and AlphaFold3 modeling we sketched out the features of copper-ligand complexes for CrtA. In contrast with ferrisiderophore-specific TBDTs, no high-affinity chalkophore ligand of CrtA could be identified, implying two nonmutually exclusive models. In the host, CrtA might use a xenometallophore produced by another species present in the same niche to acquire copper. In vitro however, CrtA appears not to have high-affinity ligands but to import copper chelated by small molecules notably harboring carboxylate groups, which might represent a paradigm of 'scavenger' TBDTs with low ligand selectivity. We identified an essential, invariant histidine residue that might serve as a selectivity filter for copper-chelate complexes. PubMed: 41570985DOI: 10.1016/j.jbc.2026.111180 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.295 Å) |
Structure validation
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