6AMX
Crystal Structure of Nucelotide Binding Domain of O-antigen polysaccharide ABC-transporter
Summary for 6AMX
| Entry DOI | 10.2210/pdb6amx/pdb |
| Descriptor | ABC transporter, 3,6,9,12,15,18,21,24-OCTAOXAHEXACOSAN-1-OL (3 entities in total) |
| Functional Keywords | nucleotide binding domain from abct4, transport protein |
| Biological source | Aquifex aeolicus (strain VF5) |
| Total number of polymer chains | 1 |
| Total formula weight | 30051.03 |
| Authors | Zimmer, J.,Bi, Y. (deposition date: 2017-08-11, release date: 2017-11-29, Last modification date: 2024-03-13) |
| Primary citation | Bi, Y.,Mann, E.,Whitfield, C.,Zimmer, J. Architecture of a channel-forming O-antigen polysaccharide ABC transporter. Nature, 553:361-365, 2018 Cited by PubMed Abstract: O-antigens are cell surface polysaccharides of many Gram-negative pathogens that aid in escaping innate immune responses. A widespread O-antigen biosynthesis mechanism involves the synthesis of the lipid-anchored polymer on the cytosolic face of the inner membrane, followed by transport to the periplasmic side where it is ligated to the lipid A core to complete a lipopolysaccharide molecule. In this pathway, transport to the periplasm is mediated by an ATP-binding cassette (ABC) transporter, called Wzm-Wzt. Here we present the crystal structure of the Wzm-Wzt homologue from Aquifex aeolicus in an open conformation. The transporter forms a transmembrane channel that is sufficiently wide to accommodate a linear polysaccharide. Its nucleotide-binding domain and a periplasmic extension form 'gate helices' at the cytosolic and periplasmic membrane interfaces that probably serve as substrate entry and exit points. Site-directed mutagenesis of the gates impairs in vivo O-antigen secretion in the Escherichia coli prototype. Combined with a closed structure of the isolated nucleotide-binding domains, our structural and functional analyses suggest a processive O-antigen translocation mechanism, which stands in contrast to the classical alternating access mechanism of ABC transporters. PubMed: 29320481DOI: 10.1038/nature25190 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.05 Å) |
Structure validation
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