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6AN5

Crystal Structure of The Nucelotide Binding Domain of an O-antigen polysaccharide ABC-transporter

Summary for 6AN5
Entry DOI10.2210/pdb6an5/pdb
DescriptorABC transporter (1 entity in total)
Functional Keywordsnucleotide binding domain of abct4, transport protein
Biological sourceAquifex aeolicus (strain VF5)
Total number of polymer chains2
Total formula weight55320.20
Authors
Zimmer, J.,Bi, Y. (deposition date: 2017-08-12, release date: 2017-11-29, Last modification date: 2024-03-13)
Primary citationBi, 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: 29320481
DOI: 10.1038/nature25190
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (3.512 Å)
Structure validation

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数据于2025-07-02公开中

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