6AMX

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

6AMX の概要

• エントリーDOI: 10.2210/pdb6amx/pdb
• 分子名称: ABC transporter, 3,6,9,12,15,18,21,24-OCTAOXAHEXACOSAN-1-OL (3 entities in total)
• 機能のキーワード: nucleotide binding domain from abct4, transport protein
• 由来する生物種: Aquifex aeolicus (strain VF5)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 30051.03

構造登録者

Zimmer, J.,Bi, Y. (登録日: 2017-08-11, 公開日: 2017-11-29, 最終更新日: 2024-03-13)

主引用文献

Bi, Y.,Mann, E.,Whitfield, C.,Zimmer, J.
Architecture of a channel-forming O-antigen polysaccharide ABC transporter.
Nature, 553:361-365, 2018

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

実験手法

X-RAY DIFFRACTION (2.05 Å)