8DKU

CryoEM structure of the A. aeolicus WzmWzt transporter bound to the native O antigen

Summary for 8DKU

• Entry DOI: 10.2210/pdb8dku/pdb
• EMDB information: 27491
• Descriptor: ABC transporter, Transport permease protein, 6-deoxy-3-O-methyl-alpha-D-mannopyranose-(1-3)-beta-D-rhamnopyranose-(1-2)-alpha-D-rhamnopyranose (3 entities in total)
• Functional Keywords: o antigen, abc transporter, cbd-dependent, translocase
• Biological source: Aquifex aeolicus VF5; More
• Total number of polymer chains: 4
• Total formula weight: 153095.03

Authors

Spellmon, N.,Muszynski, A.,Vlach, J.,Zimmer, J. (deposition date: 2022-07-06, release date: 2022-09-21, Last modification date: 2024-06-12)

Primary citation

Spellmon, N.,Muszynski, A.,Gorniak, I.,Vlach, J.,Hahn, D.,Azadi, P.,Zimmer, J.
Molecular basis for polysaccharide recognition and modulated ATP hydrolysis by the O antigen ABC transporter.
Nat Commun, 13:5226-5226, 2022

PubMed Abstract: O antigens are ubiquitous protective extensions of lipopolysaccharides in the extracellular leaflet of the Gram-negative outer membrane. Following biosynthesis in the cytosol, the lipid-linked polysaccharide is transported to the periplasm by the WzmWzt ABC transporter. Often, O antigen secretion requires the chemical modification of its elongating terminus, which the transporter recognizes via a carbohydrate-binding domain (CBD). Here, using components from A. aeolicus, we identify the O antigen structure with methylated mannose or rhamnose as its cap. Crystal and cryo electron microscopy structures reveal how WzmWzt recognizes this cap between its carbohydrate and nucleotide-binding domains in a nucleotide-free state. ATP binding induces drastic conformational changes of its CBD, terminating interactions with the O antigen. ATPase assays and site directed mutagenesis reveal reduced hydrolytic activity upon O antigen binding, likely to facilitate polymer loading into the ABC transporter. Our results elucidate critical steps in the recognition and translocation of polysaccharides by ABC transporters.

PubMed: 36064941
DOI: 10.1038/s41467-022-32597-2

Experimental method

ELECTRON MICROSCOPY (3.2 Å)