8DKY

Crystal structure of the Aquifex aeolicus Wzt Carbohydrate Binding Domain bound to 3-O-methyl-D-mannose

Summary for 8DKY

• Entry DOI: 10.2210/pdb8dky/pdb
• Descriptor: ABC transporter, 3-O-methyl-alpha-D-mannopyranose (3 entities in total)
• Functional Keywords: o antigen abc transporter, carbohydrate binding domain, 3-o-methyl-d-mannose, sugar binding protein
• Biological source: Aquifex aeolicus VF5
• Total number of polymer chains: 2
• Total formula weight: 33674.68

Authors

Spellmon, N.,Zimmer, J. (deposition date: 2022-07-06, release date: 2022-09-21, Last modification date: 2023-10-18)

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

X-RAY DIFFRACTION (1.61 Å)