5HNO

The structure of the kdo-capped saccharide binding subunit of the O-12 specific ABC transporter, Wzt

Summary for 5HNO

• Entry DOI: 10.2210/pdb5hno/pdb
• Related: 5HNP
• Descriptor: ABC type transport system putative ATP binding protein, CHLORIDE ION (3 entities in total)
• Functional Keywords: o antigen export, carbohydrate binding subunit, abc transporter, transport protein
• Biological source: Raoultella terrigena
• Total number of polymer chains: 3
• Total formula weight: 62637.45

Authors

Mallette, E.,Mann, E.,Whitfield, C.,Kimber, M.S. (deposition date: 2016-01-18, release date: 2016-03-09, Last modification date: 2024-03-06)

Primary citation

Mann, E.,Mallette, E.,Clarke, B.R.,Kimber, M.S.,Whitfield, C.
The Klebsiella pneumoniae O12 ATP-binding Cassette (ABC) Transporter Recognizes the Terminal Residue of Its O-antigen Polysaccharide Substrate.
J.Biol.Chem., 291:9748-9761, 2016

PubMed Abstract: Export of the Escherichia coli serotype O9a O-antigenic polysaccharides (O-PS) involves an ATP-binding cassette (ABC) transporter. The process requires a non-reducing terminal residue, which is recognized by a carbohydrate-binding module (CBM) appended to the C terminus of the nucleotide-binding domain of the transporter. Here, we investigate the process in Klebsiella pneumoniae serotype O12 (and Raoultella terrigena ATCC 33257). The O12 polysaccharide is terminated at the non-reducing end by a β-linked 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) residue. The O12 ABC transporter also binds its cognate O-PS via a CBM, and export is dependent on the presence of the terminal β-Kdo residue. The overall structural architecture of the O12 CBM resembles the O9a prototype, but they share only weak sequence similarity, and the putative binding pocket for the O12 glycan is different. Removal of the CBM abrogated O-PS transport, but export was restored when the CBM was expressed in trans with the mutant CBM-deficient ABC transporter. These results demonstrate that the CBM-mediated substrate-recognition mechanism is evolutionarily conserved and can operate with glycans of widely differing structures.

PubMed: 26934919
DOI: 10.1074/jbc.M116.719344

Experimental method

X-RAY DIFFRACTION (1.7 Å)