5C76

ATP-driven lipid-linked oligosaccharide flippase PglK in apo-inward facing state (2)

Summary for 5C76

• Entry DOI: 10.2210/pdb5c76/pdb
• Descriptor: WlaB protein (1 entity in total)
• Functional Keywords: abc transporter flippase, transport protein
• Biological source: Campylobacter jejuni
• Total number of polymer chains: 4
• Total formula weight: 258350.70

Authors

Perez, C.,Gerber, S.,Locher, K.P. (deposition date: 2015-06-24, release date: 2015-08-19, Last modification date: 2024-01-10)

Primary citation

Perez, C.,Gerber, S.,Boilevin, J.,Bucher, M.,Darbre, T.,Aebi, M.,Reymond, J.L.,Locher, K.P.
Structure and mechanism of an active lipid-linked oligosaccharide flippase.
Nature, 524:433-438, 2015

PubMed Abstract: The flipping of membrane-embedded lipids containing large, polar head groups is slow and energetically unfavourable, and is therefore catalysed by flippases, the mechanisms of which are unknown. A prominent example of a flipping reaction is the translocation of lipid-linked oligosaccharides that serve as donors in N-linked protein glycosylation. In Campylobacter jejuni, this process is catalysed by the ABC transporter PglK. Here we present a mechanism of PglK-catalysed lipid-linked oligosaccharide flipping based on crystal structures in distinct states, a newly devised in vitro flipping assay, and in vivo studies. PglK can adopt inward- and outward-facing conformations in vitro, but only outward-facing states are required for flipping. While the pyrophosphate-oligosaccharide head group of lipid-linked oligosaccharides enters the translocation cavity and interacts with positively charged side chains, the lipidic polyprenyl tail binds and activates the transporter but remains exposed to the lipid bilayer during the reaction. The proposed mechanism is distinct from the classical alternating-access model applied to other transporters.

PubMed: 26266984
DOI: 10.1038/nature14953

Experimental method

X-RAY DIFFRACTION (3.94 Å)