4p31
Crystal structure of a selenomethionine derivative of E. coli LptB in complex with ADP-Magensium
Structural highlights
FunctionLPTB_ECOLI Part of the ABC transporter complex LptBFG involved in the translocation of lipopolysaccharide (LPS) from the inner membrane to the outer membrane. Probably responsible for energy coupling to the transport system.[1] [2] [3] Publication Abstract from PubMedThe cell surface of Gram-negative bacteria contains lipopolysaccharides (LPS), which provide a barrier against the entry of many antibiotics. LPS assembly involves a multiprotein LPS transport (Lpt) complex that spans from the cytoplasm to the outer membrane. In this complex, an unusual ATP-binding cassette transporter is thought to power the extraction of LPS from the outer leaflet of the cytoplasmic membrane and its transport across the cell envelope. We introduce changes into the nucleotide-binding domain, LptB, that inactivate transporter function in vivo. We characterize these residues using biochemical experiments combined with high-resolution crystal structures of LptB pre- and post-ATP hydrolysis and suggest a role for an active site residue in phosphate exit. We also identify a conserved residue that is not required for ATPase activity but is essential for interaction with the transmembrane components. Our studies establish the essentiality of ATP hydrolysis by LptB to power LPS transport in cells and suggest strategies to inhibit transporter function away from the LptB active site. Decoupling catalytic activity from biological function of the ATPase that powers lipopolysaccharide transport.,Sherman DJ, Lazarus MB, Murphy L, Liu C, Walker S, Ruiz N, Kahne D Proc Natl Acad Sci U S A. 2014 Mar 17. PMID:24639492[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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