2hqs
Crystal structure of TolB/Pal complex
Structural highlights
FunctionTOLB_ECOLI Involved in the TonB-independent uptake of group A colicins (colicins A, E1, E2, E3 and K). Necessary for the colicins to reach their respective targets after initial binding to the bacteria.[HAMAP-Rule:MF_00671] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe report the crystal structure of the Escherichia coli TolB-Pal complex, a protein-protein complex involved in maintaining the integrity of the outer membrane (OM) in all Gram-negative bacteria that is parasitized by colicins (protein antibiotics) to expedite their entry into cells. Nuclease colicins competitively recruit TolB using their natively disordered regions (NDRs) to disrupt its complex with Pal, which is thought to trigger translocation of the toxin across a locally destabilized OM. The structure shows induced-fit binding of peptidoglycan-associated lipoprotein (Pal) to the beta-propeller domain of TolB causing the N-terminus of one of its alpha-helices to unwind and several residues to undergo substantial changes in conformation. The resulting interactions with TolB are known to be essential for the stability of the complex and the bacterial OM. Structural comparisons with a TolB-colicin NDR complex reveal that colicins bind at the Pal site, mimicking rearranged Pal residues while simultaneously appearing to block induced-fit changes in TolB. The study therefore explains how colicins recruit TolB in the bacterial periplasm and highlights a novel binding mechanism for a natively disordered protein. Molecular mimicry enables competitive recruitment by a natively disordered protein.,Bonsor DA, Grishkovskaya I, Dodson EJ, Kleanthous C J Am Chem Soc. 2007 Apr 18;129(15):4800-7. Epub 2007 Mar 22. PMID:17375930[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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