Document Type

Article

Publication Date

2012

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.jmb.2012.02.034

Abstract

We 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 β-propeller domain of TolB causing the N-terminus of one of its α-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.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Molecular Biology, v. 418, issue 5, p. 267-268

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