A model for allosteric communication in drug transport by the AcrAB-TolC tripartite efflux pump
View / Open Files
Authors
Journal Title
Antibiotics
ISSN
2079-6382
Publisher
MDPI AG
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Luisi, B. (2022). A model for allosteric communication in drug transport by the AcrAB-TolC tripartite efflux pump. Antibiotics https://doi.org/10.17863/CAM.80150
Abstract
RND family efflux pumps are complex macromolecular machines involved in multidrug re-sistance by extruding antibiotics from the cell. While structural studies and molecular dynamics simulations have provided insights into the architecture and conformational states of the pumps, the path followed by conformational changes from the inner membrane protein (IMP) to the periplasmic membrane fusion protein (MFP) and to the outer membrane protein (OMP) is not fully understood. Here, we investigate AcrAB-TolC efflux pump’s allostery, by comparing resting and transport states using difference distance matrices supplemented with evolutionary couplings data and buried surface area measurements. Our analysis indicates that substrate binding by the IMP triggers quaternary level conformational changes in the MFP, which trigger OMP to switch from the closed state to the open state, accompanied by a considerable increase in the interface area between the MFP subunits and between the OMPs and MFPs. This suggests that the pump’s transport-ready state is at a more favourable energy level than the resting state, but raises the puzzle of how the pump does not become stably trapped in a transport-intermediate state. We propose a model for pump allostery that includes a downhill energetic transition process from a proposed ‘activated’ transport state back to the resting pump.
Sponsorship
ERC
Funder references
European Research Council (742210)
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.80150
This record's URL: https://www.repository.cam.ac.uk/handle/1810/332706
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.