The adaptability of the ion binding site by the Ag(I)/Cu(I) periplasmic chaperone SilF.
The periplasmic chaperone SilF has been identified as part of an Ag(I) detoxification system in Gram negative bacteria. Sil proteins also bind Cu(I), but with reported weaker affinity, therefore leading to the designation of a specific detoxification system for Ag(I). Using isothermal titration calorimetry we show that binding of both ions is not only tighter than previously thought, but of very similar affinities. We investigated the structural origins of ion binding using molecular dynamics and QM/MM simulations underpinned by structural and biophysical experiments. The results of this analysis showed that the binding site adapts to accommodate either ion, with key interactions with the solvent in the case of Cu(I). The implications of this are that Gram negative bacteria do not appear to have evolved a specific Ag(I) efflux system but take advantage of the existing Cu(I) detoxification system. Therefore, there are consequences for how we define a particular metal resistance mechanism and understand its evolution in the environment.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Published in
Journal of Biological ChemistryVolume
299Issue
11Publisher
ElsevierVersion
- VoR (Version of Record)
Rights holder
© The AuthorsPublisher statement
This is an Open Access Article. It is published by Elsevier under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Acceptance date
2023-10-04Publication date
2023-10-14Copyright date
2023ISSN
0021-9258eISSN
1083-351XPublisher version
Language
- en