Mg2+-dependent conformational equilibria in CorA and an integrated view on transport regulation
- University of Copenhagen, Denmark
- UMR 5280, CNRS, University of Lyon, France
- University of Queensland, Australia
- Stockholm University, Sweden
- Australian Nuclear Science and Technology Organization, Australia
- Institut Laue-Langevin, France
- University of Oxford, United Kingdom
Abstract
The CorA family of proteins regulates the homeostasis of divalent metal ions in many bacteria, archaea, and eukaryotic mitochondria, making it an important target in the investigation of the mechanisms of transport and its functional regulation. Although numerous structures of open and closed channels are now available for the CorA family, the mechanism of the transport regulation remains elusive. Here, we investigated the conformational distribution and associated dynamic behaviour of the pentameric Mg2+ channel CorA at room temperature using small-angle neutron scattering (SANS) in combination with molecular dynamics (MD) simulations and solid-state nuclear magnetic resonance spectroscopy (NMR). We find that neither the Mg2+-bound closed structure nor the Mg2+-free open forms are sufficient to explain the average conformation of CorA. Our data support the presence of conformational equilibria between multiple states, and we further find a variation in the behaviour of the backbone dynamics with and without Mg2+. We propose that CorA must be in a dynamic equilibrium between different non-conducting states, both symmetric and asymmetric, regardless of bound Mg2+ but that conducting states become more populated in Mg2+-free conditions. These properties are regulated by backbone dynamics and are key to understanding the functional regulation of CorA.
Data availability
SANS data have been deposited in SASBDB under IDs SASDM42, SASDM52, SASDM62, SASDM72.EM data have been uploaded to the Electron Microscopy Data Bank under IDs EMD-13326 and EMD-13327.Activity (fluorescence) data have been uploaded to GitHub at https://github.com/Niels-Bohr-Institute-XNS-StructBiophys/CorAData/.The Metadynamics simulations have been uploaded to GitHub at https://github.com/KULL-Centre/papers/tree/main/2021/CorA-Johansen-et-al.NMR data have been deposited in Biological Magnetic Resonance Data Bank under ID 50959.
Article and author information
Author details
Nicolai Tidemand Johansen
Martin Cramer Pedersen
Kresten Lindorff-Larsen
Funding
Lundbeckfonden (R155-2015-2666)
- Kresten Lindorff-Larsen
- Lise Arleth
European Commission (INFRAIA-01-2018-2019 GA 871037 (iNext Discovery))
- Tamim Darwish
- Tobias Schubeis
- Guido Pintacuda
Villum Fonden (35955)
- Nicolai Tidemand Johansen
- Tobias Schubeis
- Guido Pintacuda
ERC: European Union's Horizon 2020 research and innovation programme (ERC-2015-CoG GA 648974)
- Guido Pintacuda
Novo Nordisk Fonden (NNF15OC0016670)
- Lise Arleth
Biotechnology and Biological Sciences Research Council (BB/R00126X/1)
- Mark SP Sansom
Biotechnology and Biological Sciences Research Council (BB/N000145/1)
- Mark SP Sansom
Engineering and Physical Sciences Research Council (EP/R004722/1)
- Mark SP Sansom
Engineering and Physical Sciences Research Council (EP/R029407/1)
- Mark SP Sansom
Engineering and Physical Sciences Research Council (EP/V010948/1)
- Mark SP Sansom
Wellcome Trust (208361/Z/17/Z)
- Mark SP Sansom
National Collaborative Research Infrastructure Strategy (N/A)
- Tamim Darwish
- Mark SP Sansom
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Johansen et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Mg2+-dependent conformational equilibria in CorA and an integrated view on transport regulation
eLife 11:e71887.
https://doi.org/10.7554/eLife.71887
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