Bacterial Mechanosensitive Channels
Mechanosensitive (MS) channels protect bacteria against hypo-osmotic shock and fulfil additional functions. Hypo-osmotic shock leads to high turgor pressure that can cause cell rupture and death. MS channels open under these conditions and release unspecifically solutes and consequently the turgor pressure. They can recognise the raised pressure via the increased tension in the cell membrane. Currently, a better understanding how MS channels can sense tension on molecular level is developing because the interaction of the lipid bilayer with the channel is being investigated in detail. The MS channel of large conductance (MscL) and of small conductance (MscS) have been distinguished and studied in molecular detail. In addition, larger channels were found that contain a homologous region corresponding to MscS so that MscS represents a family of channels. Often several members of this family are present in a species. The importance of this family is underlined by the fact that members can be found not only in bacteria but also in higher organisms. While MscL and MscS have been studied for years in particular by electrophysiology, mutagenesis, molecular dynamics, X-ray crystallography and other biophysical techniques, only recently more details are emerging about other members of the MscS-family.
KeywordsMechanosensitive channels Lipid-protein interaction Hypo-osmotic shock Channel mechanism Bacterial stress response
- Carney J, East JM, Mall S et al (2006) Fluorescence quenching methods to study lipid-protein interactions. Curr Protoc Protein Sci Chapter 19:Unit 19.12Google Scholar
- Edwards MD, Li Y, Kim S et al (2005) Pivotal role of the glycine-rich TM3 helix in gating the MscS mechanosensitive channel. Nat Struc. Mol Biol 12:113–119Google Scholar
- Malcolm HR, Elmore DE, Maurer JA (2012a) Mechanosensitive behavior of bacterial cyclic nucleotide gated (bCNG) ion channels: insights into the mechanism of channel gating in the mechanosensitive channel of small conductance superfamily. Biochem Biophys Res Commun 417:972–976PubMedCrossRefGoogle Scholar