Temperature- and solvent-responsive structures of CorA protein and its membrane segments

Solvent-responsive structures of CorA Mg$^{2+}$ channel (corA) with well-defined inner (icorA) and outer (ocorA) membrane components play a critical role in selective transport of magnesium across biological membranes. Using a coarse-grained Monte Carlo simulation, we study the effects of solvent quality on the structures of corA, icorA and ocorA at different temperatures. A knowledge-based residue-residue interaction along with a set of residue-solvent interaction (\textit{Vs}) based on the hydropathy index are used in a matrix with explicit solvent particles. We monitor targeted binding of solvent particles for a range of its interaction strength ($f)$ to emulate the underlying matrix environment. We find that the spread of the structure of corA (and ocorA) measured by the radius of gyration (Rg) responds non-monotonically (i.e. the increase of Rg followed by decay) with the interaction $f$ at higher temperature; decay of Rg with $f$ at lower T is slower. The structure of icorA remains least affected by the solvent interaction strength. Effects of emulated membrane matrix may also be presented as the data becomes available.