Morphology of interacting proteins (CorA) by a coarse-grained Monte Carlo simulation

A transmembrane protein such as CorA performs selective transport of magnesium across the membrane with specific functions of its inner (iCorA) and outer (oCorA) membrane segments and known to exist as a homo-pentamer. The thermal response of iCorA is found [1, 2] to differ from that of oCorA in both native and denatured phases. Self-organized structures of proteins (CorA and iCorA) are examined by a coarse-grained model as a function of protein concentration at a range of temperatures. The collective structures show clear distinctions in morphology visually in its dilute concentration from that in the crowded (dense) protein matrix both at low and high temperatures. The effective dimension D of CorA assembly is found to be lower (D £ 2) than that of iCorA segments which remain globular (D ~ 3) at almost all length scales in its native phase. Based on the higher structural response, (i.e. structure factor and radius of gyration) in its native phase, the inner-segments may be more conducive to transient channel pathways due to cooperative protein-protein interactions.

[1] Kitjaruwankul Sunan et al. J. Chem. Phys. 145, 135101 (2016).
[2] Kitjaruwankul Sunan et al. Physica A 506, 987 (2018).