The phase behavior of membrane proteins stems from a complex synergy with the amphiphilic molecules required for their solubilization. We show that ionization of a pH-sensitive surfactant, LDAO, bound to a bacterial photosynthetic protein, the Reaction Center (RC), leads in a narrow pH range to protein liquid-liquid phase separation in surprisingly stable `droplets', forerunning reversible aggregation at lower pH. Phase segregation is promoted by increasing temperature and hindered by adding salt. RC light-absorption and photoinduced electron cycle are moreover strongly affected by phase segregation.
@article{arxiv.cond-mat/0211505,
title = {Liquid-liquid phase separation of a surfactant-solubilized membrane protein},
author = {R. Piazza and M. Pierno and E. Vignati and G. Venturoli and F. Francia and A. Mallardi and G. Palazzo},
journal= {arXiv preprint arXiv:cond-mat/0211505},
year = {2009}
}