Interaction of monogalactosyldiacylglycerol with cytochrome b6f complex in surface films

► Langmuir monolayer and Brewster angle microscopy study of MGDG/cyt b6f interaction. ► Evaluation of film phase state via surface compressional modulus analysis. ► π/A isotherms fitted by 2D-virial equation of state probe intermolecular interactions. ► Cyt b6f complex depleted MGDG molecules from the surface. ► Specific cyt b6f/MGDG interaction occurs at sub-nanomolar cyt b6f concentrations.