Protein-Protein Interaction Changes in an Archaeal Light-Signal Transduction

Figure 1

Schematic representation of pharaonis phoborhodospin (ppR) and its transducer (pHtrII). ppR and pHtrII form a 2 : 2 complex in the membrane, former of which contains all-trans retinal as the chromophore. ppR absorbs maximally at 498 nm, and light absorption initiates the photocycle. Light signal is transferred into the cytoplasmic domain through the protein structural changes of pHtrII.