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

Figure 8

Schematic drawing of the signal relay from the receptor (ppR) to the transducer (pHtrII) in the archaeal photosensory transduction. In the X-ray crystallographic structure of the complex between ppR (left) and pHtrII (right) (PDB code, 1H2S) [29], the structure of pHtrII at position 83–114 was not determined, suggesting multiple conformations of the region. The association between ppR and pHtrII originates mostly from van der Waals contacts in the transmembrane region, whereas Tyr199 and Thr189 of ppR form hydrogen bonds with Asn74 and Glu43/Ser62 of pHtrII, respectively.