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

Figure 2

(The upper region) X-ray crystallographic structure of the complex between ppR and pHtrII (PDB code, 1H2S) [29]. (The lower panel) Details of the X-ray crystallographic structure of the ppR/pHtrII complex [29] focusing on specific hydrogen bonds. Hydrogen bond between Tyr199 of ppR and Asn74 of pHtrII, whose distance is 2.7Å, and hydrogen bond between Tyr174 and Thr204 in pHtrII, whose distance is 3.2 Å, are shown. (F) and (G) helices of ppR that involve Tyr174 and Thr204, respectively, are sandwiched by the retinal chromophore and TM1 and TM2 helices of pHtrII.