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

Figure 4

(a) 𝑝pR_K minus ppR infrared difference spectra in the absence (red line) and presence (blue line) of the transducer protein, pHtrII, in the 3600–3300 cm⁻¹ region. Spectra are measured at 77 K and pH 7 upon hydration with D₂O. (b–e) 𝑝pR_K minus ppR infrared difference spectra of the wild type (black dotted lines) and mutant (solid lines; (b) Y199F, (c) Y174F, (d) T204A, (e) T204S) proteins of ppR in the presence of pHtrII in the 3600–3300 cm⁻¹ region. Spectra are measured at 77 K and pH 7 upon hydration with D₂O. The original data appeared in [20].