Flexibility of the Cytoplasmic Domain of the Phototaxis Transducer II from Natronomonas pharaonis
Figure 1
(a) X-ray crystal
structure model of the Tsr-cyt (PDB ID 1QU7) corresponding to identical
positions of the pHtrII-cyt investigated in this study. (b) Top, prediction of
coiled-coil structure for pHtrII-cyt by the COILS software (Section 2.5)
and below, prediction of secondary structure for pHtrII-cyt by the DSC software
(Section 2.5). (c) Comparison of FTIR spectra of 10 mg/mL pHtrII-cyt in
buffer C (solid line) and in dry film (dashed line) at room temperature. (d)–(f) Effects
of increasing (d) TFE, (e) glycerol ,
and (f) ammonium sulfate (in % of saturation) concentrations on far-UV CD
spectra of pHtrII-cyt recorded at protein concentration of 0.1 mg/mL at +20
(left panel, colors correspond to TFE, glycerol, or ammonium sulfate
concentration) and deduced secondary structure content (right panel, colors
correspond to the content of secondary structure elements). The secondary
structure content estimations were generated by the CONTIN/LL program from the
CDPro package (Section 2.5); secondary structure elements are designated
as follows: helix—black, sheet—red, turn—green, and random coil—blue.
