Dark recovery kinetics of YtvAL to YtvAD.

<p><b>A.</b> Dark recovery of YtvAL to YtvAD in <i>E. coli</i> colonies expressing YtvA deposited on a glass coverslip, after 5 minutes illumination with LED465, monitored through fluorescence emission of YtvAD. The blue bars indicate illumination periods with LED465, black bars indicate that colonies were kept in the dark. T = 25°C. <b>B.</b> Dark relaxation of YtvAL to YtvAD, as monitored by the recovery of fluorescence emission after switching off LED465. Blue, buffered YtvA solution; red, <i>E. coli</i> colonies expressing YtvA soaked in 10 mM phosphate buffer solution, containing 0.9% NaCl (W/V), pH = 7.4; green, <i>E. coli</i> colonies expressing YtvA smeared on a glass coverslip. T = 25°C. Black solid lines correspond to fits with a stretched exponential relaxation (<i>E. coli</i> colonies expressing YtvA smeared on a glass coverslip) or with an exponential decay (YtvA solution and bacteria soaked in a buffer). <b>C.</b> Dark relaxation of YtvAL to YtvAD after 5 minutes illumination with LED465 of <i>B. subtilis</i> colonies expressing YtvA. Green curves were measured for colonies smeared on a glass plate, red curves were obtained for colonies soaked in an isotonic buffer. Black curves are the best fits with an exponential decay (colonies soaked in a buffer) or a stretched exponential decay (colonies smeared on a glass plate). Fitting parameters are reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107489#pone-0107489-t001" target="_blank">Table 1</a>.