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. 1998 Jun 23;95(13):7396–7401. doi: 10.1073/pnas.95.13.7396

Figure 4.

Figure 4

FTIR pG − pB difference spectra of PYP and hybrid I (A) and the kinetics of the transition between pG and the pB-like intermediate of hybrid I (B). (A) FTIR difference spectra of PYP (upper trace) and hybrid I (lower trace), before minus after illumination (i.e., pG − pB spectra) were recorded as described in Materials and Methods, at pH 7.0. By using a combination of UV/Vis and IR spectroscopy, it could be derived that the levels of photoconversion of pG into the pB intermediate in the IR spectrometer, for PYP and hybrid I, were 10% and 40%, respectively. (B) A time series of spectra was measured by averaging 381 scans for each time point, during light-induced formation, and dark decay, of the pB-like intermediate of hybrid I, over a period of 20 min. Acquisition of each spectrum takes ≈4 min. The data obtained were fitted to an exponential rise (▪) or decay (•) function.