Spectral characterization of Photosystem I fluorescence at room temperature using thylakoid protein phosphorylation

An analysis is presented of the spectral changes in fluorescence emission of thylakoids at room temperature associated with phosphorylation of thylakoid polypeptides. An enhancement of fluorescence above 700 nm relative to emission at 685 nm was observed on phosphorylation, and the spectral characteristics of this enhancement were similar to the fluorescence emission spectrum of an isolated PS I particle at room temperature. The changes in the 77 K fluorescence emission spectra resulting from phosphorylation of the thylakoids were directly related to the spectral changes in fluorescence emission observed at room temperature.