Effect of phosphatidylglycerol on conformation and micro-environment of tyrosyl residue in photosystem II.

The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSII), mainly the effect of PG on conformation and microenvironment of tyrosine residues of PSII proteins were studied by Fourier transform infrared (FTIR) spectroscopy. It was found that the binding of PG to PSII particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues. In other words, the PG effect on the PSII results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm(-1) with the enhancement of the absorbance intensity. Additionally, a new spectrum of hydrogen bond was also observed. The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSII proteins.