Mechanism of selective stabilization of extrinsic polypeptides in PSII particles by glycinebetaine.
The effect of glycinebetaine in selectively stabilizing the PSII extrinsic polypeptides was studied with PSII particles treated with different methods. It wan shown that glycinebetaine markedly stabilized the PSII extrinsic polypeptides when the partictes were treated with 0.8 mol/L Tris (pH8.0) or high concentrations of NaCI. The stabilizing effect was less pronounced when the PSII particles were treated by heat shok or trichlorocetate (TCA). The capability of halogenated acetates to release extrinsic polypeptides in PSII particles was found to follow the order of decreasing molecular hydrophobicities: trichloroacetate (TCA) > dichloroacetate (DCA) > monoiodoacetate (MIA) > monobromoacetate (MBA) > monochloroacetate (MCA). All these results imply that glycinebtaine is effective in stabilizing biopolymer structure against the action of electrolytes, while it is ineffective in protecting extrinsic polypeptides in PSII particles fm dissociation induced by halogenated acetates or heat treatments which disturbed the hydmphobic interactions within the polypeptides.
Caixia
H
H
Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, 200032, Shanghai, China.
Xinjian
Y
Y
Rong
L
L
Zhangcheng
T
T
Yungang
S
S
Chumhe
X
X