Cold-shock 310-kD protein uncouples oxidative phosphorylation in plant mitochondria

We studied the effects of cold-shock 310-kD protein (CSP310) isolated from winter rye seedlings on the energetic activity of plant mitochondria. CSP31 0 was shown to enhance nonphosphorylating respiration and uncoupled oxidati ve phosphorylation in isolated mitochondria. The uncoupling effect was enha nced with increasing protein concentration. An antibody against CSP310 inte rfered with the uncoupling effect of CSP310. Free fatty acids were not evid ently involved in uncoupling. The physiological role of uncoupling between oxidation and phosphorylation during plant adaptation to low temperatures i s discussed.