Effective cryoprotection of thylakoid membranes by ATP.

摘要: Freezing of isolated spinach thylakoids in the presence NaCl uncoupled photophosphorylation from electron flow and increased permeability membranes to protons. Addition ATP prior freezing diminished membrane inactivation. On a molar basis, was at least 100 times more effective protecting damage than low-molecularweight carbohydrates such as sucrose glucose. The cryoprotective effectiveness by Mg2+. In absence carbohydrates, preservation during mM saturated about 1–2 ATP, but under these conditions were not fully protected. However, small amounts sugars which did significantly prevent thylakoid inactivation freezing, concentrations considerably lower 0.5 caused nearly complete protection. Neither ADP nor AMP could substitute for ATP. These findings indicate that cryoprotection cannot be explained colligative mechanism. It is suggested acts on chloroplast coupling factor, either modifying its conformation or preventing release membranes. results are discussed regard injury resistance vivo.