Moll B A, Eilmann M, Steinback K E
Advanced Genetic Sciences, Inc., 6701 San Pablo Avenue, Oakland, California 94608.
Plant Physiol. 1987 Feb;83(2):428-33. doi: 10.1104/pp.83.2.428.
The phosphorylation of thylakoid proteins of rice (Oryza sativa L.) was studied in vitro using [gamma-(32)P]ATP. Several thylakoid proteins are labeled, including the light-harvesting complex of photosystem II. Protein phosphorylation is sensitive to temperature, pH, and ADP, ATP, and divalent cation concentrations. In the range pH 7 to 8.2, phosphorylation of the light-harvesting polypeptides declines above pH 7.5, whereas labeling of several other thylakoid polypeptides increases. Increasing divalent cation concentration from 3 to 20 millimolar results in a decrease in phosphorylation of the 26 kilodalton light-harvesting complex polypeptide and increased phosphorylation of several other polypeptides. ADP has an inhibitory effect on the phosphorylation of the light-harvesting complex polypeptides. Phosphorylation of the 26 kilodalton light-harvesting polypeptide requires 0.45 millimolar ATP for half-maximal phosphorylation, compared to 0.3 millimolar for the 32 kilodalton phosphoprotein. Low temperature inhibits the phosphorylation of thylakoid proteins in chilling-sensitive rice. However, phosphorylation of histones by thylakoid-bound kinase(s) is independent of temperature in the range of 25 to 5 degrees C, suggesting that the effect of low temperature is on accessibility of the substrate, rather than on the activity of the kinase.
利用[γ-(32)P]ATP对水稻（Oryza sativa L.）类囊体蛋白的磷酸化作用进行了体外研究。有几种类囊体蛋白被标记，包括光系统II的捕光复合体。蛋白磷酸化对温度、pH值以及ADP、ATP和二价阳离子浓度敏感。在pH值7至8.2范围内，捕光多肽的磷酸化在pH值高于7.5时下降，而其他几种类囊体多肽的标记增加。将二价阳离子浓度从3毫摩尔增加到20毫摩尔会导致26千道尔顿捕光复合体多肽的磷酸化减少，而其他几种多肽的磷酸化增加。ADP对捕光复合体多肽的磷酸化有抑制作用。26千道尔顿捕光多肽的磷酸化达到最大磷酸化一半时需要0.45毫摩尔ATP，相比之下，32千道尔顿磷蛋白则需要0.3毫摩尔。低温抑制了冷敏感水稻中类囊体蛋白的磷酸化。然而，类囊体结合激酶对组蛋白的磷酸化在25至5摄氏度范围内与温度无关，这表明低温的影响在于底物的可及性，而非激酶的活性。
