Abstract
Cyclobutane pyrimidine dimer (CPD) photolyase, which is widely distributed amongst species, ranging from bacteria to plants, is a crucial factor for determining UVB sensitivity in plants. We previously found that the native CPD photolyase of rice was phosphorylated in vivo. There is no report that CPD photolyase is phosphorylated in organism other than rice. First, we investigated the phosphorylation state on CPD photolyase in poaceous species, such as wheat, barley, and maize, by the technique of protein phosphatase treatment or two-dimentional gel electrophoresis. As a result, native wheat CPD photolyase was also phosphorylated, while barley or maize was not.
It is important to identify the phosphorylation site of CPD photolyase, in order to understand the phosphorylated CPD photolyase function in vivo. We estimate the putative phosphorylation site by comparing the amino acid sequence of phosphorylated and nonphosphorylated CPD photolyase, and then tried to identify the phosphorylation site of rice CPD photolyase using site-directed mutagenesis method and insect cell-free translation system. As a result, we identify the phosphorylation site of native rice CPD photolyase.
