Abstract
CPD photolyase is a crucial factor for determining the sensitivity of plant to UVB. CPD photolyases classified into two classes, class I and class II, based on their similarity of amino acid sequence. Class I CPD photolyase has been studied well. However, little is known about class II CPD photolyase. To characterize rice class II CPD photolyase, the enzyme from rice leaves was purified. SDS-PAGE of the purified enzyme showed existence of two proteins of about 54- and 56-kDa, whereas rice CPD photolyase expressed from E. coli was a single 55-kDa protein. Western blot analysis using anti-rice CPD photolyase antibody showed that both proteins were CPD photolyase. Treatment with protein phosphatase revealed that the 56-kDa native rice CPD photolyase was phosphorylated, whereas the E. coli-expressed rice CPD photolyase was not. Furthermore, the purified native rice CPD photolyase had significantly higher CPD photorepair activity than the E. coli-expressed rice CPD photolyase.
