Liere K, Link G
Plant Cell Physiology and Molecular Biology, University of Bochum, D-44780 Bochum, Germany.
Nucleic Acids Res. 1997 Jun 15;25(12):2403-8. doi: 10.1093/nar/25.12.2403.
Chloroplast RNA-binding protein p54 is an endoribonuclease required for 3'end-processing of plastid precursor transcripts. We find that purified p54 can serve as a phosphate acceptor for protein kinases in vitro. Both the processing and RNA-binding activities of p54 are enhanced by phosphorylation and decreased by dephosphorylation. In addition, the enzyme is activated by the oxidized form of glutathione and inhibited by the reduced form, whereas other redox reagents that were tested showed no effect. Kinase treatment of p54 prior to oxidation by glutathione resulted in highest levels of activation, suggesting that phosphorylation and redox state act together to control p54 activity in vitro and possibly also in vivo.
叶绿体RNA结合蛋白p54是质体前体转录本3'末端加工所需的一种核糖核酸内切酶。我们发现纯化的p54在体外可作为蛋白激酶的磷酸受体。p54的加工和RNA结合活性均通过磷酸化增强,通过去磷酸化降低。此外,该酶被谷胱甘肽的氧化形式激活,被还原形式抑制,而所测试的其他氧化还原试剂则无影响。在谷胱甘肽氧化之前对p54进行激酶处理可导致最高水平的激活,这表明磷酸化和氧化还原状态共同作用以在体外以及可能在体内控制p54的活性。