Abstract

Casein kinase 2 (CK2) is a ubiquitous serine-threonine protein kinase, which of specific substrates are involved in the regulation of several vital physiological processes in plants. Detailed studies of CK2 have focused on the herbaceous species of Arabidopsis, maize, however, it has remained largely unexplored in woody trees. In this study, we identified the four genes encoding CK2α subunits in a search for Populus genome. Reorganization ofCK2α genes in Populus genome showed that its multiple copies are resulted from segmental duplication and tandem duplication events. Phylogenetic and in silicoexpression analysis indicated that, the divergence was present among poplar CK2αgenes, dividing into type I and type II, and each type represented by relatively consistent expression profile. Further docking and molecular dynamic simulations revealed that the poplar CK2α specifically recognize the special pentapeptides (XES/T*DD) of natural substrates and then introduce the phosphorylation of C-terminal region of poplar P-protein. This study will provide the insight into the understanding of interacting mechanism of poplar CK2α with their natural substrates, and be of valuable resource for further assessment of the function of phosphorylation of P-protein in woody plants.

Key words: Populus trichocarpa, phosphorylation, casein kinase 2, docking, silico simulation.