The acidic ribosomal protein P2 from Euplotes octocarinatus is phosphorylated at its N-terminal domain.
The eukaryotic acid ribosomal P0, P1, and P2 proteins share a conserved flexible C-terminal tail that is rich in acidic residues, which are involved in the interaction with elongation factor 2 during protein synthesis. Our previous work suggested that the acidic ribosomal P proteins from Euplotes octocarinatus have a special C-terminal domain. To further understand this characteristic feature, both P2 and elongation factor 2 from E. octocarinatus were overexpressed, for the first time, in Escherichia coli in this study. GST pull-down assay indicated that P2 protein from E. octocarinatus (EoP2) interacted specifically with the N-terminal domain of elongation factor 2 from E. octocarinatus (EoEF-2) in vitro. The interacting part of EoP2 is in the C-terminal domains, consistent with the observation in other organisms. Phosphorylation of the recombinant EoP2 was performed in vitro using multiple methods such as (31)P-NMR spectroscopy, native PAGE, and Phos-tag(TM) SDS-PAGE. Results showed that ribosomal protein EoP2 was phosphorylated by casein kinase II at serine 21 located at the N terminus. This phosphorylation site identified in EoP2 is quite different from that of P2 from other organisms, in which the phosphorylation site is located in the conserved C-terminal region.
a Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
Miaoqing
M
Hu
Luqin
L
Li
Jianbing
J
Chao
Yaqin
Y
Zhao
Zhiyun
Z
Zhang
Aihua
A
Liang
D001483:Base Sequence; D047390:Casein Kinase II / Q000737:chemistry; D016812:Euplotes / Q000378:metabolism*; D008969:Molecular Sequence Data; D020652:Peptide Elongation Factor 2 / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry*; D012269:Ribosomal Proteins / Q000737:chemistry*; D012694:Serine / Q000737:chemistry
D020652:Peptide Elongation Factor 2; D010750:Phosphoproteins; D015800:Protozoan Proteins; D012269:Ribosomal Proteins; C031937:phosphoprotein P2, ribosomal; D012694:Serine; D047390:Casein Kinase II