Biophysical characterization of the structural change of Nopp140, an intrinsically disordered protein, in the interaction with CK2α.
Nucleolar phosphoprotein 140 (Nopp140) is a nucleolar protein, more than 80% of which is disordered. Previous studies have shown that the C-terminal region of Nopp140 (residues 568-596) interacts with protein kinase CK2α, and inhibits the catalytic activity of CK2. Although the region of Nopp140 responsible for the interaction with CK2α was identified, the structural features and the effect of this interaction on the structure of Nopp140 have not been defined due to the difficulty of structural characterization of disordered protein. In this study, the disordered feature of Nopp140 and the effect of CK2α on the structure of Nopp140 were examined using single-molecule fluorescence resonance energy transfer (smFRET) and electron paramagnetic resonance (EPR). The interaction with CK2α was increased conformational rigidity of the CK2α-interacting region of Nopp140 (Nopp140C), suggesting that the disordered and flexible conformation of Nopp140C became more rigid conformation as it binds to CK2α. In addition, site specific spin labeling and EPR analysis confirmed that the residues 574-589 of Nopp140 are critical for binding to CK2α. Similar technical approaches can be applied to analyze the conformational changes in other IDPs during their interactions with binding partners.
Department of Chemistry, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 02707, Republic of Korea; Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea.
Jung-Hyun
JH
Na
Department of Chemistry, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 02707, Republic of Korea.
Won-Kyu
WK
Lee
Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
Yuyoung
Y
Kim
Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.
Cherlhyun
C
Jeong
Department of Chemistry, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 02707, Republic of Korea.
Seung Soo
SS
Song
Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea.
Sun-Shin
SS
Cha
Division of Biosystems Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea.
Kyou-Hoon
KH
Han
Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
Yeon-Kyun
YK
Shin
Department of Chemistry, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 02707, Republic of Korea. Electronic address: ygyu@kookmin.ac.kr.
Yeon Gyu
YG
Yu
D001665:Binding Sites; D047390:Casein Kinase II / Q000737:chemistry / Q000648:ultrastructure; D004789:Enzyme Activation; D064267:Intrinsically Disordered Proteins; D009687:Nuclear Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D010750:Phosphoproteins / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D064267:Intrinsically Disordered Proteins; C075564:NOLC1 protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; C570325:CSNK2A1 protein, human; D047390:Casein Kinase II
Casein kinase 2; Electron para-magnetic resonance; Intrinsically disordered protein; Nopp140; Single-molecule FRET; Structural diversity