Structural disorder and local order of hNopp140.

TitleStructural disorder and local order of hNopp140.
Publication TypeJournal Article
Year of Publication2013
AuthorsTantos, Á., K. Szrnka, B. Szabo, M. Bokor, P. Kamasa, P. Matus, A. Bekesi, K. Tompa, K-H. Han, and P. Tompa
JournalBiochim Biophys Acta
Date Published2013 Jan
Type of Articleidp
KeywordsCasein Kinase II, Circular Dichroism, Humans, Nuclear Magnetic Resonance, Biomolecular, Nuclear Proteins, Phosphoproteins, Protein Structure, Secondary, Protein Structure, Tertiary, Transcription Factor TFIIB

Human nucleolar phosphoprotein p140 (hNopp 140) is a highly phosphorylated protein inhibitor of casein kinase 2 (CK2). As in the case of many kinase-inhibitor systems, the inhibitor has been described to belong to the family of intrinsically disordered proteins (IDPs), which often utilize transient structural elements to bind their cognate enzyme. Here we investigated the structural status of this protein both to provide distinct lines of evidence for its disorder and to point out its transient structure potentially involved in interactions and also its tendency to aggregate. Structural disorder of hNopp140 is apparent by its anomalous electrophoretic mobility, protease sensitivity, heat stability, hydrodynamic behavior on size-exclusion chromatography, (1)H NMR spectrum and differential scanning calorimetry scan. hNopp140 has a significant tendency to aggregate and the change of its circular dichroism spectrum in the presence of 0-80% TFE suggests a tendency to form local helical structures. Wide-line NMR measurements suggest the overall disordered character of the protein. In all, our data suggest that this protein falls into the pre-molten globule state of IDPs, with a significant tendency to become ordered in the presence of its partner as demonstrated in the presence of transcription factor IIB (TFIIB).

Alternate JournalBiochim. Biophys. Acta
PubMed ID22906532