The TFE-induced transient native-like structure of the intrinsically disordered σ470 domain of Escherichia coli RNA polymerase

• Published in: European biophysics journal 2014-12, Vol.43 (12), p.581-594
• Main Authors: Kaczka, Piotr, Winiewska, Maria, Zhukov, Igor, Rempoła, Bożenna, Bolewska, Krystyna, Łoziński, Tomasz, Ejchart, Andrzej, Poznańska, Anna, Wierzchowski, Kazimierz L., Poznański, Jarosław
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biophysics; Cell Biology; DNA-Directed RNA Polymerases - chemistry; DNA-Directed RNA Polymerases - metabolism; Dose-Response Relationship, Drug; Escherichia coli - enzymology; Intrinsically Disordered Proteins - chemistry; Intrinsically Disordered Proteins - metabolism; Life Sciences; Membrane Biology; Molecular Dynamics Simulation; Movement - drug effects; Nanotechnology; Neurobiology; Original Paper; Protein Folding - drug effects; Protein Structure, Tertiary - drug effects; Trifluoroethanol - pharmacology
• ISSN: 0175-7571; 1432-1017
• DOI: 10.1007/s00249-014-0987-4

The transient folding of domain 4 of an E. coli RNA polymerase σ 70 subunit ( r EC σ 4 70 ) induced by an increasing concentration of 2,2,2-trifluoroethanol (TFE) in an aqueous solution was monitored by means of CD and heteronuclear NMR spectroscopy. NMR data, collected at a 30 % TFE, allowed the estimation of the population of a locally folded r EC σ 4 70 structure (CSI descriptors) and of local backbone dynamics ( 15 N relaxation). The spontaneous organization of the helical regions of the initially unfolded protein into a TFE-induced 3D structure was revealed from structural constraints deduced from 15 N- to 13 C-edited NOESY spectra. In accordance with all the applied criteria, three highly populated α-helical regions, separated by much more flexible fragments, form a transient HLHTH motif resembling those found in PDB structures resolved for homologous proteins. All the data taken together demonstrate that TFE induces a transient native-like structure in the intrinsically disordered protein.