title: The TFE-induced transient native-like structure of the intrinsically disordered σ₄⁷⁰ domain of Escherichia coli RNA polymerase.
abstract: The transient folding of domain 4 of an E. coli RNA polymerase σ⁷⁰ subunit (rECσ₄⁷⁰) 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 rECσ₄⁷⁰ 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.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kaczka
authors.forename: Maria
authors.initials: M
authors.lastname: Winiewska
authors.forename: Igor
authors.initials: I
authors.lastname: Zhukov
authors.forename: Bożenna
authors.initials: B
authors.lastname: Rempoła
authors.forename: Krystyna
authors.initials: K
authors.lastname: Bolewska
authors.forename: Tomasz
authors.initials: T
authors.lastname: Łoziński
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ejchart
authors.forename: Anna
authors.initials: A
authors.lastname: Poznańska
authors.forename: Kazimierz L
authors.initials: KL
authors.lastname: Wierzchowski
authors.forename: Jarosław
authors.initials: J
authors.lastname: Poznański
mesh_terms: D020816:Amino Acid Motifs; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000201:enzymology*; D064267:Intrinsically Disordered Proteins / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D009068:Movement / Q000187:drug effects; D017510:Protein Folding / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D014270:Trifluoroethanol / Q000494:pharmacology*
chemical_list: D064267:Intrinsically Disordered Proteins; D014270:Trifluoroethanol; D012321:DNA-Directed RNA Polymerases