Osmolyte-induced folding of an intrinsically disordered protein: Folding mechanism in the absence of ligand

Yu Chu Chang, Terrence G. Oas

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Understanding the interconversion between thermodynamically distinguishable states present in a protein folding pathway provides not only the kinetics and energetics of protein folding but also insights into the functional roles of these states in biological systems. The protein component of the bacterial RNase P holoenzyme from Bacillus subtilis (P protein) was previously shown to be unfolded in the absence of its cognate RNA or other anionic ligands. P protein was used in this study as a model system to explore general features of intrinsically disordered protein (IDP) folding mechanisms. The use of trimethylamine N-oxide (TMAO), an osmolyte that stabilizes the unliganded folded form of the protein, enabled us to study the folding process of P protein in the absence of ligand. Transient stopped-flow kinetic traces at various final TMAO concentrations exhibited multiphasic kinetics. Equilibrium ";cotitration"; experiments were performed using both TMAO and urea during the titration to produce a urea-TMAO titration surface of P protein. Both kinetic and equilibrium studies show evidence of a previously undetected intermediate state in the P protein folding process. The intermediate state is significantly populated, and the folding rate constants are relatively slow compared to those of intrinsically folded proteins similar in size and topology. The experiments and analysis described serve as a useful example for mechanistic folding studies of other IDPs.

Original languageEnglish
Pages (from-to)5086-5096
Number of pages11
JournalBiochemistry
Volume49
Issue number25
DOIs
Publication statusPublished - Jun 29 2010
Externally publishedYes

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Intrinsically Disordered Proteins
Protein folding
Protein Folding
Ligands
Proteins
Urea
Kinetics
Inosine Diphosphate
Ribonuclease P
Titration
Holoenzymes
Bacterial Proteins
Bacillus subtilis
Membrane Proteins
Bacilli
Biological systems
RNA
Rate constants
trimethyloxamine
Experiments

ASJC Scopus subject areas

  • Biochemistry

Cite this

Osmolyte-induced folding of an intrinsically disordered protein : Folding mechanism in the absence of ligand. / Chang, Yu Chu; Oas, Terrence G.

In: Biochemistry, Vol. 49, No. 25, 29.06.2010, p. 5086-5096.

Research output: Contribution to journalArticle

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