Structural features of cytochrome c′ folding intermediates revealed by fluorescence energy-transfer kinetics
AUTOR(ES)
Lee, Jennifer C.
FONTE
National Academy of Sciences
RESUMO
We employed fluorescence energy-transfer probes to investigate the polypeptide dynamics accompanying cytochrome c′ folding. Analysis of fluorescence energy-transfer kinetics from wild-type Trp-72 or Trp-32 in a crystallographically characterized (1.78 Å) Q1A/F32W/W72F mutant shows that there is structural heterogeneity in denatured cytochrome c′. Even at guanidine hydrochloride concentrations well beyond the unfolding transition, a substantial fraction of the polypeptides (≈50%) adopts compact conformations (tryptophan-to-heme distance, ≈25 Å) in both pseudo-wild-type (Q1A) and mutant proteins. A burst phase (≤5 ms) is revealed when stopped flow-triggered refolding is probed by tryptophan intensity: measurements on the Q1A protein show that ≈75% of the Trp-72 fluorescence (83% for Trp-32) is quenched within the mixing deadtime, suggesting that most of the polypeptides have collapsed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=137495Documentos Relacionados
- α-Synuclein structures from fluorescence energy-transfer kinetics: Implications for the role of the protein in Parkinson's disease
- Surveyor Substrates: Energy-Transfer Gauges of Active Center Topography during Catalysis*
- Revealing competitive Förster-type resonance energy-transfer pathways in single bichromophoric molecules
- Cytochrome c′ folding triggered by electron transfer: Fast and slow formation of four-helix bundles
- Loss of Heterozygosity Assay for Molecular Detection of Cancer Using Energy-transfer Primers and Capillary Array Electrophoresis
