title: Direct observation of protein folding in nanoenvironments using a molecular ruler.
abstract: We observe folding of horse heart cytochrome c in various environments including nano-compartments (micelles and reverse micelles). Using picosecond-resolved Förster resonance energy transfer (FRET) dynamics of an extrinsic covalently attached probe dansyl (donor) at the surface of the protein to a heme group (acceptor) embedded inside the protein, we measured angstrom-resolved donor-acceptor distances in the environments. The overall structural perturbations of the protein revealed from the FRET experiments are in close agreement with our circular dichroism (CD) and dynamic light scattering (DLS) studies on the protein in a variety of solution conditions. The change of segmental motion of the protein due to imposed restriction in the nano-compartments compared to that in bulk buffer is also revealed by temporal fluorescence anisotropy of the dansyl probe.
authors.affiliation: Unit for Nano Science and Technology, SN Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, India.
authors.forename: Rupa
authors.initials: R
authors.lastname: Sarkar
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Shaw
authors.forename: S Shankara
authors.initials: SS
authors.lastname: Narayanan
authors.forename: Fernando
authors.initials: F
authors.lastname: Dias
authors.forename: Andy
authors.initials: A
authors.lastname: Monkman
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Pal
mesh_terms: D002942:Circular Dichroism; D031541:Fluorescence Resonance Energy Transfer; D017510:Protein Folding; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet