Conformations of a Metastable SH3 Domain Characterized by smFRET and an Excluded-Volume Polymer Model.

ABSTRACT: Conformational states of the metastable drkN SH3 domain were characterized using single-molecule fluorescence techniques. Under nondenaturing conditions, two Förster resonance energy transfer (FRET) populations were observed that corresponded to a folded and an unfolded state. FRET-estimated radii of gyration and hydrodynamic radii estimated by fluorescence correlation spectroscopy of the two coexisting conformations are in agreement with previous ensemble x-ray scattering and NMR measurements. Surprisingly, when exposed to high concentrations of urea and GdmCl denaturants, the protein still exhibits two distinct FRET populations. The dominant conformation is expanded, showing a low FRET efficiency, consistent with the expected behavior of a random chain with excluded volume. However, appr

SUBMITTER: Mazouchi A 

PROVIDER: S-EPMC4833778 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature