Random coil negative control reproduces the discrepancy between scattering and FRET measurements of denatured protein dimensions.

ABSTRACT: Small-angle scattering studies generally indicate that the dimensions of unfolded single-domain proteins are independent (to within experimental uncertainty of a few percent) of denaturant concentration. In contrast, single-molecule FRET (smFRET) studies invariably suggest that protein unfolded states contract significantly as the denaturant concentration falls from high (∼6 M) to low (∼1 M). Here, we explore this discrepancy by using PEG to perform a hitherto absent negative control. This uncharged, highly hydrophilic polymer has been shown by multiple independent techniques to behave as a random coil in water, suggesting that it is unlikely to expand further on the addition of denaturant. Consistent with this observation, small-angle neutron scattering indicates that the dimensions of PE

SUBMITTER: Watkins HM 

PROVIDER: S-EPMC4450392 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature