Zinc porphyrin: a fluorescent acceptor in studies of Zn-cytochrome c unfolding by fluorescence resonance energy transfer.

ABSTRACT: FRET between the zinc porphyrin (ZnP) chromophore in zinc-substituted cytochrome c (Zn-cyt c) and an Alexa Fluor dye attached to specific surface sites was used to characterize Zn-cyt c unfolding. The use of ZnP as a fluorescent acceptor eliminates the need to doubly label the protein with exogenous dyes to perform FRET experiments in which both donor and acceptor fluorescence is monitored. The requirement for attachment of only one dye also minimizes perturbation to the protein. This sensitive technique allowed for the determination of distances between the label placed at six different sites and ZnP through a range of denaturant concentrations. Fitting of the data to a three-state model provides distances in the unfolding intermediate. The use of ZnP as a fluorescent acceptor of energy i

SUBMITTER: Ensign AA 

PROVIDER: S-EPMC2504770 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature