Structural changes in erythroid, nonerythroid spectrin in presence of increasing concentrations of urea and GuHCl monitored by fluorescence spectroscopy at pH 8.0 and 25°C.
<p>Fluorescence emission spectra of (A) erythroid spectrin and (B) nonerythroid spectrin are shown for the native (a), the unfolded protein in 8M urea (b) and the unfolded protein in 6M GuHCl (c). Changes in the ratio of intensities at 337nm and 350nm of tryptophan fluorescence (F<sub>337</sub>/F<sub>350</sub>) against the denaturant concentrations are shown in (C) for erythroid spectrin and (D) for non-erythroid spectrin. The data are normalized by taking (F<sub>337</sub>/F<sub>350</sub>) of native protein as 100%. Urea and GuHCl induced unfolding are shown by changes in steady state fluorescence anisotropy (r) in (E) erythroid and (F) nonerythroid spectrin and by the changes in emission maxima (λ<sub>max</sub>) in (G) erythroid and (H) nonerythroid spectrin respectively.</p
