Sedimentation velocity analysis.

<p>The continuous sedimentation coefficient distribution of (A) wild-type and (B) K315A mutant protein at different urea concentration were shown. Peaks in grey color represent the unfolded wild-type and mutant protein in 0, 2.5, 3, 3.5 and 4.5 M urea and in 0, 0.25, 0.7, 1.3, 1.5, 2, 2.5, 3.5 and 4.5 M urea, respectively. Wild-type and mutant protein denatured in 3.5 and 2.5 M urea were diluted to final 0.6 and 0.3 M urea, respectively, in 50 mM Tris-acetic acid buffer, pH 7.5, were shown as dark gray peaks. The protein concentration used in all assays was 0.2 mg/mL.