Figure 2
(A) SDS-PAGE of bacterial lysate, showing the predominate expression of P21-His6 in the insoluble fraction. Lanes: (MW) molecular weight markers, (BI) lysate before IPTG induction, (IF) insoluble fraction after induction and (SF) soluble fraction after induction. Arrow indicates the position of P21-His6. (B) Circular dichroism (CD) spectra of refolded and soluble P21-His6. Superposition of rP21-His6 (blue) and sP21-His6 (green) CD spectra at 20°C. Refolded and soluble protein samples have similar secondary structure composition. (C) Comparison between 1D1H NMR spectra of sP21-His6 and rP21-His6, showing exactly the same structure for both proteins. Spectrum of refolded (blue) and soluble (red) protein; spectra difference after normalization (green). The marked peaks indicate (c) low weight contaminants, (d) DSS and (e) residual ethanol.
