Figure 1.

Probe proteins in-cell NMR properties and relaxation. (A) shows the proteins TTHA^pwt (blue), HAH1^pwt (red), and SOD1^barrel (green) including secondary structure elements. The electrostatic surface of each protein is displayed, with blue-colored patches belonging to the basic, positively charged residues arginine or lysine and the red colored patches belonging to the acidic, negatively charged residues glutamate or aspartate. The surface charge mutations are highlighted as black spheres. (B) depicts HMQC spectra of the reporter protein electroporated into live A2780 cells. (C) In-cell NMR relaxation data of the three basis reporter proteins are shown. Signal intensity attenuation obtained from the R₁ (dark gray) and R₂ (light gray) experiments are shown as filled circles and the corresponding fitted single exponential fits are shown as solid lines. The error bars in the relaxation rates are estimated from the signal-to-noise-ratio in each experiment (Supporting Information Methods).