Figure 3.

(a) ²H MRD profile, R₁(ω₀), from free-tumbling MbCO at 25 °C and pD 7.0, scaled to N_W = 3 × 10⁴. The error bars are up to twice the symbol size. The solid curve is a single-component fit to the solid data points (ω₀/2π > 0.9 MHz), with the parameters in Table 1. The bulk water (dotted line) and external hydration shell (dashed line) contributions are shown. (b) Amplitude NS_iso² (red squares) and correlation time τ_C (blue circles), obtained from single-component fits to five MRD profiles, versus pD. The dotted lines are visual guides.