Figure 1.

(a) ¹H/¹⁵N refocused-HSQC spectra of ¹⁵N labeled L99A of T4 lysozyme at 298 K at different oxygen concentrations from 0.27 mM to 6.4 mM. Amide groups showing significant changes in ¹⁵N chemical shift are indicated. (b) ¹H/¹³C constant time HSQC spectra of ¹³C/¹⁵N labeled L99A of T4 lysozyme at different oxygen concentrations from 0.27 mM to 8.9 mM. Positive and negative crosspeaks are presented by same color. Methyl groups showing significant changes in ¹H/¹³C chemical shift and a loss of crosspeak intensities are indicated.