Figure 1

Two dimensional 15N-1H HSQC spectra of 15N-labeled (A) SMA (magenta), (B) LEN Q89H (red), (C) LEN T94H (green), and (D) LEN Y96Q (blue) recorded at 800 MHz 1H frequency and 25 °C, overlaid on the spectrum of LEN (black). The spectra for all other SMA-like mutants of LEN mutants were virtually identical to LEN (see Supplementary Fig. S1). The backbone amide resonance assignments are indicated in corresponding colors.