Figure 4.

Comparison of HX MS patterns for the Notch1 NRR in “off” and “on” states. (A) Time course of exchange, comparing deuteration of the Notch1 NRR in closed and open (EDTA-treated) states. The ribbon diagram of the Notch1 NRR is colored according to the effect of EDTA treatment. Regions exhibiting faster deuteration in the presence of EDTA (with an absolute difference in mass of at least 0.5 Da at some point during the exchange experiment) are colored red, and regions with no detectable change in the deuteration rate (an absolute difference in mass of less than 0.5 Da at some point during the exchange experiment) are green. Gray regions correspond to segments for which no peptide mapping data are available. (B,C) Semi-logarithmic plots showing the relative deuterium level of two different regions (see Supplemental Figure 3B for all other peptides) of the Notch1 NRR in closed and open states. Data acquired from two independent experiments are shown to highlight the reproducibility of the measurements. Panel B encompasses the site of S2 cleavage and panel C corresponds to a section of the core helix in the hydrophobic core of the HD domain. See also Figures S2 and S3, Table S1, and Movie S2.