R1, R2, [1H]-15N NOE, R2R1 products and R2/R1 ratios are shown for apo- and Ca2+-C-CaM in the absence (open circles) and presence (closed circles) of PEP-19. The dashed (with out PEP-19) and solid lines (with PEP-19) in Panels C, D, G and H indicate the mean +1.0 SD. Asterisks denote resonances with significant line-broadening in the presence of PEP-19.