TABLE 1.

Chemical shift anisotropy parameters for ¹³C-labeled carbonyl carbons in Aβ_1-40 fibrils, determined from analyses of spinning sideband intensities in spectra as in Fig. 1

Sample	δ (ppm)	η
D23,V24-Aβ1-40	80.4	0.68
V24,G25-Aβ1-40 (V24 carbonyl)	86.9	0.70
V24,G25-Aβ1-40 (G25 carbonyl)	78.3	0.80
G25,S26-Aβ1-40	78.4	0.77
K28,G29-Aβ1-40	79.3	0.85
G29,A30-Aβ1-40	79.2	0.75

Except in the case of V24,G25-Aβ_1-40, values are averages for two labeled sites with unresolved ¹³C NMR signals. and , where δ₁₁, δ₂₂, and δ₃₃ are the principal values of the chemical shift anisotropy tensor and Uncertainties in δ and η are approximately ±4%.