Table 1.

¹³C NMR Chemical Shifts in Spectra of D23N-Aβ40 Fibrils^a

peptide	residue	CO	Cα	Cβ	Cγ	Cδ	Cε	Cζ
D23N	F19	171.9	54.2	42.3	136.7	129.6
RC	F19	174.1	56.0	37.9	137.2	130.2	129.8	128.2
∂ ∂	F19	2.2	1.8	-4.4
D23N	E22	172.1	~52.8	~30.2	33.9	180.7
RC	E22	174.9	54.9	28.2	33.9	181.7
∂ ∂	E22	2.8	2.1	-1.4
D23N	V24	173.2, 173.2	60.4, 59.1	31.5, 33.4	20.5
RC	V24	174.6	60.5	31.2	19.4, 18.6
∂ ∂		1.4	0.1, 1.4	-0.3, 2.2
D23N	G25	171.7	43.8
RC	G25	173.2	43.4
∂ ∂	G25	1.5	-0.4
D23N	K28	172.1	53.2	~32.8	~22.6	27.2	40.6
RC	K28	174.9	54.5	31.4	23.0	27.3	40.2
∂ ∂	K28	2.8	1.3	-1.4
D23N	L34	172.3	52.4	44.4	25.4	~23.3
RC	L34	175.9	53.4	40.7	25.2	23.2, 21.6
∂ ∂	L34	3.6	1.0	-3.7

^a13C NMR chemical shifts (ppm, relative to tetramethylsilane) in spectra of D23N-Aβ40 fibrils. For comparison, values are given for random coil peptides, from Wishart et al. (50), adjusted to the tetramethylsilane reference by subtracting 1.7 ppm. The secondary chemical shift, ∂∂, is defined as the difference between the chemical shift for a random coil and that for D23N-Aβ40, i.e., ∂∂=∂D23N - ∂RC. Shifts that follow the trend for β-sheets have deviations greater than 0.5 ppm from random coil values, negative for CO and Cα and positive for Cβ. In general, chemical shift values are accurate to with ±0.1 ppm; for Glu22 and Lys28, some of the peaks were broad and of low intensity, and the values reported are ±0.5 ppm.