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. Author manuscript; available in PMC: 2011 Mar 31.
Published in final edited form as: J Am Chem Soc. 2010 Mar 31;132(12):4295–4309. doi: 10.1021/ja910186u

Table 4.

Fitted CSA tensors for α-helix, β-strand and overall protein.

σZZ (ppm) σXX (ppm) σYY (ppm) β(°) Δσ (ppm) η
α-helixa −115±5 71±8 44±11 19.8±1.2 −173±7 0.23±0.17
β-stranda −108±4 71±4 38±7 18.8±2.4 −162±6 0.31±0.11
Alla −111±8 69±11 42±9 19.6±2.5 −166±9 0.25±0.17
a

Average and standard deviation for CSA tensor components experimentally derived for the backbone amide 15N nuclei in GB3. Values apply to the absence of thermal motions, i.e., Δσ values observed by solid state NMR are expected to be scaled down by √(S2) ≈ 0.95 relative to values reported in the table. Three parameters (Δσ, η, β) are fitted for each 15N site. The root-mean-square deviations from the reported averaged values reflect the CSA variability in α-helix, β-strand, and all residues.