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. Author manuscript; available in PMC: 2010 Nov 1.
Published in final edited form as: J Biomol NMR. 2009 Jul 31;45(3):245–253. doi: 10.1007/s10858-009-9358-3

Table 1.

Calculated isotropic 15N chemical shieldings (in ppm) for selected helical residues in GB3 using various models

Residue Model A
neutrala 		Model B Model C Direct HB
partner		 Indirect
HB
partner
neutrala −CH3b neutrala neutrala −CH3b neutrala
A26 131.50 126.75 128.46 121.31 122.21 D22 A29
E27 139.12 130.13 130.65 124.19 125.17 A23 F30
K28 136.88 130.37 131.31 123.84 125.06 E24 K31
A29 137.51 131.70 131.98 125.41 125.74 T25 Q32
F30 137.00 131.07 130.23 125.56 126.55 A26 Y33
K31 134.22 124.33 123.80 120.23 119.27 E27 A34
Q32 136.10 128.96 130.39 124.17 125.53 K28 N35
Y33 133.22 126.64 126.47 120.05 120.96 A29 D36
Residue Model A Model B Model C
* CFP c −CH3b * partial CFP d CFP c −CH3b * CFP c
A26 131.50 126.52 126.75 128.28 120.33 121.58 121.31 120.07 120.57
E27 127.38 120.64 119.59 120.12 113.06 110.49 112.96 113.98 112.65
K28 147.65 136.05 141.32 134.65 127.07 127.86 135.63 128.42 127.58
A29 134.53 130.89 129.06 129.45 122.01 125.63 123.42 122.20 124.26
F30 137.00 130.40 131.07 130.23 122.80 123.34 125.56 125.01 124.27
K31 140.56 127.09 130.10 125.80 120.89 117.52 125.99 123.17 118.08
Q32 132.26 129.49 125.69 127.96 121.33 121.86 122.65 122.70 122.23
Y33 133.22 132.59 126.64 132.02 123.70 125.18 120.05 124.78 125.96
a

neutral: all ionizable side chains were made neutral.

b

−CH3: All nonalanine residues other than residues i and i−1 had their side chains modified to be −CH3.

c

CFP: The calculation was performed in the presence of AMBER charges representing GB3 atoms that were not included in the model.

d

“Model B partial CFP”: This calculation was performed in the presence of AMBER charges representing atoms that were not included in Model B but were included in Model C.

*

generic model (A, B, or C) with no additional modifications.