Table 1.

¹³C chemical shifts of N. clavipes major and minor ampullate spider silk along with chemical shifts from polypeptides with known secondary structures

13C chemical shift (in ppm from TMS)
residue	major silk	minor silk	α-helix	β-sheet	random coil	31-helix	β-turn
Ala Cβ	17.5	17.4	14.8- 16.0	19.9- 20.7	19.1	17.4	16.5- 17.4
Ala Cβ	20.9	20.8
Ala Cβ	23.3	23.1
Ala Cα	49.0	49.0	52.3- 52.8	48.2- 49.3	52.5	48.9	50.8- 51.7
Ala Cα	49.2
Ala Cα	50.0
Ala CO	172.5*	172.8*	176.2- 176.8	171.6- 172.4	177.8	174.6	176.8- 177.5
Ala CO	175.4*	175.5*
Gln Cβ	32	28.0	25.6- 26.3	29.0- 29.9	29.4
Gln Cγ	33.2	31.9	29.7- 29.8	29.7- 29.9	33.7
Gln Cα	52.9	53.8	56.4- 57.0	51.0- 51.4	56.2
Gln CO	172.1		175.4- 175.9	171.9- 172.2	176.0
Gln Cδ	176.5	177.8*			180.5
Gly Cα	43.3	43.1		43.2- 44.3	45.1	41.4- 42.5	43.8- 44.1
Gly CO	169.3*	169.2*		168.4- 169.7	174.9	171.2- 173.1	170.6- 170.7
Gly CO	171.8*	171.9*
Ser Cα	55.5*	55.9*	59.2	54.5- 55.0	58.3		58.0
Ser Cβ	62.0 *	60.3*	60.7	62.3- 63.9	63.8		60.7
Ser Cβ	64.3*	61.9*
Ser Cβ		64.1*
Ser CO	172.2		170.0- 171.2	174.6	173.7

Nephila clavipes Ma and Mi chemical shifts are from previous work ²³, ²⁷, except where noted.

^*Chemical shifts extracted from INADEQUATE data of wetted silk in this study. Chemical shifts of known secondary structures from model pepides ⁴⁹-⁵⁹, random coil conformation ⁴², and Silk I β-turn structure ⁶⁰-⁶⁴. The ¹³C chemical shifts are in parts per million (ppm) with tetramethylsilane (TMS) as the 0 ppm reference. The label ‘CO’ indicates the peptide backbone carbonyl for a specific amino acid.