Table 3. Harmonic stiffness of tubulin conformational angles, k_BT/rad².

PDB id	Nucleotide	Interface	Bending stiffness	Twisting (torsional) stiffness
3J6F	GDP	intra	930 ± 120	990 ± 150
3J6E	GTP	intra	1100 ± 120	1160 ± 100
3J6F	GDP	inter	1290 ± 510	760 ± 60
3J6E	GTP	inter	350 ± 110	410 ± 70