Overlay spectra of refocused INEPT spectrum of TLQP-21 13C and 15N labeled at P4-R6-A9 (A,B), P4-A6-R9-R11-P19-A20 (C,D) or A16-L17-P18 (E,F) with resonance assignments indicated. Experiments were performed in buffer (A,C,E) or in the presence of 3T3L1 cells after 24 hour incubation at 37°C (B,D,F). G,H. Chemical shift index of TLQP-21 in buffer (red) or in the presence of 3T3L1 cells (blue) (Schwarzinger, et al., 2000).