Figure 2.

Synthesis of INS-6 and NMR Spectra. (A) Native ligation of N- and C-terminal segments. The eight cysteines are shown, including cysteine that participates in thioester ligation. Peptide sequences refer to intact INS-6. (B) Reverse-phase HPLC purification of reduced INS-6 polypeptide from ligation mixture. N- and C-terminal segments are labeled N and C, respectively. (C) One-dimensional ¹H-NMR spectrum of folded INS-6 in H₂O at pH 3.7 (left) and in D₂O at pD 3.4 (right) at 25°C. (D) Fingerprint region of NOESY spectrum (mixing time 200 msec).