Two-dimensional NMR studies on des-pentapeptide-insulin. Proton resonance assignments and secondary structure analysis.

The shortened analogue of insulin, des-(B26-B30)-pentapeptide insulin, has been characterized by two-dimensional 1H NMR. The 1H resonance assignments and the secondary structure in water solution are discussed The results indicate that the secondary structure in solution is very similar to that reported for the crystalline state. A high flexibility of both A and B chains is observed. Of the two conformations seen in the 2-Zn insulin crystals and indicated as molecules 1 and 2 (Chinese nomenclature), the structure of the analogue is more similar to that of molecule 1.