STRUCTURE OF MONOMERIC PORCINE DESB1-B2 DESPENTAPEPTIDE (B26-B30) INSULIN AT 1.65 ANGSTROM RESOLUTION

Insulin has a concentration of 10(-8)-10(-11) M in the blood which ens ures that it circulates and exerts its physiological functions in viva as a monomer. The crystal structure of monomeric porcine desB1-B2 des pentapeptide (B26-B30) insulin (DesB1-2 DPT) with M-r = 4934 Da has be en determined at 1.65 Angstrom resolution using the molecular replacem ent method. A structural comparison between DesB1-2 DPI and 2Zn insuli n reveals that the conformation of DesB1-2 DPI is more similar to mole cule I than molecule II of 2Zn insulin. The remarkable conformational difference between B25-Phe in DesB1-2 DPI and B25-Phe in despentapepti de (B26-B30) insulin (DPI) indicates that the residue B25-Phe possesse s great flexibility and mobility.