STRUCTURE AND BIOLOGICAL-ACTIVITY OF HAGFISH INSULIN

An isomorphously phased electron density map of hagfish (Myxine glutinosa) insulin has been calculated at a resolution of 3·1 Å spacing. The molecule crystallises with one molecule per asymmetric unit but is organised as a symmetric dimer lying on a 2-fold crystal axis. The structure of the hagfish insulin monomer is much more similar to that of pig insulin molecule 2 than molecule 1 of the dimer that constitutes one third of the 2 Zn insulin hexamer. There are different conformations however at the N and C termini of the B-chain. At the C terminus the two final residues on hagfish insulin partially obscure the A1 glycine residue, which in pig insulin is exposed. This structural difference has been shown, however, not to be responsible for the reduced activity of the hagfish insulin. © 1979.