Electronic energy levels and hopping conductivity of an entire molecule of hagfish insulin

Abstract

The quantum-chemical calculation of an entire molecule of hagfish insulin was done by the ENFC method in which the matrix elements were calculated at the ab initio level using a minimal basis set with simulation of the aqueous solution environment. The ac conductivity for hagfish insulin was also calculated at the ab initio level by random walk theory. All the results were compared with those of pig insulin. It is shown that the reduction of HOMOs and LOMOs localized on the active sites of hagfish insulin agrees with the decrease in the biological reactivity of the insulin. The analysis of primary hopping events showed that a different sequence could influence the biological activity of insulin through the distribution of the hopping centers and the quantities of the hopping frequencies. The curve of the frequency versus ac conductivity of hagfish insulin shows that the different amino acid sequences of proteins influence the hopping conductivity. However, the electronic properties of native proteins are dominated by the three-dimensional conformations. Finally, the electronic mechanism of trans-membrane signal transforms by insulin and its receptor, which had been proposed by Ye and Ladik, was clearly described.