Solution structure of proinsulin: connecting domain flexibility and prohormone processing.

The folding of proinsulin, the single-chain precursor of insulin, ensures native disulfide pairing in pancreatic beta-cells. Mutations that impair folding cause neonatal diabetes mellitus. Although the classical structure of insulin is well established, proinsulin is refractory to crystallization.

Expression, purification, and PC1-mediated processing of (H10D, P28K, and K29P)-human proinsulin.

Our previous methods for the generation of recombinant human proinsulin were inadequate in terms of reproducibility and yield. In addition, it was difficult to perform structure/function studies on proinsulin because of its tendency to form hexamers. We have developed an improved procedure, which overcomes many of the technical purification problems, and results in a potentially monomeric version of modified proinsulin.