Biomimetic Synthesis of Lispro Insulin via a Chemically Synthesized "Mini-Proinsulin" Prepared by Oxime-Forming Ligation
ABSTRACT Here we report a proof-of-principle study demonstrating the efficient folding, with concomitant formation of the correct disulfides, of an isolated polypeptide insulin precursor of defined covalent structure. We used oxime-forming chemical ligation to introduce a temporary "chemical tether" to link the N-terminal residue of the insulin A chain to the C-terminal residue of the insulin B chain; the tether enabled us to fold/form disulfides with high efficiency. Enzymatic removal of the temporary chemical tether gave mature, fully active insulin. This chemical tethering principle could form the basis of a practical, high yield total synthesis of insulin and analogues.
- Angewandte Chemie International Edition 07/2010; DOI:10.1002/anie.201002659 · 11.34 Impact Factor
- Angewandte Chemie International Edition 10/2010; 49(42):7624-6. DOI:10.1002/anie.201003018 · 11.34 Impact Factor
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ABSTRACT: Type 1B diabetes (typically with early onset and without islet autoantibodies) has been described in patients bearing small coding sequence mutations in the INS gene. Not all mutations in the INS gene cause the autosomal dominant Mutant INS-gene Induced Diabetes of Youth (MIDY) syndrome, but most missense mutations affecting proinsulin folding produce MIDY. MIDY patients are heterozygotes, with the expressed mutant proinsulins exerting dominant-negative (toxic gain of function) behavior in pancreatic beta cells. Here we focus primarily on proinsulin folding in the endoplasmic reticulum, providing insight into perturbations of this folding pathway in MIDY. Accumulated evidence indicates that, in the molecular pathogenesis of the disease, misfolded proinsulin exerts dominant effects that initially inhibit insulin production, progressing to beta cell demise with diabetes.Trends in Endocrinology and Metabolism 11/2010; 21(11):652-9. DOI:10.1016/j.tem.2010.07.001 · 8.87 Impact Factor