Effect of proline mutations on the monomer conformations of amylin

Chi Cheng Chiu, Sadanand Singh, Juan J. De Pablo

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

The formation of human islet amyloid polypeptide (hIAPP) is implicated in the loss of pancreatic β-cells in type II diabetes. Rat amylin, which differs from human amylin at six residues, does not lead to formation of amyloid fibrils. Pramlintide is a synthetic analog of human amylin that shares three proline substitutions with rat amylin. Pramlintide has a much smaller propensity to form amyloid aggregates and has been widely prescribed in amylin replacement treatment. It is known that the three prolines attenuate β-sheet formation. However, the detailed effects of these proline substitutions on full-length hIAPP remain poorly understood. In this work, we use molecular simulations and bias-exchange metadynamics to investigate the effect of proline substitutions on the conformation of the hIAPP monomer. Our results demonstrate that hIAPP can adopt various β-sheet conformations, some of which have been reported in experiments. The proline substitutions perturb the formation of long β-sheets and reduce their stability. More importantly, we find that all three proline substitutions of pramlintide are required to inhibit β conformations and stabilize the α-helical conformation. Fewer substitutions do not have a significant inhibiting effect.

Original languageEnglish
Pages (from-to)1227-1235
Number of pages9
JournalBiophysical Journal
Volume105
Issue number5
DOIs
Publication statusPublished - 2013 Sep 3

All Science Journal Classification (ASJC) codes

  • Biophysics

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