Solution structures of rat amylin peptide: simulation, theory, and experiment.
Amyloid deposits of amylin in the pancreas are an important characteristic feature found in patients with Type-2 diabetes. The aggregate has been considered important in the disease pathology and has been studied extensively. However, the secondary structures of the individual peptide have not been clearly identified. In this work, we present detailed solution structures of rat amylin using a combination of Monte Carlo and molecular dynamics simulations. A new Monte Carlo method is presented to determine the free energy of distinct biomolecular conformations. Both folded and random-coil conformations of rat amylin are observed in water and their relative stability is examined in detail. The former contains an alpha-helical segment comprised of residues 7-17. We find that at room temperature the folded structure is more stable, whereas at higher temperatures the random-coil structure predominates. From the configurations and weights we calculate the alpha-carbon NMR chemical shifts, with results that are in reasonable agreement with experiments of others. We also calculate the infrared spectrum in the amide I stretch regime, and the results are in fair agreement with the experimental line shape presented herein.
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Wisconsin, USA.
Allam S
AS
Reddy
Lu
L
Wang
Yu-Shan
YS
Lin
Yun
Y
Ling
Manan
M
Chopra
Martin T
MT
Zanni
James L
JL
Skinner
Juan J
JJ
De Pablo
D000465:Algorithms; D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D058228:Islet Amyloid Polypeptide; D007700:Kinetics; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009010:Monte Carlo Method; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry; D017510:Protein Folding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D051381:Rats; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D010455:Peptides; D014867:Water