Int. J. Mol. Sci. 2013, 14(3), 6241-6258; doi:10.3390/ijms14036241
Article

Adsorption and Orientation of Human Islet Amyloid Polypeptide (hIAPP) Monomer at Anionic Lipid Bilayers: Implications for Membrane-Mediated Aggregation

Received: 18 February 2013; in revised form: 11 March 2013 / Accepted: 12 March 2013 / Published: 19 March 2013
(This article belongs to the Special Issue Protein Folding 2013)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Protein misfolding and aggregation cause serious degenerative diseases, such as Alzheimer’s and type II diabetes. Human islet amyloid polypeptide (hIAPP) is the major component of amyloid deposits found in the pancreas of type II diabetic patients. Increasing evidence suggests that β-cell death is related to the interaction of hIAPP with the cellular membrane, which accelerates peptide aggregation. In this study, as a first step towards understanding the membrane-mediated hIAPP aggregation, we investigate the atomic details of the initial step of hIAPP-membrane interaction, including the adsorption orientation and conformation of hIAPP monomer at an anionic POPG lipid bilayer by performing all-atom molecular dynamics simulations. We found that hIAPP monomer is quickly adsorbed to bilayer surface, and the adsorption is initiated from the N-terminal residues driven by strong electrostatic interactions of the positively-charged residues K1 and R11 with negatively-charged lipid headgroups. hIAPP binds parallel to the lipid bilayer surface as a stable helix through residues 7–22, consistent with previous experimental study. Remarkably, different simulations lead to the same binding orientation stabilized by electrostatic and H-bonding interactions, with residues R11, F15 and S19 oriented towards membrane and hydrophobic residues L12, A13, L16 and V17 exposed to solvent. Implications for membrane-mediated hIAPP aggregation are discussed.
Keywords: type 2 diabetes; human islet amyloid polypeptide; anionic palmitoyl oleolyohosphatidyl glycerol (POPG) bilayer; adsorption dynamics; binding orientation; peptide-lipid interaction; molecular dynamics simulations
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MDPI and ACS Style

Jia, Y.; Qian, Z.; Zhang, Y.; Wei, G. Adsorption and Orientation of Human Islet Amyloid Polypeptide (hIAPP) Monomer at Anionic Lipid Bilayers: Implications for Membrane-Mediated Aggregation. Int. J. Mol. Sci. 2013, 14, 6241-6258.

AMA Style

Jia Y, Qian Z, Zhang Y, Wei G. Adsorption and Orientation of Human Islet Amyloid Polypeptide (hIAPP) Monomer at Anionic Lipid Bilayers: Implications for Membrane-Mediated Aggregation. International Journal of Molecular Sciences. 2013; 14(3):6241-6258.

Chicago/Turabian Style

Jia, Yan; Qian, Zhenyu; Zhang, Yun; Wei, Guanghong. 2013. "Adsorption and Orientation of Human Islet Amyloid Polypeptide (hIAPP) Monomer at Anionic Lipid Bilayers: Implications for Membrane-Mediated Aggregation." Int. J. Mol. Sci. 14, no. 3: 6241-6258.

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