TY - JOUR

T1 - Early stages of amyloid fibril formation studied by liquid-state NMR: the peptide hormone glucagon

AU - Svane, Anna Sigrid Pii

AU - Jahn, Kasper

AU - Deva, Taru

AU - Malmendal, Anders

AU - Otzen, Daniel

AU - Dittmer, Jens

AU - Nielsen, Niels Chr

PY - 2008/7/1

Y1 - 2008/7/1

N2 - The 29-residue peptide hormone glucagon forms amyloid fibrils within a few hours at low pH. In this study, we use glucagon as a model system to investigate fibril formation by liquid-state (1)H-NMR spectroscopy One-dimensional, correlation, and diffusion experiments monitoring the fibril formation process provide insight into the early stages of the pathway on which the molecules aggregate to fibrils. In conjunction with these techniques, exchange experiments give information about the end-state conformation. Within the limits of detection, there are no signs of larger oligomeric intermediates in the course of the fibril formation process. Kinetic information is extracted from the time course of the residual free glucagon signal decay. This suggests that glucagon amyloids form by a nucleated growth mechanism in which trimers (rather than monomers) of glucagon interact directly with the growing fibrils rather than with each other. The results of proton/deuterium exchange experiments on mature fibrils with subsequent dissolution show that the N-terminal of glucagon is the least amenable to exchange, which indicates that this part is strongly involved in the intermolecular bonds of the fibrils.

AB - The 29-residue peptide hormone glucagon forms amyloid fibrils within a few hours at low pH. In this study, we use glucagon as a model system to investigate fibril formation by liquid-state (1)H-NMR spectroscopy One-dimensional, correlation, and diffusion experiments monitoring the fibril formation process provide insight into the early stages of the pathway on which the molecules aggregate to fibrils. In conjunction with these techniques, exchange experiments give information about the end-state conformation. Within the limits of detection, there are no signs of larger oligomeric intermediates in the course of the fibril formation process. Kinetic information is extracted from the time course of the residual free glucagon signal decay. This suggests that glucagon amyloids form by a nucleated growth mechanism in which trimers (rather than monomers) of glucagon interact directly with the growing fibrils rather than with each other. The results of proton/deuterium exchange experiments on mature fibrils with subsequent dissolution show that the N-terminal of glucagon is the least amenable to exchange, which indicates that this part is strongly involved in the intermolecular bonds of the fibrils.

KW - Amyloid

KW - Computer Simulation

KW - Crystallization

KW - Glucagon

KW - Magnetic Resonance Spectroscopy

KW - Models, Chemical

KW - Models, Molecular

KW - Phase Transition

KW - Protein Conformation

KW - Solutions

U2 - 10.1529/biophysj.107.122895

DO - 10.1529/biophysj.107.122895

M3 - Journal article

C2 - 18339765

VL - 95

SP - 366

EP - 377

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 1

ER -