Several point mutations can modulate protein structure and dynamics, leading to different natures. Especially in the case of amyloidogenic proteins closely related to neurodegenerative diseases, structural changes originating from point mutations can affect fibrillation kinetics. Herein, we rationally designed mutant candidates to inhibit the fibrillation process of amyloid-β with its point mutants through multistep in silico analyses. Our results showed that the designed mutants induced kinetic self-assembly suppression and reduced the toxicity of the aggregate. A multidisciplinary biophysical approach with small-angle X-ray scattering, ion mobility-mass spectrometry, mass spectrometry, and additional in silico experiments was performed to reveal the structural basis associated with the inhibition of fibril formation. The structure-based design of the mutants with suppressed self-assembly performed in this study could provide a different perspective for modulating amyloid aggregation based on the structural understanding of the intrinsically disordered proteins.

Amyloid proteins that undergo self-assembly to form insoluble fibrillar aggregates have attracted much attention due to their role in biological and pathological significance in amyloidosis. This study aims to understand...

Flexible structures of intrinsically disordered proteins (IDPs) are crucial for versatile functions in living organisms, which involve interaction with diverse partners. Electrospray ionization ion mobility mass spectrometry (ESI‐IM‐MS) has been widely applied for structural characterization of apo‐state and ligand‐associated IDPs via two‐dimensional separation in the gas phase. Gas‐phase IDP structures have been regarded as kinetically trapped states originated from conformational features in solution. However, an implication of the states remains elusive in the structural characterization of IDPs, because it is unclear what structural property of IDPs is preserved. Recent studies have indicated that the conformational features of IDPs in solution are not fully reproduced in the gas phase. Nevertheless, the molecular interactions captured in the gas phase amplify the structural differences between IDP conformers. Therefore, an IDP conformational change that is not observed in solution is observable in the gas‐phase structures obtained by ESI‐IM‐MS. Herein, we have presented up‐to‐date researches on the key implications of kinetically trapped states in the gas phase with a brief summary of the structural dynamics of IDPs in ESI‐IM‐MS.

Herein, we successfully developed an entropically favored helical supramolecular self-assembly from a triphenylamine-based 4 in a green solvent in order to mimic the structural transformations that occurs during the self-assembly...

Hemoglobin (Hb) is a major oxygen-transporting protein with allosteric properties reflected in the structural changes that accompany binding of O2. Glycated hemoglobin (GHb), which is a minor component of human red cell hemolysate, is generated by a nonenzymatic reaction between glucose and hemoglobin. Due to the long lifetime of human erythrocytes (∼120 days), GHb is widely used as a reliable biomarker for monitoring long-term glucose control in diabetic patients. Although the structure of GHb differs from that of Hb, structural changes relating to the oxygen affinity of these proteins remain incompletely understood. In this study, the oxygen-binding kinetics of Hb and GHb are evaluated, and their structural dynamics are investigated using solution small-angle X-ray scattering (SAXS), electrospray ionization mass spectrometry equipped with ion mobility spectrometry (ESI-IM-MS), and molecular dynamic (MD) simulations to understand the impact of structural alteration on their oxygen-binding properties. Our results show that the oxygen-binding kinetics of GHb are diminished relative to those of Hb. ESI-IM-MS reveals structural differences between Hb and GHb, which indicate the preference of GHb for a more compact structure in the gas phase relative to Hb. MD simulations also reveal an enhancement of intramolecular interactions upon glycation of Hb. Therefore, the more rigid structure of GHb makes the conformational changes that facilitate oxygen capture more difficult creating a delay in the oxygen-binding process. Our multiple biophysical approaches provide a better understanding of the allosteric properties of hemoglobin that are reflected in the structural alterations accompanying oxygen binding.