Cu/Zn-superoxide dismutase forms fibrillar hydrogels in a pH-dependent manner via a water-rich extended intermediate state

Autor: Hironobu Eguchi, Naoto Oba, Tadashi Inoue, Yoshiaki Furukawa, Daisaku Yoshihara, Ichihashi Motoko, Keiichiro Suzuki, Haruhiko Sakiyama, Eiichi Tokuda, Michiru Wagatsuma, Noriko Fujiwara
Jazyk: angličtina
Rok vydání: 2018
Předmět:
0301 basic medicine
Protein Denaturation
Conformational change
lcsh:Medicine
Sodium Chloride
Biochemistry
Physical Chemistry
Molecular Self Assembly
chemistry.chemical_compound
Superoxide Dismutase-1
Materials Physics
Chemical Precipitation
Denaturation (biochemistry)
lcsh:Science
Materials
chemistry.chemical_classification
Multidisciplinary
Viscosity
Chemistry
Physics
Chemical Reactions
Classical Mechanics
Hydrogels
Hydrogen-Ion Concentration
Recombinant Proteins
Deformation
Physical Sciences
Self-healing hydrogels
Agarose
Thioflavin
Research Article
Amyloid
Globular protein
Amorphous Solids
Materials Science
Viscoelastic Substances
macromolecular substances
Fibril
Precipitates
03 medical and health sciences
Humans
Benzothiazoles
Damage Mechanics
lcsh:R
Water
Biology and Life Sciences
Proteins
Acoustics
Quartz crystal microbalance
Kinetics
030104 developmental biology
Chemical Properties
Mixtures
Amyloid Proteins
Biophysics
lcsh:Q
Globular Proteins
Protein Multimerization
Gels
Zdroj: PLoS ONE, Vol 13, Iss 10, p e0205090 (2018)
PLoS ONE
ISSN: 1932-6203
Popis: Under certain conditions, amyloid-like fibrils can develop into three-dimensional networks and form hydrogels by a self-assembly process. When Cu/Zn superoxide dismutase (SOD1), an anti-oxidative enzyme, undergoes misfolding, fibrillar aggregates are formed, which are a hallmark of a certain form of familial amyotrophic lateral sclerosis (ALS). However, the issue of whether SOD1 fibrils can be assembled into hydrogels remains to be tested. Here, we show that the SOD1 polypeptides undergo hydrogelation accompanied by the formation of thioflavin T-positive fibrils at pH 3.0 and 4.0, but not at pH 5.0 where precipitates are formed. The results of viscoelastic analyses indicate that the properties of SOD1 hydrogels (2%) were similar to and slightly more fragile than a 0.25% agarose gel. In addition, monitoring by a quartz crystal microbalance with admittance analysis showed that the denaturing of immobilized SOD1 on a sensor under the hydrogelation conditions at pH 3.0 and 4.0 resulted in an increase in the effective acoustic thickness from ~3.3 nm (a folded rigid form) to ~50 and ~100 nm (an extended water-rich state), respectively. In contrast, when SOD1 was denatured under the same conditions at pH 5.0, a compact water-poor state with an effective acoustic thickness of ~10 nm was formed. The addition of physiological concentrations of NaCl to the pH 4.0 sample induced a further extension of the SOD1 with larger amounts of water molecules (with an effective acoustic thickness of ~200 nm) but suppressed hydrogel formation. These results suggest that different denatured intermediate states of the protein before self-assembly play a major role in determining the characteristics of the resulting aggregates and that a conformational change to a suitable level of extended water-rich intermediate state before and/or during intermolecular assembling is required for fibrillation and hydrogelation in the case of globular proteins.
Databáze: OpenAIRE
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