Understanding protein amyloidogenesis is an important topic in protein science, fueled by the role of amyloid aggregates, especially oligomers, in the etiology of a number of devastating human degenerative diseases. However, the mechanisms that determine the formation of amyloid oligomers remain elusive due to the high complexity of the amyloidogenesis process. For instance, gold nanoparticles promote or inhibit amyloid fibrillation. We have functionalized gold nanorods with a metal-chelating group to selectively immobilize soluble RepA-WH1, a model synthetic bacterial prionoid, using a hexa-histidine tag (H6). H6-RepA-WH1 undergoes stable amyloid oligomerization in the presence of catalytic concentrations of anisotropic nanoparticles. Then, in a physically separated event, such oligomers promote the growth of amyloid fibers of untagged RepA-WH1. SERS spectral changes of H6-RepA-WH1 on spherical citrate-AuNP substrates provide evidence for structural modifications in the protein, which are compatible with a gradual increase in β-sheet structure, as expected in amyloid oligomerization.
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http://dx.doi.org/10.1002/anie.201604970 | DOI Listing |
Int J Biol Macromol
January 2025
School of Physical Science and Technology, Ningbo University, Ningbo 315211, China; Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States. Electronic address:
Human calcitonin (hCT) is a peptide hormone that regulates calcium homeostasis, but its abnormal aggregation can disrupt physiological functions and increase the risk of medullary thyroid carcinoma. To elucidate the mechanisms underlying hCT aggregation, we investigated the self-assembly dynamics of hCT segments (hCT, hCT, and hCT) and the folding and dimerization of full-length hCT through microsecond atomistic discrete molecular dynamics (DMD) simulations. Our results revealed that hCT and hCT predominantly existed as isolated monomers with transient small-sized oligomers, indicating weak aggregation tendencies.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States.
ConspectusProtein higher-order structure (HOS) is key to biological function because the mechanisms of protein machinery are encoded in protein three-dimensional structures. Mass spectrometry (MS)-based protein footprinting is advancing protein structure characterization by mapping solvent-accessible regions of proteins and changes in H-bonding, thereby providing higher order structural information. Footprinting provides insights into protein dynamics, conformational changes, and interactions, and when conducted in a differential way, can readily reveal those regions that undergo conformational change in response to perturbations such as ligand binding, mutation, thermal stress, or aggregation.
View Article and Find Full Text PDFBrain Res
December 2024
Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China. Electronic address:
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-beta (Aβ) and leading to cellular senescence and cognitive deficits. Cellular senescence contributes significantly to the pathogenesis of AD through the senescence-associated secretory phenotype (SASP), exacerbating Aβ deposition. This study investigates the protective effects of 3-N-Butylphthalide (NBP), a compound derived from Apium graveolens Linn (Chinese celery), on Aβ-induced cellular senescence in U87 cells.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
School of Chemical and Biological Engineering, Institute of Engineering Research, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Stable hollow-type microspheres (MSs) have been fabricated using α-synuclein (αS), an amyloidogenic protein, via freeze-induced protein self-assembly. This assembly process involves three steps: rapid freezing to form spherical protein condensates from αS oligomers, frozen annealing to form a crust on the condensate and freeze-drying to create an interior lumen via the three-dimensional (3D) coffee-stain effect. The crust produced during the frozen-annealing step is a β-sheet-mediated protein structure that is presumed to be created at the quasi-liquid layer of the protein-ice interface and thus contributes to the stability of MSs in aqueous solutions at room temperature without any additional surface stabilization.
View Article and Find Full Text PDFACS Appl Bio Mater
December 2024
MOE Key Laboratory of Bio-Intelligent Manufacturing, Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
Recent clinical studies have highlighted the presence of microclots in the form of amyloid fibrinogen particles (AFPs) in plasma samples from Long COVID patients. However, the clinical significance of these abnormal, nonfibrillar self-assembly aggregates of human fibrinogen remains debated due to the limited understanding of their structural and biological characteristics. In this study, we present a method for generating mimetic microclots in vitro.
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