The kinetics of dithiothreitol (DTT)-induced aggregation of alpha-lactalbumin from bovine milk has been studied using dynamic light-scattering technique. Analysis of the distribution of the particles formed in the solution of alpha-lactalbumin after the addition of DTT by size showed that the initial stage of the aggregation process was the stage of formation of the start aggregates with the hydrodynamic radius (R(h)) of 80-100nm. Further growth of the protein aggregates proceeds as a result of sticking of the start aggregates. Suppression of alpha-lactalbumin aggregation by alpha-crystallin is mainly due to the increase in the duration of the lag period on the kinetic curves of aggregation. It is assumed that the initially formed complexes of unfolded alpha-lactalbumin with alpha-crystallin were transformed to the primary clusters prone to aggregation as a result of the redistribution of the denatured protein molecules on the surface of the alpha-crystallin particles.
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http://dx.doi.org/10.1016/j.bpc.2009.11.002 | DOI Listing |
Int J Mol Sci
July 2020
Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia.
Small heat-shock proteins (sHSPs) are ATP-independent molecular chaperones that interact with partially unfolded proteins, preventing their aberrant aggregation, thereby exhibiting a chaperone-like activity. Dynamics of the quaternary structure plays an important role in the chaperone-like activity of sHSPs. However, relationship between the dynamic structure of sHSPs and their chaperone-like activity remains insufficiently characterized.
View Article and Find Full Text PDFJ Biol Chem
March 2019
From the Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350
Small heat shock proteins (sHSPs) delay protein aggregation in an ATP-independent manner by interacting with client proteins that are in states susceptible to aggregation, including destabilized states related to cellular stress. Up-regulation of sHSPs under stress conditions supports their critical role in cellular viability. Widespread distribution of sHSPs in most organisms implies conservation of function, but it remains unclear whether sHSPs implement common or distinct mechanisms to delay protein aggregation.
View Article and Find Full Text PDFAdv Biosyst
January 2018
Department of Ophthalmology, University of Missouri School of Medicine, Columbia, Missouri 65212.
Many of the newly discovered therapeutic peptides and molecules are limited by their inability to cross the cell membrane. In the present study we employed a cell penetrating peptide (CPP), VPTLK, derived from Ku70 protein, to facilitate the entry of a mini-chaperone across the cell membrane. Our previous studies suggest that the mini-chaperone peptide representing the chaperone site in αA-crystallin, which can inhibit protein aggregation associated with proteopathies, has therapeutic potential.
View Article and Find Full Text PDFInt J Biol Macromol
September 2015
Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia. Electronic address:
Macromolecular crowding can facilitate protein-protein interactions in the cell, in particular aggregation processes. To characterize the anti-aggregation activity of chaperones under conditions mimicking the crowded environment in the cell, two basic test systems are used. Test systems of the first type are based on aggregation of target proteins undergoing unfolding under different factors.
View Article and Find Full Text PDFInt J Biol Macromol
February 2015
Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia. Electronic address:
Ultraviolet radiation is a risk factor for cataractogenesis. It is believed that enhanced rates of lens opacification and cataract formation are the results of gradual loss of chaperone-like efficiency of α-crystallin upon exposure to UV light. To characterize chaperone-like activity of α-crystallin damaged by UV irradiation, a test system based on dithiothreitol-induced aggregation of holo-α-lactalbumin from bovine milk was used.
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