Inter- and intramolecular disulfide bond formation and related structural changes in the lens proteins. A Raman spectroscopic study in vivo of lens aging.

Ozaki, Yukihiro; Mizuno, A; Itoh, Koichi; Iriyama, Keiji

doi:10.1016/s0021-9258(18)47760-5

Cited by 64 publications

(16 citation statements)

References 26 publications

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“…The lowest values of the ratio did not exceed the value of 0.9, which indicated the formation of moderate-to-weak hydrogen bonds . The ratio increase observed for the CHB and CAR fibers indicated that the OH groups can be strongly bound to a negatively charged acceptor such as a carboxylate group . An increase in the ratio value was observed after the addition of pectin and locust bean gum to the dough by Linlaud et al According to Nawrocka et al, the pectin content in the fiber preparation did not affect the value of the tyrosine doublet.…”

Section: Results and Discussionmentioning

confidence: 93%

Dietary Fiber-Induced Changes in the Structure and Thermal Properties of Gluten Proteins Studied by Fourier Transform-Raman Spectroscopy and Thermogravimetry

Nawrocka

Szymańska-Chargot

Miś

et al. 2016

J. Agric. Food Chem.

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Interactions between gluten proteins and dietary fiber supplements at the stage of bread dough formation are crucial in the baking industry. The dietary fiber additives are regarded as a source of polysaccharides and antioxidants, which have positive effects on human health. The fiber enrichment of bread causes a significant reduction in its quality, which is connected with changes in the structure of gluten proteins. Changes in the structure of gluten proteins and their thermal properties induced by seven commercial dietary fibers (fruit, vegetable, and cereal) were studied by FT-Raman spectroscopy and thermogravimetry (TGA), respectively. For this aim the bread dough at 500 FU consistency was made of a blend of wheat starch and wheat gluten as well as the fiber, the content of which ranged from 3 to 18% w/w. The obtained results revealed that all dietary fibers apart from oat caused similar changes in the secondary structure of gluten proteins. The most noticeable changes were observed in the regions connected with hydrogen-bonded β-sheets (1614 and 1684 cm(-1)) and β-turns (1640 and 1657 cm(-1)). Other changes observed in the gluten structure, concerning other β-structures, conformation of disulfide bridges, and aromatic amino acid microenvironment, depend on the fibers' chemical composition. The results concerning structural changes suggested that the observed formation of hydrogen bonds in the β-structures can be connected with aggregation or abnormal folding. This hypothesis was confirmed by thermogravimetric results. Changes in weight loss indicated the formation of a more complex and strong gluten network.

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Section: Results and Discussionmentioning

confidence: 93%

Dietary Fiber-Induced Changes in the Structure and Thermal Properties of Gluten Proteins Studied by Fourier Transform-Raman Spectroscopy and Thermogravimetry

Nawrocka

Szymańska-Chargot

Miś

et al. 2016

J. Agric. Food Chem.

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“…30 Meanwhile, the band at 509 cm À1 comes from the S-S vibration, indicating the presence of the disulfide bond in the nanoparticles. 31 To in situ monitor the formation of the S-S bond during the growth process of Au@organosilica nanoparticles, a roughened SERS-active Au electrode was immersed into a mixture of MPS and NH 4 OH solution and the SERS spectra were measured with time. No S-S band was observed before the hydrolysis, whereas the S-S band was found to increase with the hydrolysis time (Fig.…”

Section: Resultsmentioning

confidence: 99%

Au@organosilica multifunctional nanoparticles for the multimodal imaging

et al. 2011

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The increasing application of nanomaterials in biosensor and imaging sets a higher demand on the multifunctionalities of nanomaterials for obtaining multiple parameters of a same system under a same condition. In this work, multifunctional Au@organosilica nanoparticles with high stability were conveniently synthesized by direct hydrolyzing of 3-mercaptopropyltriethoxysilane in an aqueous solution in the presence of a Au core. Modification of the Au core with Raman reporters and the organosilica shell with fluorophore before and after the hydrolysis, respectively, produces multifunctional nanoparticles exhibiting Rayleigh scattering of the Au core, fluorescence signals of the fluorophores and surface-enhanced Raman scattering (SERS) of the Raman reporters. The nanoparticles can be used as multimodal tracers for living cell imaging and related biological research.National Basic Research Program of China[2007CB935603, 2009CB930703, 2007DFC40440]; Natural Science Foundation of China[20620130427, 20825313, 20827003, 21021120456, 21021002

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“…Although the crystallins are cytosolic, and therefore initially fold in a reducing environment, the redox potential of lens cytosol shifts toward increasingly oxidizing values during the course of aging and, especially, cataractogenesis (41). Accordingly, the proportion of Cys residues forming disulfide bonds increases over time (42), and mature cataracts show disulfide cross-linking in over half the lens protein content (43).…”

mentioning

confidence: 99%

An Internal Disulfide Locks a Misfolded Aggregation-prone Intermediate in Cataract-linked Mutants of Human γD-Crystallin

Serebryany

Woodard

Adkar

et al. 2016

Journal of Biological Chemistry

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Considerable mechanistic insight has been gained into amyloid aggregation; however, a large number of non-amyloid protein aggregates are considered "amorphous," and in most cases, little is known about their mechanisms. Amorphous aggregation of ␥-crystallins in the eye lens causes cataract, a widespread disease of aging. We combined simulations and experiments to study the mechanism of aggregation of two ␥D-crystallin mutants, W42R and W42Q: the former a congenital cataract mutation, and the latter a mimic of age-related oxidative damage. We found that formation of an internal disulfide was necessary and sufficient for aggregation under physiological conditions. Two-chain all-atom simulations predicted that one non-native disulfide in particular, between Cys 32 and Cys 41 , was likely to stabilize an unfolding intermediate prone to intermolecular interactions. Mass spectrometry and mutagenesis experiments confirmed the presence of this bond in the aggregates and its necessity for oxidative aggregation under physiological conditions in vitro. Mining the simulation data linked formation of this disulfide to extrusion of the N-terminal ␤-hairpin and rearrangement of the native ␤-sheet topology. Specific binding between the extruded hairpin and a distal ␤-sheet, in an intermolecular chain reaction similar to domain swapping, is the most probable mechanism of aggregate propagation.

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Inter- and intramolecular disulfide bond formation and related structural changes in the lens proteins. A Raman spectroscopic study in vivo of lens aging.

Cited by 64 publications

References 26 publications

Dietary Fiber-Induced Changes in the Structure and Thermal Properties of Gluten Proteins Studied by Fourier Transform-Raman Spectroscopy and Thermogravimetry

Dietary Fiber-Induced Changes in the Structure and Thermal Properties of Gluten Proteins Studied by Fourier Transform-Raman Spectroscopy and Thermogravimetry

Au@organosilica multifunctional nanoparticles for the multimodal imaging

An Internal Disulfide Locks a Misfolded Aggregation-prone Intermediate in Cataract-linked Mutants of Human γD-Crystallin

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