Quantitative NMR study of heat-induced aggregation of eye-lens crystallin proteins under crowding conditions

Camilles, Maria; Link, Susanne; Balbach, Jochen; Saalwächter, Kay; Krushelnitsky, Alexey

doi:10.1016/j.bbapap.2018.07.007

Cited by 5 publications

(4 citation statements)

References 41 publications

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“…It should be noted here that in this respect the globular state of cyclic macromolecules in melts qualitatively differs from the globular state of biological proteins whose constituent elements make relatively small displacements relative to sufficiently fixed positions in the system of the globule center of mass. The dynamics and structure of the former have been intensively studied by the so-called T 2 dispersion method. − …”

Section: Resultsmentioning

confidence: 99%

Spin Relaxation and Dynamics of Ring Poly(ethylene oxide) in Melts

Lindt,

Fatkullin,

Mattea

et al. 2024

Macromolecules

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The spin relaxation of protons and deuterons was investigated in melts of ring poly(ethylene oxide) (PEO) macromolecules with a molecular mass varying from 5280 to 96,000 Da. Comparison of the frequency dispersion of NMR spin− lattice relaxation rates with corresponding rates in the melts of linear PEO of similar molecular masses shows that there is a significant mutual interpenetration of neighboring ring macromolecules, although less pronounced than in their linear counterparts. The mean-squared displacement of ring segments in the investigated frequency interval corresponding to the time interval 8 × 10 −9 to 2 × 10 −5 s depends on time as ⟨r n 2 (t)⟩ ∝ t 0.39 , in agreement with neutron spin echo (NSE) results. Decays of the normalized Hahn echo signal in ring macromolecules are exponential within experimental errors, unlike for their linear counterparts where strongly nonexponential behavior is found. This indicates the absence of dynamic heterogeneity of ring segments seen by NMR and associated with the presence of end segments in their linear analogues.

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Section: Resultsmentioning

confidence: 99%

Spin Relaxation and Dynamics of Ring Poly(ethylene oxide) in Melts

Lindt,

Fatkullin,

Mattea

et al. 2024

Macromolecules

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“…While others have looked at the effects of crowding on crystallin function, [ 28 , 41 , 87 , 88 ] few have investigated multiple crystallins simultaneously in vitro. Our materials platform highlights the need to consider all combinations of crystallin subtypes when assaying the dense fluid‐like packing and short‐range order of the lens.…”

Section: Discussionmentioning

confidence: 99%

Design and Characterization of Model Systems that Promote and Disrupt Transparency of Vertebrate Crystallins In Vitro

Bergman,

Hernandez,

Deffler

et al. 2023

Advanced Science

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Positioned within the eye, the lens supports vision by transmitting and focusing light onto the retina. As an adaptive glassy material, the lens is constituted primarily by densely‐packed, polydisperse crystallin proteins that organize to resist aggregation and crystallization at high volume fractions, yet the details of how crystallins coordinate with one another to template and maintain this transparent microstructure remain unclear. The role of individual crystallin subtypes (α, β, and γ) and paired subtype compositions, including how they experience and resist crowding‐induced turbidity in solution, is explored using combinations of spectrophotometry, hard‐sphere simulations, and surface pressure measurements. After assaying crystallin combinations, β‐crystallins emerged as a principal component in all mixtures that enabled dense fluid‐like packing and short‐range order necessary for transparency. These findings helped inform the design of lens‐like hydrogel systems, which are used to monitor and manipulate the loss of transparency under different crowding conditions. When taken together, the findings illustrate the design and characterization of adaptive materials made from lens proteins that can be used to better understand mechanisms regulating transparency.

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“…[18,19] Notably, this behavior is distinct from many other proteins, which usually show a strong degree of rotational-translational coupling upon crowding. [20] We also established low-resolution 1 H NMR relax-ometry as a simple tool to monitor aggregation under crowding conditions, [21,22] showing that highly concentrated 𝛾B-crystallin aggregates slowly at 60 °C, while 𝛼B-crystallin forms transparent gels. In-depth studies of the latter are underway.…”

Section: Introductionmentioning

confidence: 99%

Early Stage UV‐B Induced Molecular Modifications of Human Eye Lens γD‐Crystallin

Weininger

Neudorf

Gröger

et al. 2023

Macromolecular Bioscience

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In the human eye lenses, the crystallin proteins facilitate transparency, light refraction, as well as UV light protection. A deregulated balanced interplay between α‐, β‐, and γ‐crystallin can cause cataract. γD‐crystallin (hγD) is involved in the energy dissipation of absorbed UV light by energy transfer between aromatic side chains. Early UV‐B induced damage of hγD with molecular resolution is studied by solution NMR and fluorescence spectroscopy. hγD modifications are restricted to Tyr 17 and Tyr 29 in the N‐terminal domain, where a local unfolding of the hydrophobic core is observed. None of the tryptophan residues assisting fluorescence energy transfer is modified and hγD is remained soluble over month. Investigating isotope‐labeled hγD surrounded by eye lens extracts from cataract patients reveals very week interactions of solvent‐exposed side chains in the C‐terminal hγD domain and some remaining photoprotective properties of the extracts. Hereditary E107A hγD found in the eye lens core of infants developing cataract shows under the here used conditions a thermodynamic stability comparable to the wild type but an increased sensitivity toward UV‐B irradiation.

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Quantitative NMR study of heat-induced aggregation of eye-lens crystallin proteins under crowding conditions

Cited by 5 publications

References 41 publications

Spin Relaxation and Dynamics of Ring Poly(ethylene oxide) in Melts

Spin Relaxation and Dynamics of Ring Poly(ethylene oxide) in Melts

Design and Characterization of Model Systems that Promote and Disrupt Transparency of Vertebrate Crystallins In Vitro

Early Stage UV‐B Induced Molecular Modifications of Human Eye Lens γD‐Crystallin

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