Preferential interaction among lens proteins as evidenced from accessibility of crystallins to ammonia gas

Bettelheim, Frederick A.; Zigler, J. Samuel

doi:10.1016/0014-4835(88)90006-1

Cited by 11 publications

(1 citation statement)

References 21 publications

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“…This is in keeping with our earlier observation (Goosey et al, 1980) that P-crystallin is more sensitive than a-crystallin to photodynamic crosslinking. It is also interesting that this order is comparable to the order of "accessibility on total sites" of the various crystallins to ammonia gas y > P > u-crystallin (Bettelheim and Zigler, 1988), since in our present experiments, gaseous oxygen in its singlet excited state diffuses into the protein solution and reacts. We note, however, that this order is different from that of the vulnerability of these molecules to direct photo-oxidation, i.e.…”

Section: Inhibition Of Protein Crosslinking By Blocking Hissupporting

confidence: 57%

The Reaction of Singlet Oxygen With Proteins, With Special Reference to Crystallins

Balasubramanian¹,

Du²,

Zigler³

1990

Photochem & Photobiology

126

120

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Photosensitized oxidation of the eye lens proteins, the crystallins, is thought to lead to protein crosslinks and high molecular weight aggregates. Such protein modifications may be important factors in the formation of lens opacities or cataracts. We focus attention here on type 2 photo-oxidation involving the reaction of singlet oxygen (1O2) with crystallins and some "control" proteins. We find that: (1) trp residues are oxidized to N-formyl kynurenine and related products, but this in itself does not lead to the production of high molecular weight protein aggregates of the protein; (2) tyr residues react with 1O2 but we do not detect dihydroxyphenylalanine or bityrosine nor are protein crosslinks formed as a result; (3) oxidation of his residues appears necessary for high molecular weight protein covalent aggregates to form. Proteins devoid of his, e.g. melittin or bovine pancreatic trypsin inhibitor, do not form high molecular weight products upon reaction with 1O2. Prior reaction and blocking of his inhibits the crosslinking reactions. (4) The oxidized protein is seen to be more acidic than the parent and has an altered tertiary structure. (5) Among the crystallins, reactivity towards 1O2 varies in the order gamma greater than beta greater than alpha and also gamma A/E greater than gamma D greater than gamma B crystallin.

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Section: Inhibition Of Protein Crosslinking By Blocking Hissupporting

confidence: 57%

The Reaction of Singlet Oxygen With Proteins, With Special Reference to Crystallins

Balasubramanian¹,

Du²,

Zigler³

1990

Photochem & Photobiology

126

120

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Birefringence of actin

Kakar

Bettelheim

1991

Biopolymers

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The total strain birefringence of F-actin isolated from chicken gizzards was measured as a function of elongation in thin transparent films. Each film held at a certain elongation in a jig was allowed to swell in a penetrating but nondissolving liquid. Seven liquids with different refractive indices were employed. The thickness of the film in each swelling liquid was obtained once equilibrium was established. At each elongation, from 0 to 16%, a Wiener curve was obtained. The minima of the Wiener curves yielded the intrinsic birefringence of F-actin as a function of elongation. The intrinsic birefringence increases with elongation up to 16%, above which the thin films break. The form birefringence at a set refractive index also increases with elongation. The implication of the strain birefringence of F-actin is discussed as it affects the optical properties, mainly light scattering, of tissues such as the fiber cells of lens of the eye.

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Second virial coefficient of α‐crystallin

Wang

Bettelheim

1989

Proteins

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Light scattering studies were performed on bovine alpha-crystallin measuring the scattering intensities as a function of scattering angle, concentration, and temperature. The data yielded the molecular weight, radius of gyration, and second virial coefficient of alpha-crystallin at different temperatures. The second virial coefficient increased with increasing temperature. Both the enthalpy and entropy of solution of alpha-crystallin are positive. The Flory theta temperature was found to be 271 K.

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Preferential interaction among lens proteins as evidenced from accessibility of crystallins to ammonia gas

Cited by 11 publications

References 21 publications

The Reaction of Singlet Oxygen With Proteins, With Special Reference to Crystallins

The Reaction of Singlet Oxygen With Proteins, With Special Reference to Crystallins

Birefringence of actin

Second virial coefficient of α‐crystallin

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