The aggregation of a beta-crystallin water solution exposed to XeCl laser radiation demonstrates the dependence of scattering-exposure curve (scattering versus exposure) on laser intensity. The main features of this dependence can be understood by the relaxation of a partly denaturated state of a protein within some finite relaxation time. These photoactivated states originate from the absorption of UV photons.
View Article and Find Full Text PDFThe results of the investigations of photoaggregation of the main eye lens proteins alpha-, beta- and gamma-crystallins and the model protein carbonic anhydrase in response to pulsed irradiation by a XeCI laser at 308 nm in the wide range of pulse energy densities (w) and pulse repetition rates (F) have been reviewed. A nonlinear dependence of aggregation efficiency on the values of w, F, and the concentration of protein solution was found. A theoretical model that qualitatively describes the experimental results was developed.
View Article and Find Full Text PDFThere is a potential of therapeutic action on certain stages of caractogenesis, in particular on the aggregation of water-soluble proteins of cytoplasmic lens fiber cells, giving rise to insoluble protein complexes. The effect of a combined preparation (N-acetyl carnosine and D-patethine), acting by the chaperon-like mechanism, was studied in vivo on a prolonged rat model of UV-induced cataract. The use of the combined preparation consisting of a mixture of peptides of N-acetyl carnosine and D-patethine in a ratio of 1:1 as ocular instillations and intraperitoneal injections could slow down the development of UV-induced cataract in vivo.
View Article and Find Full Text PDFUV-induced aggregation of betaL-crystallin, one of the major lens proteins, was studied under its pulse radiation with XeCl laser at a wavelength of 308 nm. Unlike the in vitro tested dipeptides L-carnosine, N-acetyl carnosine, D-panthetine, and particularly their combination, the so-called new chaperon was demonstrated to slow down the rate of photoaggregatin of beta-crystallin. The new chaperon, a mixture of D-pathethine and N-acetyl carnosine was ascertained to protect a mixture of betaL- and alpha-crystallins from UV-induced aggregation to a greater extent than D-pathethine or N-acetyl carnosine used alone.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
September 2005
Purpose: Exposure to UV-B light (wavelength, 290-320 nm) is a well-documented risk factor for age-related cataracts. As the lens ages, beta-crystallins tend to undergo proteolytic cleavage of their terminal extensions. To delineate the effects of loss of terminal arms on beta-crystallin function, the sensitivity of purified recombinant wild-type (rbetaA3) to UV-irradiation induced aggregation was compared with that of betaA3-crystallin missing the N-terminal extension (rbetaA3tr).
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