Spectroscopic studies on human lens crystallins.
Biochim Biophys Acta
; 832(2): 197-203, 1985 Nov 29.
Article
em En
| MEDLINE
| ID: mdl-4063377
ABSTRACT
Human lens crystallins were studied by absorption, circular dichroism and fluorescence spectroscopy. The absorption spectra in the near-ultraviolet region show some differences in intensity, but spectral features are similar, except for the alpha-crystallin, which gives a fine structure due to phenylalanine between 250 and 270 nm. Tryptophan fluorescence and near-ultraviolet circular dichroism indicate that tryptophan residues are more exposed in alpha-crystallin than in either beta- or gamma-crystallin, and that the degree of exposure decreases in the order of alpha less than beta 1 greater than beta 2 greater than beta 3 greater than gamma. The far ultraviolet CD suggests that these proteins exist mainly in a beta-sheet conformation and that the amount does not vary much among them. The greater exposure of the tryptophan residues in the high-molecular-weight crystallins may reflect greater unfolding in their protein domains. Spectroscopic measurements are thus useful in predicting protein tertiary structure in the absence of the complete sequence and X-ray data. The fact that the high-molecular-weight proteins exist in a more unfolded state may render them more vulnerable to exogeneous insults, and these effects may be studied by spectroscopic measurements.
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Base de dados:
MEDLINE
Assunto principal:
Cristalinas
Limite:
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1985
Tipo de documento:
Article