Acrylamide and iodide fluorescence quenching as a structural probe of tryptophan microenvironment in bovine lens crystallins
作者:
PhillipsS. R.,
WilsonL. J.,
BorkmanR. F.,
期刊:
Current Eye Research
(Taylor Available online 1986)
卷期:
Volume 5,
issue 8
页码: 611-620
ISSN:0271-3683
年代: 1986
DOI:10.3109/02713688609015126
出版商: Taylor&Francis
数据来源: Taylor
摘要:
Fluorescence quenching using acrylamide and iodide quenchers has been used to investigate the microenvironments of tryptophan residues in bovineα-,β-, andγ-crystallin fractions. Acrylamide quenching is very senstive to the degree of tryptophan accessibility to the solvent containing the acrylamide. Since acrylamide is able to diffuse into the interior of the protein, accessibility to acrylamide may result from Trp residues lying at the surface of the protein or from the existence of channels leading to the interior of the protein. Iodide ion is hydrated and is limited by its large size and charge to quenching of tryptophan residues lying at or near the surface of proteins. Tryptophan residues in the lens crystallin fractions were found to be highly accessible to acrylamide, yet the rate of quenching by acrylamide was very low, indicating that the tryptophan residues of the lens crystallin fractions occupy predominately hydrophobic environments. The high accessibility to acrylamide likely results from diffusion of acrylamide into the interior of the protein. Accessibility to iodide was much lower, as was the rate of quenching by iodide, adding support to the conclusions from acrylamide quenching.
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