Open AccessFurther characterization of structural and electric properties of non‐spherical α‐crystallin
Author(s) -
HAERINGEN Bart,
BOGAERDE Marco R.,
EDEN Don,
GRONDELLE Rienk,
BLOEMENDAL Michael
Publication year - 1993
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1993.tb18229.x
Subject(s) - dipole , size exclusion chromatography , circular dichroism , chemistry , crystallin , population , crystallography , molecule , ultraviolet , elution , analytical chemistry (journal) , molecular physics , chromatography , physics , optics , organic chemistry , biochemistry , enzyme , demography , sociology
Recently we have shown that the population of native α‐crystallin, isolated using size‐exclusion chromatography from eye lenses of calves, is multimodal. Most of the protein probably possesses an almost spherical appearance, but at least one of the other modes represents more extended, ellipsoidally and/or cylindrically shaped molecules [Van Haeringen, B., Eden, D., Van den Bogaerde, M. R., Van Grondelle, R. & Bloemendal, M. (1992) Eur. J. Biochem. 210 , 211–216]. In the present study, we characterize various subpools of a single α‐crystallin size‐exclusion chromatography elution peak by means of transient‐electric‐birefringence measurements, ultraviolet linear‐dichroism spectroscopy and analytical fast protein liquid chromatography. It is concluded that the fractions have a well‐defined stable mass and are not in reversible equilibrium with each other. All pools appear to be composed of at least two types of differently shaped molecules. The hydrodynamic dimensions and electric properties of the different α‐crystallin species are characterized. The non‐spherical α‐crystallin is found to be optically and electrically more anisotropic, and to contain a larger permanent electric dipole moment than the spherical form. A model for the composition of the α‐crystallin pool is presented.