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Small‐angle light and X‐ray scattering measurements of a protein–oligosaccharide complex mucin in solution
Author(s) -
Watanabe Yasushi,
Inoko Yoji
Publication year - 2007
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889807009247
Subject(s) - small angle x ray scattering , radius of gyration , scattering , chemistry , light scattering , fractal dimension , analytical chemistry (journal) , crystallography , multiangle light scattering , small angle scattering , molecule , gyration , chromatography , optics , fractal , polymer , physics , organic chemistry , geometry , mathematical analysis , mathematics
The molecular assembly and the chain conformation of intact bovine submaxillary mucin (BSM) in solution over wide‐ranging concentrations were characterized by using low‐angle laser light scattering and small‐angle X‐ray scattering (SAXS) methods. The specific refractive index increment of BSM was estimated to be 0.152 ml g −1 and was used to determine the molecular weight of BSM by low‐angle laser light scattering photometry combined with high‐performance gel chromatography. The total molecular weight of BSM was 55 million and the molecular weight of the main fractionated components was about 2 million. Fractal analysis of the SAXS data revealed that the intact BSM molecule is a chain with excluded volume (fractal dimension 1.67) at concentrations of 1.4 and 3.6 mg ml −1 and a chain with a Gaussian chain character (fractal dimension 2) at concentrations of 7.2–15 mg ml −1 . Moreover, the Kratky plots of the SAXS data showed that the chain conformation of BSM molecules is a Gaussian (unfolded) structure in solution. The estimated cross‐sectional radius of gyration value lay in the range 0.65–0.76 nm, which is reasonable for a long thin shape.