Double-globular structure of porcine stomach mucin: A small-angle X-ray scattering study

Di Cola, Emanuela, Yakubov, Gleb E. and Waigh, Thomas A. (2008) Double-globular structure of porcine stomach mucin: A small-angle X-ray scattering study. Biomacromolecules, 9 11: 3216-3222. doi:10.1021/bm800799u

Author Di Cola, Emanuela
Yakubov, Gleb E.
Waigh, Thomas A.
Title Double-globular structure of porcine stomach mucin: A small-angle X-ray scattering study
Journal name Biomacromolecules   Check publisher's open access policy
ISSN 1525-7797
Publication date 2008
Sub-type Article (original research)
DOI 10.1021/bm800799u
Volume 9
Issue 11
Start page 3216
End page 3222
Total pages 7
Language eng
Subject 1502 Banking, Finance and Investment
2505 Materials Chemistry
2507 Polymers and Plastics
2502 Biomaterials
Abstract We present evidence from small-angle X-ray scattering synchrotron experiments that porcine stomach mucin (MUC6) contains a double-globular comb structure. Analysis of the amino acid sequence of the peptide comb backbone indicates that the globular structure is determined by both the charge and hydrophobicity of the amino acids and the placement of the short hydrophilic carbohydrate side chains (∼2.5 nm). The double-globular structure is, thus, due to a block copolymer type hydrophobic polyampholyte charge instability in contrast to the random copolymer instabilities observed previously with synthetic polyelectrolytes (particularly polystyrene sulfonates). Careful filtering was required to exclude multimonomer aggregates from the X-ray measurements. A double Guinier analysis (Rg - 26 nm) and a double power law fit are consistent with two globules per chain in low salt conditions. The average radius of the globules is ∼10 nm in salt-free condition (double Guinier fit) and the average distance of intrachain separation of the globules is 48 nm. The addition of salt causes a significant decrease in the radius of gyration (14 nm 100 mM NaCl) of the chains and is attributed to the contraction of the glycosylated peptide spacer between the two globules (the globular size continues to be ∼ 10 nm and the globule separation is then 18 nm). Without salt, the scaling of the semidilute mesh size (ξ) as a function of the mucin concentration (c) is ξ ∼ c-0.45 compared with ξ ∼ c-0.28 in high salt conditions, highlighting the globular nature of the chains. In contrast, hydrophilic flexible polyelectrolytes have a stronger concentration dependence of ξ when excess salt is added.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
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Citation counts: TR Web of Science Citation Count  Cited 26 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 27 times in Scopus Article | Citations
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Created: Thu, 14 May 2015, 16:41:20 EST by Gleb Yakubov