Skip to main content
NCBI home page
Biophysical Journal logoLink to Biophysical Journal
. 2002 Sep;83(3):1661–1670. doi: 10.1016/S0006-3495(02)73934-9

Heterogeneity and persistence length in human ocular mucins.

A N Round 1, M Berry 1, T J McMaster 1, S Stoll 1, D Gowers 1, A P Corfield 1, M J Miles 1
PMCID: PMC1302262  PMID: 12202389

Abstract

Atomic force microscopy (AFM) has been used to investigate the heterogeneity and flexibility of human ocular mucins and their subunits. We have paid particular attention, in terms of theory and experiment, to the problem of inducing the polymers to assume equilibrium conformations at a surface. Mucins deposited from a buffer containing Ni(2+) ions adopt extended conformations on mica akin to those observed for DNA under similar conditions. The heterogeneity of the intracellular native mucins is evident from a histogram of contour lengths, reflecting, in part, the diversity of mucin gene products expressed. Reduction of the native mucin with dithiothreitol, thereby breaking the S==S bonds between cysteine residues, causes a marked reduction in polymer length. These results reflect the modes of transport and assembly of newly synthesized mucins in vivo. By modifying the worm-like chain model for applicability to two dimensions, we have confirmed that under the conditions employed mucin adsorbs to mica in an equilibrated conformation. The determined persistence length of the native mucin, 36 nm, is consistent with that of an extended, flexible polymer; such characteristics will influence the properties of the gels formed in vivo.

Full Text

The Full Text of this article is available as a PDF (538.1 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Amerongen A. V., Bolscher J. G., Veerman E. C. Salivary mucins: protective functions in relation to their diversity. Glycobiology. 1995 Dec;5(8):733–740. doi: 10.1093/glycob/5.8.733. [DOI] [PubMed] [Google Scholar]
  2. Bensimon D, Simon AJ, Croquette V, V, Bensimon A. Stretching DNA with a receding meniscus: Experiments and models. Phys Rev Lett. 1995 Jun 5;74(23):4754–4757. doi: 10.1103/PhysRevLett.74.4754. [DOI] [PubMed] [Google Scholar]
  3. Berry M., Ellingham R. B., Corfield A. P. Membrane-associated mucins in normal human conjunctiva. Invest Ophthalmol Vis Sci. 2000 Feb;41(2):398–403. [PubMed] [Google Scholar]
  4. Berry M., Ellingham R. B., Corfield A. P. Polydispersity of normal human conjunctival mucins. Invest Ophthalmol Vis Sci. 1996 Dec;37(13):2559–2571. [PubMed] [Google Scholar]
  5. Berry M., McMaster T. J., Corfield A. P., Miles M. J. Exploring the molecular adhesion of ocular mucins. Biomacromolecules. 2001 Summer;2(2):498–503. doi: 10.1021/bm000145y. [DOI] [PubMed] [Google Scholar]
  6. Bustamante C., Marko J. F., Siggia E. D., Smith S. Entropic elasticity of lambda-phage DNA. Science. 1994 Sep 9;265(5178):1599–1600. doi: 10.1126/science.8079175. [DOI] [PubMed] [Google Scholar]
  7. Carlstedt I., Davies J. R. Glycoconjugates facing the outside world. Biochem Soc Trans. 1997 Feb;25(1):214–219. doi: 10.1042/bst0250214. [DOI] [PubMed] [Google Scholar]
  8. Carpita N. C., Gibeaut D. M. Structural models of primary cell walls in flowering plants: consistency of molecular structure with the physical properties of the walls during growth. Plant J. 1993 Jan;3(1):1–30. doi: 10.1111/j.1365-313x.1993.tb00007.x. [DOI] [PubMed] [Google Scholar]
  9. Davies J. R., Svitacheva N., Lannefors L., Kornfält R., Carlstedt I. Identification of MUC5B, MUC5AC and small amounts of MUC2 mucins in cystic fibrosis airway secretions. Biochem J. 1999 Dec 1;344(Pt 2):321–330. [PMC free article] [PubMed] [Google Scholar]
  10. Desseyn J. L., Aubert J. P., Porchet N., Laine A. Evolution of the large secreted gel-forming mucins. Mol Biol Evol. 2000 Aug;17(8):1175–1184. doi: 10.1093/oxfordjournals.molbev.a026400. [DOI] [PubMed] [Google Scholar]
  11. Ellingham R. B., Berry M., Stevenson D., Corfield A. P. Secreted human conjunctival mucus contains MUC5AC glycoforms. Glycobiology. 1999 Nov;9(11):1181–1189. doi: 10.1093/glycob/9.11.1181. [DOI] [PubMed] [Google Scholar]
  12. Fleiszig S. M., Zaidi T. S., Ramphal R., Pier G. B. Modulation of Pseudomonas aeruginosa adherence to the corneal surface by mucus. Infect Immun. 1994 May;62(5):1799–1804. doi: 10.1128/iai.62.5.1799-1804.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Frontali C., Dore E., Ferrauto A., Gratton E., Bettini A., Pozzan M. R., Valdevit E. An absolute method for the determination of the persistence length of native DNA from electron micrographs. Biopolymers. 1979 Jun;18(6):1353–1373. doi: 10.1002/bip.1979.360180604. [DOI] [PubMed] [Google Scholar]
  14. Hagerman P. J. Investigation of the flexibility of DNA using transient electric birefringence. Biopolymers. 1981 Jul;20(7):1503–1535. doi: 10.1002/bip.1981.360200710. [DOI] [PubMed] [Google Scholar]
  15. Hansma H. G., Kim K. J., Laney D. E., Garcia R. A., Argaman M., Allen M. J., Parsons S. M. Properties of biomolecules measured from atomic force microscope images: a review. J Struct Biol. 1997 Jul;119(2):99–108. doi: 10.1006/jsbi.1997.3855. [DOI] [PubMed] [Google Scholar]
  16. Hansma H. G., Laney D. E. DNA binding to mica correlates with cationic radius: assay by atomic force microscopy. Biophys J. 1996 Apr;70(4):1933–1939. doi: 10.1016/S0006-3495(96)79757-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Hansma H. G. Surface biology of DNA by atomic force microscopy. Annu Rev Phys Chem. 2001;52:71–92. doi: 10.1146/annurev.physchem.52.1.71. [DOI] [PubMed] [Google Scholar]
  18. Hazlett L. D., Moon M., Berk R. S. In vivo identification of sialic acid as the ocular receptor for Pseudomonas aeruginosa. Infect Immun. 1986 Feb;51(2):687–689. doi: 10.1128/iai.51.2.687-689.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Herrmann A., Davies J. R., Lindell G., Mårtensson S., Packer N. H., Swallow D. M., Carlstedt I. Studies on the "insoluble" glycoprotein complex from human colon. Identification of reduction-insensitive MUC2 oligomers and C-terminal cleavage. J Biol Chem. 1999 May 28;274(22):15828–15836. doi: 10.1074/jbc.274.22.15828. [DOI] [PubMed] [Google Scholar]
  20. Liu B., Rayment S., Oppenheim F. G., Troxler R. F. Isolation of human salivary mucin MG2 by a novel method and characterization of its interactions with oral bacteria. Arch Biochem Biophys. 1999 Apr 15;364(2):286–293. doi: 10.1006/abbi.1999.1141. [DOI] [PubMed] [Google Scholar]
  21. McIntire T. M., Brant D. A. Imaging of individual biopolymers and supramolecular assemblies using noncontact atomic force microscopy. Biopolymers. 1997 Aug;42(2):133–146. doi: 10.1002/(SICI)1097-0282(199708)42:2<133::AID-BIP3>3.0.CO;2-O. [DOI] [PubMed] [Google Scholar]
  22. McKenzie R. W., Jumblatt J. E., Jumblatt M. M. Quantification of MUC2 and MUC5AC transcripts in human conjunctiva. Invest Ophthalmol Vis Sci. 2000 Mar;41(3):703–708. [PubMed] [Google Scholar]
  23. McMaster T. J., Berry M., Corfield A. P., Miles M. J. Atomic force microscopy of the submolecular architecture of hydrated ocular mucins. Biophys J. 1999 Jul;77(1):533–541. doi: 10.1016/S0006-3495(99)76910-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Mikkelsen A., Stokke B. T., Christensen B. E., Elgsaeter A. Flexibility and length of human bronchial mucin studied using low-shear viscometry, birefringence relaxation analysis, and electron microscopy. Biopolymers. 1985 Sep;24(9):1683–1704. doi: 10.1002/bip.360240904. [DOI] [PubMed] [Google Scholar]
  25. Mou J., Czajkowsky D. M., Zhang Y., Shao Z. High-resolution atomic-force microscopy of DNA: the pitch of the double helix. FEBS Lett. 1995 Sep 11;371(3):279–282. doi: 10.1016/0014-5793(95)00906-p. [DOI] [PubMed] [Google Scholar]
  26. Rivetti C., Guthold M., Bustamante C. Scanning force microscopy of DNA deposited onto mica: equilibration versus kinetic trapping studied by statistical polymer chain analysis. J Mol Biol. 1996 Dec 20;264(5):919–932. doi: 10.1006/jmbi.1996.0687. [DOI] [PubMed] [Google Scholar]
  27. Round A. N., Rigby N. M., MacDougall A. J., Ring S. G., Morris V. J. Investigating the nature of branching in pectin by atomic force microscopy and carbohydrate analysis. Carbohydr Res. 2001 Apr 12;331(3):337–342. doi: 10.1016/s0008-6215(01)00039-8. [DOI] [PubMed] [Google Scholar]
  28. Schaper A., Starink J. P., Jovin T. M. The scanning force microscopy of DNA in air and in n-propanol using new spreading agents. FEBS Lett. 1994 Nov 21;355(1):91–95. doi: 10.1016/0014-5793(94)01166-4. [DOI] [PubMed] [Google Scholar]
  29. Schellman J. A. Flexibility of DNA. Biopolymers. 1974 Jan;13(1):217–226. doi: 10.1002/bip.1974.360130115. [DOI] [PubMed] [Google Scholar]
  30. Sheehan J. K., Brazeau C., Kutay S., Pigeon H., Kirkham S., Howard M., Thornton D. J. Physical characterization of the MUC5AC mucin: a highly oligomeric glycoprotein whether isolated from cell culture or in vivo from respiratory mucous secretions. Biochem J. 2000 Apr 1;347(Pt 1):37–44. [PMC free article] [PubMed] [Google Scholar]
  31. Sheehan J. K., Hanski C., Corfield A. P., Paraskeva C., Thornton D. J. Mucin biosynthesis and macromolecular assembly. Biochem Soc Trans. 1995 Nov;23(4):819–821. doi: 10.1042/bst0230819. [DOI] [PubMed] [Google Scholar]
  32. Thundat T., Allison D. P., Warmack R. J., Brown G. M., Jacobson K. B., Schrick J. J., Ferrell T. L. Atomic force microscopy of DNA on mica and chemically modified mica. Scanning Microsc. 1992 Dec;6(4):911–918. [PubMed] [Google Scholar]
  33. Vollrath F., Knight D. P. Liquid crystalline spinning of spider silk. Nature. 2001 Mar 29;410(6828):541–548. doi: 10.1038/35069000. [DOI] [PubMed] [Google Scholar]
  34. Wentzell L. M., Halford S. E. DNA looping by the Sfi I restriction endonuclease. J Mol Biol. 1998 Aug 21;281(3):433–444. doi: 10.1006/jmbi.1998.1967. [DOI] [PubMed] [Google Scholar]
  35. Wickström C., Davies J. R., Eriksen G. V., Veerman E. C., Carlstedt I. MUC5B is a major gel-forming, oligomeric mucin from human salivary gland, respiratory tract and endocervix: identification of glycoforms and C-terminal cleavage. Biochem J. 1998 Sep 15;334(Pt 3):685–693. doi: 10.1042/bj3340685. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES