Journal of Dental Research, Vol 66, 436-441, Copyright © 1987 by International & American Associations for Dental Research Online Journals

ARTICLES

Structural aspects of salivary glycoproteins

M. J. Levine, M. S. Reddy, L. A. Tabak, R. E. Loomis, E. J. Bergey, P. C. Jones, R. E. Cohen, M. W. Stinson and I. Al-Hashimi

The protective functions of saliva are attributed, in part, to its serous and mucous glycoproteins. We have studied, as representative molecules, the proline-rich glycoprotein (PRG) from human parotid saliva and the high (MG1) and low (MG2) molecular weight mucins from submandibular-sublingual saliva. PRG (38.9 kDa) contains 40% carbohydrate consisting of 6 triantennary N-linked units and a single peptide chain of 231 amino acids, 75% of which = PRO + GLY + GLN. PRG's secondary structure is comprised of 70% random coil (naked regions) and 30% beta-turns (glycosylated domains). MG1 (greater than 10(3) kDa) contains 15% protein (several disulfide linked subunits), 78% carbohydrate (290 units of 4-16 residues), 7% sulfate, and small amounts of covalently linked fatty acids. MG2 (200-250 kDa) contains 30% protein (single peptide chain), 68% carbohydrate (170 units of 2-7 residues), and 2% sulfate. The major carbohydrate units of MG2 are: NeuAc alpha 2,3Gal beta 1,3GalNAc,Gal beta 1,3GalNAc, and Fuc alpha 1,2Gal beta 1,3GalNAc. MG1 contains hydrophobic domains, as evidenced by its ability to bind fluorescent hydrophobic probes; MG2 does not. Collectively, the biochemical and biophysical comparisons between MG1 and MG2 indicate that these two mucins are structurally different. Several functional properties of MG1, MG2, and PRG have been examined, including their presence in two-hour in vivo enamel pellicle, binding to synthetic hydroxyapatite, lubricating properties, and interactions with oral streptococci. The data presented suggest that these glycoproteins may have multiple functions which are predicated, in part on their carbohydrate units. The potential significance of the structure-function relationships of these glycoproteins to the oral ecology is discussed.

This article has been cited by other articles:

				E.J. Helmerhorst and F.G. Oppenheim Saliva: a Dynamic Proteome J. Dent. Res., August 1, 2007; 86(8): 680 - 693. [Abstract] [Full Text] [PDF]

				S. Li and L. A. Bobek Functional Analysis of Human MUC7 Mucin Gene 5'-Flanking Region in Lung Epithelial Cells Am. J. Respir. Cell Mol. Biol., November 1, 2006; 35(5): 593 - 601. [Abstract] [Full Text] [PDF]

				N. Sterer and M. Rosenberg Streptococcus salivarius Promotes Mucin Putrefaction and Malodor Production by Porphyromonas gingivalis. J. Dent. Res., October 1, 2006; 85(10): 910 - 914. [Abstract] [Full Text] [PDF]

				Y. Yao, E. A. Berg, C. E. Costello, R. F. Troxler, and F. G. Oppenheim Identification of Protein Components in Human Acquired Enamel Pellicle and Whole Saliva Using Novel Proteomics Approaches J. Biol. Chem., February 7, 2003; 278(7): 5300 - 5308. [Abstract] [Full Text] [PDF]

				C. Jespersgaard, G. Hajishengallis, M. W. Russell, and S. M. Michalek Identification and Characterization of a Nonimmunoglobulin Factor in Human Saliva That Inhibits Streptococcus mutans Glucosyltransferase Infect. Immun., March 1, 2002; 70(3): 1136 - 1142. [Abstract] [Full Text] [PDF]

				N. Sterer, R. Bar-Ness Greenstein, and M. Rosenberg {beta}-Galactosidase Activity in Saliva is Associated with Oral Malodor J. Dent. Res., March 1, 2002; 81(3): 182 - 185. [Abstract] [Full Text] [PDF]

				K. A. Thomsson, A. Prakobphol, H. Leffler, M. S. Reddy, M. J. Levine, S. J. Fisher, and G. C. Hansson The salivary mucin MG1 (MUC5B) carries a repertoire of unique oligosaccharides that is large and diverse Glycobiology, January 1, 2002; 12(1): 1 - 14. [Abstract] [Full Text] [PDF]

				S. Ruhl, J. O. Cisar, and A. L. Sandberg Identification of Polymorphonuclear Leukocyte and HL-60 Cell Receptors for Adhesins of Streptococcus gordonii and Actinomyces naeslundii Infect. Immun., November 1, 2000; 68(11): 6346 - 6354. [Abstract] [Full Text] [PDF]

				H. Situ and L. A. Bobek In Vitro Assessment of Antifungal Therapeutic Potential of Salivary Histatin-5, Two Variants of Histatin-5, and Salivary Mucin (MUC7) Domain 1 Antimicrob. Agents Chemother., June 1, 2000; 44(6): 1485 - 1493. [Abstract] [Full Text]

				R. Crombie, R. L. Silverstein, C. MacLow, S. F. A. Pearce, R. L. Nachman, and J. Laurence Identification of a CD36-related Thrombospondin 1-binding Domain in HIV-1 Envelope Glycoprotein gp120: Relationship to HIV-1-specific Inhibitory Factors in Human Saliva J. Exp. Med., January 5, 1998; 187(1): 25 - 35. [Abstract] [Full Text] [PDF]

				T. Oho, H. Yu, Y. Yamashita, and T. Koga Binding of Salivary Glycoprotein-Secretory Immunoglobulin A Complex to the Surface Protein Antigen of Streptococcus mutans Infect. Immun., January 1, 1998; 66(1): 115 - 121. [Abstract] [Full Text] [PDF]