Streptococcal glucan-binding lectins do not recognize methylated α-1,6 glucans
The glucan-binding lectin (GBL) ofStreptococcus sobrinus is cell associated, enabling the bacteria to be aggregated by α-1,6 glucans. Glucans, such as amylose, pullulan, laminarin and nigeran, have no affinity for the lectin. High molecular weight α-1,6 glucans (dextrans) readily aggregate the bacteria, whereas low molecular weight glucans inhibit the aggregation brought about by the high molecular weight species. Methylated glucan T-2000 (an α-1,6 glucan with an average molecular weight of 2 × 106 Da) aggregated the bacteria very poorly when the extent of methylation (DS, or degree of substitution) was high, and less poorly when the DS was low. Similarly, methylated low molecular weight α-1,6 glucan was a poor inhibitor of aggregation induced by the high molecular weight glucan T-2000. Because the methylation occurred primarily on the hydroxyl of C-2, it is suggested that the hydroxyl is needed for formation of the lectin-glucan complex. It appears that the GBL is not only stereospecific in interaction with glucans, but also regiospecific, interacting only with the underivatized α-1,6-glucan.
KeywordsGlucan lectin methylation
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- 1.Drake D, Taylor KG, Bleiweis AD, Doyle RJ (1988)Infect Immunol 56:1864–72.Google Scholar
- 2.Doyle RJ, Taylor KG (1994)Cells Mater 4:91–100.Google Scholar
- 3.Gibbons RJ (1983) InGlucosyltransferases, Glucans, Sucrose and Dental Caries (Doyle RJ, Ciardi JE, eds) pp. 11–19. Arlington, VA: IRL Press.Google Scholar
- 4.Loesche WJ (1986)Microbiol Rev 50:353–80.Google Scholar
- 5.Curtiss R III (1985)Curr Top Microbiol Immunol 118:253–77.Google Scholar
- 6.Seymour F, Knapp RD, Lamberts BL (1980)Carbohydr Res 84: 187–95.Google Scholar
- 7.Cheetham NWH, Slodki ME, Walker GJ (1991)Carbohydr Polym 14:3–16.Google Scholar
- 8.Kobayashi K, Sumimoto H (1981)Macromolecules 14:253.Google Scholar
- 9.Hakomori S (1964)J Biochem (Tokyo)55:205–208.Google Scholar
- 10.Singh S, Porter RA, Doyle RJ, Taylor KG (1995)J Carbohydr Chem (submitted).Google Scholar
- 11.Ofek I, Doyle RJ (1994)Bacterial Adhesion to Cells and Tissues. New York: Chapman and Hall.Google Scholar
- 12.Singh J, Taylor KG, Doyle RJ (1993)Carbohydr Res 244:137–47.Google Scholar