About the Lectin

A highly specific mannose binding lectin has been isolated from snowdrop bulbs 1 . The lectin is a pure tetrameric protein (Mr=50kDa) whose primary structure was established by both chemical sequencing and cloning 2 . The X-ray structure of GNA complexed with methyl α-D-mannoside has been solved at 2.3 Å resolution 3 . Unlike other mannose specific lectins, GNA does not react with glucose. High mannose type glycoproteins containing multiple terminal mannose α(1,3)mannose residues react most strongly with the lectin. Purified GNA selectively binds to specific components of both human and mouse serum. Immoblilized GNA has been used successfully to isolate mouse IgM from hybridoma serum 4 . GNA does not react with any mouse, bovine, or human IgG subclasses. Human IgM is a high mannose glycoprotein 5 , but it does not react with GNA. Only a single human serum glycoprotein, α-2 macroglobulin, binds to immobilized GNA 2 . This is in dramatic contrast to other mannose specific lectins, which bind to numerous serum components. GNA shows inhibitory activity against retroviruses 6 , and has been shown to diminish the infectivity of HIV in cell culture assay 7 . It binds to the envelope glycoprotein gp 120 of HIV and SIV 8 , and in its immobolized form has been employed in the isolation of this protein 9 . It has also been applied to typing β-hemolytic streptococci 10 .

REFERENCES

  1. Van Damme, E. J. M., et al. (1987) FEBS Lett. 215 : 140-144.
  2. Van Damme, E. J. M., et al. (1991) Eur. J. Biochem. 202 : 23-30.
  3. Hester, G., et al. (1995) Nature Structure Biol. 2(6) : 472-479.
  4. Shibuya, N., et al. (1988) Arch. Biochem. Biophys. 267 : 676-680.
  5. Chapman, A. and Kornfeld, R. (1979) J. Biol. Chem. 254 :816-823.
  6. Balzarini, J. (1991) Antimicrob. Agents Chemotherapy 35 : 410-416
  7. Animashaun, T., et al. (1993) Antiviral Chem. Chemotherapy 4 : 145-153.
  8. Mahmood, N. andHay, A. J. (1992) J. Immunol. Methods 151 : 9-13.
  9. Gilljam, G. (1993) AIDS Res. Human Retroviruses 9 : 431-438.
  10. Kellens, J. T. C., et al. (1993) J. Med. Microb. 30 : 440-445.

Product Characteristics
Buffer 0.01M Phosphate – 0.15M NaCl, pH 7.2-7.4.
Blood Group Appears to react only with type O cells. NOTE: the age of the blood cells may be important for reactivity of this lectin. Fresh erythrocytes react better than older cells.
Activity Less than 15 μg/ml will agglutinate human type O erythrocytes.
Inhibitory Carbohydrate Mannose α(1,3)mannose. High concentrations of mannose (> 0.2M) can also be used as an inhibitor.
Molecular Weight Three bands by SDS-PAGE of MW=26,000, 30,000 and 44,000.