Mh. Mansour et al., CHARACTERIZATION OF BIOMPHALARIA-ALEXANDRINA-DERIVED LECTINS RECOGNIZING A FUCOSYLLACTOSE-RELATED DETERMINANT ON SCHISTOSOMES, Molecular and biochemical parasitology, 69(2), 1995, pp. 173-184
Two novel lectins that bind selectively to a schistosome-associated fu
cosyllactose-related determinant have been characterized and purified
from the hemolymph of Biomphalaria alexandrina, the snail vector of Sc
histosoma mansoni. Both lectins were purified by affinity chromatograp
hy on a column of equimolar mixture of D- and L-glucose coupled to epo
xy-activated Sepharose 6B and sequential elution by D-glucose (designa
ted BaSI) and L-fucose (designated BaSII). Assessment of the structura
l characteristics, by one- and two-dimensional polyacrylamide gel elec
trophoresis, indicated that BaSI and BaSII were structurally distinct,
and exist in their native forms as multimers of non-covalently associ
ated subunits, that were of different sizes in BaSI and of equal size
in BaSII. Removal of N-linked glycans by Endo-beta-N-acetylglucosamini
dase F resolved the heterodisperse pattern of BaSI subunits into two s
pots of 13.2 kDa (pI 7.2) and 10.1 kDa (pI 5.8), and collapsed the aci
dic charge microheterogeneity of the BaSII subunit into a single spot
that corresponded in terms of molecular weight and pi to the basic 13.
2-kDa subunit of BaSI. In miracidial binding and inhibition assays wit
h different sugars, both lectins exhibited selectivity towards a fucos
yllactose sequence, but BaSII had a higher binding preference to fucos
e moieties. BaSII-Sepharose 4B affinity chromatography and analysis on
two-dimensional gels indicated that multiple copies of the fucosyllac
tose-related determinant were expressed by heterogeneous, acidic glyco
proteins in the miracidial stage of S. mansoni.