Structural highlights
Function
MVL_MICVR Carbohydrate-binding protein that binds oligomannosides such as Man(6)GlcNAc(2) with sub-micromolar affinities. The specificity of MVL is unique in that its minimal target comprises the Man-alpha-(1->6)-Man-beta-(1->4)-GlcNAc-beta-(1->4)-GlcNAc tetrasaccharide core (Man(2)A) found in N-linked oligomannosides. Displays hemagglutininating activity on rabbit, horse and hen erythrocytes. This activity is inhibited by yeast mannan. Does not bind mono- and disachharides. Inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations through carbohydrate-mediated interactions with high-mannose residues on the surface of the HIV envelope glycoprotein gp120. Unexpectedly for a lectin, one of the 2 oligomannose binding sites of MVL can catalyze the cleavage of chitin fragments (such as chitotriose, i.e. GlcNAc(3) or GlcNAc-beta-(1->4)-GlcNAcbeta-(1->4)-GlcNAc, and chitotetraose, i.e. GlcNAc(4)) to GlcNAc. This weak glycosidase activity is restricted to the C-terminal carbohydrate-binding site. Does not cleave Man(3)GlcNAc(2) or the tetrasaccharide Man(2)A.
See Also