Localisation of amino acid sequence stretches containing a continuous epitope on the surface of the two Lathyrus ochrus isolectins.

A series of 66 overlapping heptapeptides covering the complete amino acid sequences of the heavy subunits (beta chains) of the two Lathyrus ochrus isolectins (LoLI and LoLII) were synthesised and coupled to bovine serum albumin used as a carrier protein, and the conjugates were allowed to react with polyclonal antibodies directed against the whole isolectins. A similar approach was previously carried out with a series of 21 peptides corresponding to the light subunits (alpha chains) of the two isolectins. Of this total of 87 conjugates, 54 reacted significantly with the polyclonal antibodies. They corresponded to 8 linear peptides laid out along the entire sequences of both subunits, most of them being localised along the heavy subunits. All these continuous/sequential epitopes fall into regions predicted to be putative determinants, according to their hydrophilicity, flexibility and solvent accessibility.