Relative intensities of recognition factors at two combining sites of Ralstonia solanacearum lectin (RSL) for accommodating lFucα1→, dManα1→ and Galβ1→3/4GlcNAc glycotopes

Owing to the weak reactivities of monomeric dManα1 and Galβ1→3/4GlcNAcβ (Iβ/IIβ) glycotopes with Ralstonia solanacearum lectin (RSL), their recognition roles were previously ignored. In this study, the interaction intensities of RSL toward four monomeric glycotopes lFucα1→, dManα1→ and Iβ/IIβ within two combining sites were established by both enzyme-linked lectinosorbent and inhibition assays. It was found that high density of lFucα1→ complex enhanced the recognition intensities at lFucα1→ site, polyvalent dManα1→ was essential for binding at the dManα1→ site and polyvalent Iβ/IIβ was required at lFucα1→ site. The peculiar recognition systems of RSL are very different from other well known microbial lectins.

► RSL has two different (lFucα→ and dMan) combining sites. ► RSL glycotope potency is lFuc > dMan >> Galβ1→3/4GlcNAc(I/II). ► RSL super glycotope (polyvalent) potency is I/II and dMan >> lFuc. ► Sophisticated systems are required for the combining sites of microbial lectins.