Evidence of two polygalacturonases produced by a mycorrhizal ericoid fungus during its saprophytic growth

Abstract The NH₂-terminal amino sequence through the first 20 amino acids was obtained for transferrin-binding protein (TBP)1 from three strains of Neisseria meningitidis . These were identical except for a glutamine to a glycine substitution at residue 6 in one case. The sequences of the NH₂-terminal 20 amino acids of TBP2 from the same three strains were also determined; one TBP2 had a M _r of 68 000 and the other two of 78 000. Sequences were identical up to residue 13 in all three proteins. Peptides based on the NH₂-terminal sequences of TBP1 and 2 were synthesized, linked to Keyhole Limpet haemocyanin and used to raise antibodies in rabbits. Anti-peptide antibodies cross-reacted on immunoblotting with the respective TBPs from all meningococcal strains tested, as well as with those from N. gonorrhoeae suggesting that the NH₂-terminals of these proteins are well conserved in the Neisseria . Neither anti-peptide serum reacted with the analogous TBP1 and 2 from Haemophilus influenzae , although common epitopes have previously been shown to exist.