Non-glycosylated recombinant pro-concanavalin A is active without polypeptide cleavage.

The complex post-translational processing of concanavalin A (Con A) in maturing jackbeans is unique because the non-glycosylated mature active protein is circularly permuted in primary sequence relative to its own inactive precursor (glycosylated pro-Con A) and to other legume lectins. We show here that non-glycosylated pro-Con A expressed in bacteria from recombinant cDNA (rec-pro-Con A) folds in vivo and in vitro to a stable form which is active without further processing. N-glycosylation alone must therefore be sufficient to inactivate pro-Con A--a novel role for glycosylation in regulating activity during protein maturation.