THE ESCHERICHIA-COLI K99 PERIPLASMIC CHAPERONE FANE IS A MONOMERIC PROTEIN

The monomeric or dimeric nature of the K99 periplasmic chaperone FanE was examined. The gene encoding FanE was subcloned in a pINIIIA1 deriv ative expression vector. A complementation experiment showed that the subcloned FanE was biologically functional. The protein was purified f rom the periplasm of cells harbouring the constructed plasmid. Automat ed Edman degradation experiments confirmed the predicted N-terminal am ino acid sequence of FanE. A polyclonal mouse antiserum was raised aga inst the FanE chaperone. The monomeric or oligomeric nature of the pro tein in the periplasm was studied by gel filtration, immunoblotting an d chemical cross-linking experiments. The results indicated that FanE is a monomeric protein, in contrast to the K88 periplasmic chaperone.