protein was excised and used as a source of antigen. Polyclonal antisera were prepared in a New Zealand White rabbit by Cocalico Biologicals (Reamstown, PA).

     For adsorption of antibodies reacting with PduJ and E. coli proteins, two 200 ml cultures of BE231 were prepared using LB/kanamycin/1% glucose medium incubated at 37oC in 1 1 baffled flasks with shaking at 275 RPM. When the cells reached an OD600 of

0.8, expression of recombinant PduJ-His8 protein was induced by addition of 1 mM IPTG. An acetone powder made out of whole cells was used to adsorb antibodies reacting with the PduJ protein as described (Harlow and Lane 1988). Western Blots

     Cultures were grown in NCE minimal medium supplemented with 0.4% PD, 1%

succinate and the amino acids: valine, leucine, isoleucine, and threonine. The pellet from 1 ml of cells was mixed with enough Tris-Tricine loading buffer to obtain an OD600 of 1. Samples were boiled for 8 minutes at 1000 C, and 20 pl (equivalent to protein from 0.02 OD600 of cells) was separated on a 16.5%Tris-Tricine gel. Electro-blotting was performed in 10 mM MES, 20% MeOH, pH 6.0 using a Mini Trans-Blot Electrophoretic Transfer Cell (Bio-Rad), run at 20 V constant for 14.5 hours at 40 C using a PowerPac 1000 power supply (Bio-Rad). The membrane used was Hybond-P (Amersham Pharmacia Biotech, Buckinghamshire, England). Membranes were probed as described previously (Harlow and Lane 1988) using anti-PduA polyclonal antiserum diluted 1:7000 in blocking buffer as the primary antiserum and goat anti-rabbit IgG-AP conjugate (BioRad) diluted 1:3000 in blocking buffer as the secondary antibody. The alkaline color developing reagents, 5-bromo-4-chloro-3-indoyl phosphate p-toluidine salt and p-nitro blue tetrazolium chloride, were used as specified in the manufacturer's directions (BioRad).