GENETIC-ANALYSIS OF THE AGROCINOPINE CATABOLIC REGION OF AGROBACTERIUM-TUMEFACIENS TI PLASMID PTIC58, WHICH ENCODES GENES REQUIRED FOR OPINE AND AGROCIN 84 TRANSPORT

The acc region, subcloned from pTiC58 of classical nopaline and agroci nopine A and B Agrobacterium tumefaciens C58, allowed agrobacteria to grow using agrocinopine B as the sole source of carbon and energy. acc is approximately 6 kb in size. It consists of at least five genes, ac cA through accE, as defined by complementation analysis using subclone d fragments and transposon insertion mutations of acc carried on diffe rent plasmids within the same cell. All five regions are required for agrocin 84 sensitivity, and at least four are required for agrocinopin e and agrocin 84 uptake. The complementation results are consistent wi th the hypothesis that each of the five regions is separately transcri bed. Maxicell experiments showed that the first of these genes, accA, encodes a 60-kDa protein. Analysis of osmotic shock fractions showed t his protein to be located in the periplasm. The DNA sequence of the ac cA region revealed an open reading frame encoding a predicted polypept ide of 59,147 Da. The amino acid sequence encoded by this open reading frame is similar to the periplasmic binding proteins OppA and DppA of Escherichia coli and Salmonella typhimurium and OppA of Bacillus subt ilis.