THE SEQUENCE OF A SYMBIOTICALLY ESSENTIAL BRADYRHIZOBIUM-JAPONICUM OPERON CONSISTING OF TRPD, TRPC AND A MOAC-LIKE GENE

The 2767 bp BamHI-HindIII fragment specifying the trpDC genes of B. ja ponicum I-110 was sequenced. The trpD and trpC genes each have three h ighly conserved 'Crawford' consensus sequences and are part of an oper on with three open reading frames (ORFs). The third ORF has a predicte d product with 58% amino-acid sequence identity with the gene product of E. coli moaC, a gene encoding an enzyme involved in biosynthesis of the molybdenum cofactor required for the activity of nitrate reductas e and other Mo cofactor-requiring enzymes.