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. japonicum I-110 was sequenced. The trpD and trpC genes each have three highly conserved 'Crawford' consensus sequences and are part of an operon with three open reading frames (ORFs). The third ORF has a predicted 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 reductase and other Mo cofactor-requiring enzymes.