Identification of a third thioredoxin gene from Corynebacterium nephridii.

We identified and sequenced a gene encoding a third thioredoxin (C3) from Corynebacterium nephridii. The determined nucleotide sequence encodes a thioredoxin of 145 amino acid residues, which is larger than most thioredoxins found in microbial cells and contains 6 cysteine residues. C. nephridii thioredoxin C3 is able to serve as a subunit of T7 DNA polymerase. C. nephridii is the first nonphotosynthetic procaryotic organism known to carry three different thioredoxins.