Abstract
Three genes encoding enzymes involved in the biosynthesis of
pyrimidines have been found to constitute an operon in Lactococcus
lactis. Two of the genes are the well-known pyr genes pyrDb and
pyrF, encoding dihydroorotate dehydrogenase and orotidine
monophosphate decarboxylase, respectively. The third gene encodes
a protein which was shown to be necessary for the activity of the
pyrDb-encoded dihydroorotate dehydrogenase; we propose to name the
gene pyrK. The pyrK-encoded protein is homologous to a number of
proteins which are involved in electron transfer. The lactococcal
pyrKDbF operon is highly homologous to the corresponding part of
the much-larger pyr operon of Bacillus subtilis. orf2, the pyrK
homolog in B. subtilis, has also been shown to be necessary for
pyrimidine biosynthesis (A.E. Kahler and R.L. Switzer, J.
Bacteriol. 178:5013-5016, 1996). Four genes adjacent to the
operon, i.e., orfE, orfA, orfC, and gidB, were also sequenced.
Three of these were excluded as members of the pyr operon by
insertional analysis (orfA) or by their opposite direction of
transcription (orfE and gidB). orfC, however, seems to be the
distal gene in the pyrKDbF-orfC operon.
Original language | English |
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Journal | Journal of Bacteriology |
Volume | 178 |
Issue number | 16 |
Pages (from-to) | 5005-5012 |
ISSN | 0021-9193 |
Publication status | Published - 1996 |