TABLE 1.

Genetics and predicted enzymology of amino acid biosynthesis in L. helveticus CNRZ 32

Amino acid(s)Gene(s) presentaPredicted productPathwayEssentialb
Ala araT Aromatic aminotransferase (EC 2.6.1.57)CompletecNo
bcaT Branched-chain aminotransferase (EC 2.6.1.42)
ataA-CAminotransferase (EC 2.6.1.-)
Arg argF d*Ornithine carbamoyltransferase (EC 2.1.3.3)IncompleteYes
arcC d*Carbamate kinase (EC 2.7.2.2)
arcA d Arginine deiminase (EC 3.5.3.6)
carA Carbamoyl-phosphate synthase A (EC 6.3.4.16)
carB Carbamoyl-phosphate synthase B (EC 6.3.4.16)
odcI Ornithine decarboxylase (EC 4.1.1.17)
odiC Ornithine decarboxylase (EC 4.1.1.17)
Asn, Asp asnA Aspartate-ammonia ligase (EC 6.3.1.1)IncompleteAsn or Asp
asnB Asparagine synthase (EC 6.3.5.4)
ans Asparaginase (EC 3.5.1.1)
aspC*Aspartic aminotransferase (EC 2.6.1.1)
asd*Aspartate-semialdehyde dehydrogenase (EC 1.2.1.11)
ppc d Phosphoenolpyruvate carboxylase (EC 4.1.1.31)
Glu glnA Glutamate-ammonia ligase (EC 6.3.1.2)IncompleteYes
aspC Aspartic aminotransferase (EC 2.6.1.1)
Gln glnA Glutamate-ammonia ligase (EC 6.3.1.2)From GluNo
Cys cysK* O-Acetylserine (thiol) lyase (EC 2.5.1.47)CompleteNo
cbl*Cystathionine-beta-lyase (EC 4.4.1.8)
cysE*Serine acetyl-transferase (EC 2.3.1.30)
Met metA*Homoserine-O-succinyl transferase (EC 2.3.1.46)IncompleteYes
cysK2 d* O-Acetylserine (thiol) lyase (EC 2.5.1.47)
metE 5-Methyltetrahydropteroyl(Glu3)-homocysteine
    methyltransferase (EC 2.1.1.14)
patC d Cystathionine-gamma-lyase (EC 4.4.1.1)
Lys lysA*Diaminopimelate decarboxylase (EC 4.1.1.20)CompletecYes
dapD*2,3,4,5-Tetrahydropyridine-2,6-dicarboxylate N-succinyltransferase (EC 2.3.1.117)
dapE*Succinyl-diaminopimelate desuccinylase (EC 3.5.1.18)
dapA*Dihydrodipicolinate synthase (EC 4.2.1.52)
dapB*Dihydrodipicolinate reductase (EC 1.3.1.26)
aspC*Aspartic aminotransferase (EC 2.6.1.1)
asd*Aspartate-semialdehyde dehydrogenase (EC 1.2.1.11)
lysC Aspartate kinase (EC 2.7.2.4)
dapF Diaminopimelate epimerase (EC 5.1.1.7)
ataA-CAminotransferase (EC 2.6.1.-)
Ile, Leu, Val bcaT Branched-chain aminotransferase (EC 2.6.1.42)IncompleteYes
ilvB Acetolactate synthase (EC 2.2.1.6)
Phe, Tyr, Pro araT Aromatic aminotransferase (EC 2.6.1.57)IncompleteYes
aspC Aspartic aminotransferase (EC 2.6.1.1)
HisnoneIncompleteYes
PrononeIncompleteYes
Ser glyA Glycine hydroxymethyltransferase (EC 2.1.2.1)CompleteNo
glyK Glycerate kinase (EC 2.7.1.31)
serC*Phosphoserine transaminase (EC 2.6.1.52)
serA*Phosphoglycerate dehydrogenase (EC 1.1.1.95)
ycsE Phosphoserine phosphatase (EC 3.1.3.3)
sdaB d l-Serine ammonia-lyase B (EC 4.3.1.17)
sdaA l-Serine ammonia-lyase A (EC 4.3.1.17)
Gly glyA Glycine hydroxymethyltransferase (EC 2.1.2.1)From SerNo
ThrnoneIncompleteYes
  • a Genes for the same amino acid with a shared symbol (* or †) are adjacent to one another in an operon-like structure in the genome and are listed in predicted order of sequential transcription.

  • b As determined by Christensen and Steele (4).

  • c Pathway completion assumes activity for one or more transamination reactions is provided by the aromatic-chain (araT), aspartic (aspC), or branched-chain (bcaT) aminotransferase or by one of three other predicted amino acid aminotransferases (ataA-C) whose genes were identified in the L. helveticus CNRZ 32 genome.

  • d Probable pseudogene; the product is predicted to lack biological activity.