Plasticity in the purine-thiamine metabolic network of Salmonella.
In Salmonella enterica, 5-aminoimidazole ribonucleotide (AIR) is the precursor of the 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) pyrophosphate moiety of thiamine and the last intermediate in the common HMP/purine biosynthetic pathway. AIR is synthesized de novo via five reactions catalyzed by the purF, -D, -T, -G, and -I gene products. In vivo genetic analysis demonstrated that in the absence of these gene products AIR can be generated if (i) methionine and lysine are in the growth medium, (ii) PurC is functional, and (iii) 5-amino-4-imidazolecarboxamide ribotide (AICAR) has accumulated. This study provides evidence that the five steps of the common HMP/purine biosynthetic pathway can be bypassed in the synthesis of AIR and thus demonstrates that thiamine synthesis can be uncoupled from the early purine biosynthetic pathway in bacteria.
Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706, USA.
Jannell V
JV
Bazurto
Diana M
DM
Downs
D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D006639:Histidine / Q000378:metabolism; D019877:Hydroxymethyl and Formyl Transferases / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009709:Nucleotide Deaminases / Q000235:genetics / Q000378:metabolism; D010427:Pentose Phosphate Pathway / Q000235:genetics; D011687:Purines / Q000378:metabolism*; D012265:Ribonucleotides / Q000378:metabolism; D019779:Salmonella enterica / Q000235:genetics* / Q000378:metabolism*; D013831:Thiamine / Q000378:metabolism*
D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D011687:Purines; D012265:Ribonucleotides; C113120:inosine monophosphate synthase; D000620:Aminoimidazole Carboxamide; D006639:Histidine; D019877:Hydroxymethyl and Formyl Transferases; D009709:Nucleotide Deaminases; C031143:AICA ribonucleotide; D013831:Thiamine