<p>This entry represents a structural domain with a core structure consisting of beta-alpha-beta-alpha-beta(2), which is found in two enzymes of the purine biosynthetic pathway: at the N-terminal of aminoimidazole ribonucleotide (AIR) synthetase (PurM) [<cite idref="PUB00014643"/>], as well as the N1 and N2 domains of formylglycinamide ribonucleotide (FGAR) amidotransferase (PurL) (PurM-like module) [<cite idref="PUB00016818"/>]. PurM and PurL utilise ATP to activate the oxygen of an amide within their substrate toward nucleophilic attack by a nitrogen. PurM uses the product of PurL, formylglycinamidine ribonucleotide (FGAM) and ATP to make AIR, ADP and P(i). It is also found as domains 1 and 3 in phosphoribosylformylglycinamidine synthase II (smPurL) (<db_xref db="EC" dbkey="6.3.5.3"/>) (carries a duplication: tandem repeats of two PurM-like units arranged like the PurM subunits in the dimer) [<cite idref="PUB00037958"/>].</p><p>This domain is also found at the N-terminal of thiamine monophosphate kinase (<db_xref db="EC" dbkey="2.7.4.16"/>) (ThiL) [<cite idref="PUB00016093"/>]. ThiL phosphorylates thiamin monophosphate to form thiamin pyrophosphate, an essential cofactor that is synthsised de novo by <taxon tax_id="602">Salmonella typhimurium</taxon>.</p>