The THI5 gene family of Saccharomyces cerevisiae comprises four highly conserved members named THI5, THI11, THI12 and THI13 []. All are homologues of Schizosaccharomyces pombe Nmt1 (THI3), which is thought to function in the biosynthesis of hydroxymethylpyrimidine (HMP), a precursor of vitamin B1, thiamin []. This entry includes the THI5 family, Nmt1 and other homologues [], including bacterial homologues ThiY []and RibY [], which are substrate-binding components of ABC transporters for vitamins B1 and B2 respectively.THI5 is responsible for the synthesis of 4-amino-5-(hydroxymethyl)-2-methylpyrimidine phosphate (HMP-P) in the thiamine biosynthetic pathway of eukaryotes [, ].
