Two distinct pathways for thymidylate (dTMP) synthesis in (hyper)thermophilic Bacteria and Archaea. (1st April 2004)

• Record Type: Journal Article
• Authors: Leduc, D.; Graziani, S.; Meslet-Cladiere, L.; Sodolescu, A.; Liebl, U.; Myllykallio, H.
• Is Part Of: Biochemical Society transactions. Volume 32:Number 2(2004)
• Page Start: 231
• Page End: 235
• Publication Date: 2004-04-01
• Subjects: DNA evolution -- flavoprotein -- hyperthermophile -- thymidylate synthase; Biochemistry -- Congresses; 572
• DOI: 10.1042/bst0320231
• Languages: English
• ISSNs: 0300-5127

Abstract

Abstract : The hyperthermophilic anaerobic archaeon Pyrococcus abyssi, which lacks thymidine kinase, incorporates label from extracellular uracil, but not from thymidine, into its DNA. This implies that P. abyssi must synthesize dTMP (thymidylate), an essential precursor for DNA synthesis, de novo . However, iterative similarity searches of the three completed Pyrococcus genomes fail to detect candidate genes for canonical thymidylate synthase ThyA, suggesting the presence of alternative pathways for dTMP synthesis. Indeed, by identifying a novel class of flavin-dependent thymidylate synthases, ThyX, we have recently proven that two distinct pathways for de novo synthesis of dTMP are operational in the microbial world. While both thyX and thyA can be found in hyperthermophilic micro-organisms, the phylogenetic distribution of thyX among hyperthermophiles is wider than that of thyA . In this contribution, we discuss the differences in the distinct mechanisms of dTMP synthesis, with a special emphasis on hyperthermophilic micro-organisms.