The Leishmania donovani UMP synthase is essential for promastigote viability and has an unusual tetrameric structure that exhibits substrate-controlled oligomerization.
French, J.B., Yates, P.A., Soysa, D.R., Boitz, J.M., Carter, N.S., Chang, B., Ullman, B., Ealick, S.E.(2011) J Biol Chem 286: 20930-20941
- PubMed: 21507942 
- DOI: 10.1074/jbc.M111.228213
- Primary Citation of Related Structures:  
3QW3, 3QW4 - PubMed Abstract: 
The final two steps of de novo uridine 5'-monophosphate (UMP) biosynthesis are catalyzed by orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC). In most prokaryotes and simple eukaryotes these two enzymes are encoded by separate genes, whereas in mammals they are expressed as a bifunctional gene product called UMP synthase (UMPS), with OPRT at the N terminus and OMPDC at the C terminus ...