Trypanosomal dUTPases as Potential Targets for Drug Design

Abstract

Parasites of the Trypanosomatidae family are responsible for diseases that afflict several million people worldwide. Currently there is an urgent need for new drugs against these diseases and an approach to drug discovery is the study of biochemical and structural properties of a potential target and the subsequent design of specific compounds. Trypanosomatid genes coding for enzymes which distinctively hydrolyze dUTP have been isolated by genetic complementation in Escherichia coli mutants defective in dUTPase activity. An analysis of these sequences from Leishmania major and Trypanosoma cruzi showed that no significant similarity could be established with the family of known dUTPases and that the five consensus motifs were absent. However, limited similarity was identified for three motifs present in an enzyme related in function the dCTPase-dUTPase from T phages and 35 percent identity with a putative dUTPase identified in the eubacteria Campylobacter jejuni. T. cruzi and L. major dUTPases were highly similar and catalyzed in a specific fashion the hydrolysis of dUTP. A detailed kinetic study of both enzymes revealed that dUDP is also an efficient substrate of the enzyme while other nucleotides are poorly hydrolyzed. The enzyme is essential for viability in Leishmania and is up-regulated by inhibitors of dTMP synthesis. Thus, a new family of dUTPases might exist in certain organisms that bear no sequence or structure similarity with eukaryotic enzymes accomplishing the same function and that may constitute potential drug targets for the development of specific inhibitors.

Structure and activity of the Saccharomyces cerevisiae dUTP pyrophosphatase DUT1, an essential housekeeping enzyme

“…dUTPase is essential for DNA integrity and viability in many prokaryotic and eukaryotic organisms including Escherichia coli , Saccharomyces cerevisiae , trypanosomes and human cancer cells [7–9]. The E. coli hypomorphic dUTPase mutant dut-1 retains less than 1% of wild-type dUTPase activity and is still viable.…”

The Crystal Structure of the Leishmania major Deoxyuridine Triphosphate Nucleotidohydrolase in Complex with Nucleotide Analogues, dUMP, and Deoxyuridine

“…Inhibition of dUTPase activity results in futile cycles of DNA repair that ultimately cause the fragmentation of DNA and cell death (4,5). dUTPase activity also appears to be essential in L. major (6) and the related parasite Trypanosoma brucei, where an RNAi approach was used to knock down dUTPase expression, resulting in decreased cell proliferation and growth in both procyclic and bloodstream forms of the organism (7). dUTPases have been characterized extensively both biochemically and structurally in many species.…”

Pyrimidine metabolism in schistosomes: A comparison with other parasites and the search for potential chemotherapeutic targets

“…Enzyme activity of dUTPase has been reported in the nematodes; Trichinella spiralis and T. pseudospiralis (Rode et al, 2000), and the protozoa; Plasmodium falciparum (Whittingham et al, 2005), Leishmania major (Camacho et al, 1997), Trypanosoma cruzi (Hidalgo-Zarco and González-Pazanowska, 2001; Bernier-Villamor et al, 2002) and T. brucei (Castillo-Acosta et al, 2008). The protozoan enzymes were subjected to detailed analysis and characterization.…”