Publications by authors named "Edward A Valera-Vera"

In Leishmania, the nucleotide-sugar UDP-galactose can be synthesized by a salvage pathway, the Isselbacher route, involving phosphorylation of galactose and the action of UDP-sugar pyrophosphorylase. The first enzyme of the pathway, galactokinase, has yet to be studied in this parasite. Here, we report a molecular and biochemical characterization of this enzyme in Leishmania mexicana.

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Article Synopsis
  • Arginine kinase (AK) is an enzyme linked to allergic reactions in invertebrates and is also present in the parasite T. cruzi, which causes Chagas disease.
  • The study investigated the presence of specific antibodies against T. cruzi AK (TcAK) in patients with chronic Chagas disease (CCD) and found differing levels of IgG and IgE antibodies between infected and non-infected individuals.
  • Results suggest that TcAK might play a role in influencing B cell responses and could contribute to allergic reactions during T. cruzi infection, revealing a potential new target for understanding immune responses in affected patients.
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Trypanosoma cruzi is the causative agent of Chagas disease. There are only two approved treatments, both of them unsuitable for the chronic phase, therefore the development of new drugs is a priority. Trypanosoma cruzi arginine kinase (TcAK) is a promising drug target since it is absent in humans and it is involved in cellular stress responses.

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Background: NME23/NDPKs are well conserved proteins found in all living organisms. In addition to being nucleoside diphosphate kinases (NDPK), they are multifunctional enzymes involved in different processes such as DNA stability, gene regulation and DNA repair among others. TcNDPK1 is the canonical NDPK isoform present in Trypanosoma cruzi, which has nuclease activity and DNA-binding properties in vitro.

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Enolase is a glycolytic enzyme that catalyzes the interconversion between 2-phosphoglycerate and phosphoenolpyruvate. In trypanosomatids, enolase was proposed as a key enzyme after in silico and in vivo analysis and it was validated as a protein essential for the survival of the parasite. Therefore, enolase constitutes an interesting enzyme target for the identification of drugs against Chagas disease.

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Amino acids and polyamines are involved in relevant processes for the parasite Trypanosoma cruzi, like protein synthesis, stress resistance, life cycle progression, infection establishment and redox balance, among others. In addition to the biosynthetic routes of amino acids, T. cruzi possesses transport systems that allow the active uptake from the extracellular medium; and in the case of polyamines, the uptake is the unique way to obtain these compounds.

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Polyamines are essential compounds to all living organisms and in the specific case of Trypanosoma cruzi, the causative agent of Chagas disease, they are exclusively obtained through transport processes since this parasite is auxotrophic for polyamines. Previous works reported that retinol acetate inhibits Leishmania growth and decreases its intracellular polyamine concentration. The present work describes a combined strategy of drug repositioning by virtual screening followed by in vitro assays to find drugs able to inhibit TcPAT12, the only polyamine transporter described in T.

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Article Synopsis
  • Researchers cloned and sequenced two galactokinase genes (TcGALK-1 and TcGALK-2) from Trypanosoma cruzi, producing an active and soluble enzyme from TcGALK-1 and a less soluble enzyme from TcGALK-2 when expressed in E. coli.
  • The study found different Km values for galactose and ATP for both proteins, with substrate inhibition by ATP noted in TcGALK-2, while confirming their presence in glycosomes.
  • Phylogenetic analysis showed that T. cruzi galactokinases are closely related to those from Leishmania spp. and emphasized their potential role in utilizing galactose as a carbon source in glucose-depleted environments.
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Arginine kinase catalyzes the reversible transphosphorylation between ADP and phosphoarginine which plays a critical role in the maintenance of cellular energy homeostasis. Arginine kinase from the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, meets the requirements to be considered as a potential therapeutic target for rational drug design including being absent in its mammalian hosts. In this study a group of polyphenolic compounds was evaluated as potential inhibitors of arginine kinase using molecular docking techniques.

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