Trypanosoma cruzi synthesizes proline via a Δ1-pyrroline-5-carboxylate reductase whose activity is fine-tuned by NADPH cytosolic pools
| Autor: | Maria Carolina Elias, Letícia Marchese, Ariel Mariano Silber, Carla Cristi Avila, Rodolpho Ornitz Oliveira Souza, Flávia Silva Damasceno, Karel Olavarria, Brian S. Mantilla |
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| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Proline Trypanosoma cruzi Respiratory chain Glutamic Acid Oxidative phosphorylation Mitochondrion Reductase 01 natural sciences Biochemistry Electron Transport 03 medical and health sciences chemistry.chemical_compound Cytosol Biosynthesis Pyrroles Molecular Biology 030304 developmental biology chemistry.chemical_classification 0303 health sciences Cell Biology NADPH oxidation Amino acid Mitochondria chemistry MITOCÔNDRIAS Pyrroline Carboxylate Reductases Oxidation-Reduction NADP 010606 plant biology & botany |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 1470-8728 |
| Popis: | In Trypanosoma cruzi, the etiological agent of Chagas disease, the amino acid proline participates in processes related to T. cruzi survival and infection, such as ATP production, cell differentiation, host-cell invasion, and in protection against osmotic, nutritional, and thermal stresses and oxidative imbalance. However, little is known about proline biosynthesis in this parasite. Δ1-Pyrroline-5-carboxylate reductase (P5CR, EC 1.5.1.2) catalyzes the biosynthesis of proline from Δ1-pyrroline-5-carboxylate (P5C) with concomitant NADPH oxidation. Herein, we show that unlike other eukaryotes, T. cruzi biosynthesizes proline from P5C, which is produced exclusively from glutamate. We found that TcP5CR is an NADPH-dependent cytosolic enzyme with a Kmapp for P5C of 27.7 μM and with a higher expression in the insect-resident form of the parasite. High concentrations of the co-substrate NADPH partially inhibited TcP5CR activity, prompting us to analyze multiple kinetic inhibition models. The model that best explained the obtained data included a non-competitive substrate inhibition mechanism (Kiapp=45±0.7μM). Therefore, TcP5CR is a candidate as a regulatory factor of this pathway. Finally, we show that P5C can exit trypanosomatid mitochondria in conditions that do not compromise organelle integrity. These observations, together with previously reported results, lead us to propose that in T. cruzi TcP5CR participates in a redox shuttle between the mitochondria and the cytoplasm. In this model, cytoplasmic redox equivalents from NADPH pools are transferred to the mitochondria using proline as a reduced metabolite, and shuttling to fuel electrons to the respiratory chain through proline oxidation by its cognate dehydrogenase. |
| Databáze: | OpenAIRE |
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