de Freitas Nascimento Janaína, Barisón María Julia, Torres Montanaro Gabriela, Marchese Letícia, Oliveira Souza Rodolpho Ornitz, Silva Letícia Sophia, Aparecida Guarnieri Alessandra, Silber Ariel Mariano
Laboratory of Biochemistry of Tryps - LaBTryps, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.
Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou, Belo Horizonte, MG, Brazil.
Microb Cell. 2025 Jun 25;12:157-172. doi: 10.15698/mic2025.06.853. eCollection 2025.
the causing agent of Chagas disease, is the only known trypanosomatid pathogenic to humans having a complete histidine to glutamate pathway, which involves a series of four enzymatic reactions that convert histidine into downstream metabolites, including urocanate, 4-imidazolone-5-propionate, N-formimino-L-glutamate and L-glutamate. Recent studies have highlighted the importance of this pathway in ATP production, redox balance, and the maintenance of cellular homeostasis in . In this work, we focus on the first step of the histidine degradation pathway, which is performed by the enzyme histidine ammonia lyase. Here we determined the kinetic and biochemical parameters of the histidine ammonia-lyase. By generating null mutants of this enzyme using CRISPR-Cas9 we observed that disruption of the first step of the histidine degradation pathway completely abolishes the capability of this parasite to metabolise histidine, compromising the use of this amino acid as an energy and carbon source. Additionally, we showed that the knockout of the histidine ammonia lyase affects metacyclogenesis when histidine is the only metabolizable source and diminishes trypomastigote infection .
恰加斯病的病原体，是已知的唯一一种对人类致病的锥虫，具有完整的从组氨酸到谷氨酸的途径，该途径涉及一系列四个酶促反应，将组氨酸转化为下游代谢产物，包括尿刊酸、4-咪唑酮-5-丙酸、N-甲酰亚氨基-L-谷氨酸和L-谷氨酸。最近的研究强调了该途径在产生ATP、氧化还原平衡以及维持细胞内稳态方面的重要性。在这项工作中，我们聚焦于组氨酸降解途径的第一步，这一步由组氨酸氨裂解酶催化。在这里，我们测定了组氨酸氨裂解酶的动力学和生化参数。通过使用CRISPR-Cas9技术构建该酶的缺失突变体，我们观察到组氨酸降解途径第一步的破坏完全消除了这种寄生虫代谢组氨酸的能力，损害了其将这种氨基酸用作能量和碳源的能力。此外，我们还表明，当组氨酸是唯一可代谢的来源时，组氨酸氨裂解酶的敲除会影响无鞭毛体的形成，并降低锥鞭毛体的感染能力。
