Departamento de Química Biológica, Instituto de Biología Molecular y Celular de Rosario, Universidad Nacional de Rosario, Argentina.
FEMS Microbiol Lett. 2010 Nov;312(2):133-41. doi: 10.1111/j.1574-6968.2010.02109.x.
Trypanosoma cruzi, the etiologic agent for Chagas’ disease, has requirements for several cofactors, one of which is heme. Because this organism is unable to synthesize heme, which serves as a prosthetic group for several heme proteins (including the respiratory chain complexes), it therefore must be acquired from the environment. Considering this deficiency, it is an open question as to how heme A, the essential cofactor for eukaryotic CcO enzymes, is acquired by this parasite. In the present work, we provide evidence for the presence and functionality of genes coding for heme O and heme A synthases, which catalyze the synthesis of heme O and its conversion into heme A, respectively. The functions of these T. cruzi proteins were evaluated using yeast complementation assays, and the mRNA levels of their respective genes were analyzed at the different T. cruzi life stages. It was observed that the amount of mRNA coding for these proteins changes during the parasite life cycle, suggesting that this variation could reflect different respiratory requirements in the different parasite life stages.
克氏锥虫是恰加斯病的病原体，它需要几种辅助因子，其中一种是血红素。由于该生物体不能合成血红素，而血红素是几种血红素蛋白（包括呼吸链复合物）的辅基，因此它必须从环境中获取。考虑到这种缺陷，克氏锥虫如何获得真核 CcO 酶的必需辅助因子血红素 A 是一个悬而未决的问题。在本工作中，我们提供了存在和功能的证据编码血红素 O 和血红素 A 合酶的基因，分别催化血红素 O 的合成及其转化为血红素 A。使用酵母互补测定法评估了这些 T. cruzi 蛋白的功能，并分析了它们各自基因在 T. cruzi 不同生活阶段的 mRNA 水平。观察到这些蛋白的 mRNA 编码量在寄生虫生命周期中发生变化，表明这种变化可能反映了不同寄生虫生活阶段的不同呼吸需求。
