Los Milagros Camara Maria de, Bouvier Leon, Reigada Chantal, Digirolamo Fabio A, Saye Melisa, Pereira Claudio A
Instituto de Tecnologia, Universidad Argentina de la Empresa, Buenos Aires, Argentina.
Instituto de Investigaciones Biotecnologicas, Buenos Aires, Argentina.
Folia Parasitol (Praha). 2017 Feb 17;64:2017.006. doi: 10.14411/fp.2017.006.
Nucleoside diphosphate kinases (NDPK) are key enzymes involved in the intracellular nucleotide maintenance in all living organisms, especially in trypanosomatids which are unable to synthesise purines de novo. Four putative NDPK isoforms were identified in the Trypanosoma cruzi Chagas, 1909 genome but only two of them were characterised so far. In this work, we studied a novel isoform from T. cruzi called TcNDPK3. This enzyme presents an atypical N-terminal extension similar to the DM10 domains. In T. cruzi, DM10 sequences targeted other NDPK isoform (TcNDPK2) to the cytoskeleton, but TcNDPK3 was localised in glycosomes despite lacking a typical peroxisomal targeting signal. In addition, TcNDPK3 was found only in the bloodstream trypomastigotes where glycolytic enzymes are very abundant. However, TcNDPK3 mRNA was also detected at lower levels in amastigotes suggesting regulation at protein and mRNA level. Finally, 33 TcNDPK3 gene orthologs were identified in the available kinetoplastid genomes. The characterisation of new glycosomal enzymes provides novel targets for drug development to use in therapies of trypanosomatid associated diseases.
核苷二磷酸激酶（NDPK）是所有生物体内参与细胞内核苷酸维持的关键酶，尤其是在无法从头合成嘌呤的锥虫中。在1909年克氏锥虫的基因组中鉴定出了四种假定的NDPK同工型，但到目前为止仅对其中两种进行了表征。在这项研究中，我们研究了一种来自克氏锥虫的新型同工型，称为TcNDPK3。这种酶具有类似于DM10结构域的非典型N端延伸。在克氏锥虫中，DM10序列将其他NDPK同工型（TcNDPK2）靶向细胞骨架，但尽管缺乏典型的过氧化物酶体靶向信号，TcNDPK3却定位于糖体中。此外，仅在糖酵解酶非常丰富的血流型锥鞭毛体中发现了TcNDPK3。然而，在无鞭毛体中也检测到了较低水平的TcNDPK3 mRNA，这表明在蛋白质和mRNA水平上存在调控。最后，在现有的动基体基因组中鉴定出了33个TcNDPK3基因直系同源物。新的糖体酶的表征为开发用于治疗锥虫相关疾病的药物提供了新的靶点。
