Smith L E, Uemura H, Eichinger D
Department of Pathology, New York University School of Medicine, NY, USA.
Mol Biochem Parasitol. 1996 Jul;79(1):21-33. doi: 10.1016/0166-6851(96)02634-5.
Several protozoan parasites of human have been found to express enzymes capable of releasing terminal sialic acid residues from host glycans. These include enzymes similar in activity to bacterial and viral sialidases, as well as a novel type of enzyme, trans-sialidase, which can transfer sialic acid from one carbohydrate chain to another. Here we report the isolation of a gene and a gene fragment from the kinetoplastid Trypanosoma rangeli which encode products related in sequence to the trans-sialidase enzyme of T. cruzi. The gene fragment ORF is nearly identical to that of the complete gene, which encodes an enzymatically inactive protein. When the ORF of the gene fragment is fused to fragments from related genes, it encodes a product with sialidase activity. Both predicted T. rangeli protein products also have other potential structural features found in bacterial sialidases and in members of a previously described Trypanosoma trans-sialidase superfamily.
已发现几种人类原生动物寄生虫能表达可从宿主聚糖释放末端唾液酸残基的酶。这些酶包括活性与细菌和病毒唾液酸酶相似的酶，以及一种新型酶——转唾液酸酶，它可将唾液酸从一条碳水化合物链转移至另一条。在此，我们报告从动基体锥虫罗氏锥虫中分离出一个基因和一个基因片段，它们编码的产物在序列上与克氏锥虫的转唾液酸酶相关。该基因片段的开放阅读框（ORF）与完整基因的ORF几乎相同，完整基因编码一种无酶活性的蛋白质。当该基因片段的ORF与相关基因的片段融合时，它编码一种具有唾液酸酶活性的产物。两种预测的罗氏锥虫蛋白产物还具有在细菌唾液酸酶以及先前描述的锥虫转唾液酸酶超家族成员中发现的其他潜在结构特征。
