猫血管紧张素转换酶2的三维结构模拟与真核表达

Three Dimensional Structure Modelling of Feline ACE2 and Its Eukaryotic Expression

家猫能自然及人工感染SARS病毒,本研究旨在探讨家猫ACE2潜在的SARS病毒受体功能。以人血管紧张素转换酶2(ACE2)序列为模板,用同源模建法模拟了家猫ACE2的三维空间结构,发现家猫ACE2与人ACE2结构十分相似,其结合严重急性呼吸综合症(SARS)病毒囊膜纤突(S)蛋白的关键氨基酸的同源性很高(15/18)。将家猫血管紧张素转换酶2基因N端1-367 aa对应的基因片段及其跨膜区克隆到真核表达载体pcDNA3.1/myc-his(+)B中,构建了表达质粒pcDNA-mA367,转染HeLa细胞,间接免疫荧光检测表明fACE2的N端片段已在细胞膜上成功表达。

Domestic cats were demonstrated to be susceptible for experimental and natural infection of SARS-CoV. This study aimed to explore the potential receptor function of feline angiotensin-converting enzyme 2 （ACE2） which is the functional receptor of SARS-CoV in humans. The three-dimensional structure of feline ACE2 was predicted by homology modeling using human ACE2 amino acid sequences as the template. The feline ACE2 dimensional structure is very similar to that of human ACE2. Furthermore, the deduced amino acids between cat and human ACE2 that are critical to contact with SARS-CoV receptor binding region shared a high homology （15/18）. To get a tool to study feline ACE2 function as the SARS-CoV receptor, an eukaryotic expression vector encoding ACE2 N terminal 1-367 aa combined with the transmembrane region （740-762 aa） pcDNA-mA367 was constructed. The fACE2 gene expression on HeLa cells was successfully expressed detected by indirect immunofluorescence assay.