[Genomic characterization of SARS coronavirus: a novel member of coronavirus]

In March 2003, SARS-CoV, a novel coronavirus which has been proved to be a pathogen causing Severe Acute Respiratory Syndrome (SARS). The complete genome of SARS-CoV has been sequenced by international collaboration including China. In the present study, the genome sequences were collected from NCBI and genomic characterization was analyzed. SARS-CoV has a genome of 28-30 kb including 11 ORFs (Open Reading Frames), which is consistent with that of coronavirus family, and its genome organization is similar to those of other coronaviruses as well. SARS-CoV evolutionally closes to other coronavirus in their corresponding proteins, such as spike protein, small membrane protein and nucleocapsid protein. In some regions of the genome, the genomic sequence of SARS-CoV was significantly different from that of other coronavirus, and has a self-conservative genomic sequence. Moreover, its encoding protein sequences were greatly different from those of other coronavirus. The analysis indicated that SARS-CoV has lower redundancy, that is, it has a high variation possibility. It may not be a variant of other coronaviruses but a novel coronavirus, which existed independently in nature and was not recognized by human being before, although SARS-CoV is morphologically similar to other coronavirus and belongs to coronavirus family. The sequences of its genes and encoding proteins are substantially different from those of other coronavirus.