[Over-expression in Escherichia coli and purification of nucleocaspid and membrane protein of SARS coronavirus].

Genes encoding nucleocaspid (N) and membrane (M) protein of SARS coronavirus were obtained by RT-PCR and were cloned into expression vector pET22b and pBV222. DNA sequencing showed that the genes cloned from a patient in Beijing were identical to the gene sequences from reported Toronto strain. The genes were over-expressed in E. coli either as inclusion body or as soluble form. The recombinant proteins were purified by ion-exchange, or ion-exchange followed by metal chelate affinity chromatography. The recombinant N protein was demonstrated highly antigenic and could be employed as antigen to detect SARS antibodies in ELISA system for SARS diagnosis.