Homodimerization of the c-Abl protein tyrosine kinase / 生物工程学报

The c-Abl nonreceptor tyrosine kinase is activated in the cellular responses to genotoxic, oxidative and other forms of stress. Using tagged forms of c-Abl, the present studies demonstrate that c-Abl forms homodimers in cells. The results show that the c-Abl N-terminal regions interact with the corresponding C-terminal regions of both partners in the dimmer. Specifically, the c-Abl SH3 domain binds to a proline-rich motif at amino acids 958-982 in the c-Abl C-terminal region. Deletion of the proline-rich motif disrupts dimmer formation. These findings provide the first evidence that c-Abl forms homodimers and indicate that homodimerization can contribute to the regulation of c-Abl activity.

Over-expression in Escherichia coli and purification of nucleocaspid and membrane protein of SARS coronavirus / 生物工程学报

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.