| 摘要 |
<p>A gene coding for the IgG binding domains of protein G, and a gene coding for a chimeric receptor containing one IgG binding domain of both Protein A and Protein G, were chemically synthesized. Genes were constructed from three 'cassettes' each encoding a different domain. Synthetic protein G (SG) and chimeric protein BG (SBG) were inserted into a plasmid vector containing a tac promoter and an ampicillin-resistance gene; allowing both amplification and expression in E. coli. In addition to the IgG binding sites, engineered Fc receptors contain a proline-rich, hydrophilic carboxyl terminus providing for immobilization to solid support, and a factor Xa cleavable site providing for their use in isolation and affinity purification of other genes cloned to the 5' end of these genes. The genes were expressed in E. coli; the biological activity of the expressed proteins was demonstrated by immunoblotting with human IgG as well as by a competitive enzyme-linked immunoadsorbent assay with different subsclasses of human IgG.</p> |
