Struture Analysis and Selective Fragment Cloning of 52 kD Ro/SSA Antigen / 中华皮肤科杂志

ABSTRACT

Objective To detect the possible epitopes of 52 000 dalton Ro/SSA autoantigen and selectively clone the antigen fragment containing the leucine zipper motif. Methods The structure of 52 000 dalton Ro/SSA autoantigen was analyzed by protein structure analysis system. The cDNA encoding the antigen fragments from amino acid (aa) 119 to 264 was amplified from cDNA first strands of human heart by polymerase chain reaction (PCR). The PCR product was inserted into the vector pMTY4, and transfected E. coli pop 2136 for fusion protein production. Results Computer analysis showed that the 52 000 dalton Ro/SSA antigen had alpha helixes in its structure, and had good antigenicity, moderate flexibility and poor surface probability. The PCR product was 440bp in length. The recombinant fusion protein was 28 000 dalton. DNA sequencing proved the accuracy of the research. Conclusion The 52 000 dalton Ro/SSA autoantigen has good antigenicity. The cloning of the antigen fragment will help to elucidate the possible role of leucine zipper motif in forming the epitope of the antigen.