Sequence analysis,cloning expression and immunogenicity analysis of lactate dehydrogenase gene from Taenia solium / 中国人兽共患病学报

ABSTRACT

The structure and properties about encoding protein of lactate dehydrogenase A from Taenia solium(Ts LDH-A)were analyzed and predicted by bioinformatics in this study.The immunological characteristics of this novel gene were also analyzed by cloning and expressing.The full-length cDNA encoding Ts LDH-A was identified from the cDNA plasmid library by blastx and rpsblast programs provided by NCBI.The physico-chemical properties and structures of Ts LDH-A were analyzed by tools provided by ExPASy.And the B cell epitopes of Ts LDH-A were predicted by the B Cell Epitope Prediction Tools provided by IEDB Analysis Resource.The PCR amplified coding region of Ts LDH-A was cloned into the prokaryotic expression vector pET-28a (+) and expressed in E.coli BL21 with IPTG induction.The immunogenicity of the purified recombinant protein was analyzed by Western Blotting.It was demonstrated that the amino acid sequence of Ts LDH-A had identity with that of LDH-A from other specie and there was a conserved LDH domain in the deduced amino acid sequence.The full-length cDNA sequence encoding Ts LDH-A included a complete open reading frame(ORF)of 1332 bp and coded to a putative protein with 331 amino acids.The molecular weight of Ts LDH-A was predicted to be 35461.1 Da and the coding protein was demonstrated to contain 3 trans-membrane regions and 4 main B cell epitopes.The active site of L-lactate dehydrogenase located at the epitope aa190-199.The 3 key residues in the catalytic site of enzyme were conserved in different species and located near to each other in spatial position.PCR,double enzyme restriction and DNA sequencing were used to identify pET28a (+)-Ts LDH-A.The recombinant protein could react with the rat's sera as well as the sera from the patients and the swine infected Taenia solium.It is clear that the full-length cDNA sequence encoding Ts LDH-A can be screened from the cDNA library of adult Taenia solium by bioinformatics analysis and can be used to investigate the structure and properties about gene and encoding protein of Ts LDH-A as well as the immunological activities of gene expression in the prokaryotic system.