Cloning and of structure prediction of outer membrane protein P5 gene of Haemophilus parasuis

A pair of primers were designed according to Haemophilus parasuis outer membrane protein gene sequences published in the GenBank,and outer membrane protein gene 5(OMP5) of Haemophilus parasuis isolate was amplified by PCR.The fragment was inserted into the pMD18-T vector,then sequenced and the outer membrane protein secondary structure,antigenic determinants,signal peptide and transmembrane domain of Haemophilus parasuis were predicted with the bioinformatics and molecular biology software.The result showed the OMP5 of HPS GDH15 was 1 116 bp in size,encoding 371 amino acid residues.Compared with the SH0165 outer membrane protein gene published in GenBank,the homology of nucleotide sequence and amino acid were both 100%.The protein structure prediction showed that it was a mixed pattern protein,containing the α-helix,β-pleated sheet,β-turn and random coil.Regions of β-turn and random coil would become the antigenic epitopes.It has 15 antigenic determinants,1 signal peptide and the best cutting site was between amino acids 21 and 22.But transmembrane domain did not exist in it and no similar three dimensional structure was found.The OMP5 of Haemophilus parasuis GDH15 isolate was conservative,it could be used for the development of genetic engineering vaccine and ELISA method.