Abstract: To lucubrate bionomics of PalA in Haemophilus parasuis (Hps), the complete palA gene was amplified by PCR with a pair of specific primers designed and synthesized, and was cloned and sequenced. The Hps PalA was analyzed and predicted by the tools of bioinformatics in the following aspects: the composition and alignment of nucleic acid sequences and amino acid sequences, molecular structure, physical and chemical characters, secondary and tertiary structure of protein and so on. The results revealed that 462 bp fragment of the palA gene was amplified by PCR; There were less similarity in nucleic acid sequences than amino acid sequences among five Hps strains; The palA gene preferred mostly to GCA and AAA; The PalA(PI=6.28) showed weak acidity; and main component of all secondary structures included α spiral, random coil and extended strand; The homology of the amino acid of Hps PalA and Haemophilus influenza Pal is 71.97%; The 3D models of Hps PalA were successfully constructed based on the template of Pal of H. influenza; Like Pal, the tertiary structure of Hps PalA also contained a Binding pocket region which included Y80, F39 and L84. The homology modelling successfully of Hps PalA provided a refer to lucubrate the PalA.

Key words: Haemophilus parasuis, palA, sequence analysis, homology modelling