Abstract: This study was aimed to clone and express the NYD-SP27 gene in sheep,and analyze the bioinformatics of its expressed protein.A pair of specific primers were designed based on the sequence of NYD-SP27 gene (accession No.:KX905090) in GenBank,and the NYD-SP27 gene fragment was amplified by PCR method.The recombinant plasmid pMD19-T-NYDSP27 was constructed and then transformed into E.coli DH5α competent cells.The plasmid was identified by restriction enzyme digestion.The recombinant plasmid pET-22b(+)-NYDSP27 was constructed and then transformed into E.coli BL21(DE3) competent cells.The expressed protein was induced by IPTG and identified by SDS-PAGE and Western blotting.The amino acid sequence encoded by NYD-SP27 gene was analyzed by bioinformatics methods.The results showed that the 1 617 bp gene fragment was successfully amplified,and two fragments of 5 400 and 1 617 bp were digested by Nde Ⅰ and Xho Ⅰ,indicating that the recombinant plasmid pET-22b(+)-NYDSP27 was successfully constructed.The expressed recombinant protein was about 60 ku.The NYD-SP27 recombinant protein was an inclusion body with a molecular formula of C₂₇₉₈H₄₃₁₉N₇₃₇O₈₁₉S₁₉.The total number of atoms was 6 892,the theoretical isoelectric point (pI) was 6.16,which was an acidic protein,the instability coefficient was 46.96,which was an unstable protein,and the average hydrophilicity was -0.403.The protein had no signal peptide and transmembrane structure,and had 39 potential phosphorylation sites and 24 epitopes.In the secondary structure of NYD-SP27 protein,alpha helix,beta turn,extended chain and random coil accounted for 26.21%,3.90%,18.03% and 51.86%,respectively.This results might provide reference data and material basis for further study of regulatory mechanisms of NYD-SP27 protein in sheep.

Key words: NYD-SP27 gene; prokaryotic expression; bioinformatics analysis