Objective  To provide theoretical basis for prevention and control of Orf in Fujian, the molecular characteristics and biological functions of ORFV011 genes of the vaccine strain and ORFV-PN strain were compared.

  Methods  ORFV011 genes from the two strains were cloned and sequenced for comparison and analysis using bioinformatics software.

  Results  The sequencing results indicated that both genes composed of 1 137 nucleotides coding 378 amino acids. The nucleotide sequence similarity of ORFV011 of the ORFV-PN strain was 98.6% with that of the vaccine strain, while 98.4% with that of the lentogen strain D1701. The amino acid sequence similarity of ORFV011 of the ORFV-PN strain with either the vaccine strain or the D1701 strain was the same at 98.7%. There were 16 nucleotide mutations and 5 amino acid variations in the gene of the ORFV-PN strain as compared to that of the vaccine strain. On the secondary structure, the encoded protein by ORFV011 gene of the ORFV-PN strain and the vaccine strain had 34.13% (or 129/378) and 30.42% (or 115/378) alpha helixes, respectively; 6.08% (or 23/378) and 6.88% (or 26/378) beta turns, respectively; 37.3% (or 141/378) and 39.15% (or 148/378) random coils, respectively; and, 22.49% (or 85/378) and 23.54% (or 89/378) extended strands, respectively. The predicted three-dimensional structure of ORFV011 of the ORFV-PN strain showed differences on the alpha helixes and random coils as compared with that of the vaccine strain.

  Conclusion  It appeared that ORFV011 of the ORFV-PN strain deviated from that of the vaccine strain in sequence as well as secondary and three-dimensional structures. Thus, special attention must be placed in monitoring and controlling the Orf.