Sequence characteristics of Rhipicephalus microplus Enolase gene and prediction of structure and antigenic epitopes of its encoding protein

Abstract

To analyze the sequence characteristics of Rhipicephalus microplus Enolase gene, and to predict the secondary and tertiary structure and antigenic epitopes of the Enolase protein. Sixty-two engorged female R. microplus were sampled from a yellow cattle breeding farm in Zhijiang County, Huaihua City, Hunan Province in June 25, 2022. Genomic DNA was isolated from R. microplus, and the Enolase gene was amplified using PCR assay, followed by cloning, sequencing and expression of the amplification product. The sequence characteristics of the Enolase gene were analyzed using the software Clustal X, and the gene sequence was translated into amino acid sequences. The secondary and tertiary structures of the Enolase protein were deduced using the software PRABI, and the physicochemical properties of the Enolase protein were analyzed using the software PRABI. In addition, the B- and T-cell epitopes of the Enolase protein were predicted using the software ABCpred Prediction, Scratch, IEDB and NetCTL. The R. microplus Enolase gene sequence was 1 323 bp in size, and the contents of A, T, G and C bases were 24.5%, 22.5%, 27.0% and 26.0%,with 47.0% of A + T content and 53.0% of G + C content. The R. microplus Enolase gene encoded 434 amino acids, and the Enolase protein had a molecular weight of 47.12 kDa. The secondary structure of the Enolase protein contained 186 α-helixes (42.86%), 32 β-turns (7.37%), 144 random coils (33.18%) and 72 extended strands (16.59%). The Enolase protein was most probably present in cytoplasm (76.7%), followed by in mitochondrion (39.1%) and nucleus (21.7%), and the Enolase protein had no signal peptide or transmembrane domain. In addition, the Enolase protein had 14 B-cell dominant epitopes and 8 T-cell dominant epitopes. The R. microplus Enolase gene sequence exhibits a GC preference, and its encoding Enolase protein is an acidic and hydrophilic protein, with α-helixes and random coils as its primary structure, and presenting B- and T-cell dominant epitopes, which is a potential target for development of vaccines against R. microplus.