Fig. 1

Bioinformatics analysis of the conserved membrane-associated antigen, Bm8. a Conserved domain search indicated that the protein has a homolog with a known structure at 274–423; two transmembrane regions were detected by the TMHMM Server(https://dtu.biolib.com/DeepTMHMM). Numbers from 0 to 500 represent the length of the protein sequence. The transmembrane region is shown in blue. b Multiple sequence alignment by ClustalW of the conserved membrane-associated sequences of Babesia microti with other apicomplexan protozoa (Plasmodium berghei, Plasmodium falciparum, Plasmodium vivax, Babesia bovis, Theileria annulata and Toxoplasma gondii). The green box shows the synthetic conservative polypeptide regions (i.e. all amino acids are identical); areas marked in yellow represent incompletely conserved protein regions (i.e. at least 4 of the 6 samples have identical amino acids). The green box shows the conserved polypeptides among Babesia, Plasmodium, Theileria and Toxoplasma with the synthesized peptides of B. microti selected in this study. c Phylogenetic tree of the sequence of the conserved membrane-associated sequences with other apicomplexan protozoa species. The scale bar represents the nucleotide substitutions per position. Branch lengths represent the amount of genetic distance change between the strains. d Three-dimensional structural models of erythrocyte membrane-associated conserved protein of Bm8 predicted by SWISS-MODEL program. The conserved membrane-associated sequences of other apicomplexan protozoa (P. berghei, P. vivax, B. bovis, and T. annulata) were predicted simultaneously. The green regions represent the high antigenic conservative polypeptides applied in this study. Bm8, B. microti protein 8