The SAG2 antigen of Toxoplasma gondii and the 31-kDa surface antigen of Sarcocystis muris share similar sequence features.
In the search for similar cysteine distribution patterns among surface antigens of members of the phylum of Apicomplexa, we found a resemblance between TgSAG2, a 22-kDa surface antigen of Toxoplasma gondii, and the C-terminal half of a 31-kDa surface antigen of Sarcocystis muris, SmSAG1. The overall degree of similarity is low, corresponding to 28% of identity in the 146 amino acids aligned. However, the conservative spacing between the cysteine residues suggest that this similarity might have functional implications. The described amino acid similarity provides a new clue to the molecular relationship between two closely related coccidian parasites.
Cesbron-Delauw
M F
MF
INSERM U415, Institut Pasteur de Lille, France.
D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry*; D000954:Antigens, Surface / Q000737:chemistry*; D008969:Molecular Sequence Data; D015800:Protozoan Proteins; D012522:Sarcocystis / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D014122:Toxoplasma / Q000276:immunology*
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; C097089:p31 protein, Sarcocystis; C067547:surface antigen P22, Toxoplasma