Cryptosporidiosis is an important parasite causing severe diseases in the immunodeficient people especially AIDS patients. Cryptosporidiosis has been also reported as a common serious primary cause of outbreaks of diarrhea in newborn calves. The aim of this study was to analyze different bioinformatics’ characterization of sporozoite surface antigen P 23 of Cryptosporidium parvum. Our result showed that this protein has 111 amino acids, MW 11232.39 Da and PI 5.18. the number of negatively and positive charged residues was 16 and 14 residues, respectively. The total number of atoms was 1564. The estimated half-life for P 23 protein was as follows: 30 h (mammalian reticulocytes, in vitro), > 20 h (yeast, in vivo) and > 10 h (Escherichia coli, in vivo). The instability index (II) is computed to be 70.11 and Aliphatic index was 44.59. Also, our survey showed that P 23 has high antigenicity and it is not an allergen. This protein has four Serin phosphorylation sites and one acylation site. Transmembrane domains and subcellular localization of P 23 were 62.2 %: nuclear, 8.7 %: cytoskeletal, 4.3 %: cytoplasmic and 4.3 % plasma membrane. Secondary structure prediction in the P 23 sequence showed to 51 (45.95%) alpha helix, 58 (52.25%) random coil and 2 (1.8%) extended strands. moreover, 3D structure of this protein was predicted and refined. For this protein, three high-ranked linear epitopes were determined using BCPREDS server. Also, at least five linear epitopes with high score were confirmed by ABCpred Prediction Server. this survey confirm that P23 could be a favorable candidate for vaccination against C. parvum infection.
