Three-dimensional features of positively selected sites in the disordered region of human interleukin 21. (A) Cartoon of the NMR structure of human interleukin 21 (PDB Code: 2OQP) including its disordered region indicating B-factor scores from the molecular dynamics analysis. Three residues have been identified as positively selected in a PAML branch-site test (Ser81, Gly85, and Arg91) in the disordered region. (B) Molecular dynamics analysis; shown are the B-factors of all residues. Here, B-factors reflect the fluctuation of single amino acids (Cα atom) about their average positions during the MD simulation. The predicted disordered region by MobiDB is indicated in green as well as the three identified residues under positive selection (S81, G85, and R91).
