PCA and Free energy landscape analysis
PCA was also performed using GROMACS [77] modules like gmx covar & gmx anaeig, which create and diagonalize covariance matrix of atomic coordinates of atoms. Movies which shows the movement of protein along the first two principal components were created using VMD, with principal components calculated for the unmodified tau (Tau_plane), tau-glycan complex (Tau_glyc) and the phosphorylated systems (Tau_phos, Tau_p356, Tau_p352) [80], after extracting the frames corresponding to the first two PCs using gmx anaeig. Free energy landscape was calculated with the radius of gyration and end to end distance as two reaction coordinates, using gmx sham module of GROMACS [77].