Take a protein structure from Protein Data Bank (PDB). Calculate: 1. Consider the protein structure as a reduced chain (virtual bond model), where each residue i is represented by its alpha carbon C and side chain centroids Si. The successive alpha carbons are connected by virtual bonds. li, 0i, and di refer to the bond length between residue i and residue i-1, the bond angle between the bond vectors i and i-1 and torsional (rotational/dihedral) angle defined by the bond vectors i+1, i and i-1. 1 and 0% are the bond length and bond angle associated with the side chain of residue i, respectively. Sy Si co 1+1 0-1 a. Calculate the virtual bond length, bond angle and torsional angle associated with each residue