Table 22.1.1.3 

The mean standard volume, the standard deviation about the mean and the frequency of occurrence of each residue in the protein core are given. Considering cysteine (Cyh, reduced) to be chemically different from cystine (Cys, involved in a disulfide and hence oxidized) gives 21 different residues. These residue volumes are adapted from the ProtOr parameter set (also known as the BL+ set) in Tsai et al. (1999) and Tsai et al. (2001). For this set, the averaging is done over 87 representative high-resolution crystal structures, only buried atoms not in contact with ligands are selected, the radii set shown in the last column of Table 22.1.1.1 is used and the volumes are computed in the presence of the crystal water. The frequencies for buried residues are from Harpaz et al. (1994).