sidechain = Group('cyx_sidechain')
peptide = Group('peptide_nt')
bonds = [Bond(peptide.C_alpha, sidechain.C_beta), ]
symbol = 'Cyx'
amber_charge = {peptide.N: 0.2069, sidechain.H_beta_3: 0.068, sidechain.C_beta: -0.0277, peptide.C: 0.6123, peptide.O: -0.5713, peptide.H_2: 0.1815, peptide.H_alpha: 0.0922, peptide.H_1: 0.1815, peptide.H_3: 0.1815, peptide.C_alpha: 0.1055, sidechain.S_gamma: -0.0984, sidechain.H_beta_2: 0.068, }
name = 'cystine (s-s_bridge)'
chain_links = [None, peptide.C]
