S_gamma = Atom('s')
C_beta = Atom('ch2')
bonds = [Bond(S_gamma, C_beta), ]
amber91_atom_type = {S_gamma: 'S', C_beta: 'C2', }
pdbmap = [('CYX', {'CB': C_beta, 'SG': S_gamma, }, ), ]
name = 'cyx_sidechain'
