loop_ _chem_comp_bond.comp_id _chem_comp_bond.atom_id_1 _chem_comp_bond.atom_id_2 _chem_comp_bond.value_order phe N CA sing phe CA C sing phe C O doub phe CB CA sing phe CB CG sing phe CG CD1 arom phe CD1 CE1 arom phe CE1 CZ arom phe CZ CE2 arom phe CE2 CD2 arom phe CD2 CG arom val N CA sing val CA C sing val C O doub val CB CA sing val CB CG1 sing val CB CG2 sing