loop_ _pdbx_feature_assembly.id _pdbx_feature_assembly.assembly_id _pdbx_feature_assembly.feature_name _pdbx_feature_assembly.feature _pdbx_feature_assembly.feature_type _pdbx_feature_assembly.feature_assigned_by _pdbx_feature_assembly.feature_citation_id 1 b1 'biological process' 'nitrogen metabolism' value GO GO