loop_ _pdbx_nonpoly_feature_evidence.ordinal _pdbx_nonpoly_feature_evidence.comp_id _pdbx_nonpoly_feature_evidence.label_asym_id _pdbx_nonpoly_feature_evidence.type _pdbx_nonpoly_feature_evidence.experimental_support _pdbx_nonpoly_feature_evidence.details 1 SF4 B 'Group charge' 'Electron paramagnetic resonance spectrometry' ?