Antibiotics 1 Bacteria 1 Bacterial species 1 Bacteroides fragilis 1 Constituent proteins Essential elements 1 G protein 1 Guanosine triphosphate 1 Hydrolysis 1 Iron 1 Iron oxides 1 Machinery 1 Mass spectrometry 1 N-terminals 1 Prokaryotics 1 Protein-protein interactions 1 Proteins 1 Reducing conditions 1 X ray crystallography 1 X ray scattering 1