1bo4 is a 2 chain structure with sequence from Serratia marcescens. The February 2012 RCSB PDB Molecule of the Month feature on Aminoglycoside Antibiotics by David Goodsell is 10.2210/rcsb_pdb/mom_2012_2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.