1ddz is a 2 chain structure with sequence from Porphyridium purpureum. The January 2004 RCSB PDB Molecule of the Month feature on Carbonic Anhydrase by Shuchismita Dutta and David S. Goodsell is 10.2210/rcsb_pdb/mom_2004_1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.