Crystal structures of the binary and ternary complexes of 7-alpha-hydroxysteroid dehydrogenase from Escherichia coli

The crystal structures of the binary complex of 7-alpha-hydroxysteroid dehydrogenase (HSDH) from Escherichia coli at 2.3 angstroms resolution and a ternary complex of 7-alpha HSDH, complexed with NADH, 7-oxoglycochenodeoxycholic acid at 1.8 angstroms resolution are presented. There are large conformation changes upon substrate binding. The side chains of a tyrosine and a serine residue indirectly interact with the substrate.