... porphyrin ring of heme, producing biliverdinIXa, iron, and carbon monoxide utilizing reducing equiv-alents [1]. In mammals, HO is mainly involved in hememetabolism f or the purpose of recovering ... shown in the first line are those in Syn HO-1. Gly130,Gly134, Gly135, and Asp131 correspond to Gly139, Gly143, Gly144, and Asp140 in human and rat HO-1s and to Gly135, Gly139, Gly140, and Asp136 in ... were clearly seen in the electron density map and included in the subsequent refinements. After a few cyclesof water picking and energy minimization refinementswithout restraints by noncrystallographic...