Organometallic myoglobins: Formation of Fe–carbon bonds and distal pocket effects on aryl ligand conformations.

Bioorganometallic Fe–C bonds are biologically relevant species that may result from the metabolism of natural or synthetic hydrazines. The molecular structures of four new sperm whale mutant myoglobin derivatives with Fe–aryl moieties, namely H64A–tolyl- m , H64A–chlorophenyl- p , H64Q–tolyl- m , and H64Q–chlorophenyl- p , have been determined at 1.7–1.9 Å resolution. The structures reveal conformational preferences for the substituted aryls resulting from attachment of the aryl ligands to Fe at the site of net –NHNH 2 release from the precursor hydrazines, and show distal pocket changes that readily accommodate these bulky ligands. [ABSTRACT FROM AUTHOR]