Editing Myoglobin (section)

==Synthetic analogues==
Many models of myoglobin have been synthesized as part of a broad interest in [[transition metal dioxygen complex]]es.  A well known example is the ''picket fence porphyrin'', which consists of a ferrous complex of a sterically bulky derivative of [[tetraphenylporphyrin]].<ref name="pmid1068445">{{cite journal | vauthors = Collman JP, Brauman JI, Halbert TR, Suslick KS | title = Nature of O2 and CO binding to metalloporphyrins and heme proteins | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 73 | issue = 10 | pages = 3333–7 | date = Oct 1976 | pmid = 1068445 | pmc = 431107 | doi = 10.1073/pnas.73.10.3333 | bibcode = 1976PNAS...73.3333C | doi-access = free }}</ref> In the presence of an [[imidazole]] ligand, this ferrous complex reversibly binds O<sub>2</sub>.  The O<sub>2</sub> substrate adopts a bent geometry, occupying the sixth position of the iron center.  A key property of this model is the slow formation of the μ-oxo dimer, which is an inactive diferric state.  In nature, such deactivation pathways are suppressed by protein matrix that prevents close approach of the Fe-porphyrin assemblies.<ref>{{cite book | vauthors = Lippard SJ, Berg JM | title = Principles of Bioinorganic Chemistry | publisher = University Science Books | location = Mill Valley, CA | year = 1994 | isbn = 0-935702-73-3 }}</ref>
:[[File:PicketFenceGenericRevised.png|thumb|300px|center|A picket-fence porphyrin complex of Fe, with axial coordination sites occupied by methylimidazole (green) and [[dioxygen]].  The R groups flank the O<sub>2</sub>-binding site.]]