Tetrapyrroles, like the porphyrins heme and chlorophyll, are essential compounds of the metabolism of almost all organisms on earth. They are integral parts of the electron transport chains utilized during photosynthesis and oxidative phosphorylation. Moreover, various enzymes utilize tetrapyrrole cofactors. The synthesis of haem is an essential process, and the enzymatic steps of its biosynthetic pathway have been highly conserved throughout evolution. During porphyrin biosynthesis coproporphyrinogen III oxidase catalyzes the oxidative decarboxylation of coproporphyrinogen III (coprogen) to form protoporphyrinogen IX (protogen). In bacteria two structurally unrelated CPOs, one oxygen-dependent (HemF) and one oxygen-independent (HemN), catalyze this reaction. Whereas molecular oxygen is the electron acceptor in aerobic systems, facultative anaerobes can carry out the reaction in the absence of oxygen by way of a different enzyme in the presence of adenosine triphosphate (ATP), oxidised pyridine nucleotide and methionine. Here you can see a recent crystal structure of the Oxygen-dependent coproporphyrinogen-III oxidase (hemF) from Klebsiella aerogenes (PDB code: 8T7W)

#molecularart ... #immolecular ... #heme ... #oxidase ... #oxygen-dependent ... #biosynthesis ... #klebsiella ... #xray

Structure rendered with @proteinimaging and depicted with @corelphotopaint