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Second-Coordination Sphere Effects on Selectivity and Specificity of Heme and Nonheme Iron Enzymes.

Sam P De Visser
Published in: Chemistry (Weinheim an der Bergstrasse, Germany) (2020)
Mononuclear iron-containing enzymes are highly versatile oxidants that often react stereospecifically and/or regioselectively with substrates. Combined experimental and computational studies on heme monooxygenases, nonheme iron dioxygenases and halogenases have revealed the intricate details of the second-coordination sphere, which determine this specificity and selectivity. These second-coordination sphere effects originate from the positioning of the substrate and oxidant, which involve the binding of the co-factors and substrate into the active site of the protein. In addition, some enzymes affect the selectivity and reactivity through charge-stabilization from nearby bound cations/anions, an induced electric field or through the positioning of salt bridges and hydrogen-bonding interactions to first-coordination sphere iron ligands and/or the substrate. Examples of all of these second-coordination sphere effects in iron-containing enzymes and how these influence structure and reactivity are given.
Keyphrases
  • structural basis
  • iron deficiency
  • ionic liquid
  • binding protein
  • peripheral blood