The Protein Environment Drives Selectivity for Sulfide Oxidation by an Artificial Metalloenzyme

Abstract

MAGIC Mn-salen mETALLOZYME: The design of an original, artificial, inorganic, complex-protein adduct, has led to a better understanding of the synergistic effects of both partners. The exclusive formation of sulfoxides by the hybrid biocatalyst, as opposed to sulfone in the case of the free inorganic complex, highlights the modulating role of the inorganic-complex-binding site in the protein. Artificial metalloenzymes based on the incorporation of Mn-salen complexes into human serum albumin display high efficiency and selectivity for sulfoxide production during sulfide oxidation. The reactions carried out by the artificial metallozymes are comparable to those carried out by natural biocatalysis. We have found that the polarity of the protein environment is crucial for selectivity and that a synergy between both partners of the hybrid results in the novel activity.

The structure of the periplasmic nickel-binding protein NikA provides insights for artificial metalloenzyme design

“…Purification of NikA and synthesis of ''NikA-metal complex'' hybrids Complexes 1-6 were synthesized as previously described [13,16,17]. Cytoplasmic apoNikA was overproduced and purified as already reported [12].…”

Protein Design: Toward Functional Metalloenzymes

“…572 The Mn(III)–salen complexes used are shown in Scheme 13. Binding studies showed that the presence of charged R-groups could improve the binding affinity at pH 7.0, leading to more stable Mn(III)–salen⊂HSA hybrid proteins.…”

An Artificial Enzyme Made by Covalent Grafting of an FeII Complex into β‐Lactoglobulin: Molecular Chemistry, Oxidation Catalysis, and Reaction‐Intermediate Monitoring in a Protein

“…The catalyst:thioanisole:H 2 O 2 stoichiometric ratio was 1:1000:100, and the oxidant was delivered over 45 min by syringe pump. Interestingly, the unique product detected was phenylmethylsulfoxide, which is likely related to the large substrate/oxidant ratio 18. Figure 6 shows the product formation as a function of time for both 1 ⊂BLG and the model complex [(L 5 2 )Fe II Cl] + .…”