4 publications

4 publications

Hemozymes Peroxidase Activity Of Artificial Hemoproteins Constructed From the Streptomyces Lividans Xylanase A and Iron(III)-Carboxy-Substituted Porphyrins

Mahy, J.-P.

Bioconjug. Chem. 2008, 19, 899-910, 10.1021/bc700435a

To develop artificial hemoproteins that could lead to new selective oxidation biocatalysts, a strategy based on the insertion of various iron-porphyrin cofactors into Xylanase A (Xln10A) was chosen. This protein has a globally positive charge and a wide enough active site to accommodate metalloporphyrins that possess negatively charged substituents such as microperoxidase 8 (MP8), iron(III)-tetra-α4-ortho-carboxyphenylporphyrin (Fe(ToCPP)), and iron(III)-tetra-para-carboxyphenylporphyrin (Fe(TpCPP)). Coordination chemistry of the iron atom and molecular modeling studies showed that only Fe(TpCPP) was able to insert deeply into Xln10A, with a KD value of about 0.5 µM. Accordingly, Fe(TpCPP)-Xln10A bound only one imidazole molecule, whereas Fe(TpCPP) free in solution was able to bind two, and the UV–visible spectrum of the Fe(TpCPP)-Xln10A-imidazole complex suggested the binding of an amino acid of the protein on the iron atom, trans to the imidazole. Fe(TpCPP)-Xln10A was found to have peroxidase activity, as it was able to catalyze the oxidation of typical peroxidase cosubstrates such as guaiacol and o-dianisidine by H2O2. With these two cosubstrates, the KM value measured with the Fe(TpCPP)-Xln10A complex was higher than those values observed with free Fe(TpCPP), probably because of the steric hindrance and the increased hydrophobicity caused by the protein around the iron atom of the porphyrin. The peroxidase activity was inhibited by imidazole, and a study of the pH dependence of the oxidation of o-dianisidine suggested that an amino acid with a pKA of around 7.5 was participating in the catalysis. Finally, a very interesting protective effect against oxidative degradation of the porphyrin was provided by the protein.


Metal: Fe
Ligand type: Porphyrin
Host protein: Xylanase A (XynA)
Anchoring strategy: Supramolecular
Optimization: ---
Max TON: ---
ee: ---
PDB: ---
Notes: kcat/KM = 1083 M-1 * s-1

Incorporation of Manganese Complexes into Xylanase: New Artificial Metalloenzymes for Enantioselective Epoxidation

Mahy, J.-P.; Ricoux, R.

ChemBioChem 2012, 13, 240-251, 10.1002/cbic.201100659

Enantioselective epoxidation: An artificial metalloenzyme obtained by noncovalent insertion of MnIII‐meso‐tetrakis(para‐carboxyphenyl)porphyrin Mn(TpCPP) into xylanase 10A from Streptomyces lividans as a host protein was able to catalyse the oxidation of para‐methoxystyrene by KHSO5 with a 16 % yield and the best enantioselectivity (80 % in favour of the R isomer) ever reported for an artificial metalloenzyme.


Metal: Mn
Ligand type: Porphyrin
Host protein: Xylanase A (XynA)
Anchoring strategy: Supramolecular
Optimization: ---
Reaction: Epoxidation
Max TON: 21
ee: 80
PDB: ---
Notes: ---

Selective Oxidation of Aromatic Sulfide Catalyzed by an Artificial Metalloenzyme: New Activity of Hemozymes

Mahy, J.-P.

Org. Biomol. Chem. 2009, 7, 3208, 10.1039/b907534h

Two new artificial hemoproteins or “hemozymes”, obtained by non covalent insertion of Fe(III)-meso-tetra-p-carboxy- and -p-sulfonato-phenylporphyrin into xylanase A from Streptomyces lividans, were characterized by UV-visible spectroscopy and molecular modeling studies, and were found to catalyze the chemo- and stereoselective oxidation of thioanisole into the S sulfoxide, the best yield (85 ± 4%) and enantiomeric excess (40% ± 3%) being obtained with Fe(III)-meso-tetra-p-carboxyphenylporphyrin-Xln10A as catalyst in the presence of imidazole as co-catalyst.


Metal: Fe
Ligand type: Porphyrin
Host protein: Xylanase A (XynA)
Anchoring strategy: Supramolecular
Optimization: ---
Reaction: Sulfoxidation
Max TON: 145
ee: 40
PDB: ---
Notes: ---

Various Strategies for Obtaining Artificial Hemoproteins: From "Hemoabzymes" to "Hemozymes"

Mahy, J.-P.

Biochimie 2009, 91, 1321-1323, 10.1016/j.biochi.2009.03.002

The design of artificial hemoproteins that could lead to new biocatalysts for selective oxidation reactions of organic compounds presents a huge interest especially in pharmacology, both for a better understanding of the metabolic profile of drugs and for the synthesis of enantiomerically pure molecules that could be involved in the design of drugs. The present results show that the so-called “host-guest strategy” that involves the non-covalent incorporation of anionic water-soluble iron-porphyrins into xylanase A from Streptomyces lividans, a low cost protein, leads to such an artificial hemoprotein that is able to perform the stereoselective oxidation of sulfides.


Metal: Fe
Ligand type: Porphyrin
Host protein: Xylanase A (XynA)
Anchoring strategy: Supramolecular
Optimization: Chemical
Reaction: Sulfoxidation
Max TON: ---
ee: 36
PDB: ---
Notes: ---