Kamer, P.C.J.; Laan, W.

ChemCatChem 2013, 5, 1184-1191, 10.1002/cctc.201200671

The development of artificial copper enzymes from sterol carrier protein type 2 like domain (SCP‐2L) for the use in asymmetric catalysis was explored. For this purpose, proteins were modified with various nitrogen donor ligands. Maleimide‐containing ligands were found most suitable for selective cysteine bio‐conjugation. Fluorescence spectroscopy was used to confirm copper binding to an introduced phenanthroline ligand, which was introduced in two unique cysteine containing SCP‐2L mutants. Copper adducts of several modified SCP‐2L templates were applied in asymmetric Diels–Alder reactions. A clear influence of both the protein environment and the introduced ligand was found in the asymmetric Diels–Alder reaction between azachalcone and cyclopentadiene. A promising enantioselectivity of 25 % ee was obtained by using SCP‐2L V83C modified with phenanthroline–maleimide ligand. Good endo selectivity was observed for SCP‐2L modified with the dipicolylamine‐based nitrogen donor ligand. These artificial metalloenzymes provide a suitable starting point for the implementation of various available techniques to optimise the performance of this system.

Bian, H.-D.; Huang, F.-P.

RSC Adv. 2016, 6, 44154-44162, 10.1039/C6RA08153C

Enantioselective oxidation of a series of alkyl aryl sulfides catalyzed by a novel VIV8 cluster is tested in an aqueous medium in the presence of serum albumin. The procedure is simple, environmentally friendly, selective, and highly reactive.

Kamer, P.C.J.; Laan, W.

Chem. - Eur. J. 2011, 17, 4680-4698, 10.1002/chem.201003646

Many bioinspired transition‐metal catalysts have been developed over the recent years. In this review the progress in the design and application of ligand systems based on peptides and DNA and the development of artificial metalloenzymes are reviewed with a particular emphasis on the combination of phosphane ligands with powerful molecular recognition and shape selectivity of biomolecules. The various approaches for the assembly of these catalytic systems will be highlighted, and the possibilities that the use of the building blocks of Nature provide for catalyst optimisation strategies are discussed.

Bian, H.-D.; Huang, F.-P.

Tetrahedron: Asymmetry 2017, 28, 1700-1707, 10.1016/j.tetasy.2017.10.021

Four coordination complexes ML derived from an achiral Schiff base ligand (H2L = 2,2′-[(1,2-ethanediyl)bis(nitrilopropylidyne)]bisphenol) have been synthesized and characterized. A method is described for the enantioselective oxidation of a series of aryl alkyl sulfides using the coordination complexes in the presence of serum albumins (SAs) in an aqueous medium at ambient temperature. The mixture of metal complexes with serum albumins is useful for inducing asymmetric catalysis. The complex, albumin source and substrate influence stereoselective sulfoxidation. At optimal pH with the appropriate oxidant, some of ML/SA systems are identified as very efficient catalysts, giving the corresponding sulfoxides in excellent chemical yield (up to 100%) and good enantioselectivity (up to 94% ee) in certain cases. UV–visible spectroscopic data provide evidence that stronger binding between the complex and serum albumin lead to higher enantioselectivity.

Kamer, P.C.J.; Laan, W.

Dalton Trans. 2010, 39, 8477, 10.1039/c0dt00239a

The preparation of hybrid transition metalloproteins by thiol-selective incorporation of organometallic rhodium- and ruthenium complexes is described. Phosphine ligands and two rhodium-diphosphine complexes bearing a carboxylic acid group were coupled to the cysteine of PYP R52G, yielding a metalloenzyme active in the rhodium catalyzed hydrogenation of dimethyl itaconate. The successful coupling was shown by 31P NMR spectroscopy and ESI mass spectroscopy. In addition wild-type PYP (PYP WT), PYP R52G and ALBP were successfully modified with a (η6-arene) ruthenium(II) phenanthroline complex via a maleimide linker.

Imanaka, T.

FEBS Lett. 1995, 375, 273-276, 10.1016/0014-5793(95)01224-3

In order to engineer a new type of catalytic antibody, we attempt to use a monoclonal antibody L chain as a host protein for a porphyrin. TCPP (meso‐tetrakis(4‐carboxyphenyl)porphyine) was chemically synthesized and Balb/c mice were immunized using TCPP as a hapten. Two hybridoma cells (03‐1, 13‐1), that produce monoclonal antibody against TCPP, were obtained. Genes for both H and L chains of monoclonal antibodies were cloned, sequenced and overexpressed using E. coli as a host. ELISA and fluorescence quenching method show that the independent antibody L chains from both Mab03‐1 and Mab13‐1 have specific interaction with TCPP. Furthermore, the recombinant antibody L chain from Mab13‐1 exhibits much higher peroxidase activity than TCPP Fe(III) alone. The enzyme activity was detectable with pyrogallol and ABTS (2,2‐azinobis‐3‐ethylbenzthiazolin‐6‐sulfonic acid) but not with catechol. This new catalytic antibody was extremely thermostable. Optimum temperature of the peroxidase reaction by the complex of 13‐1L chain and TCPP Fe(III) was 90°C, while that the TCPP Fe(III) alone was 60°C.