We study the hyperactivation of α‐chymotrypsin (α‐ChT) using the acrylate polymer poly(2‐carboxyethyl) acrylate (PCEA) in comparison to the commonly used poly(acrylic acid) (PAA). The polymers are added during the enzymatic cleavage reaction of the substrate N‐glutaryl‐L‐phenylalanine p‐nitroanilide (GPNA). Enzyme activity assays reveal a pronounced enzyme hyperactivation capacity of PCEA, which reaches up to 950% activity enhancement, and is significantly superior to PAA (revealing an activity enhancement of approx. 450%). In a combined experimental and computational study, we investigate α‐ChT/polymer interactions to elucidate the hyperactivation mechanism of the enzyme. Isothermal titration calorimetry reveals a pronounced complexation between the polymer and the enzyme. Docking simulations reveal that binding of polymers significantly improves the binding affinity of GPNA to α‐ChT. Notably, a higher binding affinity is found for the α‐ChT/PCEA compared to the α‐ChT/PAA complex. Further molecular dynamics (MD) simulations reveal changes in the size of the active site in the enzyme/polymer complexes, with PCEA inducing a more pronounced alteration compared to PAA, facilitating an easier access for the substrate to the active site of α‐ChT.

Rational re-design of the substrate pocket of phenylpropanoid-flavonoid O-methyltransferase (PFOMT) from Mesembryanthe-mum crystallinum, an enzyme that selectively methylates the 3’-position (= meta-position) in catechol-moieties of flavonoids to guiacol-moieties, provided the basis for the generation of variants with opposite, i. e. 4’- (para-) regioselectivity and enhanced catalytic efficiency. A double variant (Y51R/N202W) identified through a newly developed colorimetric assay efficiently modified the para-position in flavanone and flavano-nol substrates, providing access to the sweetener molecule hesperetin and other rare plant flavonoids having an isovanil-loid motif.

Catalyst discovery and development requires the screening of large reaction sets necessitating analytic methods with the potential for high‐throughput screening. These techniques often suffer from substrate dependency or the requirement of expert knowledge. Chromatographic techniques (GC/LC) can overcome these limitations but are generally hampered by long analysis time or the need for special equipment. The herein developed multiple injections in a single experimental run (MISER) GC‐MS technique allows a substrate independent 96‐well microtiter plate analysis within 60 min. This method can be applied to any laboratory equipped with a standard GC‐MS. With this concept novel, unspecific peroxygenase (UPO) chimeras, could be identified, consisting of subdomains from three different fungal UPO genes. The GC‐technique was additionally applied to evaluate an YfeX library in an E. coli whole‐cell system for the carbene‐transfer reaction on indole, which revealed the thus far unknown axial heme ligand tryptophan.

Bioinspired, synthetic porphyrin complexes are important catalysts in organic synthesis and play a pivotal role in efficient carbene transfer reactions. The advances in this research area stimulated recent, “chemo‐inspired” developments in biocatalysis. Today, both synthetic iron complexes and enzymes play an important role to conduct carbene transfer reactions. The advances and potential developments in both research areas are discussed in this concept article.

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The molecular actions of mitogen-activated protein kinases (MAPKs) are ultimately accomplished by the substrate proteins where phosphorylation affects their molecular properties and function(s), but knowledge regarding plant MAPK substrates is currently still fragmentary. Here, we uncovered a previously uncharacterized protein family consisting of three proline/serine-rich proteins (PRPs) that are substrates of stress-related MAPKs. We demonstrated the importance of a MAPK docking domain necessary for protein–protein interaction with MAPKs and consequently also for phosphorylation. The main phosphorylated site was mapped to a residue conserved between all three proteins, which when mutated to a non-phosphorylatable form, differentially affected their protein stability. Together with their distinct gene expression patterns, this differential accumulation of the three proteins upon phosphorylation probably contributes to their distinct function(s). Transgenic over-expression of PRP, the founding member, led to plants with enhanced resistance to Pseudomonas syringae pv. tomato DC3000. Older plants of the over-expressing lines have curly leaves and were generally smaller in stature. This growth phenotype was lost in plants expressing the phosphosite variant, suggesting a phosphorylation-dependent effect. Thus, this novel family of PRPs may be involved in MAPK regulation of plant development and / or pathogen resistance responses. As datamining associates PRP expression profiles with hypoxia or oxidative stress and PRP-overexpressing plants have elevated levels of reactive oxygen species, PRP may connect MAPK and oxidative stress signaling.

Three different reductases have been fused to CYP153 monooxygenase from Marinobacter aquaeolei. The most promising candidate has been analysed in terms of its linker part, which connects the reductase with the haem domain through sequence alignment of the corresponding reductase family CYP116B. To improve the artificial fusion construct, the linker length has been varied, thereby only altering the non‐conserved middle part of the linker. This way seven artificial fusion constructs have been engineered, which varied in linker length between 11 and 32 amino acids (“natural” is 16). These variations showed a substantial impact on the fusion construct. The best mutant, extended by two amino acids, showed an improved activity (67 %), higher stability (67 % more active haem domain after 2 h) and a coupling efficiency of 94 % (55 % higher than before). Presented in this paper is an approach to find and optimise artificial fusion constructs for P450 monooxygenases.

The structure of a P450 ω‐hydroxylase bound to its fatty acid product was determined, which revealed a narrow substrate tunnel that leads to the heme. The introduction of an arginine side chain in proximity to the carboxyl group of the fatty acid led to a reduced KM value for dodecanoic acid, which suggests the importance of an anchoring point in the active site. An increase in the flexibility of the substrate recognition region was also engineered, which resulted in a threefold improved product formation.

The reduction of activated C=C double bonds is an important reaction in synthetic chemistry owing to the potential formation of up to two new stereogenic centers. Artificial nicotinamide cofactors were recently presented as alternative suppliers of hydride equivalents needed for alkene reduction. To study the effect of cofactors on the reduction of activated alkenes, a set of N‐substituted synthetic nicotinamide cofactors with differing oxidation potentials were synthesized and their electrochemical and kinetic behavior was studied. The effects of the synthetic cofactors on enzyme activity of four ene reductases are outlined in this study, where the cofactor mimic with an N‐substituted 4‐hydroxy‐phenyl residue led to a sixfold higher vmax relative to the natural cofactor NADH.

The Wittig‐type carbonyl olefination reaction has no biocatalytic equivalent. To build complex molecular scaffolds, however, C−C bond‐forming reactions are pivotal for biobased economy and synthetic biology. The heme‐containing E. coli protein YfeX was found to catalyze carbonyl olefination by reaction of benzaldehyde with ethyl diazoacetate under aerobic conditions in the absence of a triphenylphosphine oxophile. The reaction was performed in whole cells and showed a product formation of 440 mg L−1 in 1 h. It was, moreover, shown that the reaction could be performed under Wittig‐analogue conditions in the presence of triphenylphosphine or triphenylarsine.