A series of synthetic nicotinamide cofactors were synthesized to replace natural nicotinamide cofactors and promote enoate reductase (ER)-catalyzed reactions without compromising activity or stereoselectivity of the bioreduction process. Conversions and enantioselectivities of up to >99% were obtained for C=C bioreductions and the process was successfully upscaled. Furthermore, high chemoselectivity was observed when employing these nicotinamide cofactor mimics (mNADs) with crude extracts in ER-catalyzed reactions.The asymmetric reduction of conjugated C=C double bonds using enoate reductases (ERs, EC 1.3.1.31) is receiving great interest in preparative organic chemistry.1 § Both authors contributed equally.

To date, water has been poorly studied as the sacrificial electron donor for biocatalytic redox reactions using isolated enzymes. Here we demonstrate that water can also be turned into a sacrificial electron donor to promote biocatalytic redox reactions. The thermodynamic driving force required for water oxidation is obtained from UV and visible light by means of simple titanium dioxide-based photocatalysts. The electrons liberated in this process are delivered to an oxidoreductase by simple flavin redox mediators. Overall, the feasibility of photobiocatalytic, water-driven bioredox reactions is demonstrated.

Viral infection is an intricate process that requires the concerted action of both viral and host cell components. Entry of viruses into cells is initiated by interactions between viral proteins and their cell surface receptors. Despite recent progress, the molecular mechanisms underlying the multistep reovirus entry process are poorly understood. Using atomic force microscopy, we investigated how the reovirus σ1 attachment protein binds to both α-linked sialic acid (α-SA) and JAM-A cell-surface receptors. We discovered that initial σ1 binding to α-SA favors a strong multivalent anchorage to JAM-A. The enhanced JAM-A binding by virions following α-SA engagement is comparable to JAM-A binding by infectious subvirion particles (ISVPs) in the absence of α-SA. Since ISVPs have an extended σ1 conformer, this finding suggests that α-SA binding triggers a conformational change in σ1. These results provide new insights into the function of viral attachment proteins in the initiation of infection and open new avenues for the use of reoviruses as oncolytic agents.

A photocatalytic regeneration approach for the oxidized nicotinamide cofactors NAD(P)+ is presented. By simple irradiation with visible light, the rate of flavin‐mediated NAD(P)H oxidation is accelerated by two orders of magnitude. Catalytic use of the flavin is straightforward under aerobic conditions. Combined with alcohol dehydrogenases, photoenzymatic oxidation schemes are obtained allowing for selective, O2‐driven oxidation of primary and secondary alcohols. The simplicity and practical applicability of this oxidation approach is demonstrated in the oxidative lactonization of 1,4‐ and 1,5‐diols. Under nonoptimized conditions, total turnover numbers of 170 and 340 are achieved for the nicotinamide cofactor and the flavin catalyst, respectively.

No abstract

No abstract

A bi-enzymatic cascade for the redox-isomerisation of allylic alcohol is presented. Coupling of an alcohol dehydrogenase to an enoate reductase has been successfully applied in one pot for the isomerisation of an allylic alcohol to the corresponding ketone. Critical parameters for yield and selectivity have been investigated.

No abstract