Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Weissenborn, M. J.; Löw, S. A.; Borlinghaus, N.; Kuhn, M.; Kummer, S.; Rami, F.; Plietker, B.; Hauer, B.;Enzyme-Catalyzed Carbonyl Olefination by the E. coli Protein YfeX in the Absence of PhosphinesChemCatChem81636-1640(2016)DOI: 10.1002/cctc.201600227
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.
Publikation
Löw, S. A.; Löw, I. M.; Weissenborn, M. J.; Hauer, B.;Enhanced Ene-Reductase Activity through Alteration of Artificial Nicotinamide Cofactor SubstituentsChemCatChem8911-915(2016)DOI: 10.1002/cctc.201501230
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.
Publikation
Hoffmann, S. M.; Weissenborn, M. J.; Gricman, ?.; Notonier, S.; Pleiss, J.; Hauer, B.;The Impact of Linker Length on P450 Fusion Constructs: Activity, Stability and CouplingChemCatChem81591-1597(2016)DOI: 10.1002/cctc.201501397
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.
Publikation
Hoffmann, S. M.; Danesh-Azari, H.-R.; Spandolf, C.; Weissenborn, M. J.; Grogan, G.; Hauer, B.;Structure-Guided Redesign of CYP153AM.aq for the Improved Terminal Hydroxylation of Fatty AcidsChemCatChem83234-3239(2016)DOI: 10.1002/cctc.201600680
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.