Generating Site Saturation Mutagenesis Libraries and Transferring Them to Broad Host-Range Plasmids Using Golden Gate Cloning.

Protein engineering is an established method for tailoring enzymatic reactivity. A commonly used method is directed evolution, where the mutagenesis and natural selection process is mimicked and accelerated in the laboratory. Here, we describe a reliable method for generating saturation mutagenesis libraries by Golden Gate cloning in a broad host range plasmid containing the pBBR1 replicon.

The iron nitrogenase reduces carbon dioxide to formate and methane under physiological conditions: A route to feedstock chemicals.

Nitrogenases are the only known enzymes that reduce molecular nitrogen (N) to ammonia. Recent findings have demonstrated that nitrogenases also reduce the greenhouse gas carbon dioxide (CO), suggesting CO to be a competitor of N. However, the impact of omnipresent CO on N fixation has not been investigated to date.

Modular Low-Copy-Number Plasmid Vectors for Rhodobacterales with Extended Host Range in Alphaproteobacteria.

Members of the alphaproteobacterial order Rhodobacterales are metabolically diverse and highly abundant in the ocean. They are becoming increasingly interesting for marine biotechnology, due to their ecological adaptability, wealth of versatile low-copy-number plasmids, and their ability to produce secondary metabolites. However, molecular tools for engineering strains of this bacterial lineage are limited.

Structural insights into the iron nitrogenase complex.

Nitrogenases are best known for catalyzing the reduction of dinitrogen to ammonia at a complex metallic cofactor. Recently, nitrogenases were shown to reduce carbon dioxide (CO) and carbon monoxide to hydrocarbons, offering a pathway to recycle carbon waste into hydrocarbon products. Among the three nitrogenase isozymes, the iron nitrogenase has the highest wild-type activity for the reduction of CO, but the molecular architecture facilitating these activities has remained unknown.

The Conversion of Carbon Monoxide and Carbon Dioxide by Nitrogenases.

Nitrogenases are the only known family of enzymes that catalyze the reduction of molecular nitrogen (N ) to ammonia (NH ). The N reduction drives biological nitrogen fixation and the global nitrogen cycle. Besides the conversion of N , nitrogenases catalyze a whole range of other reductions, including the reduction of the small gaseous substrates carbon monoxide (CO) and carbon dioxide (CO ) to hydrocarbons.

Boron-Doped Polycyclic π-Electron Systems with an Antiaromatic Borole Substructure That Forms Photoresponsive B-P Lewis Adducts.

Heteroatom doping is a powerful strategy to alter the electronic structure of polycyclic aromatic hydrocarbons (PAHs). Especially boron doping endows PAH scaffolds with electron-accepting character and Lewis acidic centers. Herein, we report that embedding a five-membered borole ring into a polycyclic skeleton imparts the π-system with antiaromatic character and thereby induces unique properties and behavior.