Living systems possess a rich biochemistry that can be harnessed through metabolic engineering to produce valuable therapeutics, fuels and fine chemicals. In spite of the tools created for this purpose, many organisms tend to be recalcitrant to modification or difficult to optimize. Crude cellular extracts, made by lysis of cells, possess much of the same biochemical capability, but in an easier to manipulate context. Metabolic engineering in crude extracts, or cell-free metabolic engineering, can harness these capabilities to feed heterologous pathways for metabolite production and serve as a platform for pathway optimization. However, the inherent biochemical potential of a crude extract remains ill-defined, and consequently, the use of such extracts can result in inefficient processes and unintended side products. Herein, we show that changes in cell growth conditions lead to changes in the enzymatic activity of crude cell extracts and result in different abilities to produce the central biochemical precursor pyruvate when fed glucose. Proteomic analyses coupled with metabolite measurements uncover the diverse biochemical capabilities of these different crude extract preparations and provide a framework for how analytical measurements can be used to inform and improve crude extract performance. Such informed developments can allow enrichment of crude extracts with pathways that promote or deplete particular metabolic processes and aid in the metabolic engineering of defined products.

A family of four new neodymium­(III) compounds containing either sulfite or a mixture of hydrogen-sulfate and sulfite ligands has been hydrothermally synthesized. The low solubility of lanthanide sulfite compounds has, in the past, made the isolation of single-crystalline products difficult. To obtain these phases, sodium sulfite (Na2SO3) and sodium bisulfite (NaHSO3) were employed as both anion sources and pH regulators. The in situ oxidation of sulfite to sulfate was controlled by dictating the pH of the starting solutions with these ligands. Sulfites were found to form at a neutral pH, whereas, when the pH was increased, the oxidation of sulfite to sulfate was observed in the crystalline products. The products discussed herein reveal the pH controlled process of in situ oxidation in these hydrothermal reactions.

The first lanthanide sulfite compound with a secondary ligand, Nd(SO 3 )(C 2 H 3 O 2 ), was hydrothermally synthesized and solved with single-crystal X-ray diffraction. In order to prevent the facile oxidation of the sulfite to sulfate, careful control of both pH and reaction temperature were required for successful synthesis of the title compound; even slight changes in conditions allow for the facile * Prof. Dr. E. M. Villa E-Mail: EricVilla@Creighton.edu [a]

No abstract

No abstract