ACS Synthetic Biology最新文献

Artepillin C is a diprenylated phenylpropanoid with various pharmacological benefits for human health. Its natural occurrence is limited to a few Asteraceae plants, such as Baccharis species, necessitating a stable supply through synthetic biology. In Saccharomyces cerevisiae, the utilization of aromatic substrates within the cell was limited, resulting in very low production of artepillin C. In this study, we used AcPT1, a p-coumaric acid (p-CA)-specific diprenyltransferase, in Komagataella phaffii to produce artepillin C. Detailed studies revealed that the critical bottleneck in K. phaffii was the supply of prenyl diphosphates, not phenylpropanoid flux. By enhancing the prenyl substrate pathway through overexpression of isopentenyl diphosphate isomerase and a truncated HMG-CoA reductase, we achieved a strong increase in artepillin C production. A major part of artepillin C was accumulated in yeast cells. One of the advantages of K. phaffii is its superior growth and ability to achieve high cell density cultivation compared to that of S. cerevisiae. Therefore, fed-batch cultivation with glycerol was performed. As a result, the dry cell weight (DCW) reached 61.0 g/L, and the intracellular amount of de novo produced artepillin C reached 187.3 μg/DCW. Analysis of intermediates revealed that the supply of p-CA constituted a bottleneck in artepillin C production in the engineered strain. By enhancing the p-CA supply, the intracellular accumulation of artepillin C reached 1200 μg/DCW even in batch cultivation. Moreover, the total intra- and extracellular amounts of artepillin C reached 12.5 mg/L, marking the highest de novo synthesis amount of artepillin C reported thus far, even under batch cultivation conditions.

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Blue light illumination can be detected by light-oxygen-voltage (LOV) photosensing proteins and translated into a range of biochemical responses, facilitating the generation of novel optogenetic tools to control cellular function. Here, we develop new variants of our previously described VP-EL222 light-dependent transcription factor and apply them to study the phosphate-responsive signaling (PHO) pathway in the budding yeast Saccharomyces cerevisiae, exemplifying the utilities of these new tools. Focusing first on the VP-EL222 protein itself, we quantified the tunability of gene expression as a function of light intensity and duration and demonstrated that this system can tolerate the addition of substantially larger effector domains without impacting function. We further demonstrated the utility of several EL222-driven transcriptional controllers in both plasmid and genomic settings, using the PHO5 and PHO84 promoters in their native chromosomal contexts as examples. These studies highlight the utility of light-controlled gene activation using EL222 tethered to either artificial transcription domains or yeast activator proteins (Pho4). Similarly, we demonstrate the ability to optogenetically repress gene expression with EL222 fused to the yeast Ume6 protein. We finally investigated the effects of moving EL222 recruitment sites to different locations within the PHO5 and PHO84 promoters, as well as determining how this artificial light-controlled regulation could be integrated with the native controls dependent on inorganic phosphate (P_i) availability. Taken together, our work expands the applicability of these versatile optogenetic tools in the types of functionalities that they can deliver and the biological questions that can be probed.

Minimally invasive neural interfaces can be used to diagnose, manage and treat many disorders, with reduced risks of surgical complications. However, endovascular probes lack access to key cortical, subcortical and spinal targets, and are not typically explantable after endothelialization. Here we report the development and testing, in sheep, of endocisternal neural interfaces that approach brain and spinal cord targets through inner and outer spaces filled with cerebrospinal fluid. Thus, the interfaces gain access to the entire brain convexity, to deep brain structures within the ventricles and to the spinal cord from the spinal subarachnoid space. We combined an endocisternal neural interface with wireless miniature magnetoelectrically powered bioelectronics so that it can be freely navigated percutaneously from the spinal space to the cranial subarachnoid space, and from the cranial subarachnoid space to the ventricles. In sheep, we show recording and stimulation functions, as well as repositioning of the flexible electrodes and explantation of the interface after chronic implantation. Minimally invasive endocisternal bioelectronics may enable chronic and transient therapies, particularly for stroke rehabilitation and epilepsy monitoring.

In metabolic engineering, increasing chemical production usually involves manipulating the expression levels of key enzymes. However, limited synthetic tools exist for modulating enzyme activity beyond the transcription level. Inspired by natural post-translational mechanisms, we present targeted enzyme degradation mediated by optically controlled nanobodies. We applied this method to a branched biosynthetic pathway, deoxyviolacein, and observed enhanced product specificity and yield. We then extend the biosynthesis pathway to violacein and show how simultaneous degradation of two target enzymes can further shift production profiles. Through the redirection of metabolic flux, we demonstrate how targeted enzyme degradation can be used to minimize unwanted intermediates and boost the formation of desired products.

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Background and aims

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Conclusion

Impact and implications

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