Molecular engineering articles within Nature Communications

PKU patients have elevated phenylalanine levels which can result in neurological impairment. Here the authors utilize biosensor-based ultra-high-throughput screening to optimize PAL activity in a synthetic biotic platform for improved in vivo performance.

Isoflavonoids are a class of industrially important plant natural products, but their low abundance and structural complexity limits their availability. Here, the authors engineer Saccharomyces cerevisiae metabolism to become a platform for efficient production of daidzein which is core chemical scaffold for isoflavonoid biosynthesis, and show its application for production of bioactive glucosides from glucose.

Heterologous expression of recombinant proteins often results in misfolding, aggregation and degradation. Here, we show an in vivo dual-biosensor system that simultaneously assesses protein translation and protein folding, thereby enabling rapid screening of expression strains as well as mutant libraries.

The directed evolution of antibodies yields important tools for research and therapy. Here the authors develop a periplasmic phage-assisted continuous evolution platform for improvement of protein-protein interactions in the disulfidecompatible E. coli periplasm.

Genome engineering is challenging compared to plasmid DNA manipulation. Here the authors create a simple methodology called SEGA that enables genome engineering by combining DNA and bacterial cells followed by identification of recombinant clones by a change in colour when grown on agar plates.

Genetic code expansion strategies are limited to specific codons that can be reassigned to new amino acids. Here the authors show that quadruplet-decoding tRNAs (qtRNAs) can be rapidly discovered and evolved to decode new quadruplet codons, enabling four independent decoding events in a single protein in living cells.

Proteins evolve through the modular rearrangement of domains. Here the authors introduce MISER, a minimization by iterative size-exclusion and recombination method to make all possible deletions of a protein, uncovering functions for Cas9 domains involved in DNA binding.

Ribosome kinetics are rate-limiting for protein synthesis. Here the authors evolve diverse 16S rRNAs for enhanced protein synthesis rates and genetic code expansion efficiencies in vivo.

Practical implementation of genetic circuits is difficult due to low predictability and time-intensive troubleshooting. Here the authors present Cyberloop, which interfaces a computer with single cells to enable cell-in-the-loop testing and optimization of circuit designs before they are built.

While prime editing is a promising technology, PE2 systems often have low efficiency. Here the authors fuse a Rad51 DNA-binding domain to create hyPE2 with improved editing efficiency.

Genetic sensors can be created by mix and matching DNA-binding modules with ligand-binding modules. Here the authors use a computational model to overcome module incompatibilities and restore function by rescuing key interactions.

Circularised nanodiscs (cNDs) are able to stabilise large lipid bilayer patches and are used for structural and functional studies. Current techniques to build cNDs have numerous steps and low yields; here the authors report a single step construction method using the SpyCatcher-SpyTag system.

CRISPR prime editing enables double-strand break free engineering of the genome. Here the authors present a toolkit for prime editing in E. coli.

Bacterial biosensors have promising applications in medical and environmental diagnostics. Here the authors use EMeRALD synthetic receptors to design bile salt sensors for use in liver transplant patient serum.

Existing Förster Resonance Energy Transfer (FRET) biosensors are often limited in their sensitivity. Here the authors report FRET-seq which they use to identify Fyn and ZAP70 kinase biosensors with enhanced performance, and use them to image T-cell activation and screen drugs.

Synthetic pathways represent a metabolic burden on host cells. Here the authors engineer Cra-binding sites to prevent misregulation in glycerol and carotenoid overproducing E. coli strains.

The use of synthetic organisms could provide opportunities for discovery and advanced manufacturing of medical drugs. Here the authors use a semi-synthetic organism with an expanded genetic code to generate site-specific chemical modifications in human IL-2.

Experimental analysis of gene drive population dynamics has mostly been limited to small cage trials. Here the authors, to fill the gap between lab based studies and field studies, use large indoor cages and see population suppression without the emergence of resistant alleles

A key feature of living cells is the cell cycle. In this Perspective, the authors explore attempts to recreate this process and what is still required for an integrated synthetic cell cycle.

An efficient chassis for heterologous expression of biosynthetic gene clusters (BGCs) from Gram-negative bacteria is still unavailable. Here, the authors report rational construction of genome-reduced Burkholderials chassis to facilitate production of a class of new compounds by expressing BGC from Chitinimonas koreensis.

Cas13b can be harnessed to target and degrade RNA transcripts inside a cellular environment. Here the authors reprogram Cas13b to target SARSCoV-2 transcripts in infected mammalian cells and reveal its resilience to variants thanks to single mismatch tolerance.

Expanded toolkits for prokaryotic synthetic biology can enhance the dynamic range of gene expression. Here the authors move the eukaryotic transcription factor QF into E. coli and integrate it into genetic devices.

Technologies that can halt the spread of gene drives would be highly useful in controlling or reverting their effect. Here the authors use the anti-CRISPR protein AcrIIA4 to inactivate drives in A. gambiae.

Pyrrolysine (Pyl) exists in nature as the 22^nd proteinogenic amino acid, but studies of Pyl have been hindered by the difficulty and inefficiency of both its chemical and biological syntheses. Here, the authors developed an improved PANCE approach to evolve the pylBCD pathway for increased production of Pyl proteins in E. coli.

Current near-IR optogenetic systems to regulate transcription consist of a number of large protein components. Here the authors report a smaller single-component near-IR system, iLight, developed from a bacterial phytochrome that they use to control gene transcription in bacterial and mammalian cells.

Here, the authors report de novo design, optimization and characterization of tRNAs that decode UGA stop codons in E. coli. The structure of the ribosome in a complex with the designed tRNA bound to a UGA stop codon suggests that distinct A-site ligands (tRNAs versus release factors) induce distinct conformation of the stop codon within the mRNA in the decoding center.

Optimizing the concentration of different functional peptides on a surface can be a complex process. Here, the authors report on the use of a click immobilization strategy to create gradients of two different functional peptides on a surface to screen different density functions for rapid optimization.

HER2 acts an oncogenic driver in numerous cancers. Here, the authors design an anti-HER2 biparatopic and tetravalent IgG fusion with inhibitory effects in a xenograft model.

Directed evolution commonly relies on point mutations but InDels frequently occur in evolution. Here the authors report a protein-engineering framework based on InDel mutagenesis and fragment transplantation resulting in greater catalysis and longer glow-type bioluminescence of the ancestral luciferase.

The molecular architecture of DNA data storage opens up interesting possibilities and functionalities. Here the authors leverage thermodynamics to control the access of different subsets of data in a file.

Self-assembling peptides (SAPs) can be used to build biomaterials, but genetically encoded SAPs have rarely been used as building blocks in cells. Here, the authors design a SAP that can be genetically fused to target proteins to induce their intracellular clustering and modulate their signaling functions.

There exist only a handful of methods to engineer reproductive barriers in eukaryotes. Here the authors use CRISPR to engineer multiple barriers in D. melanogaster and model their spread.

The cascade of innovations in biotechnology opens new pathways for biological warfare. The international laboratory network being developed under the UN Secretary-General’s Mechanism could provide vital evidence in case of an alleged biological attack.

Culex mosquitoes are a global vector for insect-borne diseases, though progress with genetic tools lags behind other mosquito species. Here the authors present a Cas9-based toolkit and methods that could support future gene drive development in these mosquitoes.

Engineered live bacteria could represent a new class of therapeutic treatment for human disease. Here, the authors use a human gut-on-a-chip microfluidics system to characterize an engineered live bacterial therapeutic, designed for the treatment of phenylketonuria, and to construct mathematical models that predict therapeutic strain function in non-human primates.

CRISPR-Cas9 is a gene editing tool that can be used to modulate gene expression. Here, the authors report the generation of a mouse model that express all components of the CRISPR-Cas9 guide directed Synergistic Activation Mediator (SAM), demonstrate that gene activation can be achieved with various delivery methods and include generation of a disease model of hypercholesterolemia

There are few robust circuit architectures for sequential gene perturbations. Here, the authors use a modular recombinase-based design that sequentially edits loci, synchronizes cells, and deletes itself.

CRISPR-based genetic elements can copy themselves across host genomes. Here the authors introduce CopyCatcher, a gene-drive related system for detecting and quantifying somatic gene conversion events.

Manipulating animal physiology can be difficult because of the complexity of multicellular systems. Here the authors use engineered bacteria to modulate Caenorhabditis elegans gene expression through genetic circuit controlled RNAi.

Transient transfections are routinely used in basic and synthetic biology studies to unravel pathway regulation and to probe and characterise circuit designs. As each experiment has a component of intrinsic variability, reporter gene expression is usually normalized with co-delivered genes that act as transfection controls. Recent reports in mammalian cells highlight how resource competition for gene expression leads to biases in data interpretation, with a direct impact on co-transfection experiments. Here we define the connection between resource competition and transient transfection experiments and discuss possible alternatives. Our aim is to raise awareness within the community and stimulate discussion to include such considerations in future experimental designs, for the development of better transfection controls.

Current aptamer discovery approaches are unable to probe the complete space of possible sequences. Here, the authors use machine learning to facilitate the development of DNA aptamers with improved binding affinities, and truncate them without significantly compromising binding affinity.

Base editors can induce transcriptome-wide RNA off-target editing independent of gRNA. Here, the authors engineer ABEmax variants with minimized RNA off-target activities.

Intrinsically disordered FG-Nups line the Nuclear Pore Complex (NPC) lumen and form a selective barrier where transport of most proteins is inhibited, whereas specific transporter proteins are able to pass. Here, the authors reconstitute the selective behaviour of the NPC by introducing a rationally designed artificial FG-Nup that demonstrates that no specific spacer sequence nor a spatial segregation of different FG-motif types are needed to create selective NPCs.

Eukaryotic genetic switches are more complex than prokaryotic ones, complicating their design. Here the authors present a workflow for parallel screening, selection and evolution of yeast genetic switches.

Here, the authors present DisCo (Disassembly of Condensates), a method that allows the fast, inducible, and specific disruption of tagged condensates in mammalian cells. DisCo uses chemical dimerizers to induce the recruitment of a ligand into condensates leading to condensate disassembly.

Synthetic biology circuits are finding application in a wide range of computational devices, such as contaminant detection. Here, the authors design 2D paper circuits in which the spatial orientation of the cellular components specifies function.

Existing in vivo mutagenesis tools are limited by low mutation diversity and mutation rates. Here the authors present TRIDENT for targeted, continual and inducible diversification of genes of interest using deaminases fused to T7 RNA polymerase.

RaPID (Random non-standard Peptides Integrated Discovery) enables discovery of small macrocyclic peptides binding desired targets. Here, the authors propose lasso-grafting: the RaPID-derived peptides are implanted onto diverse proteins and maintain both the binding properties of the cyclic peptide and the host protein function.

NHEJ alleles and Cas9 remnants after a gene drive introduction are scientific and public concerns. Here, the authors use split drives with recoded rescue elements to target essential genes and minimize the appearance of NHEJ alleles while also leaving no trace of Cas9.