Biology subjects

Trettel, D.

Publications and source records attributed to Trettel, D..

3 recordsLinked to original sources

bioRxiv2025

Engineering Spatial Control of Bacterial Organelles

Bacteria were once thought to lack organelles, but it is now clear they confine cellular reactions using an array of membrane- and protein-based compartments. A central question, however, is how bacterial organelles are organized in the cell, and whether their spatial control can be engineered. Here, we show that a two-protein system (McdAB) that positions carboxysomes - CO2-fixing organelles found in autotrophic bacteria - can be repurposed to provide programmable spatial control to diverse organelles in Escherichia coli. McdAB not only restores proper assembly and positioning of heterologously produced carboxysomes in E. coli, but can also be reprogrammed to spatially organize all other known types of bacterial organelles, including encapsulins, biomolecular condensates, and even membrane-bound organelles. Programmable spatial organization of bacterial organelles establishes a new design principle for synthetic biology, where the location of reactions is as tunable as their content. Our work paves the way for more efficient biocatalysis in engineered microbes.

microbiology↗

bioRxiv2024

A blueprint for biomolecular condensation driven by bacterial microcompartment encapsulation peptides

Bacterial microcompartments (BMC) are protein organelles with diverse metabolic capabilities. Their functional diversity is determined by an enzymatic core that is sequestered within a structurally conserved protein shell architecture. Segregation of protein cargo into the BMC is enabled by encapsulation peptides (EPs), which are short helical domains fused to core proteins through a disordered linker. Here, we investigate how EPs drive multicomponent cargo assembly into biomolecular condensates. In vitro experiments supported by molecular dynamics simulations demonstrate the importance of both conserved hydrophobic packing and electrostatic interactions in stabilizing trimeric EP bundles. Topological rearrangements of EP domains can drive programmable liquid-or gel-like partitioning in vitro and in vivo. This partitioning is found to be EP-specific, modular and can co-assemble at least three fluorescent reporters. In summary, we describe the molecular features necessary to drive biomolecular condensation using a widespread peptide tag. This work can serve as a blueprint for implementing EP biotechnology across diverse applications.

molecular biology↗

bioRxiv2024

A robust synthetic biology toolkit to advance carboxysome study and design

Carboxysomes are polyhedral protein organelles that microorganisms use to facilitate carbon dioxide assimilation. They are composed of a modular protein shell which envelops an enzymatic core mainly comprised of physically coupled Rubisco and carbonic anhydrase. While the modular construction principles of carboxysomes make them attractive targets as customizable metabolic platforms, their size and complexity can be a hinderance. In this work, we design and validate a plasmid set - the pXpressome toolkit -in which -carboxysomes are robustly expressed and remain intact and functional after purification. We tested this toolkit by introducing mutations which influence carboxysome structure and performance. We find that deletion of vertex-capping genes results in formation of larger carboxysomes while deletion of facet forming genes produces smaller particles, suggesting that adjusting the ratio of these proteins can rationally affect morphology. Through a series of fluorescently labeled constructs, we observe this toolkit leads to more uniform expression and better cell health than previously published carboxysome expression systems. Overall, the pXpressome toolkit facilitates the study and redesign of carboxysomes with robust performance and improved phenotype uniformity. The pXpressome toolkit will support efforts to remodel carboxysomes for enhanced carbon fixation or serve as a platform for other nanoencapsulation goals.

synthetic biology↗