Peroxisome compartmentalization of a toxic enzyme improves alkaloid production.

Eukaryotic cells compartmentalize metabolic pathways in organelles to achieve optimal reaction conditions and avoid crosstalk with cytosolic factors. We found that cytosolic expression of norcoclaurine synthase (NCS), the enzyme that catalyzes the first committed reaction in benzylisoquinoline alkaloid biosynthesis, is toxic in Saccharomyces cerevisiae and, consequently, restricts (S)-reticuline production. We developed a compartmentalization strategy that alleviates NCS toxicity while promoting increased (S)-reticuline titer.

Publisher Correction: Modular and tunable biological feedback control using a de novo protein switch.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

De novo design of bioactive protein switches.

Allosteric regulation of protein function is widespread in biology, but is challenging for de novo protein design as it requires the explicit design of multiple states with comparable free energies. Here we explore the possibility of designing switchable protein systems de novo, through the modulation of competing inter- and intramolecular interactions. We design a static, five-helix 'cage' with a single interface that can interact either intramolecularly with a terminal 'latch' helix or intermolecularly with a peptide 'key'.

Modular and tunable biological feedback control using a de novo protein switch.

De novo-designed proteins hold great promise as building blocks for synthetic circuits, and can complement the use of engineered variants of natural proteins. One such designer protein-degronLOCKR, which is based on 'latching orthogonal cage-key proteins' (LOCKR) technology-is a switch that degrades a protein of interest in vivo upon induction by a genetically encoded small peptide. Here we leverage the plug-and-play nature of degronLOCKR to implement feedback control of endogenous signalling pathways and synthetic gene circuits.