Peptide Coacervates Can Protect Sequestered Oligonucleotides from Nucleases and Release Them for Transcription and Translation.

We demonstrate that coacervates, membraneless organelles formed by liquid-liquid phase separation, sequester and protect short DNA reporters and a functional luciferase gene from enzymatic degradation by various nucleases. Associative coacervates, formed by electrostatic interactions between polyhistidine peptides and ATP, inhibit degradation very efficiently. This protection arises from strong electrostatic interactions between the peptides and oligonucleotides, limiting the enzyme access to recognition and active sites. In contrast, simple coacervates based on a sticker-and-spacer model peptide exhibited limited protection. Oligonucleotide release from associative coacervates can be triggered by external stimuli such as ionic strength or temperature increases, enabling controlled release. Using a cell-free transcription-translation system, we demonstrated that in the presence of nucleases, the associative coacervate samples protected and maintained luciferase production. The ability to protect and controllably release functional genetic material makes coacervates promising candidates for further development as biocompatible delivery vehicles and components of cell-free synthetic biology platforms.