Tuning the Dynamics of Viral-Factories-Inspired Compartments Formed by Peptide-RNA Liquid-Liquid Phase Separation.

Viral factories are intracellular microcompartments formed by mammalian viruses in their host cells, and contain necessary machinery for viral genome replication, capsid assembly, and maturation, thus serving as "factories" for formation of new viral particles. Recent evidence suggests that these compartments are formed by liquid-liquid phase separation (LLPS) of viral proteins and nucleic acids and present dynamic properties. In this work, inspired by the remarkable functionalities of viral factories, dynamic compartments that are formed by complexation between a minimalistic, disordered peptide and RNA are designed. By systematic studies using sequence variants it is shown that the material properties of the compartments can be modulated by changes to the peptide sequence, at the single amino acid level. Moreover, by taking this approach to the next step, liquid compartments with light-induced tunable dynamics are developed. The results demonstrate that the material properties of liquid droplets can be temporally regulated by increasing peptide polarity and charge, and that these changes can be further utilized for controlled partitioning and release of payloads from the compartments.

Selective Stepwise Arylation of Unprotected Peptides by PtIV Complexes.

LPtIV F(Aryl) complexes bearing a bulky bidentate 2-[bis(adamant-1-yl)phosphino]phenoxide ligand (L) demonstrate excellent reactivity and selectivity in the arylation of X-H (X=S, N) bonds of amino acid residues in unprotected peptides under mild, including aqueous, conditions. Stepwise addition of these complexes allowed a convenient one-pot introduction of different aromatic groups in the X-H bonds of Cys and N terminus. PtIV reagents can also be used to further arylate N-H bonds in Lys and Trp providing access to peptides bearing multiple aromatic groups.

Self-Assembled Peptide Nano-Superstructure towards Enzyme Mimicking Hydrolysis.

The structural arrangement of amino acid residues in native enzymes underlies their remarkable catalytic properties, thus providing a notable point of reference for designing potent yet simple biomimetic catalysts. Herein, we describe a minimalistic approach to construct a dipeptide-based nano-superstructure with enzyme-like activity. The self-assembled biocatalyst comprises one peptide as a single building block, readily synthesized from histidine. Through coordination with zinc ion, the peptide self-assembly procedure allows the formation of supramolecular ß-sheet ordered nanocrystals, which can be used as basic units to further construct higher-order superstructure. As a result, remarkable hydrolysis activity and enduring stability are demonstrated. Our work exemplifies the use of a bioinspired supramolecular assembly approach to develop next-generation biocatalysts for biotechnological applications.