Designing a Light-Induced Glycosylation Reaction for Poststage Synthesis of ADP-2″-Deoxyribosyl Derivatives.

Modifications on the hydroxyl groups of ADP-ribosyl units can provide valuable tools for investigating ADP-ribosylation-related molecular interactions, but the chemical syntheses of these compounds are usually difficult due to their inherent complex structures. In this study, we report a poststage synthetic protocol for accessing novel ADP-2″-deoxyribosyl derivatives through designing a light-induced biomimetic reaction, and SPR assays revealed effective binding of ADP-2″-deoxyribosyl peptides to MacroH2A1.1 with a high affinity (KD = 3.75 × 10-6 M).

Photoswitchable CAR-T Cell Function In Vitro and In Vivo via a Cleavable Mediator.

Chimeric antigen receptor (CAR)-T-based therapeutics are a breakthrough in cancer treatment; however, they are hampered by constitutive activation, which leads to worrisome side effects. Engineering CAR-T cells to be as tightly controllable as possible remains a topic of ongoing investigation. Here, we report a photoswitchable approach that uses a mediator for the at-will regulation of CAR-T cells. This mediator carries dual folate and fluorescein isothiocyanate moieties tethered by an ortho-nitrobenzyl ester photocleavable linker. CAR-T cells were shown to be highly cytotoxic to targeted cells only in the presence of the mediator and acted in a dose-dependent manner. The toxicity of CAR-T cells can be rapidly terminated by cleavage of the mediator, and the effects of CAR-T cells can be activated again by resupplementation with the mediator without compromising tumor therapy. The approach described here provides a direction for enhancing the controllability of CAR-T cells and can likely be applied in other immunotherapies.

An efficient and easily-accessible ligand for Cu(I)-catalyzed azide-alkyne cycloaddition bioconjugation.

A novel ligand (6) for copper-catalyzed azide-alkyne cycloaddition (CuAAC) in bioconjugation has been developed. Both in vitro and in vivo experiments indicate that 6 is more efficient and less cytotoxic than the canonical CuAAC ligands. Besides, 6 is easily accessible and can be prepared at gram scale. Our study reveals that 6 might be an ideal CuAAC ligand for bioconjugations.

Optimization of Replication, Transcription, and Translation in a Semi-Synthetic Organism.

Previously, we reported the creation of a semi-synthetic organism (SSO) that stores and retrieves increased information by virtue of stably maintaining an unnatural base pair (UBP) in its DNA, transcribing the corresponding unnatural nucleotides into the codons and anticodons of mRNAs and tRNAs, and then using them to produce proteins containing noncanonical amino acids (ncAAs). Here we report a systematic extension of the effort to optimize the SSO by exploring a variety of deoxy- and ribonucleotide analogues. Importantly, this includes the first in vivo structure-activity relationship (SAR) analysis of unnatural ribonucleoside triphosphates. Similarities and differences between how DNA and RNA polymerases recognize the unnatural nucleotides were observed, and remarkably, we found that a wide variety of unnatural ribonucleotides can be efficiently transcribed into RNA and then productively and selectively paired at the ribosome to mediate the synthesis of proteins with ncAAs. The results extend previous studies, demonstrating that nucleotides bearing no significant structural or functional homology to the natural nucleotides can be efficiently and selectively paired during replication, to include each step of the entire process of information storage and retrieval. From a practical perspective, the results identify the most optimal UBP for replication and transcription, as well as the most optimal unnatural ribonucleoside triphosphates for transcription and translation. The optimized SSO is now, for the first time, able to efficiently produce proteins containing multiple, proximal ncAAs.