Applications of genetic code expansion technology in eukaryotes

Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to proteins.In eukaryotes,genetic code expansion(GCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic systems.GCE is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch regulation.Therefore,there is keen interest in utilizing GCE in eukaryotic systems.This review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.

Pharmacological inhibition of BAP1 recruits HERC2 to competitively dissociate BRCA1-BARD1, suppresses DNA repair and sensitizes CRC to radiotherapy

Radiotherapy is widely used in the management of advanced colorectal cancer(CRC).However,the clinical efficacy is limited by the safe irradiated dose.Sensitizing tumor cells to radiotherapy via interrupting DNA repair is a promising approach to conquering the limitation.The BRCA1-BARD1 complex has been demonstrated to play a critical role in homologous recombination(HR)DSB repair,and its functions may be affected by HERC2 or BAP1.Accumulated evidence illustrates that the ubiquitination-deubiquitination balance is involved in these processes;however,the precise mechanism for the cross-talk among these proteins in HR repair following radiation hasn’t been defined.Through activity-based profiling,we identified PT33 as an active entity for HR repair suppression.Subsequently,we revealed that BAP1 serves as a novel molecular target of PT33 via a CRISPR-based deubiquitinase screen.Mechanistically,pharmacological covalent inhibition of BAP1 with PT33 recruits HERC2 to compete with BARD1 for BRCA1 interaction,interrupting HR repair.Consequently,PT33 treatment can substantially enhance the sensitivity of CRC cells to radiotherapy in vitro and in vivo.Overall,these findings provide a mechanistic basis for PT33-induced HR suppression and may guide an effective strategy to improve therapeutic gain.

Catalytic enantioselective domino alkenylation-alkynylation of alkenes: stereoselective synthesis of 5–7 membered azacycles and carbocycles

Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as pronucleophiles.The new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and tetrahydroazepines.Moreover,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.

Oxidative lactonization of C(sp^(3))–H bond in methyl aromatic alcohols enabled by proton-coupled electron transfer

Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for the oxidative lactonization of benzylic C(sp^(3))–H bonds enabled by the synergistic interactions of organic dye-type rose bengal,n-Bu_(4)N∙Br,O_(2) and Na_(2)HPO_(4) under visible light irradiation.This reaction does not require transition metal catalysts or strong oxidants.A range of structurally diverse phthalides has been synthesized with excellent selectivity and high functional group compatibility.The late-stage application of this reaction to the preparation of structurally complex phthalides demonstrates its synthetic utility.