66 research outputs found
Four of a Kind: A Complete Collection of ADP-Ribosylated Histidine Isosteres Using Cu(I)- and Ru(II)-Catalyzed Click Chemistry
This is the final version. Available from American Chemical Society via the DOI in this record.âŻThe data underlying this study are available in the published article and its online Supporting Material. The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.joc.3c00827.Adenosine diphosphate ribosylation (ADP-ribosylation) is a crucial post-translational modification involved in important regulatory mechanisms of numerous cellular pathways including histone maintenance and DNA damage repair. To study this modification, well-defined ADP-ribosylated peptides, proteins, and close analogues thereof have been invaluable tools. Recently, proteomics studies have revealed histidine residues to be ADP-ribosylated. We describe here the synthesis of a complete set of triazole-isosteres of ADP-ribosylated histidine to serve as probes for ADP-ribosylating biomachinery. By exploiting Cu(I)- and Ru(II)-catalyzed click chemistry between a propargylglycine building block and an α- or ÎČ-configured azidoribose, we have successfully assembled the α- and ÎČ-configured 1,4- and 1,5-triazoles, mimicking N(Ï)- and N(Ï)-ADP-ribosylated histidine, respectively. The ribosylated building blocks could be incorporated into a peptide sequence using standard solid-phase peptide synthesis and transformed on resin into the ADP-ribosylated fragments to provide a total of four ADP-ribosyl triazole conjugates, which were evaluated for their chemical and enzymatic stability. The 1,5-triazole analogues mimicking the N(Ï)-substituted histidines proved susceptible to base-induced epimerization and the ADP-ribosyl α-1,5-triazole linkage could be cleaved by the (ADP-ribosyl)hydrolase ARH3.Biotechnology and Biological Sciences Research Council (BBSRC)Wellcome TrustWellcome TrustOvarian Cancer Research Allianc
PARP14 is a PARP with both ADP-ribosyl transferase and hydrolase activities
This is the final version. Available on open access from the American Association for the Advancement of Science via the DOI in this recordData availability:
The MS proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE (92) partner repository with the dataset identifier PXD043452.PARP14 is a mono-ADP-ribosyl transferase involved in the control of immunity, transcription, and DNA replication stress management. However, little is known about the ADP-ribosylation activity of PARP14, including its substrate specificity or how PARP14-dependent ADP-ribosylation is reversed. We show that PARP14 is a dual-function enzyme with both ADP-ribosyl transferase and hydrolase activity acting on both protein and nucleic acid substrates. In particular, we show that the PARP14 macrodomain 1 is an active ADP-ribosyl hydrolase. We also demonstrate hydrolytic activity for the first macrodomain of PARP9. We reveal that expression of a PARP14 mutant with the inactivated macrodomain 1 results in a marked increase in mono(ADP-ribosyl)ation of proteins in human cells, including PARP14 itself and antiviral PARP13, and displays specific cellular phenotypes. Moreover, we demonstrate that the closely related hydrolytically active macrodomain of SARS2 Nsp3, Mac1, efficiently reverses PARP14 ADP-ribosylation in vitro and in cells, supporting the evolution of viral macrodomains to counteract PARP14-mediated antiviral response.Biotechnology and Biological Sciences Research Council (BBSRC)Wellcome TrustOxford University Challenge Seed FundEdward Penley Abraham Research FundOvarian Cancer Research AllianceResearch Council of NorwaySwedish Research CouncilMedical Research Council (MRC)Novo Nordisk Foundation Center for Protein ResearchDanish Council of Independent ResearchDanish Cancer Societ
Updated measurements of exclusive J/Ï and Ï(2S) production cross-sections in pp collisions at âs = 7 TeV
The differential cross-section as a function of rapidity has been measured for the exclusive production of J/Ï and Ï(2S) mesons in protonâproton collisions at âs = 7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pbâ1. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects
Studies of beauty baryon decays to D0phâ and Î+châ final states
Decays of beauty baryons to the D0phâ and Î+châ final states (where h indicates a pion or a kaon) are studied using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0ââfbâ1, collected by the LHCb detector. The Cabibbo-suppressed decays Î0bâD0pKâ and Î0bâÎ+cKâ are observed, and their branching fractions are measured with respect to the decays Î0bâD0pÏâ and Î0bâÎ+cÏâ. In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Î0b to the D0pKâ final state, and a measurement of the Î0b mass is performed. Evidence of the Î0bâÎ+cKâ decay is also reported
Molecular tools for the study of ADP-ribosylation: a unified and versatile method to synthesise native mono-ADP-ribosylated peptides
ADP-ribosylation (ADPr), as a post-translational modification, plays a crucial role in DNA-repair, immunity and many other cellular and physiological processes. Serine is the main acceptor for ADPr in DNA damage response, whereas the physiological impact of less common ADPr-modifications of cysteine and threonine side chains is less clear. Generally, gaining molecular insights into ADPr recognition and turn-over is hampered by the availability of homogeneous, ADP-ribosylated material, such as mono-ADP-ribosylated (MARylated) peptides. Here, a new and efficient solid-phase strategy for the synthesis of Ser-, Thr- and Cys-MARylated peptides is described. ADP-ribosylated cysteine, apart from being a native post-translational modification in its own right, proved to be suitable as a stabile bioisostere for ADP-ribosylated serine making it a useful tool to further biochemical research on serine ADP-ribosylation. In addition, it was discovered that the Streptococcus pyogenes encoded protein, SpyMacroD, acts as a Cys-(ADP-ribosyl) hydrolase
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Modification of picornavirus genomic RNA using 'click' chemistry shows that unlinking of the VPg peptide is dispensable for translation and replication of the incoming viral RNA
Picornaviruses constitute a large group of viruses comprising medically and economically important pathogens such as poliovirus, coxsackievirus, rhinovirus, enterovirus 71 and foot-and-mouth disease virus. A unique characteristic of these viruses is the use of a viral peptide (VPg) as primer for viral RNA synthesis. As a consequence, all newly formed viral RNA molecules possess a covalently linked VPg peptide. It is known that VPg is enzymatically released from the incoming viral RNA by a host protein, called TDP2, but it is still unclear whether the release of VPg is necessary to initiate RNA translation. To study the possible requirement of VPg release for RNA translation, we developed a novel method to modify the genomic viral RNA with VPg linked via a 'non-cleavable' bond. We coupled an azide-modified VPg peptide to an RNA primer harboring a cyclooctyne [bicyclo[6.1.0]nonyne (BCN)] by a copper-free 'click' reaction, leading to a VPg-triazole-RNA construct that was 'non-cleavable' by TDP2. We successfully ligated the VPg-RNA complex to the viral genomic RNA, directed by base pairing. We show that the lack of VPg unlinkase does not influence RNA translation or replication. Thus, the release of the VPg from the incoming viral RNA is not a prerequisite for RNA translation or replication. © 2013 The Author(s). Published by Oxford University Press
Mechanistic insights into the three steps of poly(ADP-ribosylation) reversal
Poly(ADP-ribosyl)ation (PAR) is a versatile and complex posttranslational modification composed of repeating units of ADP-ribose arranged into linear or branched polymers. This scaffold is linked to the regulation of many of cellular processes including the DNA damage response, alteration of chromatin structure and Wnt signalling. Despite decades of research, the principles and mechanisms underlying all steps of PAR removal remain actively studied. In this work, we synthesise well-defined PAR branch point molecules and demonstrate that PARG, but not ARH3, can resolve this distinct PAR architecture. Structural analysis of ARH3 in complex with dimeric ADP-ribose as well as an ADP-ribosylated peptide reveal the molecular basis for the hydrolysis of linear and terminal ADP-ribose linkages. We find that ARH3-dependent hydrolysis requires both rearrangement of a catalytic glutamate and induction of an unusual, square-pyramidal magnesium coordination geometry
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