{"database":"panorama","file_versions":[],"scores":null,"additional":{"omics_type":["Proteomics"],"submitter":["Leandro Neves"],"species":["Murine Norovirus","Mus Musculus"],"full_dataset_link":["https://panoramaweb.org/LN_VPg_nucleotidylation_2026.url"],"submitter_email":["leandroxneves@gmail.com"],"submitter_affiliation":["Centre for Proteome Research, Dept. Biochemistry & Systems Biology, University of Liverpool, Liverpool, UK"],"sample_protocol":[""],"repository":["PanoramaPublic"],"data_protocol":[""],"pubmed_abstract":["Norovirus is a leading cause of global acute gastroenteritis, yet the mechanisms underlying its replication remain incompletely understood. As a positive-sense single-stranded RNA (+ ssRNA) virus, norovirus utilizes a nucleotidylated viral protein (VPg) as a primer for synthesis of its genomic and subgenomic mRNAs. In this study, we report the efficient solid-phase synthesis of a guanylylated (also known as GMPylated) VPg-derived peptide fragment using a novel pre-guanylylated tyrosine building block equipped with acid-sensitive protecting groups. This approach enables a streamlined, one-step deprotection and cleavage process. The resulting synthetic peptide was characterised <i>via</i> LC-MS/MS, establishing its gas-phase fragmentation behaviour and confirming prior observations of a diagnostic guanine nucleobase peak at 152.0572 <i>m</i>/<i>z</i>. We subsequently applied these findings to develop a parallel reaction monitoring (PRM) assay to investigate endogenous VPg guanylylation in murine microglial cells infected with murine norovirus (MNV). Our results demonstrate that while unmodified VPg is detectable from 4 hours post-infection, the guanylylated form appears predominantly during later stages (8-12 hpi). The timing of VPg guanylylation is consistent with a model where guanylylation may serve as a regulator in the switch between anti-sense and sense RNA synthesis, though at this time this hypothesis is speculative and remains to be proven. These synthetic molecular tools and mass spectrometry assays provide a robust framework for further exploring the role of nucleotidylation in viral pathogenesis and in broader cell and pathogen biology."],"pubmed_title":["Synthesis of a guanylylated peptide derived from norovirus VPg as a molecular tool for studying norovirus replication."],"pubmed_authors":["van Puffelen Bob B, Neves Leandro Xavier LX, Steneker Roy R, Meeuwenoord Nico J NJ, Emmott Edward E, Filippov Dmitri V DV"],"additional_accession":[]},"is_claimable":false,"name":"Synthesis of guanylylated peptides derived from norovirus VPg as molecular tools for studying norovirus replication C4PR_LIV","description":"Norovirus, a member of the Caliciviridae family, is a positive-sense single-stranded RNA (+ssRNA) virus and a leading cause of acute gastroenteritis worldwide, especially affecting young children and the elderly.​​ Due to a lack of specific treatment, norovirus infection causes 200,000 deaths each year and imposes an economic burden exceeding $60 billion.​ To address this challenge and develop medicines and diagnostics, further research into norovirus reproduction is needed. Norovirus uses a nucleotidylated protein, known as VPg (viral protein genome-linked), to initiate genome replication, by acting as a replication primer. The genomic RNA of norovirus is linked by a phosphodiester bond between the 5’-terminal guanosine (norovirus) and the phenolic oxygen of a tyrosine residue (Y27 for norovirus). In this work we demonstrate the synthesis of peptides derived from guanylylated norovirus VPg and their use in proteomic studies of norovirus replication.","dates":{"publication":"Tue Sep 08 00:00:00 GMT+01:00 2026"},"accession":"PXD075074","cross_references":{"TAXONOMY":["357231","10090"],"pubmed":["42614786"]}}