title: UV radiation induces genome-mediated, site-specific cleavage in viral proteins.
abstract: Much research has been dedicated to understanding the molecular basis of UV damage to biomolecules, yet many questions remain regarding the specific pathways involved. Here we describe a genome-mediated mechanism that causes site-specific virus protein cleavage upon UV irradiation. Bacteriophage MS2 was disinfected with 254 nm UV, and protein damage was characterized with ESI- and MALDI-based FT-ICR, Orbitrap, and TOF mass spectroscopy. Top-down mass spectrometry of the products identified the backbone cleavage site as Cys46-Ser47 in the virus capsid protein, a location of viral genome-protein interaction. The presence of viral RNA was essential to inducing backbone cleavage. The similar bacteriophage GA did not exhibit site-specific protein cleavage. Based on the major protein fragments identified by accurate mass analysis, a cleavage mechanism is proposed by radical formation. The mechanism involves initial oxidation of the Cys46 side chain followed by hydrogen atom abstraction from Ser47 C(α). Computational protein QM/MM studies confirmed the initial steps of the radical mechanism. Collectively, this study describes a rare incidence of genome-induced protein cleavage without the addition of sensitizers.
authors.affiliation: Laboratory of Environmental Chemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Krista Rule
authors.initials: KR
authors.lastname: Wigginton
authors.forename: Laure
authors.initials: L
authors.lastname: Menin
authors.forename: Therese
authors.initials: T
authors.lastname: Sigstam
authors.forename: Greg
authors.initials: G
authors.lastname: Gannon
authors.forename: Michele
authors.initials: M
authors.lastname: Cascella
authors.forename: Hisham Ben
authors.initials: HB
authors.lastname: Hamidane
authors.forename: Yury O
authors.initials: YO
authors.lastname: Tsybin
authors.forename: Patrice
authors.initials: P
authors.lastname: Waridel
authors.forename: Tamar
authors.initials: T
authors.lastname: Kohn
mesh_terms: D016679:Genome, Viral / Q000528:radiation effects*; D017909:Levivirus / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D013058:Mass Spectrometry; D014466:Ultraviolet Rays; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: D014764:Viral Proteins