title: Purification, characterization and cytotoxicity assessment of Ageritin: The first ribotoxin from the basidiomycete mushroom Agrocybe aegerita.
abstract: Several species belonging to Ascomycota phylum produce extracellular ribonucleases, known as ribotoxins, which exhibit RNase activity through the cleavage of a single phosphodiester bond, located at the universally conserved sarcin/ricin loop of the large rRNA leading to inhibition of protein biosynthesis. Clarifying the structure-function relationship in ribotoxins is interesting for their use in human tumour therapy and in construction of pest resistant transgenic plants.
  
  
  
  The ribotoxin Ageritin has been isolated for the first time from the Basidiomycetes class. The enzyme, characterized by means of its amino acid composition, N-terminal sequence and a circular dichroism, structurally differs from Ascomycota ribotoxin prototype, although it was able, as α-sarcin, to release a specific α-fragment. However, it does not display aspecific ribonucleolytic activity. Ageritin exerts cytotoxicity and cell death promoting effects towards CNS model cell lines (SK-N-BE(2)-C, U-251 and C6), as vinblastine, a plant alkaloid used in cancer therapy. Moreover, our results indicate that Ageritin initially activates caspase-8, whereas caspase-9 cleavage was not detected, demonstrating the involvement of an extrinsic apoptotic pathway.
  
  
  
  Our findings show that Ageritin is the earliest diverging member of the Ascomycota ribotoxin family, suggesting that ribotoxins are more widely distributed among fungi than previously believed.
  
  
  
  Ageritin, structurally different from the widely known Ascomycota ribotoxins, with promising anti-cancer properties vs. aggressive brain tumours, has been found from the basidiomycete fungus Agrocybe aegerita. Finally, this finding highlights that the ribotoxin family has divergent members in Basidiomycota phylum, whose structural and functional characterization can give new information on ribotoxin or ribonuclease superfamilies.
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Landi
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy.
authors.forename: Severina
authors.initials: S
authors.lastname: Pacifico
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Ragucci
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Faculty of Sciences, University of Valladolid, E-47011 Valladolid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Iglesias
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Piccolella
authors.affiliation: Department of Odontostomatologic and Specialized Clinical Sciences, Polytechnic University of Marche, I-60131 Ancona, Italy.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Amici
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy.
authors.forename: Antonella M A
authors.initials: AMA
authors.lastname: Di Giuseppe
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy. Electronic address: antimo.dimaro@unina2.it.
authors.forename: Antimo
authors.initials: A
authors.lastname: Di Maro
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D055362:Agrocybe / Q000737:chemistry*; D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001487:Basidiomycota / Q000737:chemistry*; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D004722:Endoribonucleases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D014176:Protein Biosynthesis / Q000187:drug effects; D012335:RNA, Ribosomal / Q000378:metabolism; D012260:Ribonucleases / Q000737:chemistry* / Q000494:pharmacology*; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism; D012276:Ricin / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D005656:Fungal Proteins; D012335:RNA, Ribosomal; C014801:alpha-sarcin; D012276:Ricin; D004722:Endoribonucleases; D012260:Ribonucleases; D053181:Caspase 8; D053453:Caspase 9
keywords: Ageritin; Agrocybe aegerita; Apoptosis; Cytotoxicity; Ribonuclease activity; Ribotoxins