title: Insights into the Antimicrobial Mechanism of Action of Human RNase6: Structural Determinants for Bacterial Cell Agglutination and Membrane Permeation.
abstract: Human Ribonuclease 6 is a secreted protein belonging to the ribonuclease A (RNaseA) superfamily, a vertebrate specific family suggested to arise with an ancestral host defense role. Tissue distribution analysis revealed its expression in innate cell types, showing abundance in monocytes and neutrophils. Recent evidence of induction of the protein expression by bacterial infection suggested an antipathogen function in vivo. In our laboratory, the antimicrobial properties of the protein have been evaluated against Gram-negative and Gram-positive species and its mechanism of action was characterized using a membrane model. Interestingly, our results indicate that RNase6, as previously reported for RNase3, is able to specifically agglutinate Gram-negative bacteria as a main trait of its antimicrobial activity. Moreover, a side by side comparative analysis with the RN6(1-45) derived peptide highlights that the antimicrobial activity is mostly retained at the protein N-terminus. Further work by site directed mutagenesis and structural analysis has identified two residues involved in the protein antimicrobial action (Trp1 and Ile13) that are essential for the cell agglutination properties. This is the first structure-functional characterization of RNase6 antimicrobial properties, supporting its contribution to the infection focus clearance.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. d.pulido-gomez@imperial.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Pulido
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. javier.arranz@e-campus.uab.cat.
authors.forename: Javier
authors.initials: J
authors.lastname: Arranz-Trullén
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. guillem.prats.ejarque@uab.cat.
authors.forename: Guillem
authors.initials: G
authors.lastname: Prats-Ejarque
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. diego.velazquez@uab.cat.
authors.forename: Diego
authors.initials: D
authors.lastname: Velázquez
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. marc.torrent@vhir.org.
authors.forename: Marc
authors.initials: M
authors.lastname: Torrent
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. mohammed.moussaoui@uab.cat.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Moussaoui
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193 Cerdanyola del Vallès, Spain. david.pulido@e-campus.uab.cat.
authors.forename: Ester
authors.initials: E
authors.lastname: Boix
mesh_terms: D000371:Agglutination; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism*; D001424:Bacterial Infections / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D002463:Cell Membrane Permeability; D002473:Cell Wall / Q000502:physiology; D005092:Exonucleases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D016415:Sequence Alignment
chemical_list: D000900:Anti-Bacterial Agents; D005092:Exonucleases; C113574:Rad1 protein, human
keywords: RNases; antimicrobial peptides; cell agglutination; host defence; infectious diseases