title: Conserved histidine residues at the ferroxidase centre of the Campylobacter jejuni Dps protein are not strictly required for metal binding and oxidation.
abstract: Iron is an essential micronutrient for living organisms as it is involved in a broad variety of important biological processes. However, free iron inside the cell could be potentially toxic, generating hydroxyl radicals through the Fenton reaction. Dps (DNA-binding protein from starved cells) belongs to a subfamily of ferritins and can store iron atoms inside the dodecamer. The presence of a ferroxidase centre, composed of highly conserved residues, is a signature of this protein family. In this study, we analysed the role of two conserved histidine residues (H25 and H37) located at the ferroxidase centre of the Campylobacter jejuni Dps protein by replacing them with glycine residues. The C. jejuni H25G/H37G substituted variant showed reduced iron binding and ferroxidase activities in comparison with wt Dps, while DNA-binding activity remained unaffected. We also found that both CjDps wt and CjDps H25G/H37G were able to bind manganese atoms. These results indicate that the H25 and H37 residues at the ferroxidase centre of C. jejuni Dps are not strictly required for metal binding and oxidation.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Heloisa B S
authors.initials: HBS
authors.lastname: Sanchuki
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Glaucio
authors.initials: G
authors.lastname: Valdameri
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Vivian R
authors.initials: VR
authors.lastname: Moure
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C. Guadalajara, Mexico.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Rodriguez
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Pedrosa
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Victoria
authors.initials: V
authors.lastname: Korolik
authors.affiliation: Departamento de Química, Centro Politécnico, UFPR, Curitiba, PR, Brazil.
authors.forename: Ronny Rocha
authors.initials: RR
authors.lastname: Ribeiro
authors.affiliation: Setor Litoral, UFPR, Matinhos, PR, Brazil.|Departamento de Bioquímica e Biologia Molecular, UFPR Curitiba, PR, Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Brazil.
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Huergo
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D016123:Campylobacter jejuni / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D002570:Ceruloplasmin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D006639:Histidine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction
chemical_list: D001426:Bacterial Proteins; D006639:Histidine; D007501:Iron; D002570:Ceruloplasmin