title: The (unusual) aspartic acid in the metal coordination sphere of the prokaryotic zinc finger domain.
abstract: The possibility of choices of protein ligands and coordination geometries leads to diverse Zn(II) binding sites in zinc-proteins, allowing a range of important biological roles. The prokaryotic Cys2His2 zinc finger domain (originally found in the Ros protein from Agrobacterium tumefaciens) tetrahedrally coordinates zinc through two cysteine and two histidine residues and it does not adopt a correct fold in the absence of the metal ion. Ros is the first structurally characterized member of a family of bacterial proteins that presents several amino acid changes in the positions occupied in Ros by the zinc coordinating residues. In particular, the second position is very often occupied by an aspartic acid although the coordination of structural zinc by an aspartate in eukaryotic zinc fingers is very unusual. Here, by appropriately mutating the protein Ros, we characterize the aspartate role within the coordination sphere of this family of proteins demonstrating how the presence of this residue only slightly perturbs the functional structure of the prokaryotic zinc finger domain while it greatly influences its thermodynamic properties.
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: D'Abrosca
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Russo
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Palmieri
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Baglivo
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Fortuna
authors.initials: F
authors.lastname: Netti
authors.affiliation: Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy; Institute of Biostructures and Bioimaging - CNR, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Ivan
authors.initials: I
authors.lastname: de Paola
authors.affiliation: Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy; Institute of Biostructures and Bioimaging - CNR, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Zaccaro
authors.affiliation: Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy; Institute of Biostructures and Bioimaging - CNR, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Biancamaria
authors.initials: B
authors.lastname: Farina
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Iacovino
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy; Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Paolo Vincenzo
authors.initials: PV
authors.lastname: Pedone
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy; Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Isernia
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy; Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fattorusso
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy. Electronic address: gaetano.malgieri@unina2.it.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Malgieri
mesh_terms: D016960:Agrobacterium tumefaciens / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D000072417:Protein Domains; D015032:Zinc / Q000737:chemistry*; D016335:Zinc Fingers
chemical_list: D001426:Bacterial Proteins; D015032:Zinc
keywords: Aspartic acid; Prokaryotic zinc finger; Thermal unfolding; Zinc coordination