title: Structural basis for the broad specificity of a new family of amino-acid racemases.
abstract: Broad-spectrum amino-acid racemases (Bsrs) enable bacteria to generate noncanonical D-amino acids, the roles of which in microbial physiology, including the modulation of cell-wall structure and the dissolution of biofilms, are just beginning to be appreciated. Here, extensive crystallographic, mutational, biochemical and bioinformatic studies were used to define the molecular features of the racemase BsrV that enable this enzyme to accommodate more diverse substrates than the related PLP-dependent alanine racemases. Conserved residues were identified that distinguish BsrV and a newly defined family of broad-spectrum racemases from alanine racemases, and these residues were found to be key mediators of the multispecificity of BrsV. Finally, the structural analysis of an additional Bsr that was identified in the bioinformatic analysis confirmed that the distinguishing features of BrsV are conserved among Bsr family members.
authors.affiliation: Centro de Biología Molecular `Severo Ochoa', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain.
authors.forename: Akbar
authors.initials: A
authors.lastname: Espaillat
authors.affiliation: Department of Crystallography and Structural Biology, Instituto de Química-Física `Rocasolano'-CSIC, 28006 Madrid, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Carrasco-López
authors.affiliation: Department of Crystallography and Structural Biology, Instituto de Química-Física `Rocasolano'-CSIC, 28006 Madrid, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Bernardo-García
authors.affiliation: Centro Nacional de Biotecnología-CSIC, 28049 Madrid, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Pietrosemoli
authors.affiliation: Department of Crystallography and Structural Biology, Instituto de Química-Física `Rocasolano'-CSIC, 28006 Madrid, Spain.
authors.forename: Lisandro H
authors.initials: LH
authors.lastname: Otero
authors.affiliation: Centro de Biología Molecular `Severo Ochoa', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Álvarez
authors.affiliation: Centro de Biología Molecular `Severo Ochoa', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: de Pedro
authors.affiliation: Centro Nacional de Biotecnología-CSIC, 28049 Madrid, Spain.
authors.forename: Florencio
authors.initials: F
authors.lastname: Pazos
authors.affiliation: Division of Infectious Diseases, Brigham and Women's Hospital and Department of Microbiology and Immunobiology, Harvard Medical School and HHMI, Boston, MA 02115, USA.
authors.forename: Brigid M
authors.initials: BM
authors.lastname: Davis
authors.affiliation: Division of Infectious Diseases, Brigham and Women's Hospital and Department of Microbiology and Immunobiology, Harvard Medical School and HHMI, Boston, MA 02115, USA.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Waldor
authors.affiliation: Department of Crystallography and Structural Biology, Instituto de Química-Física `Rocasolano'-CSIC, 28006 Madrid, Spain.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Hermoso
authors.affiliation: Centro de Biología Molecular `Severo Ochoa', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Cava
mesh_terms: D000411:Alanine Racemase / Q000737:chemistry / Q000378:metabolism; D000591:Amino Acid Isomerases / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013379:Substrate Specificity; D014734:Vibrio cholerae / Q000737:chemistry / Q000201:enzymology*
chemical_list: D000591:Amino Acid Isomerases; D000411:Alanine Racemase
keywords: BsrV; amino-acid racemases; crystal structure; multispecificity; noncanonical d-amino acids