title: Structure of the sirtuin-linked macrodomain SAV0325 from Staphylococcus aureus.
abstract: Cells use the post-translational modification ADP-ribosylation to control a host of biological activities. In some pathogenic bacteria, an operon-encoded mono-ADP-ribosylation cycle mediates response to host-induced oxidative stress. In this system, reversible mono ADP-ribosylation of a lipoylated target protein represses oxidative stress response. An NAD(+) -dependent sirtuin catalyzes the single ADP-ribose (ADPr) addition, while a linked macrodomain-containing protein removes the ADPr. Here we report the crystal structure of the sitruin-linked macrodomain protein from Staphylococcus aureus, SauMacro (also known as SAV0325) to 1.75-Å resolution. The monomeric SauMacro bears a previously unidentified Zn(2+) -binding site that putatively aids in substrate recognition and catalysis. An amino-terminal three-helix bundle motif unique to this class of macrodomain proteins provides a structural scaffold for the Zn(2+) site. Structural features of the enzyme further indicate a cleft proximal to the Zn(2+) binding site appears well suited for ADPr binding, while a deep hydrophobic channel in the protein core is suitable for binding the lipoate of the lipoylated protein target.
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709.
authors.forename: C Denise
authors.initials: CD
authors.lastname: Appel
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709.
authors.forename: Geoffrey K
authors.initials: GK
authors.lastname: Feld
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709.
authors.forename: Bret D
authors.initials: BD
authors.lastname: Wallace
authors.affiliation: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709.
authors.forename: R Scott
authors.initials: RS
authors.lastname: Williams
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D000072417:Protein Domains; D037761:Sirtuins / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D037761:Sirtuins; D015032:Zinc
keywords: ADP-ribose; ADP-ribosylation; SAV0325; SauMacro; Staphylococcus aureus; X-ray crystallography; adenosine diphosphate ribose; lipoate; lipolyation; macrodomain; oxidative stress