title: Structural and enzymatic characterization of the streptococcal ATP/diadenosine polyphosphate and phosphodiester hydrolase Spr1479/SapH.
abstract: Spr1479 from Streptococcus pneumoniae R6 is a 33-kDa hypothetical protein of unknown function. Here, we determined the crystal structures of its apo-form at 1.90 Å and complex forms with inorganic phosphate and AMP at 2.30 and 2.20 Å, respectively. The core structure of Spr1479 adopts a four-layer αββα-sandwich fold, with Fe(3+) and Mn(2+) coordinated at the binuclear center of the active site (similar to metallophosphoesterases). Enzymatic assays showed that, in addition to phosphodiesterase activity for bis(p-nitrophenyl) phosphate, Spr1479 has hydrolase activity for diadenosine polyphosphate (Ap(n)A) and ATP. Residues that coordinate with the two metals are indispensable for both activities. By contrast, the streptococcus-specific residue Trp-67, which binds to phosphate in the two complex structures, is indispensable for the ATP/Ap(n)A hydrolase activity only. Moreover, the AMP-binding pocket is conserved exclusively in all streptococci. Therefore, we named the protein SapH for streptococcal ATP/Ap(n)A and phosphodiester hydrolase.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yong-Liang
authors.initials: YL
authors.lastname: Jiang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Zhang
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Yu
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Cheng
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Chen-Chen
authors.initials: CC
authors.lastname: Zhang
authors.affiliation: Laboratoire d'Ingénierie des Macromolécules, Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Frolet
authors.affiliation: Laboratoire d'Ingénierie des Macromolécules, Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Di Guilmi
authors.affiliation: Laboratoire d'Ingénierie des Macromolécules, Institut de Biologie Structurale Jean-Pierre Ebel, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Vernet
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: zcz@ustc.edu.cn.
authors.forename: Cong-Zhao
authors.initials: CZ
authors.lastname: Zhou
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: cyxing@ustc.edu.cn.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Chen
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000737:chemistry*; D000251:Adenosine Triphosphatases / Q000737:chemistry*; D001051:Apoenzymes / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013296:Streptococcus pneumoniae / Q000201:enzymology*
chemical_list: D001051:Apoenzymes; D001426:Bacterial Proteins; D017766:Acid Anhydride Hydrolases; D000251:Adenosine Triphosphatases; C075829:diadenosine polyphosphate hydrolase