title: Crystal structure of bacteriophage ϕNIT1 zinc peptidase PghP that hydrolyzes γ-glutamyl linkage of bacterial poly-γ-glutamate.
abstract: Poly-γ-glutamate hydrolase P (PghP) of Bacillus subtilis bacteriophage ΦNIT1 hydrolyzes the γ-glutamyl peptide linkage of extracellular poly-γ-glutamate produced by bacilli, which facilitates infection and propagation of phage progenies. Crystal structure of PghP was determined at a resolution of 1.9 Å. Structure of PghP was elucidated as a globular protein with an open α/β mixed core structure and a seven-stranded parallel/anti-parallel β-sheet. The β-sheet contained a core four-stranded parallel β-sheet. A zinc-binding motif, His-Glu-His, was identified at the C-terminal end of the β-sheet. Structure analysis demonstrated that PghP, which had not been previously classified into any peptidase/protease family due to lack of amino acid sequence similarity with known enzymes, had a catalytic center containing a zinc ion and an overall topology resembling mammalian carboxypeptidase A and related enzymes. Structural comparisons indicated important amino acid residues of PghP for catalysis and recognition of the γ-peptide bond of poly-γ-glutamate, which was confirmed by site-directed mutagenesis of PghP.
authors: Biomolecular Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan. zui@affrc.go.jp
authors: Zui
authors: Z
authors: Fujimoto
authors: Keitarou
authors: K
authors: Kimura
mesh_terms: D000595:Amino Acid Sequence; D017103:Bacillus Phages / Q000737:chemistry / Q000201:enzymology*; D001412:Bacillus subtilis / Q000821:virology*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D045726:Metalloproteases / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D015032:Zinc / Q000378:metabolism*
chemical_list: C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D045726:Metalloproteases; D015032:Zinc