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Crystal structure of bacteriophage ϕNIT1 zinc peptidase PghP that hydrolyzes γ‐glutamyl linkage of bacterial poly‐γ‐glutamate
Author(s) -
Fujimoto Zui,
Kimura Keitarou
Publication year - 2012
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.23229
Subject(s) - biochemistry , hydrolase , amino acid , bacillus subtilis , enzyme , peptide sequence , carboxypeptidase , zinc , biology , active site , bacteriophage , peptide , stereochemistry , chemistry , escherichia coli , genetics , bacteria , gene , organic chemistry
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. Proteins 2011. © 2012 Wiley Periodicals, Inc.