Open AccessLambdaSa1 and LambdaSa2 Prophage Lysins of Streptococcus agalactiae
Author(s) -
David G. Pritchard,
Shengli Dong,
Marion Kirk,
Robert T. Cartee,
John Baker
Publication year - 2007
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01783-07
Subject(s) - lysin , streptococcus agalactiae , amidase , peptidoglycan , microbiology and biotechnology , autolysin , biology , escherichia coli , streptococcus pneumoniae , streptococcus , biochemistry , cell wall , bacteria , enzyme , gene , bacteriophage , genetics , antibiotics
PutativeN -acetylmuramyl-l -alanine amidase genes from LambdaSa1 and LambdaSa2 prophages ofStreptococcus agalactiae were cloned and expressed inEscherichia coli . The purified enzymes lysed the cell walls ofStreptococcus agalactiae ,Streptococcus pneumoniae , andStaphylococcus aureus . The peptidoglycan digestion products in the cell wall lysates were not consistent with amidase activity. Instead, the structure of the muropeptide digestion fragments indicated that both the LambdaSa1 and LambdaSa2 lysins exhibited γ-d -glutaminyl-l -lysine endopeptidase activity. The endopeptidase cleavage specificity of the lysins was confirmed using a synthetic peptide substrate corresponding to a portion of the stem peptide and cross bridge ofStreptococcus agalactiae peptidoglycan. The LambdaSa2 lysin also displayed β-d -N -acetylglucosaminidase activity.