title: Analysis of the peptidoglycan hydrolase complement of Lactococcus lactis: identification of a third N-acetylglucosaminidase, AcmC.
abstract: The peptidoglycan hydrolase (PGH) complement of Lactococcus lactis was identified by amino acid sequence similarity searching of the L. lactis IL-1403 complete genome sequence. Five PGHs that are not encoded by prophages were detected, including the previously characterized AcmA and AcmB proteins. Four of these PGHs, AcmA to AcmD, contain a catalytic domain homologous to that of enterococcal muramidase, but they have different domain structures. The fifth one (YjgB) has sequence similarity with the active-site domain of peptidoglycan-specific endopeptidases. The three new PGH-encoding genes identified in this study are all actively transcribed in L. lactis subsp. cremoris MG1363. The relative abundance of their transcripts varied during growth and was maximal during the early exponential growth phase. The three encoded proteins have peptidoglycan-hydrolyzing activities which are detected only at acidic pHs by zymography. Like AcmA and AcmB, AcmC has N-acetylglucosaminidase activity rather than the N-acetylmuramidase activity predicted by sequence similarity.
authors.affiliation: Unité de Biochimie et Structure des Protéines, INRA, 78352 Jouy-en-Josas Cedex, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Huard
authors.forename: Guy
authors.initials: G
authors.lastname: Miranda
authors.forename: Yulia
authors.initials: Y
authors.lastname: Redko
authors.forename: Françoise
authors.initials: F
authors.lastname: Wessner
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Foster
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Chapot-Chartier
mesh_terms: D000118:Acetylglucosaminidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D013294:Lactococcus lactis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics*; D010457:Peptidoglycan / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan; D000118:Acetylglucosaminidase; D009238:N-Acetylmuramoyl-L-alanine Amidase