PMID:8577256

Citation	Loessner, MJ, Wendlinger, G and Scherer, S (1995) Heterogeneous endolysins in Listeria monocytogenes bacteriophages: a new class of enzymes and evidence for conserved holin genes within the siphoviral lysis cassettes. Mol. Microbiol. 16:1231-41
Abstract	Listeria monocytogenes bacteriophages A118, A500 and A511 are members of three distinct phage groups with characteristic host ranges. Their endolysin (ply) genes were cloned and expressed in Escherichia coli as demonstrated by the conferred lytic phenotype when colonies of recombinant cells were overlaid with a lawn of Listeria cells. The nucleotide sequences of the cloned DNA fragments were determined and the individual enzymes (PLY118, 30.8 kDa; PLY500, 33.4 kDa; PLY511, 36.5 kDa) were shown to have varying degrees of homology within their N-terminal or C-terminal domains. Transcriptional analysis revealed them to be 'late' genes with transcription beginning 15-20 min post-infection. The enzymes were overexpressed and partially purified and their individual specificities examined. When applied exogenously, the lysins induced rapid lysis of Listeria strains from all species but generally did not affect other bacteria. Using hydrolysis of purified listerial cell walls, PLY511 was characterized as an N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28) and shows homology in its N-terminal domain to other enzymes of this type. In contrast, PLY118 and PLY500 were shown to represent a new class of cell wall lytic enzymes which cleave between the L-alanine and D-glutamate residues of listerial peptidoglycan; these were designated as L-alanoyl-D-glutamate peptidases. These two enzymes share homology in the N-terminal domain which we propose determines hydrolytic specificity. Highly conserved holin (hol) gene sequences are present upstream of ply118 and ply500. They encode proteins of structural similarity to the product of phage lambda gene S, and are predicted to be membrane proteins which form pores to allow access of the lysins to their peptidoglycan substrates. This arrangement of conserved holin genes with downstream lysin genes among the siphoviral lysis cassettes explains why the cytoplasmic endolysins alone are not lethal, since they require a specific transport function across the cell membrane.
Links	PubMed
Keywords	Amino Acid Sequence; Bacteriolysis; Base Sequence; Carbohydrate Sequence; Cloning, Molecular; Endopeptidases/chemistry; Endopeptidases/genetics; Endopeptidases/isolation & purification; Endopeptidases/metabolism; Gene Expression/genetics; Genes, Viral; Genotype; Listeria monocytogenes/metabolism; Listeria monocytogenes/virology; Molecular Sequence Data; N-Acetylmuramoyl-L-alanine Amidase/chemistry; N-Acetylmuramoyl-L-alanine Amidase/genetics; N-Acetylmuramoyl-L-alanine Amidase/isolation & purification; Recombinant Proteins/genetics; Recombinant Proteins/isolation & purification; Sequence Alignment; Sequence Analysis; Siphoviridae/enzymology; Siphoviridae/genetics; Substrate Specificity; Viral Proteins/genetics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
BPA50:AEPE		GO:0016787: hydrolase activity	ECO:0000247:	PMID:8577256	F		Fig.3 shows high similarity between ply118 and ply500 protein sequence. wither it's a identical residue or a conservative substitution, the two enzymes share the acceptable shared identity	complete CACAO 12491
BPA50:AEPE		GO:0016787: hydrolase activity	ECO:0000314:		F		In fig.8, an optical density assay was performed on Listeria monocytogenes WSLC 1001. the assay shows a decrees in the optical density of L.monocytogenes cell wall after being exposed to PL118 (closed circles). PL118 and PL500 have acceptable sequence similarity to assume they have the same lytic function. the control(open circles) shows no effect on the cell wall without the addition of PL118.	complete CACAO 12677

References

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