Gene Ontology annotation through association of InterPro records with GO terms

Gene Ontology annotation based on Enzyme Commission mapping

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

PMID:2651121

Comparison of the amino acid sequence of the lytic enzyme from broad-host-range bacteriophage PRD1 with sequences of other cell-wall-peptidoglycan lytic enzymes.

Gene XV encodes a 149-residue, 17.3 kDa lytic enzyme whose sequence is distinctive among characterised cell-wall lytic enzymes, with only short regions of similarity to phage lysozymes.

"The gene for the lytic enzyme of the lipid-containing, broad-host-range bacteriophage PRD1 codes for a protein of 149 amino acids (17271 Da)."

PMID:7925454

Gene XV of bacteriophage PRD1 encodes a lytic enzyme with muramidase activity.

Purified recombinant P15 cleaves the beta-1,4 bond between N-acetylmuramic acid and N-acetylglucosamine in bacterial cell walls, establishing muramidase (lysozyme, EC 3.2.1.17) activity.

"The analysis of cell wall digests indicated that P15 is a glycosidase that cleaves the beta (1-4) linkage between N-acetylmuramic acid and N-acetylglucosamine, thus displaying muramidase activity."
P15 lyses chloroform-treated Gram-negative cells and showed no detectable activity against Gram-positive species in this assay.

"The purified protein P15, identified by N-terminal sequence analysis, showed a strong lytic activity against chloroform-treated Gram-negative cells. No activity against Gram-positive bacterial species could be detected."
The host-lysing lytic enzyme of PRD1 had previously been assigned to gene XV by complementation and mutant-phage analysis, which this paper confirms by expressing the cloned gene.

"The phage lyses its host by virtue of a virally-encoded lytic enzyme, the synthesis of which has been assigned to gene XV on the basis of complementation analysis and experiments with mutant phages."

PMID:10931330

Bacteriophage PRD1 DNA entry uses a viral membrane-associated transglycosylase activity.

The virion-associated glycolytic activity characterised in this paper belongs to PRD1 protein P7, a lytic transglycosylase with an accessory role in DNA entry, not to the gene XV product P15.

"We analysed wild-type PRD1 and different mutant particles in zymograms and found a glycolytic activity that was associated with protein P7."

PMID:11741849

The lytic enzyme of bacteriophage PRD1 is associated with the viral membrane.

P15 is a structural component of the PRD1 virion associated with the internal phage membrane, with its incorporation modulated by the small integral membrane proteins P20 and P22.

"We demonstrate here that P15 is also a structural component of the PRD1 virion and that it is connected to the phage membrane."
The ~15 kDa muralytic activity of PRD1 particles in peptidoglycan zymograms is due to P15 and is lost in gene XV amber mutants and in P20-deficient particles.

"Thus, we concluded that the appearance of the faster-moving clear zone in zymograms was due to the enzymatic activity of protein P15."
P15 activity is detectable in isolated, capsid-free phage membrane vesicles and in both empty and DNA-filled membranes released by guanidine treatment.

"Zymogram analysis revealed the presence of proteins P7 and P15 in both DNA-filled and empty phage membranes"
Unlike P7, P15 degrades Gram-positive (Micrococcus lysodeikticus) peptidoglycan in zymograms, consistent with the broad host range of tectiviruses.

"Protein P7 was found to be inactive, while protein P15 degraded peptidoglycan obtained from M. lysodeikticus and caused the appearance of a clear zone in zymograms."
P15 is not the principal muralytic enzyme of genome entry: particles lacking it show no delay in the initiation or rate of phage DNA replication, which instead depends on P7.

"However, in the absence of protein P15 no delay in phage DNA replication was detected, suggesting that protein P7 is the main muralytic enzyme involved in bacteriophage PRD1 DNA entry into Salmonella cells."

PMID:16030234

The Holin protein of bacteriophage PRD1 forms a pore for small-molecule and endolysin translocation.

PRD1 lyses its host with a two-component holin (P35) / endolysin (P15) system that releases progeny phage particles.

"Using infected cells and plasmid-borne lysis genes, we demonstrated that a two-component lysis system (holin-endolysin) operates to release progeny phage particles from the host cell."
The gene XV endolysin amber mutant sus232 fails to lyse the host with or without arsenate induction, as does the holin mutant, so both proteins are required.

"The same result was observed in the case of the endolysin sus232 mutant."
Plasmid-borne expression separates the two activities: potassium leakage and loss of membrane voltage are functions of holin, while the endolysin is what is needed for lysis itself.

"that endolysin was needed for cell lysis"
Holin permeabilizes the cytoplasmic membrane so that the cytosolic endolysin can reach and attack the peptidoglycan.

"Holins are small hydrophobic integral membrane proteins that permeabilize the cytoplasmic membrane (CM) and allow the endolysins to attack the peptidoglycan"