Gene Ontology annotation through association of InterPro records with GO terms
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
Electronic Gene Ontology annotations created by transferring manual GO annotations between related proteins based on shared sequence features
Combined Automated Annotation using Multiple IEA Methods
Cloning and purification of a unique lysozyme produced by Bacillus phage phi 29.
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Gene 15 was expressed in Escherichia coli, its 26 kDa product purified to near homogeneity and identified as gp15 by N-terminal sequencing, and the purified protein has lysozyme activity comparable to the T4 gene e and P22 gene 19 lysozymes. This is a direct assay on purified protein, not a mutant phenotype.
"The purified product of gene 15 has a lysozyme activity similar to other phage-type lysozymes: products of phage T4 gene e and of phage P22 gene 19."
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phi29 lysozyme is structurally unusual among phage lysozymes, the distinctive feature being the two C-terminal LysM repeats appended to the GH24 catalytic domain.
"However, to our knowledge phi 29 lysozyme is structurally unique among the phage-type lysozymes."
Bacillus subtilis phage phi29. Characterization of gene products and functions.
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The survey identifies one cistron probably involved in final lysis of the infected bacteria, whose mutants lyse late under restrictive conditions while giving a normal or larger burst after artificial lysis. The abstract does not name the cistron, and the suppressor-sensitive mutant that exists in this region of the genome is sus14(1241), in the adjacent holin gene.
"A cistron, probably involved in the final lysis of the infected bacteria, has been found."
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The paper's reach is partial even among identified products, which is relevant to how confidently any one protein can be read out of it.
"The protein products of 10 out of the 17 cistrons detected in the genome of phage phi29 have been identified."
Nucleotide sequence of Bacillus phage phi 29 genes 14 and 15: homology of gene 15 with other phage lysozymes.
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Genes 14 and 15 encode proteins of 15,014 and 28,022 Da; gp15 is a phage-type lysozyme related to the P22 and T4 enzymes.
"Gene product 15 (gp15) has considerable homology with Salmonella phage P22 lysozyme and lesser homology with Escherichia coli phage T4 lysozyme."
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The suppressor-sensitive mutant available in this part of the phi29 genome is a gene 14 mutant, which is what identifies gene 14 rather than gene 15 as the cistron behind the 1976 delayed-lysis phenotype.
"The g14 open reading frame (ORF) was confirmed by sequencing a sus14(1241) mutant."
The missing link in phage lysis of gram-positive bacteria: gene 14 of Bacillus subtilis phage phi 29 encodes the functional homolog of lambda S protein.
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Gene 14's product is the one required for efficient lysis of Bacillus subtilis, and it is a holin: expressed alone in Escherichia coli it kills without lysing, while co-expression with the phi29 lysozyme or another murein hydrolase lyses the cells, showing that protein 14 makes a nonspecific lesion in the cytoplasmic membrane through which the endolysin passes.
"Production of protein 14 in E. coli resulted in cell death, whereas production of protein 14 concomitantly with the phi 29 lysozyme or unrelated murein-degrading enzymes led to lysis, suggesting that membrane-bound protein 14 induces a nonspecific lesion in the cytoplasmic membrane."
Dual translational start motif evolutionarily conserved in the holin gene of Bacillus subtilis phage phi 29.
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The division of labour in the phi29 lysis cassette is explicit: gene 14 encodes the holin, the downstream gene 15 the lysozyme.
"The 131-codon gene 14 of Bacillus subtilis phage phi 29 encodes the holin function, whereas the downstream gene 15 codes for a lysozyme."
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Holins exist to let phage murein hydrolases reach the periplasm, which is why the endolysin's own location is the host cytoplasm until the holin acts.
"Holins represent phage encoded lysis functions required for transit of the phage murein hydrolases to the periplasm."