Participation of the host protein(s) in the morphogenesis of bacteriophage P22

Joshi, A; Siddiqui, Javed Zafar; Verma, Mukesh; Chakravorty, Maharani

doi:10.1007/bf00422910

Cited by 6 publications

(5 citation statements)

References 22 publications

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“…Even this is quite surprising since P22 antisera cannot neutralize phage MB78 [1]. However, it may throw some light on the evolution of phage tail protein gene.…”

Section: Discussionmentioning

confidence: 97%

“…Sanderson, Department of Biological sciences, University of Calgary, Alberta Canada. Bacteriophage MB78 was isolated in our laboratory [1]. Bacteria were routinely grown in LB broth [12].…”

Section: Bacteria Bacteriophages and General Manipulationsmentioning

confidence: 99%

“…The techniques for preparation of DNA and transformation were as per standard procedures [13]. Purification of phage was carried out as described earlier [1].…”

Section: Bacteria Bacteriophages and General Manipulationsmentioning

confidence: 99%

“…Bacteriophage MB78 isolated in our laboratory is a long tailed virulent phage of Salmonella enterica serovar typhimurium [1]. It contains a linear, double stranded, circularly permuted and terminally redundant DNA, which is 42 kb long.…”

Section: Introductionmentioning

confidence: 99%

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Temperature Sensitive Mutation in the 38 kDa Minor Structural Protein Gene of Phage MB78 Interferes with Phage Morphogenesis

et al. 2005

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Temperature sensitive mutation in the gene for the 38 kDa minor structural protein of the phage MB78, a virulent phage of Salmonella enterica serovar typhimurium, interferes with phage development at restrictive temperature. Electron microscopy of particles produced at non-permissive temperature indicated that the particles formed are tailless. Two types of particles are seen: (i) empty capsids, which are not perfect icosahedral (ii) icosahedral particles filled with DNA. The gene for the 38 kDa protein is located in the SalIG fragment of the phage genome. Nucleotide sequence of the SalIG fragment of MB78 as well as its temperature sensitive mutant has been determined and analysed. Such analysis indicated that in the mutant the codon GCA has been changed to GTA resulting in substitution of alanine at position 75 of the protein by valine (A75V). This makes the protein thermolabile. Our results suggest that normal functioning of this 38 kDa protein is necessary for attachment of tail fibre to the capsid. Or in other words, this 38 kDa protein is involved in phage morphogenesis.

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“…Even this is quite surprising since P22 antisera cannot neutralize phage MB78 [1]. However, it may throw some light on the evolution of phage tail protein gene.…”

Section: Discussionmentioning

confidence: 97%

“…Sanderson, Department of Biological sciences, University of Calgary, Alberta Canada. Bacteriophage MB78 was isolated in our laboratory [1]. Bacteria were routinely grown in LB broth [12].…”

Section: Bacteria Bacteriophages and General Manipulationsmentioning

confidence: 99%

“…The techniques for preparation of DNA and transformation were as per standard procedures [13]. Purification of phage was carried out as described earlier [1].…”

Section: Bacteria Bacteriophages and General Manipulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Temperature Sensitive Mutation in the 38 kDa Minor Structural Protein Gene of Phage MB78 Interferes with Phage Morphogenesis

et al. 2005

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“…9). growth of phage P22 are those reported by Joshi et al (23). These mutations were selected as conferring thiolutin resistance.…”

Section: Methodsmentioning

confidence: 99%

Oligopeptidase A is required for normal phage P22 development

1992

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The opdA gene of SalmoneUla typhimurium encodes an endoprotease, oligopeptidase A (OpdA). Strains carying opd4 mutations were deficient as hosts for phage P22. P22 and the closely related phages L and A3 formed tiny plaques on an opdA host. SalmoneUla phages 9NA, KB1, and ES18.hl were not affected by opdA mutations. Although opd4 strains displayed normal doubling times and were infected by P22 as efficiently as opdA+ strains, the burst size of infectious particles from an opd4 host was less than 1/10 of that from an opdA + host. This decrease resulted from a reduced efficiency of plating of particles from an opdAl infection. In the absence of a functional opdA4 gene, most ofthe P22 particles are defective. To identify the target of OpdA action, P22 mutants which formed plaques larger than wild-type plaques on an opdA mutant lawn were isolated.Marker rescue experiments using cloned fragments of P22 DNA localized these mutations to a 1-kb fragment.The nucleotide sequence of this fragment and a contiguous region (including all of both P22 gene 7 and gene 14) was determined. The mutations leading to opdA independence affected the region of gene 7 coding for the amino terminus of gp7, a protein required for DNA injection by the phage. Comparison of the nucleotide sequence with the N-terminal amino acid sequence of gp7 suggested that a 20-amino-acid peptide is removed from gp7 during phage development. Further experiments showed that this processing was opd4 dependent and rapid (half-life, <2 min) and occurred in the absence of other phage proteins. The opd4-independent mutations lead to mutant forms of gp7 which function without processing.Oligopeptidase A (OpdA) was identified by Vimr and Miller (42) as one of two enzymes in extracts of Salmonella typhimurium which hydrolyzed N-acetyl-L-Ala4. OpdA has been purified from both Escherichia coli (28) and S. typhimurium (9). Novak et al. (28) and Novak and Dev (27) have shown that OpdA is a signal peptide peptidase. In vitro, OpdA is the major soluble enzyme able to hydrolyze the E. coli lipoprotein signal peptide. Substrate specificity studies indicate that OpdA is an endopeptidase with a preference for Ala and Gly residues (27,28,41). Its inhibition by metal chelators (9, 28) suggests that it is a metallopeptidase.The gene encoding OpdA, opdA, has been cloned and sequenced (9). The predicted amino acid sequence of the 77-kDa OpdA protein contains a thermolysin-type metalloprotease Zn2+-binding site (9,22). The amino acid sequence shows strong similarity to another bacterial peptidase (dipeptidyl carboxypeptidase, encoded by dcp) and to a mammalian metalloprotease (rat metallopeptidase EP 24.15) that is involved in the processing of peptide hormones (9). Evidence presented in the accompanying article shows that opdA4 is the Salmonella homolog of the E. coliprlC gene (10).Mutant alleles of prlC suppress the localization defect of certain signal peptide mutations (39).Mutations in opdA were originally isolated by screening for mutants unable to use AcAla4 as a sole nitro...

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