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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 20 (1996), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Phage φ29 regulatory protein p4 activates transcription from the late A3 promoter by stabilizing σA-RNA polymerase at the promoter as a closed complex. Activation requires interaction between both proteins. Protein p4 bends the DNA upon binding. We have performed a detailed mutagenesis study of the carboxyl end of the protein, which is involved in both transcription activation and DNA bending. The results indicate that Arg-120 is the most critical residue for activation, probably mediating the interaction with RNA polymerase. Several basic residues have been identified, including Arg-120, that contribute to maintenance of the DNA bending, probably via electrostatic interactions with the DNA backbone. The degree or stability of the induced bend apparently relies on the additive contribution of all basic residues of the carboxyl end of the protein. Therefore, the activation and DNA bending surfaces overlap, and Arg-120 should interact with both DNA and RNA polymerase. As we show that protein p4 is a dimer in solution, and is bound to DNA as a tetramer, the results suggest a model in which two of the p4 subunits interact with the DNA, bending it, while the other two subunits remain accessible to interact with RNA polymerase.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of virology 83 (1985), S. 331-336 
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In guinea-pig infected with foot-and-mouth disease virus (FMDV), Langerhans cells in the foot pads increase in number and show viral antigens 24 hours post-inoculation, preceding appearance of virus in epithelial cells and vesiculation. This observation suggests that Langerhans cells may be engaged in virus transport from the blood to the non vascularized epidermis.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 102 (1992), S. S32 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract TheBacillus subtilis phage ø29 DNA polymerase, involved in protein-primed viral DNA replication, contains several amino acid consensus sequences common to other eukaryotic-type DNA polymerases. Using site-directed mutagenesis, we have studied the functional significance of a C-terminal conserved region, represented by the Lys-X-Tyr (“K-Y”) motif. Single point mutants have been constructed and the corresponding proteins have been overproduced and characterized. Measurements of the activity of the mutant proteins indicated that the invariant Lys and Tyr residues play a critical role in DNA polymerization. Interestingly, substitution of the invariant Lys either by Arg or Thr, produced enzymes with an increased or a largely reduced, respectively, capability to use a protein as primer, an intrinsic property of TP-priming DNA polymerases. On the other hand, the viral protein p6, which stimulates initiation of ø29 DNA replication by formation of a nucleoprotein complex at both DNA replication origins, increased (about 5-fold) the insertion fidelity of ø29 DNA polymerase during the formation of the TP-dAMP initiation complex. We propose a model in which the special strategy to maintain the integrity of the ø29 DNA ends, by means of a “sliding-back” mechanism, could also contribute to increase the fidelity of ø29 DNA replication.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 115 (1972), S. 31-35 
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Temperature-sensitive mutants of eleven complementation groups of phage Φ29 have been mapped by means of two-factor crosses. The results show the existence of a single non-circular linkage map. Cistrons expressed early after infection are clustered at the left end of the map.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 180 (1980), S. 539-545 
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Bacteriophage ϕ29 can infect B. subtilis minicells and synthesize all the phage-coded proteins detected in ultraviolet irradiated-infected B. subtilis cells. Synthesis of phage unit-length DNA has been obtained after infection of minicells with ϕ29. The DNA can be encapsulated in particles with a sedimentation rate similar to that of phage ϕ29 produced in B. subtilis cells. The particles produced in minicells can be adsorbed to B. subtilis cells, but infectivity has not been demonstrated because of the very low burst-size obtained.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 245 (1994), S. 529-536 
    ISSN: 1617-4623
    Keywords: Trans-complementation ; In vivo DNA replication ; Phage ø29 ; Site-directed mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protein p6 of the Bacillus subtilis phage ø29 is essential for in vivo viral DNA replication. This protein activates the initiation of ø29 DNA replication in vitro by forming a multimeric nucleoprotein complex at the replication origins. The N-terminal region of protein p6 is involved in DNA binding, as shown by in vitro studies with p6 proteins altered by deletions or missense mutations. We report on the development of an in vivo functional assay for protein p6. This assay is based on the ability of protein p6-producing B. subtilis non-suppressor (su −) cells to support growth of a ø29 sus6 mutant phage. We have used this trans-complementation assay to investigate the effect on in vivo viral DNA synthesis of missense mutations introduced into the protein p6 N-terminal region. The alteration of lysine to alanine at position 2 resulted in a partially functional protein, whereas the replacement of arginine by alanine at position 6 gave rise to an inactive protein. These results indicate that arginine at position 6 is critical for the in vivo activity of protein p6. Our complementation system provides a useful genetic approach for the identification of functionally important amino acids in protein p6.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 52 (2004), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The mechanism of bacteriophage DNA injection is poorly understood, often considered a simple process, driven merely by the packing pressure inside the capsid. In contrast to the well-established DNA packaging mechanism of Bacillus subtilis phage Ø29, that involves a molecular motor formed by the connector and a viral ATPase, nothing is known about its DNA injection into the cell. We have studied this process measuring DNA binding of p6, a viral genome organization protein. The linear DNA penetrates with a right-left polarity, in a two-step process. In the first step ∼65% of the genome is pushed into the cell most probably by the pressure built inside the viral capsid. Thus, synthesis of viral proteins from the right early operon is allowed. This step is controlled, probably by bacterial protein(s) that slow down DNA entry. In the second step at least one of the viral early proteins, p17, participates in the molecular machinery that pulls the remaining DNA inside the cell. Both steps are energy-dependent, as treatment of cells with azide overrides the whole mechanism, leading to a deregulated, passive entry of DNA.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 226 (1970), S. 1244-1245 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] RNA polymerase was purified by fractionation of extracts in a two-phase polyethylene glycoldextran sulphate system2 followed by chromatography, first on DEAEcellulose and then on 29 DNAellulose. At this stage the enzyme, purified about 200-fold with a yield of 2550 per cent, was essentially ...
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology reviews 29 (2005), S. 0 
    ISSN: 1574-6976
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: It becomes now apparent that prokaryotic DNA replication takes place at specific intracellular locations. Early studies indicated that chromosomal DNA replication, as well as plasmid and viral DNA replication, occurs in close association with the bacterial membrane. Moreover, over the last several years, it has been shown that some replication proteins and specific DNA sequences are localized to particular subcellular regions in bacteria, supporting the existence of replication compartments. Although the mechanisms underlying compartmentalization of prokaryotic DNA replication are largely unknown, the docking of replication factors to large organizing structures may be important for the assembly of active replication complexes. In this article, we review the current state of this subject in two bacterial species, Escherichia coli and Bacillus subtilis, focusing our attention in both chromosomal and extrachromosomal DNA replication. A comparison with eukaryotic systems is also presented.
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science, Ltd
    Molecular microbiology 39 (2001), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: An early expressed operon, located at the right end of the linear bacteriophage φ29 genome, contains open reading frame (ORF)16.7, whose deduced protein sequence of 130 amino acids is conserved in φ29-related phages. Here, we show that this ORF actually encodes a protein, p16.7, which is abundantly and early expressed after infection. p16.7 is a membrane protein, and the N-terminally located transmembrane-spanning domain is required for its membrane localization. The variant p16.7A, in which the N-terminal membrane anchor was replaced by a histidine-tag, was purified and characterized. Purified p16.7A was shown to form dimers in solution. To study the in vivo role of p16.7, a φ29 mutant containing a suppressible mutation in gene 16.7 was constructed. In vivo phage DNA replication was affected in the absence of p16.7, especially at early infection times. Based on the results, the putative role of p16.7 in in vivoφ29 DNA replication is discussed.
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