Antimodification activity of the ArdA and Ocr proteins

Zavilgelsky, G. B.; Kotova, V. Yu.; Расторгуев, С. М.

doi:10.1134/s1022795410081034

Cited by 13 publications

(13 citation statements)

References 18 publications

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“…The crystal structure of ArdA indicates that a monomer of ArdA should have an axial ratio of~3.5 if modelled as a prolate ellipsoid, and an f/f o of~1. 25. The observed f/f o for L127E ArdA was lower than expected, but this can be explained by the measurement of sedimentation velocity being skewed by the presence of more than one species, namely the monomer-dimer equilibrium indicated by SEC and sedimentation equilibrium.…”

Section: Sedimentation Velocity Auc Of Orf18 Arda and L127e Ardamentioning

confidence: 74%

“…ORF18 ArdA appears to be able to dissociate into monomers at low concentrations in buffer solution [17], raising the possibility that the monomer form may be active in addition to the dimer form. It may even be the case that one form targets the modification activity and the other form targets the restriction activity of the RM system, as some ArdA proteins show differential effects on restriction and modification, depending on the level of expression in vivo [16,[21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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Mutations of the domain forming the dimeric interface of the ArdA protein affect dimerization and antimodification activity but not antirestriction activity

et al. 2013

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ArdA antirestriction proteins are encoded by genes present in many conjugative plasmids and transposons within bacterial genomes. Antirestriction is the ability to prevent cleavage of foreign incoming DNA by restrictionmodification (RM) systems. Antimodification, the ability to inhibit modification by the RM system, can also be observed with some antirestriction proteins. As these mobile genetic elements can transfer antibiotic resistance genes, the ArdA proteins assist their spread. The consequence of antirestriction is therefore the enhanced dissemination of mobile genetic elements. ArdA proteins cause antirestriction by mimicking the DNA structure bound by Type I RM enzymes. The crystal structure of ArdA showed it to be a dimeric protein with a highly elongated curved cylindrical shape [McMahon SA et al. (2009) Nucleic Acids Res 37, 4887-4897]. Each monomer has three domains covered with negatively charged side chains and a very small interface with the other monomer. We investigated the role of the domain forming the dimer interface for ArdA activity via sitedirected mutagenesis. The antirestriction activity of ArdA was maintained when up to seven mutations per monomer were made or the interface was disrupted such that the protein could only exist as a monomer. The antimodification activity of ArdA was lost upon mutation of this domain. The ability of the monomeric form of ArdA to function in antirestriction suggests, first, that it can bind independently to the restriction subunit or the modification subunits of the RM enzyme, and second, that the many ArdA homologues with long amino acid extensions, present in sequence databases, may be active in antirestriction. Structured digital abstractArdA and ArdA bind by molecular sieving (1, 2) ArdA and ArdA bind by cosedimentation in solution (1,2)

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Section: Sedimentation Velocity Auc Of Orf18 Arda and L127e Ardamentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Mutations of the domain forming the dimeric interface of the ArdA protein affect dimerization and antimodification activity but not antirestriction activity

et al. 2013

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“…If a drop of this lysed culture is added to another culture of the bacilli, lysis will take place exactly as in the first. A drop of this culture will then dissolve a third culture, and so on through hundreds of transfers, d'I Ierelle attributes this phenomenon to the action of an ultramicroscopic parasite of bacteria which he named the bacteriophage [16].…”

Section: Twort-d'i Ierelle Signmentioning

confidence: 99%

Dermatology Eponyms – sign – Lexicon (T). Part 2

Brzeziński¹,

Brzeziński²

2019

Our Dermatol Online

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Hyperostosis occuring in the midline of the hard palate (Fig. 1), called torus palatinus or hyperostosis located on the lingual aspect of the mandible, termed torus mandibularis [1]. TRAMP STAMP SIGN Tattoos on women that are not religious or ceremonially required for their culture. Often on the lower back area; they were originally used to signify a life of prostitution. This practice continues today but sometimes these tattoos are now seen in the non-prostitute population, as sign of admiration for the romanticized prostitution lifestyle which is linked to drug abuse, physical violence, and sexually transmitted diseases. The origin of the term dates from the 17 th century Yakuza practice of tattooing prostitutes on the back. Prostitutes in the Edo period, called 'Yujo' tattooed themselves with the name of their regular customer as a sign of their loyalty. This tattoo is referred to as 'Irezumiko', which starts with the customer's name and ends with the kanji character 命 (inochi), which means life, so this tattoo means "I give my life to 'name'." TOY SOLDIER SIGN Linear aggregation of neoplastic lymphocytes along the dermal-epidermal junction seen in histopathology of mycosis fungoides (Fig. 2) [2].

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“…Phage- or plasmid-encoded antirestriction proteins that act as structural mimics of DNA alleviate the effects of host restriction during invasion of the host by phage or plasmid DNA ( 1 – 6 ). To date, the bacteriophage T7 protein Ocr is probably the best characterised structural mimic of double stranded DNA ( 7 – 18 ). Ocr is able to competitively inhibit Type I restriction modification (RM) systems found in eubacteria.…”

Section: Introductionmentioning

confidence: 99%

The evolutionary pathway from a biologically inactive polypeptide sequence to a folded, active structural mimic of DNA

et al. 2016

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The protein Ocr (overcome classical restriction) from bacteriophage T7 acts as a mimic of DNA and inhibits all Type I restriction/modification (RM) enzymes. Ocr is a homodimer of 116 amino acids and adopts an elongated structure that resembles the shape of a bent 24 bp DNA molecule. Each monomer includes 34 acidic residues and only six basic residues. We have delineated the mimicry of Ocr by focusing on the electrostatic contribution of its negatively charged amino acids using directed evolution of a synthetic form of Ocr, termed pocr, in which all of the 34 acidic residues were substituted for a neutral amino acid. In vivo analyses confirmed that pocr did not display any antirestriction activity. Here, we have subjected the gene encoding pocr to several rounds of directed evolution in which codons for the corresponding acidic residues found in Ocr were specifically re-introduced. An in vivo selection assay was used to detect antirestriction activity after each round of mutation. Our results demonstrate the variation in importance of the acidic residues in regions of Ocr corresponding to different parts of the DNA target which it is mimicking and for the avoidance of deleterious effects on the growth of the host.

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Antimodification activity of the ArdA and Ocr proteins

Cited by 13 publications

References 18 publications

Mutations of the domain forming the dimeric interface of the ArdA protein affect dimerization and antimodification activity but not antirestriction activity

Mutations of the domain forming the dimeric interface of the ArdA protein affect dimerization and antimodification activity but not antirestriction activity

Dermatology Eponyms – sign – Lexicon (T). Part 2

The evolutionary pathway from a biologically inactive polypeptide sequence to a folded, active structural mimic of DNA

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