Structure and synthesis of a lipid-containing bacteriophage

Salditt, M.; Braunstein, Seth N.; Camerini‐Otero, R. Daniel; Franklin, Richard M.

doi:10.1016/0042-6822(72)90133-x

Cited by 92 publications

(26 citation statements)

References 9 publications

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“…[48] DNA from bacteriophage PM2 (PM2 DNA) was prepared according to the method of Salditt et al [49] More than 95 % was in the supercoiled form, as determined by the reported method. Formamidopyrimidine DNA glycosylase [50] was obtained from Dr. S. Boiteux.…”

mentioning

confidence: 99%

Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

Joseph

Eldho

Ramaiah

2003

Chemistry A European J

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A new series of photoactivated DNA oxidizing agents in which an acridine moiety is covalently linked to viologen by an alkylidene spacer was synthesized, and their photophysical properties and interactions with DNA, including DNA cleaving properties, were investigated. The fluorescence quantum yields of the viologen-linked acridines were found to be lower than that of the model compound 9-methylacridine (MA). The changes in free energy for the electron transfer reactions were found to be favorable, and the fluorescence quenching observed in these systems is explained by an electron transfer mechanism. Intramolecular electron transfer rate constants were calculated from the observed fluorescence quantum yields and singlet lifetime of MA and are in the range from 1.06x10(10) s(-1) for 1 a (n=1) to 6x10(8) s(-1) for 1 c (n=11), that is, the rate decreases with increasing spacer length. Nanosecond laser flash photolysis of these systems in aqueous solutions showed no transient absorption, but in the presence of guanosine or calf thymus DNA, transient absorption due to the reduced viologen radical cation was observed. Studies on DNA binding demonstrated that the viologen-linked acridines bind effectively to DNA in both intercalative and electrostatic modes. Results of PM2 DNA cleavage studies indicate that, on photoexcitation, these molecules induce DNA damage that is sensitive to formamidopyrimidine DNA glycosylase. These viologen-linked acridines are quite stable in aqueous solutions and oxidize DNA efficiently and hence can be useful as photoactivated DNA-cleaving agents which function purely by the co-sensitization mechanism.

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confidence: 99%

Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

Joseph

Eldho

Ramaiah

2003

Chemistry A European J

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“…Assay for Nicking-Closing Activity. Bacteriophage PM-2 was grown and the DNA, which was used for all assays, was extracted by the method of Salditt et al (16). The RESULTS Purification of Activity.…”

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confidence: 99%

A DNA nicking-closing enzyme encapsidated in vaccinia virus: partial purification and properties.

Bauer¹,

Ressner²,

Kates³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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Vaccinia virus cores contain an activity which is able to relax both left-and right-handed superhelical DNA. This virus-specific nicking-closing enzyme has been highly purified and differs from the corresponding host enzyme in salt optimum, in sedimentation coefficient, and in polypeptide composition as determined on sodium dodecyl sulfate/polyacrylamide gels. The enzyme is probably newly synthesized after the cessation of host protein synthesis which follows virus infection. The most highly purified preparation contains two polypeptides, one of molecular weight 24,000 and the other 35,000. The former polypeptide is a major constituent of the virus (7% of total protein by weight), whereas the latter is present in a much smaller amount (0.2%). Chromatography with denatured DNA-cellulose reveals that the activity is predominately associated with those fractions enriched in the polypeptide of greater molecular weight. Many fundamental biological processes are associated with changes in the duplex winding of DNA. These include DNA replication; transcription; recombination; formation of nucleosomes; packaging of DNA in organelles, such as mitochondria or chloroplasts; formation of complex prokaryotic chromosomes (1); and encapsidation into viruses. Enzymes from several sources have recently been discovered which are able to relieve torsional stress on the DNA duplex. None of these appears to require a cofactor, and their primary function is to introduce a transient local swivel that allows the DNA to rotate in response to a torque.The prokaryotic enzymes, termed omega proteins (2), have been purified from Escherichia coli 1100 (2, 3) and from E. coli B (4) and are able to catalyze duplex rotation in the righthanded (overwinding) direction only. The eukaryotic enzymes are able to catalyze rotation in both directions and have so far been discovered in several animal cell nuclei (5-9). In the present report we show that such an activity is encapsidated in mature vaccinia virions and is active in viral cores, which are able to carry out transcription as intact complexes. The activity is not identical to the corresponding host protein and is newly synthesized following infection. This result, representing a virus-specific nicking-closing enzymet, confirms the widespread distribution of this activity.The only presently available assay for nicking-closing activity is based upon the ability of the enzyme to remove superhelical turns from closed circular duplex DNA. Such DNA molecules are subject to the topological constraint (11) that the net interstrand winding, a, is a constant and is the sum of the number MATERIALS AND METHODS Reagents. Yeast alcohol dehydrogenase and horse heart cytochrome c were obtained from Worthington and Sigma, respectively. Ethidium bromide (EtdBr) was obtained from Calbiochem, and [35S]methionine was purchased from New England Nuclear. All other chemicals were of reagent grade.Preparation of Virus. Vaccinia virus strain WR, grown in HeLa S cells, was purified by the method of Joklik (14). ...

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“…Phenanthridine and 5,5-dimethyl-1 -pyrroline N-oxide (DMPO) were obtained from Fluka (Neu-Ulm, Germany). The DNA from bacteriophage PM2 (PM2 DNA) was prepared according to the method of Salditt et al (19). More than 97% was in the supercoiled form, as determined by the method described below.…”

Section: Methodsmentioning

confidence: 99%

Photochemical and Photobiotogical Studies with Acridine and Phenanthridine Hydroperoxides in Cell‐free DNA

Adam¹,

Groer²,

Mielke³

et al. 1997

Photochem & Photobiology

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The acridine and phenanthridine hydroperoxides 3 and 7 were synthesized as photochemical hydroxyl radical sources for oxidative DNA damage studies. The generation of hydroxyl radicals upon UVA irradiation (A = 350 nm) was verified by trapping experiments with 5,5-dimethyl-1-pyrroline N-oxide and benzene. The enzymatic assays of the damage in cell-free DNA from bacteriophage PM2 caused by the acridine and phenanthridine hydroperoxides 3 and 7 under near-UVA irradiation revealed a wide range of DNA modifications. Particularly, extensive single-strand break formation and DNA base modifications sensitive to formamidopyrimidine DNA glycosylase (Fpg protein) were observed. In the photooxidation of calf thymus DNA, up to 0.69 * 0.03% 8-0x0-7,8-dihydroguanine was formed by the hydroperoxides 3 and 7 on irradiation, whose yield was reduced up to 40% in the presence of the hydroxyl radical scavengers mannitol and tert-butanol. The acridine and phenanthridine hydroperoxides 3 and 7 also induce DNA damage through the type I photooxidation process, for which photoinduced electron transfer from 2'-deoxyguanosine to the singlet states of 3 and 7 was estimated by the Rehm-Weller equation to possess a negative Gibb's free energy of ca -5 kcaY mol. Control experiments with the sensitizers acridine 1 and the acridine alcohol 4 in calf thymus and PM2 DNA confirmed the photosensitizing propensity of the UVA-absorbing chromophores. The present study emphasizes that for the development of selective and efficient photochemical hydroxyl radical sources, chromophores with low photosensitizing ability must be chosen to avoid type I and type I1 photooxidation processes.

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Structure and synthesis of a lipid-containing bacteriophage

Cited by 92 publications

References 9 publications

Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

A DNA nicking-closing enzyme encapsidated in vaccinia virus: partial purification and properties.

Photochemical and Photobiotogical Studies with Acridine and Phenanthridine Hydroperoxides in Cell‐free DNA

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