Génétique des Bactériophages

Fredericq, P

doi:10.1007/978-3-7091-7885-0_2

Cited by 5 publications

(7 citation statements)

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“…Analysis of these fragments shows that the similarity of amino acid composition and antigenic specificity of native colicin E2 and E3 (54) is entirely a result of the almost identical amino acid composition of the N-terminal fragment (115). These results are expected since these two colicins bind to the identical outer membrane receptor protein (43,102) and probably have similar modes of entry into cells (82). In contrast, the C terminal tryptic fragments of E2· and E3· are significantly different in composition (115) reflecting both the difference in the catalytic function of the two colicins and the fact that this is the region that binds homologous, but not h'�terologous, immunity protein.…”

Section: Functional and Structural Domainsmentioning

confidence: 99%

Colicins and other Bacteriocins with Established Modes of Action

Konisky¹

1982

Annu. Rev. Microbiol.

374

208

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Section: Functional and Structural Domainsmentioning

confidence: 99%

Colicins and other Bacteriocins with Established Modes of Action

Konisky¹

1982

Annu. Rev. Microbiol.

374

208

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“…The loss of the receptors by mutation renders cells resistant to the corresponding colicine. 4 (2) Lack of reversibility of the adsorption: The attachment of a colicine particle to a receptor site was irreversible under the experimental conditions ordinarily used (370C, in solutions of moderate or high ionic strength). The experiments were done with colicine K, E2, and E3.…”

mentioning

confidence: 99%

Mechanism of Action of Colicines

Nomura

1964

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

131

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“…This immunity can, however, be overcome at high doses of E3 (9). Cell extracts derived from colicinogenic cells contain an "immunity factor" that prevents the in vitro effects of E3 (3).…”

Section: Inactivation Of Ribosomes In Vitro By Colicin E3mentioning

confidence: 99%

“…(h) Some bacterial mutants, called "tolerants", have lost their sensitivity to E,, even though they still adsorb it (9,(12)(13)(14).…”

Section: Inactivation Of Ribosomes In Vitro By Colicin E3mentioning

confidence: 99%

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Inactivation of Ribosomes In Vitro by Colicin E ₃ and Its Mechanism of Action

Boon

1972

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

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The incubation of purified ribosomes with colicin E3 results in the cleavage of a terminal fragment from the 16S ribosomal RNA. The cleavage reaction requires three components: colicin E3, the 30S ribosomal subunit, and the 50S ribosomal subunit. An immunity factor found in extracts derived from colicinogenic cells prevents the in vitro inactivation of ribosomes by colicin E3. Evidence is presented suggesting that it does so by binding to the colicin molecule. The mode of action of colicin E3 in vivo can be explained by the assumption that a small fraction of the adsorbed colicin penetrates into the cell and catalytically inactivates the ribosomes.The adsorption of colicin E3 to sensitive bacteria causes a marked inhibition of protein synthesis, which results from inactivation of the ribosomes (1, 2).In a recent communication, I have demonstrated that this effect can be reproduced in vitro: ribosomes extracted from bacteria are inactivated when incubated with purified colicin E3 (3). Both the in vivo and the in vitro inactivation of ribosomes by E3 appear to be due to the cleavage of a terminal fragment of the RNA of the 30S ribosomal subunit (4,5,3). A direct interaction between colicin E3 and the ribosomes is clearly difficult to reconcile with a model of colicin action that proposes that E3 remains attached to the outer surface of the cell while causing the degradation of the ribosomes (5-7). It is, therefore, of some importance to show that the in vitro inactivation of ribosomes by E3 involves only the colicin and the ribosomal components, and that other large components, such as contaminating fragments of the bacterial envelope, are not involved.I shall describe here the results of experiments performed with purified ribosomes and ribosomal subunits. These results confirm that E3 acts directly on the ribosomes. MATERIALS AND METHODSBacterial strains: K56 and W3110 are sensitive to E3. W3110 (E3) is colicinogenic for E3.S-30 extracts for protein synthesis were prepared; assays of in vitro protein synthesis were performed as described (3).TM buffer is 50 mM Tris * HCl (pH 7.8)-30 mM ammonium chloride-10 mM magnesium acetate.Unlabeled 50S ribosomal subunits were obtained by layering 50 A260 of S-30 on a 13-ml, 5-20% sucrose gradient in 50 mM Tris HCl (pH 7.8)-30 mM ammonium chloride-1 mM magnesium acetate. The gradients were centrifuged for 4.5 hr at 4°C in a Beckman SW 40 rotor at 40,000 rpm.Ribosomes with 3H-labeled RNA were prepared as follows: W3110 was grown in the presence of [3H]uracil treated with lysozyme and EDTA, and then lysed with Brij 58 in the presence of DNase (8). S-30 extracts were obtained by centrifugation of the lysate at 30,000 X g for 50 min to eliminate cell debris. Labeled 70S ribosomes and 30S subunits were obtained by incubation of the labeled S-30 for 20 min at 37°C with amino acids under conditions allowing protein synthesis, and layering the mixture on a 13-ml, 5-20% sucrose gradient in 5 mM Tris HCl (pH 7.5)-10 mM magnesium acetate-60 mM potassium chloride. The gradients ...

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Génétique des Bactériophages

Cited by 5 publications

References 105 publications

Colicins and other Bacteriocins with Established Modes of Action

Colicins and other Bacteriocins with Established Modes of Action

Mechanism of Action of Colicines

Inactivation of Ribosomes In Vitro by Colicin E ₃ and Its Mechanism of Action

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Génétique des Bactériophages

Cited by 5 publications

References 105 publications

Colicins and other Bacteriocins with Established Modes of Action

Colicins and other Bacteriocins with Established Modes of Action

Mechanism of Action of Colicines

Inactivation of Ribosomes In Vitro by Colicin E 3 and Its Mechanism of Action

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Inactivation of Ribosomes In Vitro by Colicin E ₃ and Its Mechanism of Action