Colicine K

Hinsdill, Ronald D.; Goebel, Walther F.

doi:10.1084/jem.123.5.881

Cited by 4 publications

(5 citation statements)

References 18 publications

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“…Our early work (2) revealed that both colicins K (3) and V (4), obtained from the culture medium of the respective microorganisms, were invariably associated with the 0 antigen of the bacterium in question-an observation that was subsequently corroborated by others (5). We showed, furthermore, that when type K colicinogeny was transferred from a strain of Escherichia coli to an unrelated dysentery bacillus by mating, the bacteriocin and 0 antigen of the latter were inseparable (6). Despite this, we have always been alert to the possibility that the two might well be separate entities.…”

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confidence: 53%

“…When the colicin is recovered it has, in those instances thus far studied, proved to be associated with the lipopolysaccharide antigen of the bacillus in question (2)(3)(4)(5)(6). The use of the inducing agent mitomycin C, on the other hand, enhances the elaboration of the bacteriocin to such an extent that the latter can now actually be isolated as a free protein from the culture medium (9) or extracted from the bacterial cells themselves (9,13).…”

Section: Discussionmentioning

confidence: 99%

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The Nature of the Colicin K of Escherichia coli K235

Goebel

1973

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

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When E. coli K235 is grown in the presence of mitomycin C it elaborates part of its colicin as a protein, which has been purified by gel filtration and electrofocusing to yield a product that is serologically homogeneous. The colicin K of E. coli K235 is chemically and serologically identical with that of Proteus mirabilis. Like the colicin of the latter, the E. coli bacteriocin occurs in multiple forms that exhibit slight differences in mobility upon electrophoresis in a polyacrylamide gel.The exact chemical nature of the colicins has been established only in the past several years, an achievement made possible by the addition of inducing agents to the culture media in which the colicinogenic microorganisms are grown (1). When we began our investigations of these potent bactericidal agents in 1953 not much was known of them. Our early work (2) revealed that both colicins K (3) and V (4), obtained from the culture medium of the respective microorganisms, were invariably associated with the 0 antigen of the bacterium in question-an observation that was subsequently corroborated by others (5). We showed, furthermore, that when type K colicinogeny was transferred from a strain of Escherichia coli to an unrelated dysentery bacillus by mating, the bacteriocin and 0 antigen of the latter were inseparable (6). Despite this, we have always been alert to the possibility that the two might well be separate entities. Indeed, we showed that when the 0 antigen-bacteriocin complex was dissociated into its components, the lipopolysaccharide and protein, it was the protein that bore the bacteriocin (3). Thus, the protein nature of these agents was at that time firmly established.The first investigator to obtain a bacteriocin from cultures of a colicinogenic micororganism by induction with ultraviolet light was Reeves (7), who isolated colicin F (now colicin E2). He showed it to be a protein, albeit his substance was still contaminated with carbohydrate. Colicin K from a strain of Proteus mirabilis was the first of the bacteriocins to be obtained in a state of purity and to be unequivocally characterized as a protein (8). Its molecular weight, aminoacid composition, and immunological properties were all thoroughly described (9). Shortly thereafter, this same bacteriocin was obtained from a strain of E. coli K12 (10), and several years later a brief description of its isolation from E. coli K235 appeared (11). More recently, the isolation of colicins A, E, Q, and K, presumably in states of purity, was described (12). Some months after the characterization of colicin K from P. mirabilis (8) In this communication we shall describe the isolation of colicin K from a culture of E. coli K235 induced with mitomycin C, and we shall show that the bacteriocin apparently exists in two forms-one a protein identical in all respects with the colicin K from P. mirabilis, the other the bacteriocin associated with the 0 antigen of the bacillus (and will be described in a later communication). EXPERIMENTALPreparation of Colicin K. The col...

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confidence: 53%

Section: Discussionmentioning

confidence: 99%

The Nature of the Colicin K of Escherichia coli K235

Goebel

1973

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

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“…Sugar Content. Since colicin K contains the lipopolysaccharide of the somatic O antigen (Hinsdill and Goebel, 1966), colicins Ea-I and E3-II were examined for sugar content. Enzymatic determination of glucose after mild acid hydrolysis showed less than 0.1 mole of glucose/mole of colicin in each of these proteins.…”

Section: Resultsmentioning

confidence: 99%

Multiple forms of colicin E₃ from Escherichia coli CA-38 (col E₃, col I)

Glick¹,

Kerr²,

Gold³

et al. 1972

Biochemistry

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“…If type K colicinogeny is transferred by mating to the unrelated organism Sh. sonnei (7), again it is the type-specific O antigen which bears the bacteriocin. Here too it was found that the neutralizing antibody elicited by the colicinogenic dysentery bacillus also failed to precipitate the homologous antigen.…”

Section: Discussionmentioning

confidence: 99%

“…We have suggested, therefore, that the inability of noninduced coticin to precipitate neutralizing antibody might be due to a steric hindrance of its antibody binding sites by the lipopolysaccharide component of the complex (7). In some measure this hypothesis is made more tenable by the fact that when Col K is dissociated with liquid phenol into its lipopolysaccharide and protein constituents, the colicin-rich protein is now capable of precipitating the neutralizing antibody (10).…”

Section: Discussionmentioning

confidence: 99%

Colicin K

Tsao

Goebel

1969

The Journal of Experimental Medicine

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I t was a decade and a half ago when our laboratory initiated its investigation on the chemical and immunological nature of the colicins.These potent antibacterial substances, which are elaborated by a variety of enteric microorganisms, had never been fully characterized since their discovery by Gratia (1) in 1925. To be sure, over the years there have appeared assertions that these are proteins, and perhaps for good reason, for their biological activity was known to be destroyed by proteolytic enzymes (2). Yet a search of the literature, until but a few years ago, yielded no other convincing evidence that this was indeed their true nature. More recently this situation has changed. There are now several investigators who have obtained highly purified colicins, the syntheses of which are induced with the antibiotic mitomycin C, a reagent which kills the growing colicinogenic bacillus and radically alters its metabolic processes, but which permits, indeed even enhances, the synthesis of the bacteriocin (3-5). From such cultures there have been obtained bacteriocins which are unquestionably protein in nature. One must not lose sight of the fact, however, that the conditions under which these bacteriocins are elaborated are considerably different from those of microorganisms growing in a medium devoid of mitomycin.Our earlier work with Escherichia coli K235 (6) and with a colicinogenic strain of Shigella sonnei phase I I (7), as well as with a colon bacillus which elaborates colicin V (8), has all pointed toward the fact that the type-specific O antigen of these bacilli is in each instance bactericidal. It has been our premise that the colicins are an integral part of the O antigenic complexes and that they cannot be separated from them by electrophoretic or chromatographic means (9). It must be emphasized, however, that we have always been alert to the possibility that colicin protein and O antigen are in some way intimately bound, and that their separation might not have been achieved by the procedures employed.Early in our work we showed that the colicin K derived from E. coli K235 elaborated two types of antibodies, one which precipitated the substance, and the other which neutralized its bactericidal activity, apparently without

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Colicine K

Cited by 4 publications

References 18 publications

The Nature of the Colicin K of Escherichia coli K235

The Nature of the Colicin K of Escherichia coli K235

Multiple forms of colicin E₃ from Escherichia coli CA-38 (col E₃, col I)

Colicin K

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Colicine K

Cited by 4 publications

References 18 publications

The Nature of the Colicin K of Escherichia coli K235

The Nature of the Colicin K of Escherichia coli K235

Multiple forms of colicin E3 from Escherichia coli CA-38 (col E3, col I)

Colicin K

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Multiple forms of colicin E₃ from Escherichia coli CA-38 (col E₃, col I)