Synthesis of poly-γ-glutamyl-γ-aminobutyric acids and their reactivity with antiserum against Bacillus anthracis polypeptide

Kovács, J.; Kapoor, A.; Ghatak, U.R.; Mayers, George L.; Giannasio, V. R.; Giannotti, R.; Senyk, George; Nitecki, Danute E.; Goodman, Joel W.

doi:10.1021/bi00760a033

Cited by 9 publications

(2 citation statements)

References 16 publications

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“…The existing database is derived largely from a series of reports from Goodman and colleagues (11,12,18,28,32). These studies examined the interaction between polyclonal antibodies raised in rabbits and either native ␥DPGA or synthetic polypeptides.…”

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confidence: 99%

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Protective and Immunochemical Activities of Monoclonal Antibodies Reactive with theBacillus anthracisPolypeptide Capsule

Kozel¹,

Thorkildson²,

Brandt³

et al. 2007

Infect Immun

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Bacillus anthracis is surrounded by a polypeptide capsule composed of poly-gamma-D-glutamic acid (␥DPGA). In a previous study, we reported that a monoclonal antibody (MAb F26G3) reactive with the capsular polypeptide is protective in a murine model of pulmonary anthrax. The present study examined a library of six MAbs generated from mice immunized with ␥DPGA. Evaluation of MAb binding to the capsule by a capsular "quellung" type reaction showed a striking diversity in capsular effects. Most MAbs produced a rim type reaction that was characterized by a sharp increase followed directly by a decrease in refractive index at the capsular edge. Some MAbs produced a second capsular reaction well beneath the capsular edge, suggesting complexity in capsular architecture. Binding of MAbs to soluble ␥DPGA was assessed by a fluorescence perturbation assay in which a change in the MAb intrinsic fluorescence produced by ligand binding was used as a reporter for antigen-antibody interaction. The MAbs differed considerably in the complexity of the binding curves. MAbs producing rim type capsule reactions typically produced the more complex binding isotherms. Finally, the protective activity of the MAbs was compared in a murine model of pulmonary anthrax. One MAb was markedly less protective than the remaining five MAbs. Characteristics of the more protective MAbs included a relatively high affinity, an immunoglobulin G3 isotype, and a complex binding isotherm in the fluorescence perturbation assay. Given the relatively monotonous structure of ␥DPGA, the results demonstrate a striking diversity in the antigen binding behavior of ␥DPGA antibodies.

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“…These studies examined the interaction between polyclonal antibodies raised in rabbits and either native ␥DPGA or synthetic polypeptides. One of the findings of these early studies was indirect evidence that ␥DPGA may possess two distinct epitopes (12,18).…”

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confidence: 99%

Protective and Immunochemical Activities of Monoclonal Antibodies Reactive with theBacillus anthracisPolypeptide Capsule

Kozel¹,

Thorkildson²,

Brandt³

et al. 2007

Infect Immun

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External reversible control of recognition behavior of alpha‐peptide ribonucleic acid (α‐PRNA) through anti‐syn orientational switching of the nucleobase induced by borate esterification of the cis‐2′,3′‐diol

Wada¹,

Sato²,

Inoue³

2004

Biopolymers

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Critique of the interpretation of the circular dichroism of unordered polypeptides and proteins

Balasubramanian

1974

Biopolymers

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The circular dichroic (CD) profile characterizing unordered polypeptide chains and denatured proteins is the subject of much current attention. Tiffany and Krimm,' and Rippon and Walton2 have suggested that the doubly dichroic CD spectrum (positive band near 218 nm and a much larger negative band near 200 nm) obtained in ionized polyL-glutamic acid [(Glu),] and in polyl-lysine [(Lys),] chains characterize not an unordered conformation (abbreviated as U), but rather a conformation that contains regions of left-handed 31 helical order called the extended helix (abbreviated as EH). This conformational assignment was based on the similarity of this doubly dichroic CD profile with that of the polyL-proline I1 helix. Potential energy calculations, including ionic terms, on ionized (G~u),,~*( and also on ionized (Gl~-Ala),~ have yielded conformational minima for these ionized polymers at (+, $ ) 6 = 84O, 321", and 74O, 343", respectively, compared to the value 103", 326' for the polypropline I1 helix. These similarities in conformational parameters and CD spectra have led Rippon and Walton2 to conclude that the presence of a positive Cotton effect near 218 nm and a negative one near 200 nm is diagnostic of a polypeptide with 31 helical segmental order, i.e., the E H conformation.On the other hand, several workers'-9 have argued thqt the EH-type CD spectra are in fact representative of unordered structures, and that "much or all the CD data of Tiffany and Krimm may be interpreted fts mixtures of helical and unordered forms, and will not require invocation of a third structural form."8 We had observed earlier9 the ubiquity of the doubly dichroic CD spectra in a variety of polypeptides, both ionized and nonionic, under a variety of conditions. That such EH-type spectra might arise in diverse situations such as charge repulsions, protonation, or solvent binding has been claimed recently by Tiffany and Krirnm.lo However, in two recent important papers, Miller et al." have shown that under the conditions of residual blocking groups, concentration, and ionic strength of the medium, (Glu), is indeed not in the E H form, but is a random coil.Additional credence for the latter point of view is provided by the circular dichroic spectra of poly-&taspartic acid and poly-7-bglutamic acid that we present in Figure 1. These two polymers are variants of the usual poly-a-peptide sequence in that the former has an extra methylene group in the primary structural backbone, while poly-y-bglutamic acid has two methylene groups. Yet, as the figure reveals, both poly-8-lraspartate and poly-y-bglutamate display doubly dichroic spectra similar to those seen in ionized (Glu), or (Lys),. (The CD spectra of the acid forms of these two poly-w-peptides are interpreted in terms of a third Cotton effect, induced on the carboxylic acid chromoph0re.12,'~) Qualitatively similar CD spectra are exhibited by ionized copoly-(ybGluyaminobutyric acid),14 and also by the tertiary butyl esters of both these poly-w-amino acids in hexafluoroisopropanol. The additi...

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Synthesis of poly-γ-glutamyl-γ-aminobutyric acids and their reactivity with antiserum against Bacillus anthracis polypeptide

Cited by 9 publications

References 16 publications

Protective and Immunochemical Activities of Monoclonal Antibodies Reactive with theBacillus anthracisPolypeptide Capsule

Protective and Immunochemical Activities of Monoclonal Antibodies Reactive with theBacillus anthracisPolypeptide Capsule

External reversible control of recognition behavior of alpha‐peptide ribonucleic acid (α‐PRNA) through anti‐syn orientational switching of the nucleobase induced by borate esterification of the cis‐2′,3′‐diol

Critique of the interpretation of the circular dichroism of unordered polypeptides and proteins

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