INVESTIGADORES
BLANK Viviana Claudia
artículos
Título:
Suitable experimental conditions are required to characterize interferon-á2b synthetic peptides
Autor/es:
VIVIANA C. BLANK; CLARA PEÑA; LEONOR P. ROGUIN
Revista:
EUROPEAN JOURNAL OF BIOCHEMISTRY
Editorial:
Blackwell Synergy
Referencias:
Año: 2000 vol. 267 p. 5711 - 5716
ISSN:
0014-2956
Resumen:
The binding and antiproliferative activities of synthetic peptides 29?35 and 122?139 of interferon-á2b, both of which contain a cysteine residue in their sequences, were studied in the presence or absence of a dissociation medium containing mainly urea, dithiothreitol and 2-mercaptoethanol. Although interferon-á2b peptides either did not modify or slightly increased 125I-labelled interferon-á2b specific binding to WISH cell-membrane receptors in the absence of dissociation medium, significant binding inhibition was obtained when both peptides were assayed in dissociation medium. Furthermore, also in the presence of dissociating agents, the two fragments inhibited cell growth in a concentration-dependent manner, the 122?139 sequence being more effective than the 29?35 sequence. No additive effect on interferon binding and cell proliferation was observed when both peptides were added simultaneously. Results obtained after submitting peptide 122?139 to gel filtration or PAGE under different experimental conditions showed the presence of dimers and/or noncovalent aggregates arising from intermolecular disulfide bridges or hydrophobic interactions. Thus, our results indicated that peptide effects on 125I-labelled interferon-á2b binding and WISH cell proliferation were clearly manifested when the amount of monomeric species increased, showing that suitable experimental conditions should be used to study peptide behavior. The ability of both peptides to effectively trigger an interferon-specific biological action, such as cell growth inhibition, strongly suggested that 29?35 and 122?139 interferon-á2b fragments constitute the conformational epitope or mimotope that interacts with the cytokine-specific receptor.