engleski

ESR study of spin labelled ovalbumin

Method for the spin labelling of ovalbumin was developed. Interactions of spin labelled ovalbumin (SL-OVA) with multilayer liposomes and immunostimulating peptidoglycan monomer were investigated by Electron Spin Resonance (ESR) spectroscopy. Ovalbumin (OVA) is the major protein in avian egg-white. It belongs to the serpin (serine protease inhibitors) family but it lacks any protease inhibitory activity. Among the others OVA has been used as a model protein antigen in our investigations of adjuvant effects of immunostimulating peptides [1]. Spin labelling was succesfully applied in the study of interactions of peptidoglycan monomer and structurally related adamantyltripeptides with lipid bilayers in liposomes [2]. The aim of the present study has been to investigate the possible interactions of OVA with immunostimulating peptides and with liposomal bilayers by (ESR). Ovalbumin was spin labelled with 4-maleimido-2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO-maleimide) that binds covalently to -SH groups of cisteins and terminal amino groups of lysines. Presence of two motionally different populations of the spin labels were determined from the ESR spectra of the spin labelled ovalbumin: with a highly restricted motion relative to the protein, located far from the protein surface, and with free motion located at the protein surface. [1] J. Tomašić, I. Hanzl-Dujmović, B. Špoljar, B. Vranešić, M. Šantak, A. Jovičić, Vaccine 18 (2000) 1236-1243. [2] R. Frkanec, V. Noethig Laslo, B. Vranešić, K. Mirosavljević and J. Tomašić, Biochim. Biophys. Acta, 1611 (2003) 187-195.

ovalbumin; electron spin resonance; liposomes

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