Stability of structure of cytokine EMAP II at elevation of temperature

A. Malyna1,2, O. Kozlov1, S. Levchenko1, O. Kornelyuk1,2

1 Institute of Molecular Biology and Genetics, NAS of Ukraine
150, Akademik Zabolotnyi St., Kyiv 03143, Ukraine
2 Institute of High Technology, Taras Shevchenko National University of Kyiv
4g, Akademik Gloushkov St., Kyiv 03022, Ukraine

The objective of this study was to investigate the effect of elevation of the temperature on the stability of cytokine EMAP II by fluorescence spectroscopy. Protein expression was performed in cells of Escherichia coli BL21(DE3)pLysE and purified by metalchelate chromatography. Fluorescence spectrs of EMAP II were registered at excitation of 280 nm and fluorescence intensity was measured in the wavelength range of 300–400 nm. Local conformational transition has been observed in structure of EMAP II associated with exposure of Trp128 residue on protein surface with temperature elevation. However, for heated EMAP IIf such local conformational transition was blocked and structure of protein globule was stabilizated. These results in the overlap of “pockets” from residue Trp128 N-terminal fragment of 43 amino acid residues in EMAP ˛˛f molecule.

Keywords: EMAP II, protein denaturation, fluorescence spectroscopy, protein stabilization

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