Abstract
Integrin-linked kinase (ILK) is a ubiquitously expressed Ser/Thr kinase which plays significant role in the cell matrix interactions and growth factor signalling. In this study, guanidinium chloride (GdmCl)-induced unfolding of kinase domain of ILK (ILK193-446) was carried out at pH 7.5 and 25 degrees C. Eventually, denaturation curves of mean residue ellipticity at 222 nm ([theta](222)) and fluorescence emission spectrum were analysed to estimate stability parameters. The optical properties maximum emission (lambda(max)) and difference absorption coefficient at 292 nm (Delta epsilon(292)) were analysed. The denaturation curve was measured only in the GdmCl molar concentration ranging 3.0-4.2 M because protein was aggregating below 3.0 M of GdmCl concentrations. The denaturation process of ILK193-446 was found as reversible at [GdmCl] >= 3.0 M. Moreover, a coincidence of normalized denaturation curves of optical properties ([theta](222), Delta epsilon(292) and lambda(max)) suggesting that GdmCl-induced denaturation of ILK193-446 is a two-state process. In addition, 100 ns molecular dynamics simulations were performed to see the effects of GdmCl on the structure and stability of ILK193-446. Both the spectroscopic and molecular dynamics approaches provided clear insights into the stability and conformational properties of ILK193-446. (C) 2018 Elsevier B.V. All rights reserved.