Pyridylbenzimidazole‐Based Gold(III) Complexes: Lysozyme Metalation, DNA Binding Studies, and Biological Activity

Abstract

The lysozyme binding affinity of new Au(III) complexes, bearing pyridylbenzimidazole ligands, was investigated by ESI-MS and UV/Vis. Metalation of lysozyme happened mainly by {Au} n+ , {AuCl} 0/n+ and {AuCl 2 } n+/-. The appendage sulfonate group of pyridylbenzimidazole ligand system played a role in determining the products of interaction of HEWL with Au(III) complexes. The hydrophilic sulfonate group inhibited the ligand cleavage via the participation in several coulombic and H-bond interactions giving several AuL n+ containing adduct peaks (L = 1-[(pyridin-2-yl) benzimidazole]-propyl-sulfonic acid). The stability of the complexes in presence of ascorbic acid was examined by UV/Vis and 13 C NMR. To recognize if His15 side-chain is the [a]

Role of the Metal Center in the Modulation of the Aggregation Process of Amyloid Model Systems by Square Planar Complexes Bearing 2-(2′-pyridyl)benzimidazole Ligands

“…The stability of complexes was also evaluated in 10 mM ammonium acetate buffer at pH 6.8 that was employed for mass samples (Figure S1), see below. Since NPM1 264-277, has an intrinsic absorption band at 275 nm due to the presence of a Tyr residue , an additional control experiment was carried out to assess that observed signal variations are due to an effective interaction of the metal compounds with the peptide (Figure S2) [22,39].…”

“…The source parameters were: 3.7 kV for capillary voltage and 42 kV for cone voltage. The acquisition range was set from 600 to 2500 m/z for NPM1 264-277 and from 700 to 2500 m/z for Aβ [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] . Raw data were elaborated by using MassLynx 4.1 software (Waters, Milford, MA, USA).…”

“…The solution was maintained under magnetic stirring in a 10 mm path-length quartz cuvette. Experimental conditions: 0.1% DMSO, 10 mM borate buffer (Merck KGaA, Darmstadt, Germany) at pH = 9.0 for NPM1 264-277 and 0.1% DMSO, 10 mM sodium phosphate buffer for Aβ [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] . Reported fluorescence values are the mean of two independent experiments.…”

“…As already reported [5], the two peptides have rather different aggregation times, since they differ both in amino acidic composition and length. Thus, 1 and 2 were added to the aggregates at different times, as indicated in Figure 3 (after 15 min for NPM1 264-277 and after 90 min for Aβ [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

“…First, the effects of the presence of NPM1 264-277 and Aβ 21-40 on the spectroscopic properties of 1-3 were investigated. In particular, the changes of the intensity and/or of the position of Ligand to Metal or Metal to Ligand Charge Transfer (LMCT or MLCT) bands in the UV-Vis absorption spectra [22,39], upon the addition of peptide to a solution of the metal compounds at a fixed concentration, were monitored. The addition of both amyloid sequences to 1 (Figure 4A) causes slightly shifts of λ max that is hypsochromic for NPM1 264-277 (at 335 → 333 nm) and bathochromic for Aβ 21-40, (290 → 330 nm) .…”