Specific electrolyte effects on hemoglobin in denaturing medium investigated through electro spray ionization mass spectrometry.

Autor: Pivetta T; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy., Lusci G; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy., Carucci C; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy., Parsons DF; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy. Electronic address: drew.parsons@unica.it., Salis A; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy. Electronic address: asalis@unica.it., Monduzzi M; Dept. Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria, S.S. 554 bivio Sestu, 09042 Monserrato, Cagliari, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy. Electronic address: monduzzi@unica.it.
Jazyk: angličtina
Zdroj: Journal of inorganic biochemistry [J Inorg Biochem] 2022 Sep; Vol. 234, pp. 111872. Date of Electronic Publication: 2022 May 24.
DOI: 10.1016/j.jinorgbio.2022.111872
Abstrakt: We examine Hofmeister specific ion effects of electrolytes added to protein solution under conditions minimizing electrostatic attraction between cations and positively charged protein. Hemoglobin (Hb) in aqueous solution at the denaturing pH = 2.7 is investigated in the presence of several metal chlorides, along with sodium and potassium bromides, iodides and thiocyanates, using electrospray ionization mass spectrometry (ESI-MS). Salt concentration was varied to maximize peak intensity and bell-shaped profile in the ESI-MS spectrum. The α-chain of myoglobin is identified as the main pattern of the ESI-MS spectra in all Hb-salt systems. Both peak intensity and quality of the bell-shaped profile of the protein spectrum decrease in the cation order: K + > > Mg 2+  > Li + > > Na +  > Ca 2+  ≈ Cs +  > Rb + for Hb-Metal Chloride systems, and decrease in the anion order: Cl -  > Br -  > I -  > SCN - for systems of both Hb-NaX and Hb-KX salts. To quantify salt addition effects two Hofmeister specific electrolyte parameters H S , and P S are proposed. H S is the mean (Hb-salt)/Hb peak intensity ratio, measured for the nine peaks used for ESI-MS spectra deconvolution, taken at the same m/z values of the Hb profile. P S is the ratio between H S standard deviation and H S , and provides a specific perturbation parameter measuring the loss of protein structure. These two Hofmeister parameters give clear evidence of the effects induced either by KCl, MgCl 2 and LiCl that enhance protein peak intensity, or by NaBr, NaI, NaSCN and KSCN that induce the protein fragmentation, due to electrolyte-mediated dissociation.
(Copyright © 2022 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: