Metal-ion-specific screening of charge effects in protein amide H/D exchange and the Hofmeister series
| Autor: | Bryan F. Shaw, Richard A. Mowery, Alireza Abdolvahabi, Yunhua Shi, Jennifer L Gober |
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| Rok vydání: | 2014 |
| Předmět: |
Ions
Models Molecular Chromatography Hofmeister series Myoglobin Lysine Mass spectrometry Deuterium Amides Chemistry Techniques Analytical Analytical Chemistry Metal chemistry.chemical_compound Crystallography chemistry Acetylation Amide visual_art Metals Alkaline Earth visual_art.visual_art_medium Thermostability Hydrogen |
| Zdroj: | Analytical chemistry. 86(20) |
| ISSN: | 1520-6882 |
| Popis: | In this study, protein charge ladders and mass spectrometry were used to quantify how metal cations in the Hofmeister series (Na(+), K(+), Li(+), Mg(2+), and Ca(2+)) permute the effects of lysine acetylation on the rate of amide H/D exchange in a representative protein (myoglobin, Mb). The successive acetylation of up to 18 Lys-ε-NH3(+) groups in Mb caused a linear decrease in its global rate of amide H/D exchange (as measured by mass spectrometry), despite also decreasing the thermostability of Mb by10 °C. The ability of a metal cation to screen kinetic electrostatic effects during H/D exchange-and to abolish the protective effect of acetylation against H/D exchange-was found to depend on the position of the cation in the Hofmeister series. Na(+) and K(+) cations did not fully equalize the rates of H/D exchange among each "rung" of the charge ladder, whereas Mg(2+) and Ca(2+) did equalize rates without eliminating the hydrophobic core of the protein (i.e., without unfolding Mb); Li(+) exhibited intermediate effects. The ability of Mg(2+) and Ca(2+) to completely screen electrostatic effects associated with the H/D exchange of charge isomers of Mb suggests that Mg(2+) or Ca(2+) (but not Na(+) or K(+)) can be used to quantify the magnitude by which electrostatic charge contributes to the observed rates of amide H/D exchange in proteins. |
| Databáze: | OpenAIRE |
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