The clinically established gold drug Auranofin was reacted individually with a group of representative proteins, namely ubiquitin, ribonuclease A, carbonic anhydrase, haemoglobin and superoxide dismutase, and adduct formation was monitored in the various cases by ESI-MS analysis. We found that the reaction is highly selective for solvent exposed free cysteines that are modified through coordination of the AuPEt3+fragment. Indeed, ESI-Q-TOF MS spectra carried out on protein samples incubated with a three fold molar excess of Auranofin allowed direct detection of the native proteins bearing bound AuPEt3+fragments in the cases of carbonic anhydrase and haemoglobin. At variance, the two proteins that do not possess any free cysteine residue,i.e.ubiquitin and ribonuclease A, were unable to bind the gold fragment. In the case of superoxide dismutase, adduct formation is hindered by the scarce solvent accessibility of the free cysteine residue. These findings were further confirmed by a series of competition binding experiments with ebselen, a potent and selective cysteine-modifying reagent; we observed that pre-treatment with ebselen prevents the binding of the AuPEt3+fragment to both carbonic anhydrase and haemoglobin.

ESI MS studies highlight the selective interaction of Auranofin with protein free thiols / Zoppi C.; Messori L.; Pratesi A.. - In: DALTON TRANSACTIONS. - ISSN 1477-9226. - STAMPA. - 49:(2020), pp. 5906-5913. [10.1039/d0dt00283f]

ESI MS studies highlight the selective interaction of Auranofin with protein free thiols

Zoppi C.;Messori L.
;
Pratesi A.
2020

Abstract

The clinically established gold drug Auranofin was reacted individually with a group of representative proteins, namely ubiquitin, ribonuclease A, carbonic anhydrase, haemoglobin and superoxide dismutase, and adduct formation was monitored in the various cases by ESI-MS analysis. We found that the reaction is highly selective for solvent exposed free cysteines that are modified through coordination of the AuPEt3+fragment. Indeed, ESI-Q-TOF MS spectra carried out on protein samples incubated with a three fold molar excess of Auranofin allowed direct detection of the native proteins bearing bound AuPEt3+fragments in the cases of carbonic anhydrase and haemoglobin. At variance, the two proteins that do not possess any free cysteine residue,i.e.ubiquitin and ribonuclease A, were unable to bind the gold fragment. In the case of superoxide dismutase, adduct formation is hindered by the scarce solvent accessibility of the free cysteine residue. These findings were further confirmed by a series of competition binding experiments with ebselen, a potent and selective cysteine-modifying reagent; we observed that pre-treatment with ebselen prevents the binding of the AuPEt3+fragment to both carbonic anhydrase and haemoglobin.
2020
49
5906
5913
Goal 3: Good health and well-being for people
Zoppi C.; Messori L.; Pratesi A.
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1212681
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