Mercury(II) complex formation with glutathione in alkaline aqueous solution

Original Paper


The structure and speciation of the complexes formed between mercury(II) ions and glutathione (GSH = L-glutamyl-L-cysteinyl-glycine) have been studied for a series of alkaline aqueous solutions (\( C_{{{\text{Hg}}^{{2 + }}}}\,{\sim18\,{\rm{mmol}}\,{\rm{{dm^{-3}}}}}\) and C GSH = 40–200 mmol dm−3 at pH ∼10.5) by means of extended X-ray absorption fine structure (EXAFS) and 199Hg NMR spectroscopy at ambient temperature. The dominant complexes are [Hg(GS)2]4− and [Hg(GS)3]7−, with mean Hg–S bond distances of 2.32(1) and 2.42(2) Å observed in digonal and trigonal Hg–S coordination, respectively. The proportions of the Hg2+–glutathione complexes were evaluated by fitting linear combinations of model EXAFS oscillations representing each species to the experimental EXAFS spectra. The [Hg(GS)4]10− complex, with four sulfur atoms coordinated at a mean Hg–S bond distance of 2.52(2) Å, is present in minor amounts (<30%) in solutions containing a large excess of glutathione (C GSH ≥ 160 mmol dm−3). Comparable alkaline mercury(II) cysteine (H2Cys) solutions were also investigated and a reduced tendency to form higher complexes was observed, because the deprotonated amino group of Cys2− allows the stable [Hg(S,N-Cys)2]2− chelate to form. The effect of temperature on the distribution of the Hg2+–glutathione complexes was studied by comparing the EXAFS spectra at ambient temperature and at 25 K of a series of glycerol/water (33/67, v/v) frozen glasses with \( C_{{{\text{Hg}}^{{2 + }} }} \,{\sim7\,{\rm{mmol}}\,{\rm{{dm^{-3}}}}} \) and C GSH = 16–81 mmol dm−3. Complexes with high Hg–S coordination numbers, [Hg(GS)3]7− and [Hg(GS)4]10−, became strongly favored when just a moderate excess of glutathione (C GSH ≥28 mmol dm−3) was used in the glassy samples, as expected for a stepwise exothermic bond formation. Addition of glycerol had no effect on the Hg(II)–glutathione speciation, as shown by the similarity of the EXAFS spectra obtained at room temperature for two parallel series of Hg(II)-glutathione solutions with \( C_{{{\text{Hg}}^{{2 + }} }} \,{\sim7\,{\rm{mmol}}\,{\rm{{dm^{-3}}}}},\) with and without 33% glycerol. Also, the 199Hg NMR chemical shifts of a series of ∼18 mmol dm−3 mercury(II) glutathione solutions with 33% glycerol were not significantly different from those of the corresponding series in aqueous solution.


Mercury(II) Glutathione Solution EXAFS 199Hg NMR 



We thank Mrs. Qiao Wu and Dorothy Fox, at the Instrumentation Facility, Department of Chemistry, University of Calgary, for their skillful assistance with NMR measurements. We are grateful to Professor Jürgen Gailer, Shawn Manely and Katie Pei for the ICP measurements. X-ray absorption measurements were carried out at the Photon Factory, Tsukuba, Japan (proposal No. 2005G226) and SSRL (proposal No. 2848), a US national user facility operated by Stanford University on behalf of the US Department of Energy, Office of Basic Energy Sciences. The SSRL Structural Molecular Biology Program is supported by the Department of Energy, Office of Biological and Environmental Research, and by the National Institutes of Health, National Center for Research Resources, Biomedical Technology Program. We gratefully acknowledge the Natural Sciences and Engineering Research Council (NSERC) of Canada, Canadian Foundation of Innovations (CFI), Alberta Science and Research Investments Program (ASRIP) and Alberta Synchrotron Institute (ASI) for providing financial support. Farideh Jalilehvand is a recipient of a NSERC University Faculty Award (UFA).

Supplementary material


  1. 1.
    Meister A, Anderson ME (1983) Annu Rev Biochem 52:711–760PubMedCrossRefGoogle Scholar
  2. 2.
    Meister A (1988) J Biol Chem 263:17205–17208PubMedGoogle Scholar
  3. 3.
    Meister A, Tate SS (1976) Annu Rev Biochem 45:559–604PubMedCrossRefGoogle Scholar
  4. 4.
    Mehra RK, Mulchandani P (1995) Biochem J 307:697–705PubMedGoogle Scholar
  5. 5.
    Bae W, Mehra RK (1997) J Inorg Biochem 68:201–210CrossRefGoogle Scholar
  6. 6.
    Singhal RK, Anderson ME, Meister A (1987) FASEB J 1:220–223PubMedGoogle Scholar
  7. 7.
    Rauser WE (2001) In: Significance of glutathione in plant adaptation to the environment. Kluwer Academic, Dordrecht, pp 123–154Google Scholar
  8. 8.
    Zenk MH (1996) Gene 179:21–30PubMedCrossRefGoogle Scholar
  9. 9.
    Mehra RK, Kodati R, Abdullah R (1995) Biochem Biophys Res Commun 215:730–736PubMedCrossRefGoogle Scholar
  10. 10.
    Cotton FA, Wilkinson G, Murillo CA, Bochmann M (eds) (1999) Advanced inorganic chemistry, 6th edn. Wiley, New York, pp 614–615Google Scholar
  11. 11.
    Jalilehvand F, Leung BO, Izadifard M, Damian E (2006) Inorg Chem 45:66–73PubMedCrossRefGoogle Scholar
  12. 12.
    Oram PD, Fang X, Fernando Q, Letkeman P, Letkeman D (1996) Chem Res Toxicol 9:709–712PubMedCrossRefGoogle Scholar
  13. 13.
    Rabenstein DL, Isab AA (1982) Biochim Biophys Acta 721:374–384PubMedCrossRefGoogle Scholar
  14. 14.
    Stricks W, Kolthoff IM (1953) J Am Chem Soc 75:5673–5681CrossRefGoogle Scholar
  15. 15.
    Kapoor RC, Doughty G, Gorin G (1965) Biochim Biophys Acta 100:376–383PubMedGoogle Scholar
  16. 16.
    Neville GA, Drakenberg T (1974) Acta Chem Scand B 28:473–477PubMedCrossRefGoogle Scholar
  17. 17.
    Burford N, Eelman MD, Groom K (2005) J Inorg Biochem 99:1992–1997PubMedCrossRefGoogle Scholar
  18. 18.
    Rubino FM, Verduci C, Giampiccolo R, Pulvirenti S, Brambilla G, Colombi A (2004) J Am Soc Mass Spectrom 15:288–300PubMedCrossRefGoogle Scholar
  19. 19.
    Cheesman BV, Arnold AP, Rabenstein DL (1988) J Am Chem Soc 110:6359–6364CrossRefGoogle Scholar
  20. 20.
    Shoukry MM, Cheesman BV, Rabenstein DL (1988) Can J Chem 66:3184–3189CrossRefGoogle Scholar
  21. 21.
    Wright JG, Natan MJ, MacDonnell FM, Ralston DM, O’Halloran TV (1990) Prog Inorg Chem 38:323–412CrossRefGoogle Scholar
  22. 22.
    Fuhr BJ, Rabenstein DL (1973) J Am Chem Soc 95:6944–6950PubMedCrossRefGoogle Scholar
  23. 23.
    Percy AJ, Korbas M, Gerorge GN, Gailer J (2007) J Chromatogr A 1156:331–339PubMedCrossRefGoogle Scholar
  24. 24.
    Sudmeier JL, Birge RR, Perkins TG (1978) J Magn Reson 30:491–496Google Scholar
  25. 25.
    Bowmaker GA, Harris RK, Oh SW (1997) Coord Chem Rev 167:49–94Google Scholar
  26. 26.
    Katōno Y, Inoue Y, Chûjô R (1977) Polymer J 9:471–478CrossRefGoogle Scholar
  27. 27.
    Leung BO, Jalilehvand F, Mah V (2007) J Chem Soc Dalton Trans 4666–4674Google Scholar
  28. 28.
    Levina A, Armstrong RS, Lay PA (2005) Coord Chem Rev 249:141–160CrossRefGoogle Scholar
  29. 29.
    Nakamoto N (ed) (1997) Infrared and Raman spectra of inorganic and coordination compounds, part A, 5th edn. Wiley, New York, p 199Google Scholar
  30. 30.
    Klose G, Volke F, Peinel G, Knobloch G (1993) Magn Reson Chem 31:548–551CrossRefGoogle Scholar
  31. 31.
    Taguchi T, Ozawa T, Yashiro H (2005) Phys Scr T115:205–206CrossRefGoogle Scholar
  32. 32.
    Ressler T (1998) J Synchrotron Rad 5:118–122CrossRefGoogle Scholar
  33. 33.
    Zabinsky SI, Rehr JJ, Ankudinov A, Albers RC, Eller MJ (1995) Phys Rev B 52:2995–3009CrossRefGoogle Scholar
  34. 34.
    Ankudinov AL, Rehr JJ (1997) Phys Rev B 56:R1712–R1716CrossRefGoogle Scholar
  35. 35.
    Kim C-H, Parkin S, Bharara M, Atwood D (2002) Polyhedron 21:225–228CrossRefGoogle Scholar
  36. 36.
    Fleischer H, Dienes Y, Mathiasch B, Schimitt V, Schollmeyer D (2005) Inorg Chem 44:8087–8096PubMedCrossRefGoogle Scholar
  37. 37.
    George GN, Pickering IJ (1995) EXAFSPAK: a suite of programs for analysis of X-ray absorption spectra. SSRL, Stanford, CAGoogle Scholar
  38. 38.
    Benison GC, Di Lello P, Shokes JE, Cosper NJ, Scott RA, Legault P, Omichinski JG (2004) Biochemistry 43:8333–8345PubMedCrossRefGoogle Scholar
  39. 39.
    Atkins PW (ed) (1989) Physical chemistry, 3rd edn. Oxford University Press, Oxford, pp 221–224Google Scholar
  40. 40.
    Utschig LM, Bryson JW, O’Halloran TV (1995) Science 268:380–385PubMedCrossRefGoogle Scholar
  41. 41.
    Utschig LM, Wright JG, Dieckmann G, Pecoraro V, O’Halloran TV (1995) Inorg Chem 34:2497–2498CrossRefGoogle Scholar
  42. 42.
    Utschig LM, Baynard T, Strong C, O’Halloran TV (1997) Inorg Chem 36:2926–2927PubMedCrossRefGoogle Scholar
  43. 43.
    Natan MJ, Millikan CF, Wright JG, O’Halloran TV (1990) J Am Chem Soc 112:3255–3257CrossRefGoogle Scholar

Copyright information

© SBIC 2008

Authors and Affiliations

  1. 1.University of CalgaryCalgaryCanada

Personalised recommendations