Metallothionein dimers studied by nano-spray mass spectrometry.
Both transient and stable dimers of metallothionein have been characterized, based on earlier studies using NMR, circular dichroism and size-exclusion chromatography. Here additional characterization is provided by nanospray mass spectrometry. Rapid redistribution of metal ions between monomeric Cd7- and Zn7-metallothionein 2a is monitored by nanospray. An experiment in which theses two forms of the monomeric protein are separated by a dialysis membrane, which will pass metal ions but not proteins, confirms that a transient dimer must form for metal ions to be redistributed. On the other hand, size-exclusion chromatography of reconstituted Zn7- or Cd7-metallothionein revealed the presence of monomeric and dimeric species. These dimers do not equilibrate readily to form monomers and they are shown to be covalent.
Hathout
Yetrib
Y
Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA. hathout@wam.und.edu
Reynolds
Kristy J
KJ
Szilagyi
Zoltan
Z
Fenselau
Catherine
C
D000818:Animals; D002850:Chromatography, Gel; D019281:Dimerization; D008099:Liver / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008668:Metallothionein / Q000737:chemistry*; D036103:Nanotechnology; D011817:Rabbits
D008668:Metallothionein