Comparison of the solution conformations of human [Zn7]-metallothionein-2 and [Cd7]-metallothionein-2 using nuclear magnetic resonance spectroscopy.
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Messerle BA, Schaffer A, Vasak M, Kagi JH, Wuthrich K
Comparison of the solution conformations of human [Zn7]-metallothionein-2 and [Cd7]-metallothionein-2 using nuclear magnetic resonance spectroscopy.
J Mol Biol. 1992 May 20;225(2):433-43.
- PubMed ID
- 1593628 [ View in PubMed]
- Abstract
The solution structure of native human [Zn7]-metallothionein-2 has been compared with the previously determined structure of human [Cd7]-metallothionein-2. The comparison was based on complete sequence-specific 1H nuclear magnetic resonance assignments for human [Zn7]-metallothionein-2 obtained using the sequential assignment method. The secondary structure was found to be very similar in the [Zn7]- and [Cd7]- forms of the protein. Only seven amide protons in [Zn7]- metallothionein-2 were found to have exchange rates lower than approximately 0.2 min-1 at pH 7.0 and 10 degrees C, which corresponds closely to the results of amide proton exchange studies with the [Cd7]- form of the protein. Finally, the 1H-1H distance constraints determined from nuclear Overhauser enhancement spectroscopy for human [Zn7]-metallothionein-2 were checked for compatibility with the [Cd7]-metallothionein-2 structure. Overall, although no direct method is available for identifying the metal-polypeptide co-ordinative bonds in the Zn(2+)-containing protein, these measurements provided several independent lines of evidence showing that the [Zn7]- and [Cd7]- forms of human metallothionein-2 have the same molecular architecture.