A unique low frequency Raman band associated with metal binding to metallothionein.
We find that the low frequency Raman spectrum of Zn(II) metallothionein has a single prominent band at 138 cm-1 which is absent from the Raman spectrum of the metal-free protein. This feature is also found for Cd(II) binding to both of the independent metallothionein domains and the metallothionein from Neurospora crassa. TcO(III) coordination to metallothionein results in a similar Raman band which is also found for the complex (Ph4As)[ReO(SCH2CH2S)2]. By comparing these results to literature data for metal-thiolate complexes, this feature is identified as a bending vibration which appears to be characteristic of metal ion coordination by the metallothionein cysteines. Two likely assignments are a symmetric metal-centered mode (delta S-M-S) or a bending mode of the metal-coordinated cysteine thiolates (delta M-S-C).
Elgren
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Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755.
Wilcox
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D000818:Animals; D002104:Cadmium / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism*; D009492:Neurospora crassa; D011817:Rabbits; D013059:Spectrum Analysis, Raman; D015032:Zinc / Q000378:metabolism
D002104:Cadmium; D008668:Metallothionein; D015032:Zinc