ThemetalbindingsitesinthetwoPtcontainingmetallothioneins(Pt-MTandPt14MT)wereexaminedbymeansofPt(II)L3-edgeextendedX-rayabsorptionrinestructure(EXAFS)spectroscopy.ComparisonsbetweenthephaseandamplitudefunctionsderivedfromtheisolatedshellstothoseofPt…Pt.Pt-SandPt-NmodelcomponentsshowedthateachplatinuminPt7MTwascoordinatedbyfoursulfuratomsatadistanceof2.31±0.01A.AnalysisoftheoutershelldataofplatinumatominPt7MTindicatedbackscatteringplatinumatomatapproximate4.29A.StrkinglydifferentstructuralparametershadbeenobtainedforthePt14MTspecies.fittingofthefirstshellrevealedthateachplatinumwascoordinatedbytwosulfursatthedistanceof2.3-±0.02Aandtwonitrogensat2.02±0.02A.TheresultsoftheworkprovidedthedetailedinformationconcerningthelocalenvironmentsofthecoordinatedPt(II)inthesetwoplatinothioneins.
