Comparative 113Cd-n.m.r. studies on rabbit 113Cd7-, (Zn1,Cd6)- and partially metal-depleted 113Cd6-metallothionein-2a.
Rabbit 113Cd7-metallothionein-2a (MT) contains two metal-thiolate clusters of three (cluster B) and four (cluster A) metal ions. The 113Cd-n.m.r. spectrum of 113Cd6-MT, isolated from 113Cd7-MT upon treatment with EDTA, is similar to that of 113Cd7-MT, but the cluster B resonances are lower in intensity, suggesting its co-operative metal depletion. (Zn1,113Cd6)-MT, formed upon addition of the Zn(II) ions to 113Cd6-MT, shows 113Cd-n.m.r. features characteristic of cluster B populations containing both Cd(II) and Zn(II) ions. The overall intensity gain of the mixed cluster B resonances per Cd as to those in 113Cd6- and 113Cd7-MT suggests a stabilization effect of the bound Zn(II) ions upon the previously established intramolecular 113Cd exchange within this cluster.
Vazquez
F
F
Biochemisches Institut, Universität Zürich, Switzerland.
Vasák
M
M
D000818:Animals; D002104:Cadmium; D007554:Isotopes; D008099:Liver / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008668:Metallothionein; D011817:Rabbits; D015032:Zinc
D007554:Isotopes; C004203:cadmium-binding protein; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc