کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1925756 | 1536413 | 2011 | 7 صفحه PDF | دانلود رایگان |
Metallothioneins MTT1 and MTT2 from Tetrahymena thermophila have been characterized. The MTT1 contains mainly characteristic Cys-Cys-Cys and Cys-Cys clusters, but MTT2 contains mainly Cys-X-Cys cluster. Cd16-MTT1 mainly consists of α-helix and β-turns, in contrast, Cd11-MTT2 mainly consists of random coils. Reaction of Cd16-MTT1 and Cd11-MTT2 with nitric oxide leads to intramolecular disulfide bond formation, respectively. Binding stabilities of Cd2+, Hg2+ and Zn2+ to MTT1 are stronger than those to MTT2. Cu2+ can not replace Cd2+ from Cd16-MTT1 complex, but can replace Cd2+ from Cd11-MTT2 complex. The analysis of qRT-PCR revealed MTT2 mRNA levels were 31-fold higher than those of MTT1 under basal conditions. These results further suggest MTT1 possibly play a role in the detoxification of heavy metal ions, and MTT2 may be involved in the homeostasis of copper ions.
► There are marked differences in secondary conformation between Cd16-MTT1 and Cd11-MTT2.
► MTT1 exhibits much higher divalent metal-binding ability than MTT2.
► The binding ability of MTT2 with copper ions is stronger than cadmium ions.
Journal: Archives of Biochemistry and Biophysics - Volume 509, Issue 2, 15 May 2011, Pages 170–176