Periodical
A novel transcription initiation factor (TIF), TIF-IE, is required for homogeneous Acanthamoeba castellanii TIF-IB (SL1) to form a committed complex.
| العنوان: | A novel transcription initiation factor (TIF), TIF-IE, is required for homogeneous Acanthamoeba castellanii TIF-IB (SL1) to form a committed complex. |
|---|---|
| المؤلفون: | Radebaugh, C A, Kubaska, W M, Hoffman, L H, Stiffler, K, Paule, M R |
| المصدر: | Journal of Biological Chemistry; October 1998, Vol. 273 Issue: 42 p27708-15, 8p |
| مستخلص: | The fundamental transcription initiation factor (TIF) for ribosomal RNA expression by eukaryotic RNA polymerase I, TIF-IB, has been purified to near homogeneity from Acanthamoeba castellanii using standard techniques. The purified factor consists of the TATA-binding protein and four TATA-binding protein-associated factors with relative molecular weights of 145,000, 99,000, 96,000, and 91,000. This yields a calculated native molecular weight of 460, 000, which compares well with its mass determined by scanning transmission electron microscopy (493,000) and its sedimentation rate, which is close to RNA polymerase I (515,000). Both impure and nearly homogeneous TIF-IB exhibit an apparent equilibrium dissociation constant of 56 +/- 3 pM. However, although impure TIF-IB can form a promoter-DNA complex resistant to challenge by other promoter-containing DNAs, near homogeneous TIF-IB cannot do so. An additional transcription factor, dubbed TIF-IE, restores the ability of near homogeneous TIF-IB to sequester DNA into a committed complex. |
| قاعدة البيانات: | Supplemental Index |
Full Text Finder | تدمد: | 00219258 1083351X |
|---|