Novel zinc finger motif in the basal transcriptional machinery : three-dimensional NMR studies of the nucleic acid binding domain of transcriptional elongation factor TFIIS
Gozani, Shai N.
Yoon, Ho Sup
Jeon, Choon Ju
Weiss, Michael A.
Date of Issue1993
School of Biological Sciences
Transcriptional elongation provides a key control point in the regulation of eukaryotic gene expression. Here we describe homonuclear and lSN-heteronuclear 3D NMR studies of the nucleic acid binding domain of human transcriptional elongation factor TFIIS. This domain contains a Cys4 ZnZ+- binding site with no homology to previously characterized Cys4, Cysa, or Cysz-His2 Zn fingers. Complete lH and I5N NMR resonance assignment of a 50-residue TFIIS peptideZnz+ complex is obtained. Its solution structure, as determined by distance geometry/simulated annealing (DG/SA) calculations, exhibits a novel three-stranded antiparallel p-sheet (designated the Zn ribbon). Analogous sequence motifs occur in a wide class of proteins involved in RNA or DNA transactions, including human basal transcriptional initiation factor TFIIE. A three-dimensional model of the TFIIE Cys4 domain is obtained by DG-based homology modeling. The role of the TFIIS Zn ribbon in the control of eukaryotic transcriptional elongation is discussed.
© 1993 American Chemical Society.