Structural Characterization of the Cysteine-rich Domain of TFIIH p44 Subunit

Sébastien Fribourg,Esther Kellenberger,Hélène Rogniaux,Arnaud Poterszman,Alain Van Dorsselaer,Jean-Claude Thierry,Jean-Marc Egly,Dino Moras,Bruno Kieffer

doi:10.1074/jbc.m004960200

Abstract

In an effort to understand the structure function relationship of TFIIH, a transcription/repair factor, we focused our attention on the p44 subunit, which plays a central role in both mechanisms. The amino-terminal portion of p44 has been shown to be involved in the regulation of the XPD helicase activity; here we show that its carboxyl-terminal domain is essential for TFIIH transcription activity and that it binds three zinc atoms through two independent modules. The first contains a C4 zinc finger motif, whereas the second is characterized by a CX(2)CX(2-4)FCADCD motif, corresponding to interleaved zinc binding sites. The solution structure of this second module reveals an unexpected homology with the regulatory domain of protein kinase C and provides a framework to study its role at the molecular level.

Highlights

Transcription of protein coding genes in eukaryotes requires the formation at core promoters of a multiprotein complex composed of RNA polymerase II and the general transcription factors TFIIA, -IIB, -IID, -IIE, -IIF, and -IIH
The amino-terminal portion of the p44 subunit of TFIIH is involved in the regulation of XPD helicase activity (15)
The p44 Carboxyl-terminal Domain Is Essential for Transcription Activity—Two recombinant TFIIH complexes in which the p44 subunit was deleted at its carboxyl-terminal end from amino acid 252–395 (p44⌬(252–395)) and from 321–395 (p44⌬(321–395)) were generated

Summary

Introduction

Transcription of protein coding genes in eukaryotes requires the formation at core promoters of a multiprotein complex composed of RNA polymerase II and the general transcription factors TFIIA, -IIB, -IID, -IIE, -IIF, and -IIH (reviewed in Refs. 1–3). The amino-terminal portion of p44 has been shown to be involved in the regulation of the XPD helicase activity; here we show that its carboxyl-terminal domain is essential for TFIIH transcription activity and that it binds three zinc atoms through two independent modules. The p44 Cysteine-rich Domain Binds Three Zinc Atoms—A sequence similarity search using human p44(252–395) as the query sequence retrieved eight homologous proteins that were aligned.

Results

Conclusion