Solution structure of the C-terminal domain of TFIIH P44 subunit reveals a novel type of C4C4 ring domain involved in protein-protein interactions.
Kellenberger, E., Dominguez, C., Fribourg, S., Wasielewski, E., Moras, D., Poterszman, A., Boelens, R., Kieffer, B.(2005) J Biol Chem 280: 20785-20792
- PubMed: 15790571 
- DOI: https://doi.org/10.1074/jbc.M412999200
- Primary Citation of Related Structures:  
1Z60 - PubMed Abstract: 
The human general transcription factor TFIIH is involved in both transcription and DNA nucleotide excision repair. Among the 10 subunits of the complex, p44 subunit plays a crucial role in both mechanisms. Its N-terminal domain interacts with the XPD helicase, whereas its C-terminal domain is involved specifically in the promoter escape activity. By mutating an exposed and non-conserved cysteine residue into a serine, we produced a soluble mutant of p44-(321-395) suitable for solution structure determination. The domain adopts a C4C4 RING domain structure with sequential organization of beta-strands that is related to canonical RING domains by a circular permutation of the beta-sheet elements. Analysis of the molecular surface and mutagenesis experiments suggests that the binding of p44-(321-395) to TFIIH p34 subunit is not mediated by electrostatic interactions and, thus, differs from previously reported interaction mechanisms involving RING domains.
Organizational Affiliation: 
Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire UMR 7104, 1, rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France.