Effect of the DNA-binding domain of poly(ADP-ribose)synthetase on accurate transcription initiation in a HeLa cell lysate

The three-dimensional structure of the human Rap30 DNA-binding domain has been solved by multinuclear NMR spectroscopy. The structure of the globular domain is strikingly similar to that of linker histone H5 and its fold places Rap30 into the “winged” helix–turn–helix family of eukaryotic transcription factors. Although the domain interacts weakly with DNA, the binding surface was identified and shown to be consistent with the structure of the HNF-3/fork head–DNA complex. The architecture of the Rap30 DNA-binding domain has important implications for the function of Rap30 in the assembly of the preinitiation complex. In analogy to the function of linker histones in chromatin formation, the fold of the Rap30 DNA-binding domain suggests that its role in transcription initiation may be that of a condensation factor for preinitiation complex assembly. Functional similarity to linker histones may explain the dependence of Rap30 binding on the bent DNA environment induced by the TATA box-binding protein. Cryptic sequence identity and functional homology between the Rap30 DNA-binding domain and region 4 of Escherichia coli σ70 may indicate that the σ factors also possess a linker histone-like activity in the formation of a prokaryotic closed complex.

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The TATA-Binding Protein (TBP) from the Human Fungal PathogenCandida albicans Can Complement Defects in Human and Yeast TBPs

Journal of Bacteriology ◽

10.1128/jb.180.7.1771-1776.1998 ◽

1998 ◽

Vol 180 (7) ◽

pp. 1771-1776 ◽

Cited By ~ 2

Author(s):

Ping Leng ◽

Philip E. Carter ◽

Alistair J. P. Brown

Keyword(s):

Amino Acid ◽

Dna Binding ◽

Transcription Initiation ◽

Binding Protein ◽

Tata Binding Protein ◽

Binding Domain ◽

Amino Acid Sequences ◽

Initiation Factor ◽

Dna Binding Domain

ABSTRACT Candida albicans is the major fungal pathogen in humans, yet little is known about transcriptional regulation in this organism. Therefore, we have isolated, characterized, and expressed theC. albicans TATA-binding protein (TBP) gene (TBP1), because this general transcription initiation factor plays a key role in the activation and regulation of eukaryotic promoters. Southern and Northern blot analyses suggest that a single C. albicans TBP1 locus is expressed at similar levels in the yeast and hyphal forms of this fungus. The TBP1 open reading frame is 716 bp long and encodes a functional TBP of 27 kDa. C. albicans TBP is capable of binding specifically to a TATA box in vitro, substituting for the human TBP to activate basal transcription in vitro, and suppressing the lethal Δspt15 mutation inSaccharomyces cerevisiae. The predicted amino acid sequences of TBPs from C. albicans and other organisms reveal a striking pattern of C-terminal conservation and N-terminal variability: the C-terminal DNA-binding domain displays at least 80% amino acid sequence identity to TBPs from fungi, flies, nematodes, slime molds, plants, and humans. Sequence differences between human and fungal TPBs in the DNA-binding domain may represent potential targets for antifungal therapy.

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