Transcription factor TFIID, C-terminal/DNA glycosylase, N-terminal <p>Transcription factor TFIID (also known as TATA-binding protein, TBP) is a general factor that plays a central role in the activation of eukaryotic genes transcribed by RNA polymerase II [<cite idref="PUB00004068"/>, <cite idref="PUB00004069"/>]. TFIID binds specifically to the TATA-box promoter element, which lies close to the position of transcription initiation. The C-terminal domain (~180 residues) of eukaryotic TFIID sequences is highly conserved and is involved in TATA-box binding. The most striking feature of the domain is the presence of 2 conserved 77 amino-acid repeats. The symmetrical disposition of these features generates a saddle-shaped structure that straddles the DNA [<cite idref="PUB00004136"/>].</p><p>DNA glycosylases are involved in the repair of damaged bases in DNA, acting to cleave the bond between the damaged, modified base and the deoxyribose sugar backbone of the DNA. These DNA repair activities are conserved from bacteria to man. Different DNA glycosylases can have different overall folds, even though many of them work by a common mechanism, involving bending the DNA and clamping on to the damaged base to excise it. This entry is represented by 3-methyladenine DNA glycosylase II (AlkA) from <taxon tax_id="562">Escherichia coli</taxon> and human 8-oxoguanine glycosylase (<db_xref db="EC" dbkey="3.2.2"/>), whose N-terminal domains display a beta-alpha-beta(4)-alpha fold similar to that found in the C-terminal domain of TFIID. However, unlike TFIID, which contains a duplication of this fold, these DNA glycosylases carry only a single copy of this fold [<cite idref="PUB00016252"/>, <cite idref="PUB00016253"/>].</p>