Molecular Target Synopsis
Domains and Structures
Drugs and Clinical Candidates
Ligand Efficiency Plot
Family Cladogram
Interaction Network
Gene Expression
Gene Copy Number Variation
Germline Genetics

SSL2 (Q00578) - Overview - Molecular Target Synopsis


SSL2, General transcription and DNA repair factor IIH helicase subunit XPB
Enzyme Classification
UniProt Q00578

Also Known as RAD25_YEAST, SSL2, LOM3, RAD25, UVS112

ATP-dependent 3'-5' DNA helicase, component of the general transcription and DNA repair factor IIH (TFIIH) core complex, which is involved in general and transcription-coupled nucleotide excision repair (NER) of damaged DNA and, when complexed to TFIIK, in RNA transcription by RNA polymerase II. In NER, TFIIH acts by opening DNA around the lesion to allow the excision of the damaged oligonucleotide and its replacement by a new DNA fragment. The ATPase activity of XPB/SSL2, but not its helicase activity, is required for DNA opening. In transcription, TFIIH has an essential role in transcription initiation. When the pre-initiation complex (PIC) has been established, TFIIH is required for promoter opening and promoter escape. The ATP-dependent helicase activity of XPB/SSL2 is required for promoter opening and promoter escape. Phosphorylation of the C-terminal tail (CTD) of the largest subunit of RNA polymerase II by the kinase module TFIIK controls the initiation of transcription (PubMed:8269516, PubMed:7693549, PubMed:7961739, PubMed:8202161, PubMed:7813015, PubMed:8631896). XPB/SSL2 acts as a double-stranded DNA translocase promoting DNA opening by tracking along the nontemplate promoter strand, rotating and inserting DNA into the Pol II active site cleft, leading to DNA unwinding. May also use this translocase mechanism during DNA repair rather than physically wedging open damaged DNA (PubMed:25775526). Component of the 7-subunit TFIIH core complex composed of XPB/SSL2, XPD/RAD3, SSL1, TFB1, TFB2, TFB4 and TFB5, which is active in NER. The core complex associates with the 3-subunit CTD-kinase module TFIIK composed of CCL1, KIN28 and TFB3 to form the 10-subunit holoenzyme (holo-TFIIH) active in transcription.

Inspect Structure
See all 3D Structures for SSL2

Isoforms / Transcripts (Protein Coding)

Protein Length Ensembl Gene Ensembl Transcript Ensembl Protein Uniprot Isoform

Sub-cellular localization

UniProt: SSL2 is active in the following subcellular-locations: nucleus.
GO terms: SSL2 is active in the following subcellular-locations: cytosol, nucleotide-excision repair factor 3 complex, nucleus, transcription factor TFIIH core complex, transcription factor TFIIH holo complex, transcriptional preinitiation complex.

GO terms

Gene Copy Number Variation

In COSMIC - Cell Lines Project SSL2 has gain in 0 cell-lines, loss in 0 cell-lines and no signal in 0 cell-lines. (see details)

3D Structures

For SSL2 there are:
5 structures (5 chains) solved
0 are solved in complex with at least one small molecule ligand

(see details)
Molecular Target 3D Synopsis

Screening and Chemistry

SSL2 has been screened with compounds ( bioactivities). (see details)