DNA damage-binding protein 1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
that in humans is encoded by the ''DDB1''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Gene
The gene's position is on chromosome 11q12-q13.
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Protein
The DDB1 gene encodes the large subunit of DNA damage-binding protein, a heterodimer
In biochemistry, a protein dimer is a macromolecular complex formed by two protein monomers, or single proteins, which are usually non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' has ...
composed of a large and a small ( DDB2) subunit. DDB1 contains 1140 amino acids, amounting to a mass of 127 kDa.[
]
Function
As its name suggests, DDB1 was initially implicated in the process of a specific type of DNA repair known as nucleotide excision repair
Nucleotide excision repair is a DNA repair mechanism. DNA damage occurs constantly because of chemicals (e.g. intercalating agents), radiation and other mutagens. Three excision repair pathways exist to repair single stranded DNA damage: Nucle ...
. Since then, researchers have found that DDB1 primarily functions as a core component of the CUL4A- and CUL4B
Cullin-4B is a protein that in humans is encoded by the ''CUL4B'' gene which is located on the X chromosome. CUL4B has high sequence similarity with CUL4A, with which it shares certain E3 ubiquitin ligase functions. CUL4B is largely expressed in t ...
-based E3 ubiquitin ligase
A ubiquitin ligase (also called an E3 ubiquitin ligase) is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquiti ...
complexes. DDB1 serves as a bridge or adaptor protein which interacts with dozens of proteins known as DDB1 and CUL4-associated factors (DCAFs).
Interactions
DDB1 has been shown to interact with Transcription initiation protein SPT3 homolog
Transcription initiation protein SPT3 homolog is a protein that in humans is encoded by the ''SUPT3H'' gene.
Interactions
Transcription initiation protein SPT3 homolog has been shown to interact with GCN5L2, TAF6L, TADA3L, TAF5L, SF3B3, ...
,[ ]CUL4B
Cullin-4B is a protein that in humans is encoded by the ''CUL4B'' gene which is located on the X chromosome. CUL4B has high sequence similarity with CUL4A, with which it shares certain E3 ubiquitin ligase functions. CUL4B is largely expressed in t ...
[ and ]P21
p21Cip1 (alternatively p21Waf1), also known as cyclin-dependent kinase inhibitor 1 or CDK-interacting protein 1, is a cyclin-dependent kinase inhibitor (CKI) that is capable of inhibiting all cyclin/CDK complexes, though is primarily associate ...
.
References
Further reading
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{{DNA repair