General transcription and DNA repair factor IIH helicase subunit XPD (UniProt: P18074; also known as EC: 3.6.4.12, TFIIH subunit XPD, Basic transcription factor 2 80 kDa subunit, BTF2 p80, CXPD, DNA excision repair protein ERCC-2, DNA repair protein complementing XP-D cells, TFIIH basal transcription factor complex 80 kDa subunit, TFIIH 80 kDa subunit, TFIIH p80, Xeroderma pigmentosum group D-complementing protein) is encoded by the ERCC2 (also known as XPD, XPDC) gene (Gene ID: 2068) in human. XPD is an ATP-dependent 5′-3′ DNA helicase component of the general transcription and DNA repair factor IIH (TFIIH) core complex that is involved in general and transcription-coupled nucleotide excision repair (NER) of damaged DNA. Its ATP-binding region is localized to amino acids 7-283 and its nuclear localization is in amino acids 682-695. 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. In transcription, TFIIH plays an essential role in transcription initiation. When the pre-initiation complex has been established, TFIIH is required for promoter opening and promoter escape. Phosphorylation of the C-terminal tail of the largest subunit of RNA polymerase II by CDK-activating kinase (CAK) complex controls the initiation of transcription. XPD acts by forming a bridge between CAK and the core-TFIIH complex. Mutations in ERCC2 gene are known to cause Xeroderma pigmentosum complementation group D that is characterized by solar hypersensitivity of the skin, high predisposition for developing cancers on areas exposed to sunlight and, in some cases, neurological abnormalities. The skin develops marked freckling and other pigmentation abnormalities.，官网链接：https://www.sigmaaldrich.cn/product/mm/mabe1819 默克 科研、开发、生产。 作为生命科学行业的全球领先供应商，我们致力于为科研、生物技术开发和生产，以及制药药物疗法开发和生产提供各类解决方案和服务。

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