Structural Biology of XPB and XPD Helicases

XPB 和 XPD 解旋酶的结构生物学

• 批准号: 7563283
• 负责人: John A. Tainer
• 金额: $ 29.84万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7563283
• 关键词: ATP phosphohydrolase; Architecture; Biochemical; Biochemistry; Biological; Biological Process; Biophysics; Cell Death; Cockayne Syndrome; Complex; DNA; DNA Damage; DNA Repair; Defect; Disease; ERCC3 gene; Electrons; Eukaryota; Event; Figs - dietary; Gene Mutation; Genetic Transcription; Germ-Line Mutation; Homologous Gene; Human; In Vitro; Inherited; Knowledge; Laboratories; Lead; Length; Link; Malignant Neoplasms; Maps; Mediating; Mental Retardation; Microscopic; Molecular; Molecular Conformation; Molecular Structure; Mutation; Nerve Degeneration; Nucleotide Excision Repair; Outcome; Pathway interactions; Patients; Phenotype; Predisposition; Premature aging syndrome; Process; Proteins; Repair Complex; Resolution; Role; Skin Cancer; Specificity; Structure; Structure-Activity Relationship; Syndrome; Testing; Transcription Initiation; Transcription-Coupled Repair; Trichothiodystrophy; XPGC protein; Xeroderma Pigmentosum; base; cancer cell; clinical phenotype; disease phenotype; disease-causing mutation; helicase; human disease; in vivo; mutant; protein protein interaction; repaired; research study; structural biology; transcription factor TFIIH

Hereditary mutations in the DNA helicases XPB and XPD lead to human diseases with different phenotypes reflecting increased cancers or increased cell death: xeroderma pigmentosum (XP), XP- linked Cockayne syndrome (CS), and trichothiodystrophy (TTD). These diseases reflect the disruption of different cellular pathways: Defective nucleotide-excision repair (NER) results in XP, perturbed transcription-coupled repair (TCR) leads to CS, and transcription abnormalities combined with defective NER cause TTD. In humans, XPB and XPD helicases are part of the ten subunit TFIIH transcription/repair complex, but disease-causing mutations cluster in XPB and particularly XPD rather than in the other TFIIH proteins, excepting TFB5, so these XP helicases appear key to controlling coordination of transcription and repair. Furthermore, the repair proteins XPG and CSB interact with the XP helicases in TCR. However, there is little knowledge at the molecular level about XPB and XPD, their helicase and repair activities, or their interactions with TFB5, CSB and XPG. We aim to understand the molecular features underlying the specificity, activity, conformational controls and pathway coordination by the XPB and XPD helicases. Our hypothesis is that well-defined architectures, conformational states, and molecular interfaces of XPB and XPD helicases provide critical controls for transcription, NER, and TCR. We furthermore propose that characterizations of these features and their disruption by disease-causing mutations will provide a molecular basis to directly connect the inherited gene mutations to disease phenotypes. To test this, we herein propose to integrate structural and biophysical experiments (Tainer laboratory) with biochemical and biological experiments (Cooper laboratory). Our experiments on XPB and XPD domains and full-length proteins, their archaeal homologues, and their key assemblies will establish molecular architectures, conformational switching mechanisms, and allosteric interactions. We expect to characterize a prototypical set of helicase structures, their complexes with DNA and with protein partners, and to define the key interactions for their activities. The anticipated outcome of the proposed cross-disciplinary experiments is a molecular picture of the protein-DNA complexes, protein-protein interactions and functional states that orchestrate transcription and repair events mediated by XPB and XPD as components of TFIIH. These results will help provide a detailed molecular understanding of the processes that underlie the cancer and cell death disease phenotypes associated with XPB, XPD, TFB5, CSB and XPG patient mutations.

DNA解旋酶XPB和XPD的遗传突变导致人类不同的疾病