XRCC4 Protein Interactions with XRCC4-like Factor (XLF) Create an Extended Grooved Scaffold for DNA Ligation and Double Strand Break Repair
Journal Article
·
· Journal of Biological Chemistry
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Biosciences Division; DOE/OSTI
- Univ. of Calgary, AB (Canada). Southern Alberta Cancer Research Inst. Dept. of Biochemistry and Molecular Biology
- Univ. of Calgary, AB (Canada). Cross Cancer Inst. Dept. of Oncology
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Biosciences Division
- The Scripps Research Inst., La Jolla, CA (United States). Skaggs Inst. of Chemical Biology. Dept. of Molecular Biology
- The Scripps Research Inst., La Jolla, CA (United States). Skaggs Inst. of Chemical Biology. Dept. of Molecular Biology; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Division
The XRCC4-like factor (XLF)-XRCC4 complex is essential for nonhomologous end joining, the major repair pathway for DNA double strand breaks in human cells. Yet, how XLF binds XRCC4 and impacts nonhomologous end joining functions has been enigmatic. Here, we report the XLF-XRCC4 complex crystal structure in combination with biophysical and mutational analyses to define the XLF-XRCC4 interactions. Crystal and solution structures plus mutations characterize alternating XRCC4 and XLF head domain interfaces forming parallel superhelical filaments. XLF Leu-115 (“Leu-lock”) inserts into a hydrophobic pocket formed by XRCC4 Met-59, Met-61, Lys-65, Lys99, Phe-106, and Leu-108 in synergy with pseudo-symmetric -zipper hydrogen bonds to drive specificity. XLF C terminus and DNA enhance parallel filament formation. Super-helical XLF-XRCC4 filaments form a positively charged channel to bind DNA and align ends for efficient ligation. Collective results reveal how human XLF and XRCC4 interact to bind DNA, suggest consequences of patient mutations, and support a unified molecular mechanism for XLF-XRCC4 stimulation of DNA ligation.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER). Biological Systems Science Division
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1625074
- Journal Information:
- Journal of Biological Chemistry, Journal Name: Journal of Biological Chemistry Journal Issue: 37 Vol. 286; ISSN 0021-9258
- Publisher:
- American Society for Biochemistry and Molecular BiologyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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