TY - JOUR
T1 - XRCC4 protein interactions with XRCC4-like factor (XLF) create an extended grooved scaffold for DNA ligation and double strand break repair
AU - Hammel, Michal
AU - Rey, Martial
AU - Yu, Yaping
AU - Mani, Rajam S.
AU - Classen, Scott
AU - Liu, Mona
AU - Pique, Michael E.
AU - Fang, Shujuan
AU - Mahaney, Brandi L.
AU - Weinfeld, Michael
AU - Schriemer, David C.
AU - Lees-Miller, Susan P.
AU - Tainer, John A.
PY - 2011/9/16
Y1 - 2011/9/16
N2 - 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 super-helical filaments. XLF Leu-115 ("Leu-lock") inserts into a hydrophobic pocket formed by XRCC4 Met-59, Met-61, Lys-65, Lys-99, Phe-106, and Leu-108 in synergy with pseudo-symmetric β-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.
AB - 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 super-helical filaments. XLF Leu-115 ("Leu-lock") inserts into a hydrophobic pocket formed by XRCC4 Met-59, Met-61, Lys-65, Lys-99, Phe-106, and Leu-108 in synergy with pseudo-symmetric β-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.
UR - http://www.scopus.com/inward/record.url?scp=80052738767&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80052738767&partnerID=8YFLogxK
U2 - 10.1074/jbc.M111.272641
DO - 10.1074/jbc.M111.272641
M3 - Article
C2 - 21775435
AN - SCOPUS:80052738767
SN - 0021-9258
VL - 286
SP - 32638
EP - 32650
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 37
ER -