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2qm4
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(New page: 200px<br /><applet load="2qm4" size="350" color="white" frame="true" align="right" spinBox="true" caption="2qm4, resolution 2.30Å" /> '''Crystal structure of...)
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Revision as of 09:44, 23 January 2008
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Crystal structure of human XLF/Cernunnos, a non-homologous end-joining factor
Overview
The recently characterised 299-residue human XLF/Cernunnos protein plays a, crucial role in DNA repair by non-homologous end joining (NHEJ) and, interacts with the XRCC4-DNA Ligase IV complex. Here, we report the, crystal structure of the XLF (1-233) homodimer at 2.3 A resolution, confirming the predicted structural similarity to XRCC4. The XLF, coiled-coil, however, is shorter than that of XRCC4 and undergoes an, unexpected reverse in direction giving rise to a short distorted four, helical bundle and a C-terminal helical structure wedged between the, coiled-coil and head domain. The existence of a dimer as the major species, is confirmed by size-exclusion chromatography, analytical, ultracentrifugation, small-angle X-ray scattering and other biophysical, methods. We show that the XLF structure is not easily compatible with a, proposed XRCC4:XLF heterodimer. However, we demonstrate interactions, between dimers of XLF and XRCC4 by surface plasmon resonance and analyse, these in terms of surface properties, amino-acid conservation and, mutations in immunodeficient patients. Our data are most consistent with, head-to-head interactions in a 2:2:1 XRCC4:XLF:Ligase IV complex.
About this Structure
2QM4 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of human XLF/Cernunnos reveals unexpected differences from XRCC4 with implications for NHEJ., Li Y, Chirgadze DY, Bolanos-Garcia VM, Sibanda BL, Davies OR, Ahnesorg P, Jackson SP, Blundell TL, EMBO J. 2007 Nov 29;. PMID:18046455
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