7m3p | pdb_00007m3p
Xrcc4-Spc110p(164-207) fusion
Structural highlights
Function[XRCC4_HUMAN] Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. Binds to DNA and to DNA ligase IV (LIG4). The LIG4-XRCC4 complex is responsible for the NHEJ ligation step, and XRCC4 enhances the joining activity of LIG4. Binding of the LIG4-XRCC4 complex to DNA ends is dependent on the assembly of the DNA-dependent protein kinase complex DNA-PK to these DNA ends.[1] [2] [3] [4] Publication Abstract from PubMedMicrotubule (MT) nucleation is regulated by the gamma-tubulin ring complex (gammaTuRC), conserved from yeast to humans. In Saccharomyces cerevisiae, gammaTuRC is composed of seven identical gamma-tubulin small complex (gammaTuSC) sub-assemblies, which associate helically to template MT growth. gammaTuRC assembly provides a key point of regulation for the MT cytoskeleton. Here, we combine crosslinking mass spectrometry, X-ray crystallography, and cryo-EM structures of both monomeric and dimeric gammaTuSCs, and open and closed helical gammaTuRC assemblies in complex with Spc110p to elucidate the mechanisms of gammaTuRC assembly. gammaTuRC assembly is substantially aided by the evolutionarily conserved CM1 motif in Spc110p spanning a pair of adjacent gammaTuSCs. By providing the highest resolution and most complete views of any gammaTuSC assembly, our structures allow phosphorylation sites to be mapped, surprisingly suggesting that they are mostly inhibitory. A comparison of our structures with the CM1 binding site in the human gammaTuRC structure at the interface between GCP2 and GCP6 allows for the interpretation of significant structural changes arising from CM1 helix binding to metazoan gammaTuRC. CM1-driven assembly and activation of yeast gamma-tubulin small complex underlies microtubule nucleation.,Brilot AF, Lyon AS, Zelter A, Viswanath S, Maxwell A, MacCoss MJ, Muller EG, Sali A, Davis TN, Agard DA Elife. 2021 May 5;10. pii: 65168. doi: 10.7554/eLife.65168. PMID:33949948[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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