1e69
SMC head domain from Thermotoga maritima
Structural highlights
FunctionQ9X0R4_THEMA Required for chromosome condensation and partitioning.[HAMAP-Rule:MF_01894] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSMC (structural maintenance of chromosomes) proteins are large coiled-coil proteins involved in chromosome condensation, sister chromatid cohesion, and DNA double-strand break processing. They share a conserved five-domain architecture with three globular domains separated by two long coiled-coil segments. The coiled-coil segments are antiparallel, bringing the N and C-terminal globular domains together. We have expressed a fusion protein of the N and C-terminal globular domains of Thermotoga maritima SMC in Escherichia coli by replacing the approximately 900 residue coiled-coil and hinge segment with a short peptide linker. The SMC head domain (SMChd) binds and condenses DNA in an ATP-dependent manner. Using selenomethionine-substituted protein and multiple anomalous dispersion phasing, we have solved the crystal structure of the SMChd to 3.1 A resolution. In the monoclinic crystal form, six SMChd molecules form two turns of a helix. The fold of SMChd is closely related to the ATP-binding cassette (ABC) ATPase family of proteins and Rad50, a member of the SMC family involved in DNA double-strand break repair. In SMChd, the ABC ATPase fold is formed by the N and C-terminal domains with the 900 residue coiled-coil and hinge segment inserted in the middle of the fold. The crystal structure of an SMChd confirms that the coiled-coil segments in SMC proteins are anti-parallel and shows how the N and C-terminal domains come together to form an ABC ATPase. Comparison to the structure of the MukB N-terminal domain demonstrates the close relationship between MukB and SMC proteins, and indicates a helix to strand conversion when N and C-terminal parts come together. Crystal structure of the SMC head domain: an ABC ATPase with 900 residues antiparallel coiled-coil inserted.,Lowe J, Cordell SC, van den Ent F J Mol Biol. 2001 Feb 9;306(1):25-35. PMID:11178891[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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