1E69

SMC head domain from Thermotoga maritima

Summary for 1E69

• Entry DOI: 10.2210/pdb1e69/pdb
• Descriptor: CHROMOSOME SEGREGATION SMC PROTEIN (1 entity in total)
• Functional Keywords: chromosome segregation, smc, structural maintenance of chromosomes, coiled coil
• Biological source: THERMOTOGA MARITIMA
• Total number of polymer chains: 6
• Total formula weight: 215351.95

Authors

Lowe, J.,Cordell, S.C.,van den Ent, F. (deposition date: 2000-08-09, release date: 2000-08-09, Last modification date: 2024-05-08)

Primary citation

Lowe, J.,Cordell, S.C.,van den Ent, F.
Crystal Structure of the Smc Head Domain: An Abc ATPase with 900 Residues Antiparallel Coiled-Coil Inserted
J.Mol.Biol., 306:25-, 2001

PubMed Abstract: SMC (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.

PubMed: 11178891
DOI: 10.1006/JMBI.2000.4379

Experimental method

X-RAY DIFFRACTION (3.1 Å)