PDBsum entry 1e69

Chromosome segregation

PDB id: 1e69

Contents

Protein chains

(+ 0 more) 263 a.a. *

* Residue conservation analysis

PDB id:

1e69

Name:

Chromosome segregation

Title:

Smc head domain from thermotoga maritima

Structure:

Chromosome segregation smc protein. Chain: a, b, c, d, e, f. Fragment: smc fusion of the n- and c-terminal globular domains residues 1-152 and 1023-1164. Engineered: yes

Source:

Thermotoga maritima. Organism_taxid: 2336. Atcc: dsm3109. Cellular_location: cytosol. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Expression_system_variant: c41.

Resolution:

3.10Å R-factor: 0.250 R-free: 0.272

Authors:

J.Lowe,S.C.Cordell,F.Van Den Ent

Key ref:

J.Löwe et al. (2001). Crystal structure of the SMC head domain: an ABC ATPase with 900 residues antiparallel coiled-coil inserted. J Mol Biol, 306, 25-35. PubMed id: 11178891 DOI: 10.1006/jmbi.2000.4379

Date:

09-Aug-00 Release date: 09-Aug-00

Protein chains

Q9X0R4  (Q9X0R4_THEMA) -  Chromosome partition protein Smc from Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8)

Seq: 1170 a.a.

Struc: 263 a.a.*

* PDB and UniProt seqs differ at 116 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.2000.4379

J Mol Biol 306:25-35 (2001)

PubMed id: 11178891

Crystal structure of the SMC head domain: an ABC ATPase with 900 residues antiparallel coiled-coil inserted.

J.Löwe, S.C.Cordell, F.van den Ent.

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.

Selected figure(s)

Figure 4.
Figure 4. (a) Ribbon representation of the six non-crystallographically related molecules in the asymmetric unit of the monoclinic crystal form. Six SMChd molecules form two turns of a head-to-tail 3[1] helix (prepared with MOLSCRIPT, [Kraulis 1991]). (b) Stereo representation of the six NCS-related molecules in the asymmetric unit of the trigonal space group. The same 3[1] SMChd helix as in the monoclinic crystals is formed by each of the six molecules by crystallographic P3[1] symmetry perpendicular to the paper plane (prepared with MAIN, [Turk 1992]).

Figure 5.
Figure 5. Structure-based sequence alignment of SMChd from Thermotoga maritima (PDB ID 1E69), Rad50 from Pyrococcus furiosus (PDB ID 1F2T chains A, B), the N-terminal domain of MukB from Escherichia coli (PDB ID 1QHL), and histidine permease protein HisP from Salmonella typhimurium (PDB ID 1B0U). A preliminary sequence alignment was prepared, adjusted using the DALI [Holm and Sander 1995] results and checked for all six pairs manually in three dimensions. For clarity, non-overlapping regions in three dimensions have not been separated. The numbering corresponds to SMChd, as do the secondary structural elements. The Figure was prepared with ALSCRIPT [Barton 1993].

The above figures are reprinted by permission from Elsevier: J Mol Biol (2001, 306, 25-35) copyright 2001.

Figures were selected by an automated process.