PDBsum entry 3zgx

Cell cycle

PDB id: 3zgx

Contents

Protein chains

345 a.a.

67 a.a.

PDB id:

3zgx

Name:

Cell cycle

Title:

Crystal structure of the kleisin-n smc interface in prokaryotic condensin

Structure:

Chromosome partition protein smc. Chain: a, b. Fragment: smc head domain, residues 1-219,983-1186. Synonym: smc. Engineered: yes. Segregation and condensation protein a. Chain: c, z. Fragment: n terminal domain of scpa, residues 1-86. Synonym: kleisin.

Source:

Bacillus subtilis. Organism_taxid: 1423. Strain: 1a700. Expressed in: escherichia coli. Expression_system_taxid: 511693. Expression_system_variant: gold.

Resolution:

3.40Å R-factor: 0.242 R-free: 0.277

Authors:

F.Burmann,H.Shin,J.Basquin,Y.Soh,V.Gimenez,Y.Kim,B.Oh,S.Gruber

Key ref:

F.Bürmann et al. (2013). An asymmetric SMC-kleisin bridge in prokaryotic condensin. Nat Struct Biol, 20, 371-379. PubMed id: 23353789 DOI: 10.1038/nsmb.2488

Date:

19-Dec-12 Release date: 30-Jan-13

Protein chains

P51834  (SMC_BACSU) -  Chromosome partition protein Smc from Bacillus subtilis (strain 168)

Seq: 1186 a.a.

Struc: 345 a.a.*

Protein chains

P35154  (SCPA_BACSU) -  Segregation and condensation protein A from Bacillus subtilis (strain 168)

Seq: 251 a.a.

Struc: 67 a.a.

* PDB and UniProt seqs differ at 143 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, B, C, Z: E.C.?

DOI no: 10.1038/nsmb.2488

Nat Struct Biol 20:371-379 (2013)

PubMed id: 23353789

An asymmetric SMC-kleisin bridge in prokaryotic condensin.

F.Bürmann, H.C.Shin, J.Basquin, Y.M.Soh, V.Giménez-Oya, Y.G.Kim, B.H.Oh, S.Gruber.

ABSTRACT

Eukaryotic structural maintenance of chromosomes (SMC)-kleisin complexes form large, ring-shaped assemblies that promote accurate chromosome segregation. Their asymmetric structural core comprises SMC heterodimers that associate with both ends of a kleisin subunit. However, prokaryotic condensin Smc-ScpAB is composed of symmetric Smc homodimers associated with the kleisin ScpA in a postulated symmetrical manner. Here, we demonstrate that Smc molecules have two distinct binding sites for ScpA. The N terminus of ScpA binds the Smc coiled coil, whereas the C terminus binds the Smc ATPase domain. We show that in Bacillus subtilis cells, an Smc dimer is bridged by a single ScpAB to generate asymmetric tripartite rings analogous to eukaryotic SMC complexes. We define a molecular mechanism that ensures asymmetric assembly, and we conclude that the basic architecture of SMC-kleisin rings evolved before the emergence of eukaryotes.