5H66 image
Deposition Date 2016-11-11
Release Date 2017-03-15
Last Version Date 2023-11-08
Entry Detail
PDB ID:
5H66
Title:
Crystal structure of the Bacillus subtilis SMC head domain complexed with the cognate ScpA C-terminal domain
Biological Source:
Source Organism:
Method Details:
Experimental Method:
Resolution:
1.82 Å
R-Value Free:
0.22
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Chromosome partition protein Smc
Gene (Uniprot):smc
Chain IDs:A
Chain Length:199
Number of Molecules:1
Biological Source:Bacillus subtilis (strain 168)
Polymer Type:polypeptide(L)
Molecule:Chromosome partition protein Smc
Gene (Uniprot):smc
Mutations:E1118Q
Chain IDs:B
Chain Length:188
Number of Molecules:1
Biological Source:Bacillus subtilis (strain 168)
Polymer Type:polypeptide(L)
Molecule:Segregation and condensation protein A
Gene (Uniprot):scpA
Chain IDs:C
Chain Length:80
Number of Molecules:1
Biological Source:Bacillus subtilis (strain 168)
Primary Citation
Overall Shapes of the SMC-ScpAB Complex Are Determined by Balance between Constraint and Relaxation of Its Structural Parts
Structure 25 603 616.e4 (2017)
PMID: 28286005 DOI: 10.1016/j.str.2017.02.008

Abstact

The SMC-ScpAB complex plays a crucial role in chromosome organization and segregation in many bacteria. It is composed of a V-shaped SMC dimer and an ScpAB subcomplex that bridges the two Structural Maintenance of Chromosomes (SMC) head domains. Despite its functional significance, the mechanistic details of SMC-ScpAB remain obscure. Here we provide evidence that ATP-dependent head-head engagement induces a lever movement of the SMC neck region, which might help to separate juxtaposed coiled-coil arms. Binding of the ScpA N-terminal domain (NTD) to the SMC neck region is negatively regulated by the ScpB C-terminal domain. Mutations in the ScpA NTD compromise this regulation and profoundly affect the overall shape of the complex. The SMC hinge domain is structurally relaxed when free from coiled-coil juxtaposition. Taken together, we propose that the structural parts of SMC-ScpAB are subjected to the balance between constraint and relaxation, cooperating to modulate dynamic conformational changes of the whole complex.

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