5h69

Publication Abstract from PubMed

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.

Overall Shapes of the SMC-ScpAB Complex Are Determined by Balance between Constraint and Relaxation of Its Structural Parts.,Kamada K, Su'etsugu M, Takada H, Miyata M, Hirano T Structure. 2017 Apr 4;25(4):603-616.e4. doi: 10.1016/j.str.2017.02.008. Epub 2017, Mar 9. PMID:28286005^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.