Download MendeleyThe CTP-binding domain is disengaged from the DNA-binding domain in a cocrystal structure of Bacillus subtilis Noc-DNA complex.
Sukhoverkov, K.V., Jalal, A.S.B., Ault, J.R., Sobott, F., Lawson, D.M., Le, T.B.K.(2023) J Biol Chem 299: 103063-103063
- PubMed: 36841481
- DOI: https://doi.org/10.1016/j.jbc.2023.103063
- Primary Citation of Related Structures:
7OL9 - PubMed Abstract:
In Bacillus subtilis, a ParB-like nucleoid occlusion protein (Noc) binds specifically to Noc-binding sites (NBSs) on the chromosome to help coordinate chromosome segregation and cell division. Noc does so by binding to CTP to form large membrane-associated nucleoprotein complexes to physically inhibit the assembly of the cell division machinery. The site-specific binding of Noc to NBS DNA is a prerequisite for CTP-binding and the subsequent formation of a membrane-active DNA-entrapped protein complex. Here, we solve the structure of a C-terminally truncated B. subtilis Noc bound to NBS DNA to reveal the conformation of Noc at this crucial step. Our structure reveals the disengagement between the N-terminal CTP-binding domain and the NBS-binding domain of each DNA-bound Noc subunit; this is driven, in part, by the swapping of helices 4 and 5 at the interface of the two domains. Site-specific crosslinking data suggest that this conformation of Noc-NBS exists in solution. Overall, our results lend support to the recent proposal that parS/NBS binding catalyzes CTP binding and DNA entrapment by preventing the reengagement of the CTP-binding domain and the DNA-binding domain from the same ParB/Noc subunit.
Organizational Affiliation:
Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom.
