A CTP-dependent gating mechanism enables ParB spreading on DNA

eLife

David M Lawson¹  Clare EM Stevenson¹  Tung BK Le²  Adam SB Jalal²  Ngat T Tran²  Anjana Badrinarayanan³  Afroze Chimthanawala⁴ 

[1] Department of Biochemistry and Metabolism, John Innes Centre, Norwich, United Kingdom;Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom;National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India;National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India;SASTRA University, Thanjavur, Tamil Nadu, India;

关键词: Caulobacter crescentus;    chromosome segregation;    spreading;    molecular gates;    ParA ParB parS;    CTP;    Caulobacter crescentus;   

DOI  :  10.7554/eLife.69676

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Proper chromosome segregation is essential in all living organisms. The ParA-ParB-parS system is widely employed for chromosome segregation in bacteria. Previously, we showed that Caulobacter crescentus ParB requires cytidine triphosphate to escape the nucleation site parS and spread by sliding to the neighboring DNA (Jalal et al., 2020). Here, we provide the structural basis for this transition from nucleation to spreading by solving co-crystal structures of a C-terminal domain truncated C. crescentus ParB with parS and with a CTP analog. Nucleating ParB is an open clamp, in which parS is captured at the DNA-binding domain (the DNA-gate). Upon binding CTP, the N-terminal domain (NTD) self-dimerizes to close the NTD-gate of the clamp. The DNA-gate also closes, thus driving parS into a compartment between the DNA-gate and the C-terminal domain. CTP hydrolysis and/or the release of hydrolytic products are likely associated with reopening of the gates to release DNA and recycle ParB. Overall, we suggest a CTP-operated gating mechanism that regulates ParB nucleation, spreading, and recycling.

【 授权许可】

CC BY