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CTP regulates membrane-binding activity of the nucleoid occlusion protein Noc

Adam S B Jalal1, Ngat T Tran1, Ling J Wu2

  • 1Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.

Molecular Cell
|July 16, 2021
PubMed

Insights

Cytidine triphosphate (CTP) acts as a molecular switch for the nucleoid occlusion protein Noc. CTP binding, not hydrolysis, activates Noc

Area of Science:

  • Molecular biology
  • Biochemistry
  • Cell biology

Background:

  • Adenosine triphosphate (ATP) and guanosine triphosphate (GTP) are common molecular switches in biological processes.
  • Cytidine triphosphate (CTP) mediated molecular switches are rarely documented.
  • Nucleoid occlusion protein Noc regulates bacterial cell division by binding to DNA and the cell membrane.

Purpose of the Study:

  • To investigate the role of CTP in the function of the nucleoid occlusion protein Noc.
  • To characterize Noc as a CTPase enzyme and its regulatory mechanism.
  • To elucidate how CTP controls Noc's membrane-binding activity and nucleoprotein complex formation.

Main Methods:

  • In vitro reconstitution assays.
  • Biochemical characterization of Noc's enzymatic activity.
  • DNA-binding and membrane-association studies.

Main Results:

  • Noc functions as a CTPase, with its activity regulated by CTP.
  • CTP is essential for Noc to form nucleoprotein complexes on specific DNA sites (NBS).
  • CTP binding, rather than hydrolysis, induces a conformational change in Noc, activating its membrane-binding capacity.

Conclusions:

  • CTP acts as a novel molecular switch regulating Noc's function.
  • Noc utilizes CTP to couple DNA binding with membrane association for effective nucleoid occlusion.
  • This study reveals a new mechanism for CTP in controlling protein activity at the bacterial cell membrane.
Keywords:
CTPNocParBX-ray crystallographybacterial cell divisionin vitro reconstitutionmembrane-binding proteinnucleoid occlusion protein

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