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Updated: Jan 13, 2026
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A Purification and In Vitro Activity Assay for a pppGpp Synthetase from Clostridium difficile
Published on: November 3, 2018
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The Bacillus subtilis class A penicillin-binding protein 4 (PBP4) requires an accessory protein RpdA
Ruoqi Huang1, Yesha Patel1, John D Helmann1
1Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA.
Biorxiv : the Preprint Server for Biology
|January 7, 2026
Summary
RpdA is a newly identified regulator of PBP4 in Bacillus subtilis, crucial for cell wall synthesis. Loss of RpdA enhances resistance to cefuroxime by affecting PBP4 localization and activity.
Area of Science:
- Microbiology
- Bacterial Cell Wall Synthesis
- Protein Regulation
Background:
- Peptidoglycan (PG) synthesis is vital for bacterial cell integrity.
- Class A and B penicillin-binding proteins (PBPs) orchestrate PG synthesis for growth and division in Bacillus subtilis.
- PBP4 is a class A PBP involved in PG synthesis.
Purpose of the Study:
- To identify regulators of PBP4 function in Bacillus subtilis.
- To elucidate the role of RpdA (formerly YufK) in PBP4 activity and localization.
- To understand the impact of RpdA on bacterial response to antibiotics.
Main Methods:
- Genetic analysis, including gene inactivation and epistasis studies.
- Antibiotic sensitivity assays using cefuroxime (CEF).
- Cellular localization studies of PBP4.
Main Results:
- RpdA was identified as a specific regulator of PBP4.
- Loss of RpdA confers resistance to cefuroxime, similar to PBP4 inactivation.
- RpdA is essential for the membrane localization and activity of PBP4.
- RpdA may also play a role in undecaprenyl-phosphate recycling.
Conclusions:
- RpdA acts as a PBP4 accessory protein, critical for its localization and function.
- RpdA is involved in bacterial cell wall integrity and antibiotic resistance.
- The findings reveal a novel regulatory mechanism in bacterial PG synthesis.
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