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Updated: May 10, 2026
13:40
In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
Published on: February 17, 2014
Substrate Channel Flexibility in Pseudomonas aeruginosa MurB Accommodates Two Distinct Substrates
Ming Wei Chen1, Bernhard Lohkamp, Robert Schnell
1Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden ; School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
Plos One
|June 28, 2013
Summary
Bacterial MurB enzyme
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- UDP-N-acetylmuramic acid biosynthesis is crucial for bacterial peptidoglycan production.
- UDP-N-acetylglucosamine-enolpyruvate reductase (MurB) catalyzes a key NADPH- and FAD-dependent reaction in this pathway.
Purpose of the Study:
- To elucidate the structural basis of hydride transfer in the first half-reaction catalyzed by Pseudomonas aeruginosa MurB.
- To investigate substrate binding and catalytic mechanism through structural analysis of ternary complexes.
Main Methods:
- X-ray crystallography was employed to determine the three-dimensional structures of Pseudomonas aeruginosa MurB.
- Structures were resolved to 2.2 and 2.1 Å for two crystal forms of the ternary complex with FAD and NADP+.
- Comparison with Escherichia coli MurB structures provided insights into substrate binding and mechanism.
Main Results:
- The study revealed an unusual stacking interaction between NADP+ and FAD, suggesting a novel hydride transfer mechanism.
- Both substrates (NADP+ and UDP-N-acetylglucosamine-enolpyruvate) bind to a shared site, supporting a ping pong mechanism.
- Substrate channel flexibility allows for conformational variations, and a potassium ion may aid in substrate binding.
Conclusions:
- Structural insights into MurB function provide a basis for structure-aided drug design.
- Targeting MurB could lead to novel antibacterial strategies due to its essential role in cell wall biogenesis.
- Understanding the unique hydride transfer mechanism is key for developing effective inhibitors.
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