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Updated: May 23, 2026
08:23
Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Structural basis for nitrous oxide generation by bacterial nitric oxide reductases
Yoshitsugu Shiro1, Hiroshi Sugimoto, Takehiko Tosha
1RIKEN SPring-8 Center, Sayo, Hyogo, Japan. yshiro@riken.jp
Summary
The crystal structure of bacterial nitric oxide reductase (cNOR) from Pseudomonas aeruginosa reveals similarities to cytochrome oxidases (COX), suggesting a shared evolutionary origin. Differences in the active site may explain distinct respiratory functions.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Bacterial nitric oxide reductase (cNOR) is a key enzyme in microbial respiration.
- cNOR belongs to the haem-copper oxidase superfamily, sharing structural similarities with cytochrome oxidases (COX).
Purpose of the Study:
- To determine the crystal structure of Pseudomonas aeruginosa cNOR.
- To compare the structure of cNOR with COX enzymes.
- To propose a reaction mechanism for nitric oxide reduction.
Main Methods:
- X-ray crystallography was used to determine the cNOR structure.
- Comparative structural analysis was performed between cNOR and COX.
Main Results:
- The overall structure of cNOR is similar to the main subunit of COX.
- Significant structural differences were identified in the catalytic center and proton delivery pathway between cNOR and COX.
- A potential reaction mechanism for nitric oxide reduction to nitrous oxide was proposed based on the cNOR structure.
Conclusions:
- cNOR and COX enzymes are members of the haem-copper oxidase superfamily.
- Structural differences between cNOR and COX suggest distinct functional roles in respiration.
- The proposed mechanism provides a working hypothesis for cNOR activity.
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