Structural conservation of the B subunit in the ammonia monooxygenase/particulate methane monooxygenase superfamily

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• The ammonia monooxygenase (AMO)/particulate methane monooxygenase (pMMO) superfamily comprises diverse membrane-bound enzymes.
• Only particulate methane monooxygenase (pMMO) has been characterized at the molecular level.
• The active site of pMMO is hypothesized to be in the N-terminal region of the pmoB subunit.

Purpose of the Study:

• To investigate the structural conservation within the AMO/pMMO superfamily.
• To determine the crystal structure of the archaeal amoB subunit from Nitrosocaldus yellowstonii.

Main Methods:

• X-ray crystallography
• Protein structure determination
• Biochemical analysis

Main Results:

• The crystal structure of the Nitrosocaldus yellowstonii amoB subunit domain was determined to 1.8 Å resolution.
• The structure exhibits remarkable conservation of the overall fold compared to pMMO.
• Key differences in the structure were identified, potentially impacting enzyme function and stability.

Conclusions:

• The archaeal amoB structure shows significant conservation with pMMO, suggesting a conserved structural framework within the superfamily.
• Identified differences highlight potential variations in function and stability across different members of the AMO/pMMO superfamily.
• This study provides a structural basis for understanding the diversity and evolution of these critical enzymes.