Functionally diverse biotin-dependent enzymes with oxaloacetate decarboxylase activity

Area of Science:

• Biochemistry
• Enzymology
• Structural Biology

Background:

• Biotin-dependent enzymes are crucial for primary metabolism, catalyzing carboxylation, decarboxylation, and transcarboxylation reactions.
• These enzymes function via two distinct half-reactions involving a biotin cofactor and a carboxyltransferase domain.

Purpose of the Study:

• To provide a unified description of the carboxyltransferase domain structure and catalytic mechanism.
• To integrate recent structural findings for key biotin-dependent enzymes.

Main Methods:

• Review of recent structural data and mechanistic studies.
• Comparative analysis of pyruvate carboxylase, oxaloacetate decarboxylase, and transcarboxylase.

Main Results:

• Identified a homologous carboxyltransferase domain across diverse enzymes.
• Elucidated the two-site mechanism involving a carboxybiotin intermediate.
• Demonstrated conserved structural features and catalytic strategies.

Conclusions:

• The carboxyltransferase domain exhibits conserved structural and mechanistic properties.
• Understanding this domain advances knowledge of biotin-dependent carboxylations and decarboxylations.
• Structural insights facilitate mechanistic understanding of primary metabolic enzymes.