Insights into a dual function amide oxidase/macrocyclase from lankacidin biosynthesis

Area of Science:

• Biochemistry
• Enzymology
• Evolutionary Biology

Background:

• Acquiring new enzyme functions is rare in evolution.
• The lankacidin antibiotic pathway features LkcE, a monoamine oxidase (MAO) family enzyme with dual catalytic roles.

Purpose of the Study:

• To elucidate the molecular mechanisms underlying LkcE's unusual dual catalytic activities (amide oxidation and Mannich reaction).
• To understand the structural basis for LkcE's unique dimerization and its impact on function.
• To explore LkcE's potential as a versatile cyclization catalyst in synthetic biology.

Main Methods:

• Structural analysis of LkcE.
• Biochemical assays to characterize enzyme activity.
• Investigating active site residues and dimerization interfaces.

Main Results:

• LkcE exhibits dual catalytic activity through a unique dimerization mode, distinct from other MAO family members.
• Essential active site residues and an interdomain hinge movement are critical for the observed dual function.
• LkcE demonstrates the ability to bind alternative substrates, indicating broader catalytic potential.

Conclusions:

• The evolution of multifunctional enzymes like LkcE may necessitate alterations in both protein architecture and catalytic machinery.
• LkcE's unique structural and functional characteristics provide insights into enzyme evolution and engineering.
• LkcE shows promise as a general cyclization catalyst for applications in synthetic biology.