Vanadium haloperoxidases as noncanonical terpene synthases

Area of Science:

• Biochemistry
• Enzymology
• Organic Chemistry

Background:

• Vanadium-dependent haloperoxidases (VHPOs) are enzymes utilizing vanadate, halide ions, and hydrogen peroxide.
• VHPOs generate electrophilic halogen species for organic substrate modification.
• Some VHPOs catalyze regio- and enantioselective halogenation and cyclization of terpenes and meroterpenoids.

Purpose of the Study:

• To describe the expression, purification, and chemical assays of NapH4, a challenging VHPO.
• To investigate the catalytic activity of NapH4 on its meroterpenoid substrate.

Main Methods:

• Enzyme expression and purification of NapH4.
• Chemical assays to determine enzyme activity.
• Characterization of catalytic reactions involving NapH4.

Main Results:

• Successful expression and purification of the difficult-to-express NapH4 enzyme.
• Demonstration that NapH4 catalyzes chloronium-induced cyclization of its meroterpenoid substrate.
• Characterization of the specific halogenation and cyclization pathway mediated by NapH4.

Conclusions:

• NapH4 is a functional vanadium-dependent haloperoxidase with a role in meroterpenoid cyclization.
• The study provides insights into the mechanism of VHPO-catalyzed halogenation and cyclization reactions.
• NapH4 serves as a model enzyme for understanding complex enzymatic halogenation processes.