Related Experiment Video
Updated: Sep 16, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Structure and Mechanism of the Azomycin Biosynthetic Enzyme RohQ That Catalyzes a Spontaneous Cyclodehydration
Zi-Wang Wei1, Phillip Daniel-Ivad1, Li Zhang1
1Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Abstract:
RohQ from the azomycin biosynthetic pathway catalyzes a spontaneous cyclodehydration to form 2-aminoimidazole. Here we report the structure and mechanism of RohQ and use a serendipitously bound imidazole to pinpoint active site residues. We propose that catalysis occurs at the dimeric interface using two key aspartic acid residues for proton transfer steps to accelerate 3 × 104-fold intramolecular cyclization of a guanidino group and aldehyde, releasing water. Our work expands our understanding of de novo emerged enzymes and provides the first structural and mechanistic view of a yet-unexplored protein family.
Related Concept Videos
Acid-Catalyzed Dehydration of Alcohols to Alkenes
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation
Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...

![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)