Related Experiment Video
Updated: May 8, 2026

Structural Biology and Analytical Chemistry Approaches for Characterizing C-Glycoside Metabolic Enzymes in Human Gut Microbiota
Published on: May 23, 2025
Identification, characterization, and crystal structure of an aldo-keto reductase (AKR2E4) from the silkworm Bombyx
Kohji Yamamoto1, David K Wilson
1Faculty of Agriculture, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Abstract:
A new member of the aldo-keto reductase (AKR) superfamily with 3-dehydroecdysone reductase activity was found in the silkworm Bombyx mori upon induction by the insecticide diazinon. The amino acid sequence showed that this enzyme belongs to the AKR2 family, and the protein was assigned the systematic name AKR2E4. In this study, recombinant AKR2E4 was expressed, purified to near homogeneity, and kinetically characterized. Additionally, its ternary structure in complex with NADP(+) and citrate was refined at 1.3Å resolution to elucidate substrate binding and catalysis. The enzyme is a 33-kDa monomer and reduces dicarbonyl compounds such as isatin and 17α-hydroxy progesterone using NADPH as a cosubstrate. No NADH-dependent activity was detected. Robust activity toward the substrate inhibitor 3-dehydroecdysone was observed, which suggests that this enzyme plays a role in regulation of the important molting hormone ecdysone. This structure constitutes the first insect AKR structure determined. Bound NADPH is located at the center of the TIM- or (β/α)8-barrel, and residues involved in catalysis are conserved.
Related Concept Videos
Globular and Fibrous Proteins
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Intramolecular Aldol Reaction

