Publication Date:
2016-08-27
Description:
Ips spp. bark beetles use ipsdienol, ipsenol, ipsdienone and ipsenone as aggregation pheromone components and pheromone precursors. For Ips pini , the short-chain oxidoreductase ipsdienol dehydrogenase (IDOLDH) converts (–)-ipsdienol to ipsdienone, and thus likely plays a role in determining pheromone composition. In order to further understand the role of IDOLDH in pheromone biosynthesis, we compared IDOLDH to its nearest functionally characterized ortholog with a solved structure: human L-3-hydroxyacyl-CoA dehydrogenase type II/ amyloid-β binding alcohol dehydrogenase (hHADH II/ABAD), and conducted functional assays of recombinant IDOLDH to determine substrate and product ranges and structural characteristics. Although IDOLDH and hHADH II/ABAD had only 35% sequence identity, their predicted tertiary structures had high identity. We found IDOLDH is a functional homo-tetramer. In addition to oxidizing (–)-ipsdienol, IDOLDH readily converted racemic ipsenol to ipsenone, and stereo-specifically reduced both ketones to their corresponding (–)-alcohols. The (+)-enantiomers were never observed as products. Assays with various substrate analogs showed IDOLDH had high substrate specificity for (–)-ipsdienol, ipsenol, ipsenone and ipsdienone, supporting that IDOLDH functions as a pheromone-biosynthetic enzyme. These results suggest that different IDOLDH orthologs and or activity levels contribute to differences in Ips spp. pheromone composition.
Print ISSN:
0021-924X
Electronic ISSN:
1756-2651
Topics:
Biology
,
Chemistry and Pharmacology
