skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structural and Functional Trends in Dehydrating Bimodules from trans -Acyltransferase Polyketide Synthases

Abstract

In an effort to uncover the structural motifs and biosynthetic logic of the relatively uncharacterized trans-acyltransferase polyketide synthases, we have begun the dissection of the enigmatic dehydrating bimodules common in these enzymatic assembly lines. We report the 1.98 Å resolution structure of a ketoreductase (KR) from the first half of a type A dehydrating bimodule and the 2.22 Å resolution structure of a dehydratase (DH) from the second half of a type B dehydrating bimodule. The KR, from the third module of the bacillaene synthase, and the DH, from the tenth module of the difficidin synthase, possess features not observed in structurally characterized homologs. The DH architecture provides clues for how it catalyzes a unique double dehydration. Correlations between the chemistries proposed for dehydrating bimodules and bioinformatic analysis indicate that type A dehydrating bimodules generally produce an α/β-cis alkene moiety, while type B dehydrating bimodules generally produce an α/β-trans, γ/δ-cis diene moiety.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NIHOTHER
OSTI Identifier:
1375350
Resource Type:
Journal Article
Resource Relation:
Journal Name: Structure; Journal Volume: 25; Journal Issue: 7
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Wagner, Drew T., Zeng, Jia, Bailey, Constance B., Gay, Darren C., Yuan, Fang, Manion, Hannah R., and Keatinge-Clay, Adrian T. Structural and Functional Trends in Dehydrating Bimodules from trans -Acyltransferase Polyketide Synthases. United States: N. p., 2017. Web. doi:10.1016/j.str.2017.05.011.
Wagner, Drew T., Zeng, Jia, Bailey, Constance B., Gay, Darren C., Yuan, Fang, Manion, Hannah R., & Keatinge-Clay, Adrian T. Structural and Functional Trends in Dehydrating Bimodules from trans -Acyltransferase Polyketide Synthases. United States. doi:10.1016/j.str.2017.05.011.
Wagner, Drew T., Zeng, Jia, Bailey, Constance B., Gay, Darren C., Yuan, Fang, Manion, Hannah R., and Keatinge-Clay, Adrian T. Sat . "Structural and Functional Trends in Dehydrating Bimodules from trans -Acyltransferase Polyketide Synthases". United States. doi:10.1016/j.str.2017.05.011.
@article{osti_1375350,
title = {Structural and Functional Trends in Dehydrating Bimodules from trans -Acyltransferase Polyketide Synthases},
author = {Wagner, Drew T. and Zeng, Jia and Bailey, Constance B. and Gay, Darren C. and Yuan, Fang and Manion, Hannah R. and Keatinge-Clay, Adrian T.},
abstractNote = {In an effort to uncover the structural motifs and biosynthetic logic of the relatively uncharacterized trans-acyltransferase polyketide synthases, we have begun the dissection of the enigmatic dehydrating bimodules common in these enzymatic assembly lines. We report the 1.98 Å resolution structure of a ketoreductase (KR) from the first half of a type A dehydrating bimodule and the 2.22 Å resolution structure of a dehydratase (DH) from the second half of a type B dehydrating bimodule. The KR, from the third module of the bacillaene synthase, and the DH, from the tenth module of the difficidin synthase, possess features not observed in structurally characterized homologs. The DH architecture provides clues for how it catalyzes a unique double dehydration. Correlations between the chemistries proposed for dehydrating bimodules and bioinformatic analysis indicate that type A dehydrating bimodules generally produce an α/β-cis alkene moiety, while type B dehydrating bimodules generally produce an α/β-trans, γ/δ-cis diene moiety.},
doi = {10.1016/j.str.2017.05.011},
journal = {Structure},
number = 7,
volume = 25,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}
  • Type I modular polyketide synthases (PKSs) are polymerases that utilize acyl-CoAs as substrates. Each polyketide elongation reaction is catalyzed by a set of protein domains called a module. Each module usually contains an acyltransferase (AT) domain, which determines the specific acyl-CoA incorporated into each condensation reaction. Although a successful exchange of individual AT domains can lead to the biosynthesis of a large variety of novel compounds, hybrid PKS modules often show significantly decreased activities. Using monomodular PKSs as models, we have systematically analyzed in this paper the segments of AT domains and associated linkers in AT exchanges in vitro andmore » have identified the boundaries within a module that can be used to exchange AT domains while maintaining protein stability and enzyme activity. Importantly, the optimized domain boundary is highly conserved, which facilitates AT domain replacements in most type I PKS modules. To further demonstrate the utility of the optimized AT domain boundary, we have constructed hybrid PKSs to produce industrially important short-chain ketones. Our in vitro and in vivo analysis demonstrated production of predicted ketones without significant loss of activities of the hybrid enzymes. Finally, these results greatly enhance the mechanistic understanding of PKS modules and prove the benefit of using engineered PKSs as a synthetic biology tool for chemical production.« less
  • Cited by 4
  • Fusarium species are ubiquitous in nature, cause a range of plant diseases, and produce a variety of chemicals often referred to as secondary metabolites. Although some fungal secondary metabolites affect plant growth or protect plants from other fungi and bacteria, their presence in grain based food and feed is more often associated with a variety of diseases in plants and in animals. Many of these structurally diverse metabolites are derived from a family of related enzymes called polyketide synthases (PKSs). A search of genomic sequence of Fusarium verticillioides, F. graminearum, F. oxysporum and Nectria haematococca (anamorph F. solani) identified amore » total of 58 PKS genes. To gain insight into how this gene family evolved and to guide future studies, we conducted a phylogenomic and functional domain analysis. The resulting genealogy suggested that Fusarium PKSs represent 34 different groups responsible for synthesis of different core metabolites. The analyses indicate that variation in the Fusarium PKS gene family is due to gene duplication and loss events as well as enzyme gain-of-function due to the acquisition of new domains or of loss-of-function due to nucleotide mutations. Transcriptional analysis indicate that the 16 F. verticillioides PKS genes are expressed under a range of conditions, further evidence that they are functional genes that confer the ability to produce secondary metabolites.« less