1
|
Cui J, Ju KS. Biosynthesis of Bacillus Phosphonoalamides Reveals Highly Specific Amino Acid Ligation. ACS Chem Biol 2024. [PMID: 38885091 DOI: 10.1021/acschembio.4c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Phosphonate natural products have a history of commercial success across numerous industries due to their potent inhibition of metabolic processes. Over the past decade, genome mining approaches have successfully led to the discovery of numerous bioactive phosphonates. However, continued success is dependent upon a greater understanding of phosphonate metabolism, which will enable the prioritization and prediction of biosynthetic gene clusters for targeted isolation. Here, we report the complete biosynthetic pathway for phosphonoalamides E and F, antimicrobial phosphonopeptides with a conserved C-terminal l-phosphonoalanine (PnAla) residue. These peptides, produced by Bacillus, are the direct result of PnAla biosynthesis and serial ligation by two ATP-grasp ligases. A critical step of this pathway was the reversible transamination of phosphonopyruvate to PnAla by a dedicated transaminase with preference for the forward reaction. The dipeptide ligase PnfA was shown to ligate alanine to PnAla to afford phosphonoalamide E, which was subsequently ligated to alanine by PnfB to form phosphonoalamide F. Specificity profiling of both ligases found each to be highly specific, although the limited acceptance of noncanonical substrates by PnfA allowed for in vitro formation of products incorporating alternative pharmacophores. Our findings further establish the transaminative branch of phosphonate metabolism, unveil insights into the specificity of ATP-grasp ligation, and highlight the biocatalytic potential of biosynthetic enzymes.
Collapse
Affiliation(s)
- Jerry Cui
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Kou-San Ju
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, United States
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, Ohio 43210, United States
- Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio 43210, United States
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
2
|
Cui JJ, Zhang Y, Ju KS. Phosphonoalamides Reveal the Biosynthetic Origin of Phosphonoalanine Natural Products and a Convergent Pathway for Their Diversification. Angew Chem Int Ed Engl 2024:e202405052. [PMID: 38780891 DOI: 10.1002/anie.202405052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/18/2024] [Accepted: 05/23/2024] [Indexed: 05/25/2024]
Abstract
Phosphonate natural products, with their potent inhibitory activity, have found widespread use across multiple industries. Their success has inspired development of genome mining approaches that continue to reveal previously unknown bioactive scaffolds and biosynthetic insights. However, a greater understanding of phosphonate metabolism is required to enable prediction of compounds and their bioactivities from sequence information alone. Here, we expand our knowledge of this natural product class by reporting the complete biosynthesis of the phosphonoalamides, antimicrobial tripeptides with a conserved N-terminal l-phosphonoalanine (PnAla) residue produced by Streptomyces. The phosphonoalamides result from the convergence of PnAla biosynthesis and peptide ligation pathways. We elucidate the biochemistry underlying the transamination of phosphonopyruvate to PnAla, a new early branchpoint in phosphonate biosynthesis catalyzed by an aminotransferase with evolved specificity for phosphonate metabolism. Peptide formation is catalyzed by two ATP-grasp ligases, the first of which produces dipeptides, and a second which ligates dipeptides to PnAla to produce phosphonoalamides. Substrate specificity profiling revealed a dramatic expansion of dipeptide and tripeptide products, while finding PnaC to be the most promiscuous dipeptide ligase reported thus far. Our findings highlight previously unknown transformations in natural product biosynthesis, promising enzyme biocatalysts, and unveil insights into the diversity of phosphonopeptide natural products.
Collapse
Affiliation(s)
- Jerry J Cui
- Department of Microbiology, The Ohio State University, 318W. 12th Ave, Columbus, OH-43210, USA
| | - Yeying Zhang
- Department of Microbiology, The Ohio State University, 318W. 12th Ave, Columbus, OH-43210, USA
| | - Kou-San Ju
- Department of Microbiology, The Ohio State University, 318W. 12th Ave, Columbus, OH-43210, USA
- Division of Medicinal Chemistry and Pharmacognosy, Center for Applied Plant Sciences, Infectious Disease Institute, The Ohio State University, 318W. 12th Ave, Columbus, OH-43210, USA
| |
Collapse
|
3
|
Wilson J, Cui J, Nakao T, Kwok H, Zhang Y, Kayrouz CM, Pham TM, Roodhouse H, Ju KS. Discovery of Antimicrobial Phosphonopeptide Natural Products from Bacillus velezensis by Genome Mining. Appl Environ Microbiol 2023; 89:e0033823. [PMID: 37377428 PMCID: PMC10304907 DOI: 10.1128/aem.00338-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/16/2023] [Indexed: 06/29/2023] Open
Abstract
Phosphonate natural products are renowned for inhibitory activities which underly their development as antibiotics and pesticides. Although most phosphonate natural products have been isolated from Streptomyces, bioinformatic surveys suggest that many other bacterial genera are replete with similar biosynthetic potential. While mining actinobacterial genomes, we encountered a contaminated Mycobacteroides data set which included a biosynthetic gene cluster predicted to produce novel phosphonate compounds. Sequence deconvolution revealed that the contig containing this cluster, as well as many others, belonged to a contaminating Bacillus and is broadly conserved among multiple species, including the epiphyte Bacillus velezensis. Isolation and structure elucidation revealed a new di- and tripeptide composed of l-alanine and a C-terminal l-phosphonoalanine which we name phosphonoalamides E and F. These compounds exhibit broad-spectrum antibacterial activity, including strong inhibition against the agricultural pests responsible for vegetable soft rot (Erwinia rhapontici), onion rot (Pantoea ananatis), and American foulbrood (Paenibacillus larvae). This work expands our knowledge of phosphonate metabolism and underscores the importance of including underexplored microbial taxa in natural product discovery. IMPORTANCE Phosphonate natural products produced by bacteria have been a rich source of clinical antibiotics and commercial pesticides. Here, we describe the discovery of two new phosphonopeptides produced by B. velezensis with antibacterial activity against human and plant pathogens, including those responsible for widespread soft rot in crops and American foulbrood. Our results provide new insight on the natural chemical diversity of phosphonates and suggest that these compounds could be developed as effective antibiotics for use in medicine or agriculture.
Collapse
Affiliation(s)
- Jake Wilson
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, Ohio, USA
| | - Jerry Cui
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Toshiki Nakao
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Happy Kwok
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Yeying Zhang
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Chase M. Kayrouz
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Tiffany M. Pham
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Hannah Roodhouse
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Kou-San Ju
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, Ohio, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| |
Collapse
|
4
|
Bown L, Hirota R, Goettge MN, Cui J, Krist DT, Zhu L, Giurgiu C, van der Donk WA, Ju KS, Metcalf WW. A Novel Pathway for Biosynthesis of the Herbicidal Phosphonate Natural Product Phosphonothrixin Is Widespread in Actinobacteria. J Bacteriol 2023; 205:e0048522. [PMID: 37074199 PMCID: PMC10210982 DOI: 10.1128/jb.00485-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/23/2023] [Indexed: 04/20/2023] Open
Abstract
Phosphonothrixin is an herbicidal phosphonate natural product with an unusual, branched carbon skeleton. Bioinformatic analyses of the ftx gene cluster, which is responsible for synthesis of the compound, suggest that early steps of the biosynthetic pathway, up to production of the intermediate 2,3-dihydroxypropylphosphonic acid (DHPPA) are identical to those of the unrelated phosphonate natural product valinophos. This conclusion was strongly supported by the observation of biosynthetic intermediates from the shared pathway in spent media from two phosphonothrixin producing strains. Biochemical characterization of ftx-encoded proteins confirmed these early steps, as well as subsequent steps involving the oxidation of DHPPA to 3-hydroxy-2-oxopropylphosphonate and its conversion to phosphonothrixin by the combined action of an unusual heterodimeric, thiamine-pyrophosphate (TPP)-dependent ketotransferase and a TPP-dependent acetolactate synthase. The frequent observation of ftx-like gene clusters within actinobacteria suggests that production of compounds related to phosphonothrixin is common within these bacteria. IMPORTANCE Phosphonic acid natural products, such as phosphonothrixin, have great potential for biomedical and agricultural applications; however, discovery and development of these compounds requires detailed knowledge of the metabolism involved in their biosynthesis. The studies reported here reveal the biochemical pathway phosphonothrixin production, which enhances our ability to design strains that overproduce this potentially useful herbicide. This knowledge also improves our ability to predict the products of related biosynthetic gene clusters and the functions of homologous enzymes.
Collapse
Affiliation(s)
- Luke Bown
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ryuichi Hirota
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima, Japan
| | - Michelle N. Goettge
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jerry Cui
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - David T. Krist
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Lingyang Zhu
- Department of Chemistry and the Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Constantin Giurgiu
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Wilfred A. van der Donk
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Chemistry and the Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Kou-San Ju
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, USA
| | - William W. Metcalf
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
5
|
The functional importance of bacterial oxidative phosphonate pathways. Biochem Soc Trans 2023; 51:487-499. [PMID: 36892197 DOI: 10.1042/bst20220479] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/10/2023]
Abstract
Organophosphonates (Pns) are a unique class of natural products characterized by a highly stable C-P bond. Pns exhibit a wide array of interesting structures as well as useful bioactivities ranging from antibacterial to herbicidal. More structurally simple Pns are scavenged and catabolized by bacteria as a source of phosphorus. Despite their environmental and industrial importance, the pathways involved in the metabolism of Pns are far from being fully elucidated. Pathways that have been characterized often reveal unusual chemical transformations and new enzyme mechanisms. Among these, oxidative enzymes play an outstanding role during the biosynthesis and degradation of Pns. They are to a high extent responsible for the structural diversity of Pn secondary metabolites and for the break-down of both man-made and biogenic Pns. Here, we review our current understanding of the importance of oxidative enzymes for microbial Pn metabolism, discuss the underlying mechanistic principles, similarities, and differences between pathways. This review illustrates Pn biochemistry to involve a mix of classical redox biochemistry and unique oxidative reactions, including ring formations, rearrangements, and desaturations. Many of these reactions are mediated by specialized iron-dependent oxygenases and oxidases. Such enzymes are the key to both early pathway diversification and late-stage functionalization of complex Pns.
Collapse
|
6
|
Zhao M, Shin GY, Stice S, Bown JL, Coutinho T, Metcalf WW, Gitaitis R, Kvitko B, Dutta B. A Novel Biosynthetic Gene Cluster Across the Pantoea Species Complex Is Important for Pathogenicity in Onion. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:176-188. [PMID: 36534063 PMCID: PMC10433531 DOI: 10.1094/mpmi-08-22-0165-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Onion center rot is caused by at least four species of genus Pantoea (P. ananatis, P. agglomerans, P. allii, and P. stewartii subsp. indologenes). Critical onion pathogenicity determinants for P. ananatis were recently described, but whether those determinants are common among other onion-pathogenic Pantoea species remains unknown. In this work, we report onion pathogenicity determinants in P. stewartii subsp. indologenes and P. allii. We identified two distinct secondary metabolite biosynthetic gene clusters present separately in different strains of onion-pathogenic P. stewartii subsp. indologenes. One cluster is similar to the previously described HiVir phosphonate biosynthetic cluster identified in P. ananatis and another is a novel putative phosphonate biosynthetic gene cluster, which we named Halophos. The Halophos gene cluster was also identified in P. allii strains. Both clusters are predicted to be phosphonate biosynthetic clusters based on the presence of a characteristic phosphoenolpyruvate phosphomutase (pepM) gene. The deletion of the pepM gene from either HiVir or Halophos clusters in P. stewartii subsp. indologenes caused loss of necrosis on onion leaves and red onion scales and resulted in significantly lower bacterial populations compared with the corresponding wild-type and complemented strains. Seven (halB to halH) of 11 genes (halA to halK) in the Halophos gene cluster are required for onion necrosis phenotypes. The onion nonpathogenic strain PNA15-2 (P. stewartii subsp. indologenes) gained the capacity to cause foliar necrosis on onion via exogenous expression of a minimal seven-gene Halophos cluster (genes halB to halH). Furthermore, cell-free culture filtrates of PNA14-12 expressing the intact Halophos gene cluster caused necrosis on onion leaves consistent with the presence of a secreted toxin. Based on the similarity of proteins to those with experimentally determined functions, we are able to predict most of the steps in Halophos biosynthesis. Together, these observations indicate that production of the toxin phosphonate seems sufficient to account for virulence of a variety of different Pantoea strains, although strains differ in possessing a single but distinct phosphonate biosynthetic cluster. Overall, this is the first report of onion pathogenicity determinants in P. stewartii subsp. indologenes and P. allii. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Mei Zhao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Department of Plant Pathology, University of Georgia, Tifton GA USA
| | - Gi Yoon Shin
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Shaun Stice
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Jonathon Luke Bown
- Department of Microbiology, University of Illinois, Urbana-Champaign, IL
| | - Teresa Coutinho
- The Genomics Research Institute, University of Pretoria, Hatfield, South Africa
| | - William W. Metcalf
- Department of Microbiology, University of Illinois, Urbana-Champaign, IL
| | - Ron Gitaitis
- Department of Plant Pathology, University of Georgia, Tifton GA USA
| | - Brian Kvitko
- Department of Plant Pathology, University of Georgia, Athens GA USA
| | - Bhabesh Dutta
- Department of Plant Pathology, University of Georgia, Tifton GA USA
| |
Collapse
|
7
|
Ju KS, Nair SK. Convergent and divergent biosynthetic strategies towards phosphonic acid natural products. Curr Opin Chem Biol 2022; 71:102214. [PMID: 36202046 PMCID: PMC9722595 DOI: 10.1016/j.cbpa.2022.102214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 01/27/2023]
Abstract
The phosphonate class of natural products have received significant interests in the post-genomic era due to the relative ease with which their biosynthetic genes may be identified and the resultant final products be characterized. Recent large-scale studies of the elucidation and distributions of phosphonate pathways have provided a robust landscape for deciphering the underlying biosynthetic logic. A recurrent theme in phosphonate biosynthetic pathways is the interweaving of enzymatic reactions across different routes, which enables diversification to elaborate chemically novel scaffolds. Here, we provide a few vignettes of how Nature has utilized both convergent and divergent biosynthetic strategies to compile pathways for production of novel phosphonates. These examples illustrate how common intermediates may either be generated or intercepted to diversify chemical scaffolds and provides a starting point for both biotechnological and synthetic biological applications towards new phosphonates by similar combinatorial approaches.
Collapse
Affiliation(s)
- Kou-San Ju
- Department of Microbiology, The Ohio State University, Columbus OH 43210,Division of Medicinal Chemistry and Pharmacognosy, The Ohio State University, Columbus OH 43210,Infectious Diseases Institute. The Ohio State University, Columbus OH 43210,Corresponding authors: Kou-San Ju () and Satish K. Nair ()
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, IL 61801,Carl Woese Institute for Genomic Biology. University of Illinois, Urbana, IL 61801,Corresponding authors: Kou-San Ju () and Satish K. Nair ()
| |
Collapse
|
8
|
Zhu Y, Shiraishi T, Lin J, Inaba K, Ito A, Ogura Y, Nishiyama M, Kuzuyama T. Complete Biosynthetic Pathway of the Phosphonate Phosphonothrixin: Two Distinct Thiamine Diphosphate-Dependent Enzymes Divide the Work to Form a C-C Bond. J Am Chem Soc 2022; 144:16715-16719. [PMID: 36067081 DOI: 10.1021/jacs.2c06546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphonates often exhibit biological activities by mimicking the phosphates and carboxylates of biological molecules. The phosphonate phosphonothrixin (PTX), produced by the soil-dwelling bacterium Saccharothrix sp. ST-888, exhibits herbicidal activity. In this study, we propose a complete biosynthetic pathway for PTX by reconstituting its biosynthesis in vitro. Our intensive analysis demonstrated that two dehydrogenases together reduce phosphonopyruvate (PnPy) to 2-hydroxy-3-phosphonopropanoic acid (HPPA) to accelerate the thermodynamically unfavorable rearrangement of phosphoenolpyruvate (PEP) to PnPy. The next four enzymes convert HPPA to (3-hydroxy-2-oxopropyl)phosphonic acid (HOPA). In the final stage of PTX biosynthesis, the "split-gene" transketolase homologue, PtxB5/6, catalyzes the transfer of a two-carbon unit attached to the thiamine diphosphate (TPP) cofactor (provided by the acetohydroxyacid synthase homologue, PtxB7) to HOPA to produce PTX. This study reveals a unique C-C bond formation in which two distinct TPP-dependent enzymes, PtxB5/6 and PtxB7, divide the work to transfer an acetyl group, highlighting an unprecedented biosynthetic strategy for natural products.
Collapse
Affiliation(s)
- Yuxun Zhu
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Taro Shiraishi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jianwen Lin
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Keito Inaba
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Atsuro Ito
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yusuke Ogura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Makoto Nishiyama
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tomohisa Kuzuyama
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| |
Collapse
|