1
|
Dinoflagellate Phosphopantetheinyl Transferase (PPTase) and Thiolation Domain Interactions Characterized Using a Modified Indigoidine Synthesizing Reporter. Microorganisms 2022; 10:microorganisms10040687. [PMID: 35456738 PMCID: PMC9027781 DOI: 10.3390/microorganisms10040687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 02/01/2023] Open
Abstract
Photosynthetic dinoflagellates synthesize many toxic but also potential therapeutic compounds therapeutics via polyketide/non-ribosomal peptide synthesis, a common means of producing natural products in bacteria and fungi. Although canonical genes are identifiable in dinoflagellate transcriptomes, the biosynthetic pathways are obfuscated by high copy numbers and fractured synteny. This study focuses on the carrier domains that scaffold natural product synthesis (thiolation domains) and the phosphopantetheinyl transferases (PPTases) that thiolate these carriers. We replaced the thiolation domain of the indigoidine producing BpsA gene from Streptomyces lavendulae with those of three multidomain dinoflagellate transcripts and coexpressed these constructs with each of three dinoflagellate PPTases looking for specific pairings that would identify distinct pathways. Surprisingly, all three PPTases were able to activate all the thiolation domains from one transcript, although with differing levels of indigoidine produced, demonstrating an unusual lack of specificity. Unfortunately, constructs with the remaining thiolation domains produced almost no indigoidine and the thiolation domain for lipid synthesis could not be expressed in E. coli. These results combined with inconsistent protein expression for different PPTase/thiolation domain pairings present technical hurdles for future work. Despite these challenges, expression of catalytically active dinoflagellate proteins in E. coli is a novel and useful tool going forward.
Collapse
|
2
|
Zhang B, Fang J. Assay of selenol species in biological samples by the fluorescent probe Sel-green. Methods Enzymol 2022; 662:259-273. [PMID: 35101214 DOI: 10.1016/bs.mie.2021.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selenium (Se) is an essential trace element for diverse cellular functions. The biological significance of Se is predominantly dependent on its incorporation into the selenocysteine (Sec) for synthesis of selenoproteins (SePs), such as thioredoxin reductase family enzymes and glutathione peroxidase family enzymes. In general, the hyperactivity of the selenol group in Sec confers the Sec residue critical for functions of SePs. The Sec is much less abundant than its sulfur analog cysteine (Cys), and it remains a high challenge to detect Sec, especially in complex biological samples. We recently reported a selective fluorescent probe Sel-green for selenols and summarized the principles for design of selenol (and thiophenol) probes. Sel-green discriminates selenols from other biological species, especially thiols, under physiological conditions, and has been applied to detect both endogenous and exogenous selenol species in live cells. In this chapter, we describe a protocol and guideline for the selective detection of Sec by applying the Sel-green. This protocol is also suitable for detection of other selenol species. This practical and convenient assay would assist scientists to better understand the pivotal roles of Sec as well as SePs.
Collapse
Affiliation(s)
- Baoxin Zhang
- State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
| | - Jianguo Fang
- State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China.
| |
Collapse
|
3
|
Colon R, Wheater M, Joyce EJ, Ste Marie EJ, Hondal RJ, Rein KS. The Marine Neurotoxin Brevetoxin (PbTx-2) Inhibits Karenia brevis and Mammalian Thioredoxin Reductases by Targeting Different Residues. JOURNAL OF NATURAL PRODUCTS 2021; 84:2961-2970. [PMID: 34752085 DOI: 10.1021/acs.jnatprod.1c00795] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The brevetoxins, neurotoxins produced by Karenia brevis, the Florida red tide dinoflagellate, effect fish and wildlife mortalities and adverse public health and economic impacts during recurrent blooms. Knowledge of the biochemical consequences of toxin production for K. brevis could provide insights into an endogenous role of the toxins, yet this aspect has not been thoroughly explored. In addition to neurotoxicity, the most abundant of the brevetoxins, PbTx-2, inhibits mammalian thioredoxin reductase (TrxR). The thioredoxin system, composed of the enzymes TrxR and thioredoxin (Trx), is present in all living organisms and is responsible in part for maintaining cellular redox homeostasis. Herein, we describe the cloning, expression, and semisynthesis of the selenoprotein TrxR from K. brevis (KbTrxR) and reductase activity toward a variety of substrates. Unlike mammalian TrxR, KbTrxR reduces oxidized glutathione (GSSG). We further demonstrate that PbTx-2 is an inhibitor of KbTrxR. Covalent adducts between KbTrxR and rat TrxR were detected by mass spectrometry. While both enzymes are adducted at or near the catalytic centers, the specific residues are distinct. Biochemical differences reported for high and low toxin producing strains of K. brevis are consistent with the inhibition of KbTrxR and suggest that PbTx-2 is an endogenous regulator of this critical enzyme.
Collapse
Affiliation(s)
- Ricardo Colon
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
| | - Michelle Wheater
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Given Building Room 413B, Burlington, Vermont 05405, United States
| | - Emily J Joyce
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Given Building Room 413B, Burlington, Vermont 05405, United States
| | - Emma J Ste Marie
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Given Building Room 413B, Burlington, Vermont 05405, United States
| | - Robert J Hondal
- Department of Biochemistry, University of Vermont, 89 Beaumont Avenue, Given Building Room 413B, Burlington, Vermont 05405, United States
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
| |
Collapse
|
4
|
Williams EP, Bachvaroff TR, Place AR. A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates. Evol Bioinform Online 2021; 17:11769343211031871. [PMID: 34345159 PMCID: PMC8283056 DOI: 10.1177/11769343211031871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Many dinoflagellate species make toxins in a myriad of different molecular configurations but the underlying chemistry in all cases is presumably via modular synthases, primarily polyketide synthases. In many organisms modular synthases occur as discrete synthetic genes or domains within a gene that act in coordination thus forming a module that produces a particular fragment of a natural product. The modules usually occur in tandem as gene clusters with a syntenic arrangement that is often predictive of the resultant structure. Dinoflagellate genomes however are notoriously complex with individual genes present in many tandem repeats and very few synthetic modules occurring as gene clusters, unlike what has been seen in bacteria and fungi. However, modular synthesis in all organisms requires a free thiol group that acts as a carrier for sequential synthesis called a thiolation domain. We scanned 47 dinoflagellate transcriptomes for 23 modular synthase domain models and compared their abundance among 10 orders of dinoflagellates as well as their co-occurrence with thiolation domains. The total count of domain types was quite large with over thirty-thousand identified, 29 000 of which were in the core dinoflagellates. Although there were no specific trends in domain abundance associated with types of toxins, there were readily observable lineage specific differences. The Gymnodiniales, makers of long polyketide toxins such as brevetoxin and karlotoxin had a high relative abundance of thiolation domains as well as multiple thiolation domains within a single transcript. Orders such as the Gonyaulacales, makers of small polyketides such as spirolides, had fewer thiolation domains but a relative increase in the number of acyl transferases. Unique to the core dinoflagellates, however, were thiolation domains occurring alongside tetratricopeptide repeats that facilitate protein-protein interactions, especially hexa and hepta-repeats, that may explain the scaffolding required for synthetic complexes capable of making large toxins. Clustering analysis for each type of domain was also used to discern possible origins of duplication for the multitude of single domain transcripts. Single domain transcripts frequently clustered with synonymous domains from multi-domain transcripts such as the BurA and ZmaK like genes as well as the multi-ketosynthase genes, sometimes with a large degree of apparent gene duplication, while fatty acid synthesis genes formed distinct clusters. Surprisingly the acyl-transferases and ketoreductases involved in fatty acid synthesis (FabD and FabG, respectively) were found in very large clusters indicating an unprecedented degree of gene duplication for these genes. These results demonstrate a complex evolutionary history of core dinoflagellate modular synthases with domain specific duplications throughout the lineage as well as clues to how large protein complexes can be assembled to synthesize the largest natural products known.
Collapse
Affiliation(s)
- Ernest P Williams
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Tsvetan R Bachvaroff
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Allen R Place
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| |
Collapse
|
5
|
Raja IS, Vedhanayagam M, Preeth DR, Kim C, Lee JH, Han DW. Development of Two-Dimensional Nanomaterials Based Electrochemical Biosensors on Enhancing the Analysis of Food Toxicants. Int J Mol Sci 2021; 22:3277. [PMID: 33806998 PMCID: PMC8005143 DOI: 10.3390/ijms22063277] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 12/25/2022] Open
Abstract
In recent times, food safety has become a topic of debate as the foodborne diseases triggered by chemical and biological contaminants affect human health and the food industry's profits. Though conventional analytical instrumentation-based food sensors are available, the consumers did not appreciate them because of the drawbacks of complexity, greater number of analysis steps, expensive enzymes, and lack of portability. Hence, designing easy-to-use tests for the rapid analysis of food contaminants has become essential in the food industry. Under this context, electrochemical biosensors have received attention among researchers as they bear the advantages of operational simplicity, portability, stability, easy miniaturization, and low cost. Two-dimensional (2D) nanomaterials have a larger surface area to volume compared to other dimensional nanomaterials. Hence, researchers nowadays are inclined to develop 2D nanomaterials-based electrochemical biosensors to significantly improve the sensor's sensitivity, selectivity, and reproducibility while measuring the food toxicants. In the present review, we compile the contribution of 2D nanomaterials in electrochemical biosensors to test the food toxicants and discuss the future directions in the field. Further, we describe the types of food toxicity, methodologies quantifying food analytes, how the electrochemical food sensor works, and the general biomedical properties of 2D nanomaterials.
Collapse
Affiliation(s)
| | | | - Desingh Raj Preeth
- Chemical Biology and Nanobiotechnology Laboratory, AU-KBC Research Centre, Anna University, MIT Campus, Chromepet, Chennai 600 044, India;
| | - Chuntae Kim
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea; (I.S.R.); (C.K.)
| | - Jong Hun Lee
- Department of Food Science and Biotechnology, Gachon University, Seongnam 13120, Korea
| | - Dong Wook Han
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea; (I.S.R.); (C.K.)
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea
| |
Collapse
|
6
|
Abstract
This review covers the literature published between January and December in 2018 for marine natural products (MNPs), with 717 citations (706 for the period January to December 2018) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1554 in 469 papers for 2018), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. The proportion of MNPs assigned absolute configuration over the last decade is also surveyed.
Collapse
Affiliation(s)
- Anthony R Carroll
- School of Environment and Science, Griffith University, Gold Coast, Australia. and Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Brent R Copp
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Rohan A Davis
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia and School of Environment and Science, Griffith University, Brisbane, Australia
| | - Robert A Keyzers
- Centre for Biodiscovery, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Hamilton, New Zealand
| |
Collapse
|
7
|
Colon R, Rein KS. Essential components of the xanthophyll cycle differ in high and low toxin Karenia brevis. HARMFUL ALGAE 2021; 103:102006. [PMID: 33980446 PMCID: PMC10246377 DOI: 10.1016/j.hal.2021.102006] [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] [Received: 10/31/2020] [Revised: 02/26/2021] [Accepted: 02/27/2021] [Indexed: 06/09/2023]
Abstract
The dinoflagellate Karenia brevis, blooms annually in the Gulf of Mexico, producing a suite of neurotoxins known as the brevetoxins. The cellular toxin content of K. brevis, however, is highly variable between or even within strains. Herein, we investigate physiological differences between high (KbHT) and low (KbLT) toxin producing cultures both derived from the Wilson strain, related to energy-dependent quenching (qE) by photosystem II, and reduced thiol content of the proteome. We demonstrate that gene and protein expression of the xanthophyll cycle enzyme diadinoxanthin de-epoxidase (Dde) and monogalactosyldiacylglycerol (MGDG) synthase are not significantly different in the two cultures. Using redox proteomics, we report a significantly higher reduced cysteine content in the low toxin proteome, including plastid localized thioredoxin reductase (Trx) which can result in inactivation of Dde and activation of MGDG synthase. We also report significant differences in the lipidomes of KbHT and KbLT with respect to MGDG, which facilitates the xanthophyll cycle.
Collapse
Affiliation(s)
- Ricardo Colon
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, United States.
| |
Collapse
|