1
|
Ghosh D, Mangar P, Choudhury A, Kumar A, Saha A, Basu P, Saha D. Characterization of a hemolytic and antibiotic-resistant Pseudomonas aeruginosa strain S3 pathogenic to fish isolated from Mahananda River in India. PLoS One 2024; 19:e0300134. [PMID: 38547304 PMCID: PMC10977779 DOI: 10.1371/journal.pone.0300134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/21/2024] [Indexed: 04/02/2024] Open
Abstract
Virulent strain Pseudomonas aeruginosa isolated from Mahananda River exhibited the highest hemolytic activity and virulence factors and was pathogenic to fish as clinical signs of hemorrhagic spots, loss of scales, and fin erosions were found. S3 was cytotoxic to the human liver cell line (WRL-68) in the trypan blue dye exclusion assay. Genotype characterization using whole genome analysis showed that S3 was similar to P. aeruginosa PAO1. The draft genome sequence had an estimated length of 62,69,783 bp, a GC content of 66.3%, and contained 5916 coding sequences. Eight genes across the genome were predicted to be related to hemolysin action. Antibiotic resistance genes such as class C and class D beta-lactamases, fosA, APH, and catB were detected, along with the strong presence of multiple efflux system genes. This study shows that river water is contaminated by pathogenic P. aeruginosa harboring an array of virulence and antibiotic resistance genes which warrants periodic monitoring to prevent disease outbreaks.
Collapse
Affiliation(s)
- Dipanwita Ghosh
- Department of Biotechnology, University of North Bengal, Siliguri, West Bengal, India
| | - Preeti Mangar
- Department of Botany, University of North Bengal, Siliguri, West Bengal, India
| | - Abhinandan Choudhury
- Department of Biotechnology, University of North Bengal, Siliguri, West Bengal, India
| | - Anoop Kumar
- Department of Biotechnology, University of North Bengal, Siliguri, West Bengal, India
| | - Aniruddha Saha
- Department of Botany, University of North Bengal, Siliguri, West Bengal, India
| | - Protip Basu
- Department of Botany, Siliguri College, West Bengal, India
| | - Dipanwita Saha
- Department of Biotechnology, University of North Bengal, Siliguri, West Bengal, India
| |
Collapse
|
2
|
Osickova A, Knoblochova S, Bumba L, Man P, Kalaninova Z, Lepesheva A, Jurnecka D, Cizkova M, Biedermannova L, Goldsmith JA, Maynard JA, McLellan JS, Osicka R, Sebo P, Masin J. A conserved tryptophan in the acylated segment of RTX toxins controls their β 2 integrin-independent cell penetration. J Biol Chem 2023; 299:104978. [PMID: 37390987 PMCID: PMC10392135 DOI: 10.1016/j.jbc.2023.104978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/02/2023] Open
Abstract
The acylated Repeats in ToXins (RTX) leukotoxins, the adenylate cyclase toxin (CyaA) or α-hemolysin (HlyA), bind β2 integrins of leukocytes but also penetrate cells lacking these receptors. We show that the indoles of conserved tryptophans in the acylated segments, W876 of CyaA and W579 of HlyA, are crucial for β2 integrin-independent membrane penetration. Substitutions of W876 by aliphatic or aromatic residues did not affect acylation, folding, or the activities of CyaA W876L/F/Y variants on cells expressing high amounts of the β2 integrin CR3. However, toxin activity of CyaA W876L/F/Y on cells lacking CR3 was strongly impaired. Similarly, a W579L substitution selectively reduced HlyA W579L cytotoxicity towards cells lacking β2 integrins. Intriguingly, the W876L/F/Y substitutions increased the thermal stability (Tm) of CyaA by 4 to 8 °C but locally enhanced the accessibility to deuteration of the hydrophobic segment and of the interface of the two acylated loops. W876Q substitution (showing no increase in Tm), or combination of W876F with a cavity-filling V822M substitution (this combination decreasing the Tm closer to that of CyaA), yielded a milder defect of toxin activity on erythrocytes lacking CR3. Furthermore, the activity of CyaA on erythrocytes was also selectively impaired when the interaction of the pyrrolidine of P848 with the indole of W876 was ablated. Hence, the bulky indoles of residues W876 of CyaA, or W579 of HlyA, rule the local positioning of the acylated loops and enable a membrane-penetrating conformation in the absence of RTX toxin docking onto the cell membrane by β2 integrins.
Collapse
Affiliation(s)
- Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Man
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Kalaninova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Sciences, Charles University, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Cizkova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lada Biedermannova
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Vestec, Czech Republic
| | - Jory A Goldsmith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, The University of Texas at Austin, Austin, USA
| | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, USA
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| |
Collapse
|
3
|
Kim CY, Mitchell AJ, Kastner DW, Albright CE, Gutierrez MA, Glinkerman CM, Kulik HJ, Weng JK. Emergence of a proton exchange-based isomerization and lactonization mechanism in the plant coumarin synthase COSY. Nat Commun 2023; 14:597. [PMID: 36737607 PMCID: PMC9898226 DOI: 10.1038/s41467-023-36299-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/25/2023] [Indexed: 02/05/2023] Open
Abstract
Plants contain rapidly evolving specialized enzymes that support the biosynthesis of functionally diverse natural products. In coumarin biosynthesis, a BAHD acyltransferase-family enzyme COSY was recently discovered to accelerate coumarin formation as the only known BAHD enzyme to catalyze an intramolecular acyl transfer reaction. Here we investigate the structural and mechanistic basis for COSY's coumarin synthase activity. Our structural analyses reveal an unconventional active-site configuration adapted to COSY's specialized activity. Through mutagenesis studies and deuterium exchange experiments, we identify a unique proton exchange mechanism at the α-carbon of the o-hydroxylated trans-hydroxycinnamoyl-CoA substrates during the catalytic cycle of COSY. Quantum mechanical cluster modeling and molecular dynamics further support this key mechanism for lowering the activation energy of the rate-limiting trans-to-cis isomerization step in coumarin production. This study unveils an unconventional catalytic mechanism mediated by a BAHD-family enzyme, and sheds light on COSY's evolutionary origin and its recruitment to coumarin biosynthesis in eudicots.
Collapse
Affiliation(s)
- Colin Y Kim
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Andrew J Mitchell
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | - David W Kastner
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Claire E Albright
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | | | | | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jing-Ke Weng
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
4
|
Heterologously secreted MbxA from Moraxella bovis induces a membrane blebbing response of the human host cell. Sci Rep 2022; 12:17825. [PMID: 36280777 PMCID: PMC9592583 DOI: 10.1038/s41598-022-22480-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/14/2022] [Indexed: 01/20/2023] Open
Abstract
Many proteins of the Repeats in Toxins (RTX) protein family are toxins of Gram-negative pathogens including hemolysin A (HlyA) of uropathogenic E. coli. RTX proteins are secreted via Type I secretion systems (T1SS) and adopt their native conformation in the Ca2+-rich extracellular environment. Here we employed the E. coli HlyA T1SS as a heterologous surrogate system for the RTX toxin MbxA from the bovine pathogen Moraxella bovis. In E. coli the HlyA system successfully activates the heterologous MbxA substrate by acylation and secretes the precursor proMbxA and active MbxA allowing purification of both species in quantities sufficient for a variety of investigations. The activating E. coli acyltransferase HlyC recognizes the acylation sites in MbxA, but unexpectedly in a different acylation pattern as for its endogenous substrate HlyA. HlyC-activated MbxA shows host species-independent activity including a so-far unknown toxicity against human lymphocytes and epithelial cells. Using live-cell imaging, we show an immediate MbxA-mediated permeabilization and a rapidly developing blebbing of the plasma membrane in epithelial cells, which is associated with immediate cell death.
Collapse
|
5
|
Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:microorganisms10030518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
Collapse
|
6
|
Louise Alderley C, Greenrod STE, Friman V. Plant pathogenic bacterium can rapidly evolve tolerance to an antimicrobial plant allelochemical. Evol Appl 2022; 15:735-750. [PMID: 35603031 PMCID: PMC9108312 DOI: 10.1111/eva.13363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 12/13/2021] [Accepted: 02/10/2022] [Indexed: 11/30/2022] Open
Abstract
Crop losses to plant pathogens are a growing threat to global food security and more effective control strategies are urgently required. Biofumigation, an agricultural technique where Brassica plant tissues are mulched into soils to release antimicrobial plant allelochemicals called isothiocyanates (ITCs), has been proposed as an environmentally friendly alternative to agrochemicals. Whilst biofumigation has been shown to suppress a range of plant pathogens, its effects on plant pathogenic bacteria remain largely unexplored. Here, we used a laboratory model system to compare the efficacy of different types of ITCs against Ralstonia solanacearum plant bacterial pathogen. Additionally, we evaluated the potential for ITC‐tolerance evolution under high, intermediate, and low transfer frequency ITC exposure treatments. We found that allyl‐ITC was the most efficient compound at suppressing R. solanacearum growth, and its efficacy was not improved when combined with other types of ITCs. Despite consistent pathogen growth suppression, ITC tolerance evolution was observed in the low transfer frequency exposure treatment, leading to cross‐tolerance to ampicillin beta‐lactam antibiotic. Mechanistically, tolerance was linked to insertion sequence movement at four positions in genes that were potentially associated with stress responses (H‐NS histone like protein), cell growth and competitiveness (acyltransferase), iron storage ([2‐Fe‐2S]‐binding protein) and calcium ion sequestration (calcium‐binding protein). Interestingly, pathogen adaptation to the growth media also indirectly selected for increased ITC tolerance through potential adaptations linked with metabolism and antibiotic resistance (dehydrogenase‐like protein) and transmembrane protein movement (Tat pathway signal protein). Together, our results suggest that R. solanacearum can rapidly evolve tolerance to allyl‐ITC plant allelochemical which could constrain the long‐term efficiency of biofumigation biocontrol and potentially shape pathogen evolution with plants.
Collapse
|
7
|
Giglione C, Meinnel T. Mapping the myristoylome through a complete understanding of protein myristoylation biochemistry. Prog Lipid Res 2021; 85:101139. [PMID: 34793862 DOI: 10.1016/j.plipres.2021.101139] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 12/22/2022]
Abstract
Protein myristoylation is a C14 fatty acid modification found in all living organisms. Myristoylation tags either the N-terminal alpha groups of cysteine or glycine residues through amide bonds or lysine and cysteine side chains directly or indirectly via glycerol thioester and ester linkages. Before transfer to proteins, myristate must be activated into myristoyl coenzyme A in eukaryotes or, in bacteria, to derivatives like phosphatidylethanolamine. Myristate originates through de novo biosynthesis (e.g., plants), from external uptake (e.g., human tissues), or from mixed origins (e.g., unicellular organisms). Myristate usually serves as a molecular anchor, allowing tagged proteins to be targeted to membranes and travel across endomembrane networks in eukaryotes. In this review, we describe and discuss the metabolic origins of protein-bound myristate. We review strategies for in vivo protein labeling that take advantage of click-chemistry with reactive analogs, and we discuss new approaches to the proteome-wide discovery of myristate-containing proteins. The machineries of myristoylation are described, along with how protein targets can be generated directly from translating precursors or from processed proteins. Few myristoylation catalysts are currently described, with only N-myristoyltransferase described to date in eukaryotes. Finally, we describe how viruses and bacteria hijack and exploit myristoylation for their pathogenicity.
Collapse
Affiliation(s)
- Carmela Giglione
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Thierry Meinnel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| |
Collapse
|
8
|
Lipidation of Class IV CdiA Effector Proteins Promotes Target Cell Recognition during Contact-Dependent Growth Inhibition. mBio 2021; 12:e0253021. [PMID: 34634941 PMCID: PMC8510554 DOI: 10.1128/mbio.02530-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Contact-dependent growth inhibition (CDI) systems enable the direct transfer of protein toxins between competing Gram-negative bacteria. CDI+ strains produce cell surface CdiA effector proteins that bind specific receptors on neighboring bacteria to initiate toxin delivery. Three classes of CdiA effectors that recognize different outer membrane protein receptors have been characterized in Escherichia coli to date. Here, we describe a fourth effector class that uses the lipopolysaccharide (LPS) core as a receptor to identify target bacteria. Selection for CDI-resistant target cells yielded waaF and waaP “deep-rough” mutants, which are unable to synthesize the full LPS core. The CDI resistance phenotypes of other waa mutants suggest that phosphorylated inner-core heptose residues form a critical CdiA recognition epitope. Class IV cdi loci also encode putative lysyl acyltransferases (CdiC) that are homologous to enzymes that lipidate repeats-in-toxin (RTX) cytolysins. We found that catalytically active CdiC is required for full target cell killing activity, and we provide evidence that the acyltransferase appends 3-hydroxydecanoate to a specific Lys residue within the CdiA receptor-binding domain. We propose that the lipid moiety inserts into the hydrophobic leaflet of lipid A to anchor CdiA interactions with the core oligosaccharide. Thus, LPS-binding CDI systems appear to have co-opted an RTX toxin-activating acyltransferase to increase the affinity of CdiA effectors for the target cell outer membrane.
Collapse
|
9
|
Komaniecki G, Lin H. Lysine Fatty Acylation: Regulatory Enzymes, Research Tools, and Biological Function. Front Cell Dev Biol 2021; 9:717503. [PMID: 34368168 PMCID: PMC8339906 DOI: 10.3389/fcell.2021.717503] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022] Open
Abstract
Post-translational acylation of lysine side chains is a common mechanism of protein regulation. Modification by long-chain fatty acyl groups is an understudied form of lysine acylation that has gained increasing attention recently due to the characterization of enzymes that catalyze the addition and removal this modification. In this review we summarize what has been learned about lysine fatty acylation in the approximately 30 years since its initial discovery. We report on what is known about the enzymes that regulate lysine fatty acylation and their physiological functions, including tumorigenesis and bacterial pathogenesis. We also cover the effect of lysine fatty acylation on reported substrates. Generally, lysine fatty acylation increases the affinity of proteins for specific cellular membranes, but the physiological outcome depends greatly on the molecular context. Finally, we will go over the experimental tools that have been used to study lysine fatty acylation. While much has been learned about lysine fatty acylation since its initial discovery, the full scope of its biological function has yet to be realized.
Collapse
Affiliation(s)
- Garrison Komaniecki
- Graduate Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY, United States.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
| | - Hening Lin
- Graduate Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY, United States.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States.,Howard Hughes Medical Institute, Cornell University, Ithaca, NY, United States
| |
Collapse
|
10
|
Wang M, Lin H. Understanding the Function of Mammalian Sirtuins and Protein Lysine Acylation. Annu Rev Biochem 2021; 90:245-285. [PMID: 33848425 DOI: 10.1146/annurev-biochem-082520-125411] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein lysine acetylation is an important posttranslational modification that regulates numerous biological processes. Targeting lysine acetylation regulatory factors, such as acetyltransferases, deacetylases, and acetyl-lysine recognition domains, has been shown to have potential for treating human diseases, including cancer and neurological diseases. Over the past decade, many other acyl-lysine modifications, such as succinylation, crotonylation, and long-chain fatty acylation, have also been investigated and shown to have interesting biological functions. Here, we provide an overview of the functions of different acyl-lysine modifications in mammals. We focus on lysine acetylation as it is well characterized, and principles learned from acetylation are useful for understanding the functions of other lysine acylations. We pay special attention to the sirtuins, given that the study of sirtuins has provided a great deal of information about the functions of lysine acylation. We emphasize the regulation of sirtuins to illustrate that their regulation enables cells to respond to various signals and stresses.
Collapse
Affiliation(s)
- Miao Wang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA;
| | - Hening Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA; .,Howard Hughes Medical Institute, Cornell University, Ithaca, New York 14853, USA
| |
Collapse
|
11
|
Ahmad A, Akram W, Bashir Z, Shahzadi I, Wang R, Abbas HMK, Hu D, Ahmed S, Xu X, Li G, Wu T. Functional and Structural Analysis of a Novel Acyltransferase from Pathogenic Phytophthora melonis. ACS OMEGA 2021; 6:1797-1808. [PMID: 33521421 PMCID: PMC7841795 DOI: 10.1021/acsomega.0c03186] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/15/2020] [Indexed: 05/07/2023]
Abstract
This investigation characterizes an acyltransferase enzyme responsible for the pathogenicity of Phytophthora melonis. The protein was characterized in vitro for its physicochemical properties. The biochemical characterization, including thermal and pH stability, revealed the 35 °C temperature and 7.0 pH as the optimum conditions for the enzyme. Applying the Tween-80 solution enhanced the activity up to 124.9%. Comprehensive structural annotation revealed two domains, A (ranging from residues 260 to 620) and B (ranging from 141 to 219). Domain A had transglutaminase (T-Gase) elicitor properties, while B possessed antifreeze features. Rigorous sequence characterization of the acyltransferase tagged it as a low-temperature-resistant protein. Further, the taxonomic distribution analysis of the protein highlighted three genera in Oomycetes, i.e., Pythium, Phytophthora, and Plasmopara, bearing this protein. However, some taxonomic groups other than Oomycetes (i.e., archaea and bacteria) also contained the protein. Functional studies of structurally analogous proteins spanned 10 different taxonomic groups. These revealed TGase elicitors (10%), phytopathogen effector proteins RxLR (4%), transporter family proteins (3%), and endonucleases (1%). Other analogues having one percent of their individual share were HIV tat-specific factor 1, protocadherin fat 4, transcription factor 1, and 3-hydroxyisobutyrate dehydrogenase. Because the plant infection by P. melonis is a complex process regulated by a profusion of extracellular signals secreted by both host plants and the pathogen, this study will be of help in interpreting the cross-talk in the host-pathogen system.
Collapse
Affiliation(s)
- Aqeel Ahmad
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Waheed Akram
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Zoobia Bashir
- National
Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Iqra Shahzadi
- School
of Resource and Environmental Science, Wuhan
University, Wuhan 430072, Hubei, China
| | - Rui Wang
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Hafiz Muhammad Khalid Abbas
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Du Hu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Shakeel Ahmed
- Instituto
de Farmacia, Facultad de Ciencias, Universidad
Austral de Chile, Campus
Isla Teja, Valdivia 5090000, Chile
| | - Xiaomei Xu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Guihua Li
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Tingquan Wu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| |
Collapse
|
12
|
Park HJ, Seong HJ, Lee J, Heo L, Sul WJ, Han SW. Two DNA Methyltransferases for Site-Specific 6mA and 5mC DNA Modification in Xanthomonas euvesicatoria. FRONTIERS IN PLANT SCIENCE 2021; 12:621466. [PMID: 33841456 PMCID: PMC8025778 DOI: 10.3389/fpls.2021.621466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/25/2021] [Indexed: 05/08/2023]
Abstract
Xanthomonas euvesicatoria (Xe) is a gram-negative phytopathogenic bacterium that causes bacterial spot disease in tomato/pepper leading to economic losses in plantations. DNA methyltransferases (MTases) are critical for the survival of prokaryotes; however, their functions in phytopathogenic bacteria remain unclear. In this study, we characterized the functions of two putative DNA MTases, XvDMT1 and XvDMT2, in Xe by generating XvDMT1- and XvDMT2-overexpressing strains, Xe(XvDMT1) and Xe(XvDMT2), respectively. Virulence of Xe(XvDMT2), but not Xe(XvDMT1), on tomato was dramatically reduced. To postulate the biological processes involving XvDMTs, we performed a label-free shotgun comparative proteomic analysis, and results suggest that XvDMT1 and XvDMT2 have distinct roles in Xe. We further characterized the functions of XvDMTs using diverse phenotypic assays. Notably, both Xe(XvDMT1) and Xe(XvDMT2) showed growth retardation in the presence of sucrose and fructose as the sole carbon source, with Xe(XvDMT2) being the most severely affected. In addition, biofilm formation and production of exopolysaccharides were declined in Xe(XvDMT2), but not Xe(XvDMT1). Xe(XvDMT2) was more tolerant to EtOH than Xe(XvDMT1), which had enhanced tolerance to sorbitol but decreased tolerance to polymyxin B. Using single-molecule real-time sequencing and methylation-sensitive restriction enzymes, we successfully predicted putative motifs methylated by XvDMT1 and XvDMT2, which are previously uncharacterized 6mA and 5mC DNA MTases, respectively. This study provided new insights into the biological functions of DNA MTases in prokaryotic organisms.
Collapse
Affiliation(s)
- Hye-Jee Park
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
- R and D Innovation Center, Seoul Clinical Laboratories, Yongin, South Korea
| | - Hoon Je Seong
- Department of Systems Biotechnology, Chung-Ang University, Anseong, South Korea
| | - Jongchan Lee
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Lynn Heo
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Woo Jun Sul
- Department of Systems Biotechnology, Chung-Ang University, Anseong, South Korea
| | - Sang-Wook Han
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
- *Correspondence: Sang-Wook Han
| |
Collapse
|
13
|
Preferential modification of CyaA-hemolysin by CyaC-acyltransferase through the catalytic Ser 30-His 33 dyad in esterolysis of palmitoyl-donor substrate devoid of acyl carrier proteins. Arch Biochem Biophys 2020; 694:108615. [PMID: 33011179 DOI: 10.1016/j.abb.2020.108615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/04/2020] [Accepted: 09/29/2020] [Indexed: 11/23/2022]
Abstract
We previously demonstrated that the ~130-kDa CyaA-hemolysin domain (CyaA-Hly) from Bordetella pertussis co-expressed with CyaC-acyltransferase in Escherichia coli was acylated at Lys983 and thus activated its hemolytic activity. Here, attempts were made to provide greater insights into such toxin activation via fatty-acyl modification by CyaC-acyltransferase. Non-acylated CyaA-Hly (NA/CyaA-Hly) and CyaC were separately expressed in E. coli and subsequently purified by FPLC to near homogeneity. When effects of acyl-chain length were comparatively evaluated through CyaC-esterolysis using various p-nitrophenyl (pNP) derivatives, Michaelis-Menten steady-state kinetic parameters (KM and kcat) of CyaC-acyltransferase revealed a marked preference for myristoyl (C14:0) and palmitoyl (C16:0) substrates of which catalytic efficiencies (kcat/KM) were roughly the same (~1.5 × 103 s-1mM-1). However, pNP-palmitate (pNPP) gave the highest hemolytic activity of NA/CyaA-Hly after being acylated in vitro with a range of acyl-donor substrates. LC-MS/MS analysis confirmed such CyaC-mediated palmitoylation of CyaA-Hly occurring at Lys983, denoting no requirement of an acyl carrier protein (ACP). A homology-based CyaC structure inferred a role of a potential catalytic dyad of conserved Ser30 and His33 residues in substrate esterolysis. CyaC-ligand binding analysis via molecular docking corroborated high-affinity binding of palmitate with its carboxyl group oriented toward such a dyad. Ala-substitutions of each residue (S30A or H33A) caused a drastic decrease in kcat/KM of CyaC toward pNPP, and hence its catalytic malfunction through palmitoylation-dependent activation of NA/CyaA-Hly. Altogether, our present data evidently provide such preferential palmitoylation of CyaA-Hly by CyaC-acyltransferase through the enzyme Ser30-His33 nucleophile-activation dyad in esterolysis of palmitoyl-donor substrate, particularly devoid of a natural acyl-ACP donor.
Collapse
|
14
|
Forrest S, Welch M. Arming the troops: Post-translational modification of extracellular bacterial proteins. Sci Prog 2020; 103:36850420964317. [PMID: 33148128 PMCID: PMC10450907 DOI: 10.1177/0036850420964317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Protein secretion is almost universally employed by bacteria. Some proteins are retained on the cell surface, whereas others are released into the extracellular milieu, often playing a key role in virulence. In this review, we discuss the diverse types and potential functions of post-translational modifications (PTMs) occurring to extracellular bacterial proteins.
Collapse
Affiliation(s)
- Suzanne Forrest
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| |
Collapse
|
15
|
Osickova A, Khaliq H, Masin J, Jurnecka D, Sukova A, Fiser R, Holubova J, Stanek O, Sebo P, Osicka R. Acyltransferase-mediated selection of the length of the fatty acyl chain and of the acylation site governs activation of bacterial RTX toxins. J Biol Chem 2020; 295:9268-9280. [PMID: 32461253 DOI: 10.1074/jbc.ra120.014122] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
In a wide range of organisms, from bacteria to humans, numerous proteins have to be posttranslationally acylated to become biologically active. Bacterial repeats in toxin (RTX) cytolysins form a prominent group of proteins that are synthesized as inactive protoxins and undergo posttranslational acylation on ε-amino groups of two internal conserved lysine residues by co-expressed toxin-activating acyltransferases. Here, we investigated how the chemical nature, position, and number of bound acyl chains govern the activities of Bordetella pertussis adenylate cyclase toxin (CyaA), Escherichia coli α-hemolysin (HlyA), and Kingella kingae cytotoxin (RtxA). We found that the three protoxins are acylated in the same E. coli cell background by each of the CyaC, HlyC, and RtxC acyltransferases. We also noted that the acyltransferase selects from the bacterial pool of acyl-acyl carrier proteins (ACPs) an acyl chain of a specific length for covalent linkage to the protoxin. The acyltransferase also selects whether both or only one of two conserved lysine residues of the protoxin will be posttranslationally acylated. Functional assays revealed that RtxA has to be modified by 14-carbon fatty acyl chains to be biologically active, that HlyA remains active also when modified by 16-carbon acyl chains, and that CyaA is activated exclusively by 16-carbon acyl chains. These results suggest that the RTX toxin molecules are structurally adapted to the length of the acyl chains used for modification of their acylated lysine residue in the second, more conserved acylation site.
Collapse
Affiliation(s)
- Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Humaira Khaliq
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Anna Sukova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stanek
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
16
|
Park BS, Lee N. A bivalent fusion vaccine composed of recombinant Apx proteins shows strong protection against Actinobacillus pleuroneumoniae serovar 1 and 2 in a mouse model. Pathog Dis 2020; 77:5426212. [PMID: 30939190 DOI: 10.1093/femspd/ftz020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 03/31/2019] [Indexed: 11/12/2022] Open
Abstract
Actinobacillus pleuropneumonia (APP) causes porcine pleuropneumoniae, resulting in severe economic losses in the swine industry. Since there are diverse serotypes of APP, it is necessary for vaccines to induce cross-protection. In this report, we developed a bivalent fusion vaccine, the L vaccine composed of ApxIA and ApxIIA fragments. According to the experimental results of the L vaccine, recombinant protein specific-IgG antibody level increased significantly as well as Apx toxin specific-IgG antibody, suggesting toxin-neutralizing effect. Also, the production of both IgG1 and IgG2a indicates this fusion vaccine induces Th1 and Th2 immune reactions. In addition, lymphocytes were proliferated and immune related-cytokines of TNF-α, IL-12, IFN-γ and IL-5 were detected in the serum after the vaccination. The L vaccine showed a perfect cross-protection against APP serovar 1 and 2 that each secrete different Apx exotoxins. These findings reveal that the fusion L vaccine induces specific humoral and cellular immunity, leading to a perfect cross-protection against A. pleuropneumoniae infections in a murine model.
Collapse
Affiliation(s)
- Byung-Sun Park
- Technology Institute, KBNP, Inc., Anyang, Gyeonggi, South Korea
| | - Nakhyung Lee
- Technology Institute, KBNP, Inc., Anyang, Gyeonggi, South Korea
| |
Collapse
|
17
|
On SLW, Althaus D, Miller WG, Lizamore D, Wong SGL, Mathai AJ, Chelikani V, Carter GP. Arcobacter cryaerophilus Isolated From New Zealand Mussels Harbor a Putative Virulence Plasmid. Front Microbiol 2019; 10:1802. [PMID: 31428079 PMCID: PMC6690266 DOI: 10.3389/fmicb.2019.01802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/22/2019] [Indexed: 12/27/2022] Open
Abstract
A wide range of Arcobacter species have been described from shellfish in various countries but their presence has not been investigated in Australasia, in which shellfish are a popular delicacy. Since several arcobacters are considered to be emerging pathogens, we undertook a small study to evaluate their presence in several different shellfish, including greenshell mussels, oysters, and abalone (paua) in New Zealand. Arcobacter cryaerophilus, a species associated with human gastroenteritis, was the only species isolated, from greenshell mussels. Whole-genome sequencing revealed a range of genomic traits in these strains that were known or associated virulence factors. Furthermore, we describe the first putative virulence plasmid in Arcobacter, containing lytic, immunoavoidance, adhesion, antibiotic resistance, and gene transfer traits, among others. Complete genome sequence determination using a combination of long- and short-read genome sequencing strategies, was needed to identify the plasmid, clearly identifying its benefits. The potential for plasmids to disseminate virulence traits among Arcobacter and other species warrants further consideration by researchers interested in the risks to public health from these organisms.
Collapse
Affiliation(s)
- Stephen L W On
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - Damien Althaus
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - William G Miller
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA, United States
| | - Darrell Lizamore
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - Samuel G L Wong
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - Anso J Mathai
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - Venkata Chelikani
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, New Zealand
| | - Glen P Carter
- Doherty Applied Microbial Genomics, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| |
Collapse
|
18
|
O'Brien DP, Cannella SE, Voegele A, Raoux-Barbot D, Davi M, Douché T, Matondo M, Brier S, Ladant D, Chenal A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin. FASEB J 2019; 33:10065-10076. [PMID: 31226003 DOI: 10.1096/fj.201802442rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The adenylate cyclase (CyaA) toxin is a major virulence factor of Bordetella pertussis, the causative agent of whooping cough. CyaA is synthetized as a pro-toxin, pro-CyaA, and converted into its cytotoxic form upon acylation of two lysines. After secretion, CyaA invades eukaryotic cells and produces cAMP, leading to host defense subversion. To gain further insights into the effect of acylation, we compared the functional and structural properties of pro-CyaA and CyaA proteins. HDX-MS results show that the refolding process of both proteins upon progressive urea removal is initiated by calcium binding to the C-terminal RTX domain. We further identified a critical hydrophobic segment, distal from the acylation region, that folds at higher urea concentration in CyaA than in pro-CyaA. Once refolded into monomers, CyaA is more compact and stable than pro-CyaA, due to a complex set of interactions between domains. Our HDX-MS data provide direct evidence that the presence of acyl chains in CyaA induces a significant stabilization of the apolar segments of the hydrophobic domain and of most of the acylation region. We propose a refolding model dependent on calcium and driven by local and distal acylation-dependent interactions within CyaA. Therefore, CyaA acylation is not only critical for cell intoxication, but also for protein refolding into its active conformation. Our data shed light on the complex relationship between post-translational modifications, structural disorder and protein folding. Coupling calcium-binding and acylation-driven folding is likely pertinent for other repeat-in-toxin cytolysins produced by many Gram-negative bacterial pathogens.-O'Brien, D. P., Cannella, S. E., Voegele, A., Raoux-Barbot, D., Davi, M., Douché, T., Matondo, M., Brier, S., Ladant, D., Chenal, A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin.
Collapse
Affiliation(s)
- Darragh P O'Brien
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Sara E Cannella
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexis Voegele
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Université Paris Diderot Paris VII, Sorbonne Paris Cité, Paris, France
| | - Dorothée Raoux-Barbot
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Marilyne Davi
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Thibaut Douché
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Sébastien Brier
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Biological NMR Technical Platform, Center for Technological Resources and Research, UMR CNRS 3528, Paris, France
| | - Daniel Ladant
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexandre Chenal
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| |
Collapse
|
19
|
Abstract
Type I secretion systems (T1SS) are widespread in Gram-negative bacteria, especially in pathogenic bacteria, and they secrete adhesins, iron-scavenger proteins, lipases, proteases, or pore-forming toxins in the unfolded state in one step across two membranes without any periplasmic intermediate into the extracellular space. The substrates of T1SS are in general characterized by a C-terminal secretion sequence and nonapeptide repeats, so-called GG repeats, located N terminal to the secretion sequence. These GG repeats bind Ca2+ ions in the extracellular space, which triggers folding of the entire protein. Here we summarize our current knowledge of how Gram-negative bacteria secrete these substrates, which can possess a molecular mass of up to 1,500 kDa. We also describe recent findings that demonstrate that the absence of periplasmic intermediates, the "classic" mode of action, does not hold true for all T1SS and that we are beginning to realize modifications of a common theme.
Collapse
|
20
|
Peherstorfer S, Brewitz HH, Paul George AA, Wißbrock A, Adam JM, Schmitt L, Imhof D. Insights into mechanism and functional consequences of heme binding to hemolysin-activating lysine acyltransferase HlyC from Escherichia coli. Biochim Biophys Acta Gen Subj 2018; 1862:1964-1972. [PMID: 29908817 DOI: 10.1016/j.bbagen.2018.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND Tight regulation of heme homeostasis is a critical mechanism in pathogenic bacteria since heme functions as iron source and prosthetic group, but is also toxic at elevated concentrations. Hemolysin-activating lysine-acyltransferase (HlyC) from Escherichia coli is crucial for maturation of hemolysin A, which lyses several mammalian cells including erythrocytes liberating large amounts of heme for bacterial uptake. A possible impact and functional consequences of the released heme on events employing bacterial HlyC have remained unexplored. METHODS Heme binding to HlyC was investigated using UV/vis and SPR spectroscopy. Functional impact of heme association was examined using an in vitro hemolysis assay. The interaction was further studied by homology modeling, molecular docking and dynamics simulations. RESULTS We identified HlyC as potential heme-binding protein possessing heme-regulatory motifs. Using wild-type protein and a double alanine mutant we demonstrated that heme binds to HlyC via histidine 151 (H151). We could show further that heme inhibits the enzymatic activity of wild-type HlyC. Computational studies illustrated potential interaction sites in addition to H151 confirming the results from spectroscopy indicating more than one heme-binding site. CONCLUSIONS Taken together, our results reveal novel insights into heme-protein interactions and regulation of a component of the heme uptake system in one of the major causative agents of urinary tract infections in humans. GENERAL SIGNIFICANCE This study points to a possible novel mechanism of regulation as present in many uropathogenic E. coli strains at an early stage of heme iron acquisition from erythrocytes for subsequent internalization by the bacterial heme-uptake machinery.
Collapse
Affiliation(s)
- Sandra Peherstorfer
- Institute of Biochemistry, University of Düsseldorf, 40255 Düsseldorf, Germany
| | - Hans Henning Brewitz
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Ajay Abisheck Paul George
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Amelie Wißbrock
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Jana Maria Adam
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, University of Düsseldorf, 40255 Düsseldorf, Germany.
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany.
| |
Collapse
|
21
|
Enteroaggregative Escherichia coli is the predominant diarrheagenic E. coli pathotype among irrigation water and food sources in South Africa. Int J Food Microbiol 2018; 278:44-51. [PMID: 29702315 DOI: 10.1016/j.ijfoodmicro.2018.04.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/10/2018] [Accepted: 04/11/2018] [Indexed: 11/24/2022]
Abstract
Diarrheagenic E. coli (DEC) has been implicated in foodborne outbreaks worldwide and have been associated with childhood stunting in the absence of diarrhoea. Infection is extraordinarily common, but the routes of transmission have not been determined. Therefore, determining the most prevalent pathotypes in food and environmental sources may help provide better guidance to various stakeholders in ensuring food safety and public health and advancing understanding of the epidemiology of enteric disease. We characterized 205 E. coli strains previously isolated from producer distributor bulk milk (PDBM)(118), irrigation water (48), irrigated lettuce (29) and street vendor coleslaw (10) in South Africa. Enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) were sought. We used PCR and partial gene sequencing for all 205 strains while 46 out of 205 that showed poor resolution were subsequently characterized using cell adherence (HeLa cells). PCR and partial gene sequencing of aatA and/or aaiC genes confirmed EAEC (2%, 5 out of 205) as the only pathotype. Phylogenetic analysis of sequenced EAEC strains with E. coli strains in GenBank showing ≥80% nucleotide sequence similarity based on possession of aaiC and aatA generated distinct clusters of strains separated predominantly based on their source of isolation (food source or human stool) suggesting a potential role of virulence genes in source tracking. EAEC 24%, 11 out of 46 strains (PDBM = 15%, irrigation water = 7%, irrigated lettuce = 2%) was similarly the predominant pathotype followed by strains showing invasiveness to HeLa cells, 4%, 2 out of 46 (PDBM = 2%, irrigated lettuce = 2%), among stains characterized using cell adherence. Therefore, EAEC may be the leading cause of DEC associated food and water-borne enteric infection in South Africa. Additionally, solely using molecular based methods targeting virulence gene determinants may underestimate prevalence, especially among heterogeneous pathogens such as EAEC.
Collapse
|
22
|
Kanonenberg K, Spitz O, Erenburg IN, Beer T, Schmitt L. Type I secretion system—it takes three and a substrate. FEMS Microbiol Lett 2018; 365:4966979. [DOI: 10.1093/femsle/fny094] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/09/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Kerstin Kanonenberg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Olivia Spitz
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Isabelle N Erenburg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tobias Beer
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| |
Collapse
|
23
|
Raksanoh V, Prangkio P, Imtong C, Thamwiriyasati N, Suvarnapunya K, Shank L, Angsuthanasombat C. Structural requirement of the hydrophobic region of the Bordetella pertussis CyaA-hemolysin for functional association with CyaC-acyltransferase in toxin acylation. Biochem Biophys Res Commun 2018; 499:862-867. [PMID: 29625104 DOI: 10.1016/j.bbrc.2018.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 01/21/2023]
Abstract
Previously, we demonstrated that the ∼130-kDa CyaA-hemolysin (CyaA-Hly, Met482-Arg1706) from Bordetella pertussis was palmitoylated at Lys983 when co-expressed with CyaC-acyltransferase in Escherichia coli, and thus activated its hemolytic activity. Here, further investigation on a possible requirement of the N-terminal hydrophobic region (HP, Met482-Leu750) for toxin acylation was performed. The ∼100-kDa RTX (Repeat-in-ToXin) fragment (CyaA-RTX, Ala751-Arg1706) containing the Lys983-acylation region (AR, Ala751-Gln1000), but lacking HP, was co-produced with CyaC in E. coli. Hemolysis assay indicated that CyaA-RTX showed no hemolytic activity. Additionally, MALDI-TOF/MS and LC-MS/MS analyses confirmed that CyaA-RTX was non-acylated, although the co-expressed CyaC-acyltransferase was able to hydrolyze its chromogenic substrate-p-nitrophenyl palmitate and acylate CyaA-Hly to become hemolytically active. Unlike CyaA-RTX, the ∼70-kDa His-tagged CyaA-HP/BI fragment which is hemolytically inactive and contains both HP and AR was constantly co-eluted with CyaC during IMAC-purification as the presence of CyaC was verified by Western blotting. Such potential interactions between the two proteins were also revealed by semi-native PAGE. Moreover, structural analysis via electrostatic potential calculations and molecular docking suggested that CyaA-HP comprising α1-α5 (Leu500-Val698) can interact with CyaC through several hydrogen and ionic bonds formed between their opposite electrostatic surfaces. Overall, our results demonstrated that the HP region of CyaA-Hly is conceivably required for not only membrane-pore formation but also functional association with CyaC-acyltransferase, and hence effective palmitoylation at Lys983.
Collapse
Affiliation(s)
- Veerada Raksanoh
- Interdisciplinary Program in Biotechnology, Graduate School, Chiang Mai University, Chiang Mai 50200, Thailand; Division of Biochemistry and Biochemical Technology, Department of Chemistry, Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Center of Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Panchika Prangkio
- Division of Biochemistry and Biochemical Technology, Department of Chemistry, Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Center of Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Chompounoot Imtong
- Division of Biology, Department of Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand
| | - Niramon Thamwiriyasati
- Department of Medical Technology, Faculty of Allied Health Sciences, Burapha University, Chonburi 20131, Thailand
| | - Kittipong Suvarnapunya
- Graduate Program in Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Lalida Shank
- Division of Biochemistry and Biochemical Technology, Department of Chemistry, Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Center of Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
| | - Chanan Angsuthanasombat
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand; Laboratory of Molecular Biophysics and Chemical Biology, Biophysics Institute for Research and Development (BIRD), Fang, Chiang Mai 50110, Thailand.
| |
Collapse
|
24
|
Type I Protein Secretion-Deceptively Simple yet with a Wide Range of Mechanistic Variability across the Family. EcoSal Plus 2017; 7. [PMID: 28084193 DOI: 10.1128/ecosalplus.esp-0019-2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A very large type I polypeptide begins to reel out from a ribosome; minutes later, the still unidentifiable polypeptide, largely lacking secondary structure, is now in some cases a thousand or more residues longer. Synthesis of the final hundred C-terminal residues commences. This includes the identity code, the secretion signal within the last 50 amino acids, designed to dock with a waiting ATP binding cassette (ABC) transporter. What happens next is the subject of this review, with the main, but not the only focus on hemolysin HlyA, an RTX protein toxin secreted by the type I system. Transport substrates range from small peptides to giant proteins produced by many pathogens. These molecules, without detectable cellular chaperones, overcome enormous barriers, crossing two membranes before final folding on the cell surface, involving a unique autocatalytic process.Unfolded HlyA is extruded posttranslationally, C-terminal first. The transenvelope "tunnel" is formed by HlyB (ABC transporter), HlyD (membrane fusion protein) straddling the inner membrane and periplasm and TolC (outer membrane). We present a new evaluation of the C-terminal secretion code, and the structure function of HlyD and HlyB at the heart of this nanomachine. Surprisingly, key details of the secretion mechanism are remarkably variable in the many type I secretion system subtypes. These include alternative folding processes, an apparently distinctive secretion code for each type I subfamily, and alternative forms of the ABC transporter; most remarkably, the ABC protein probably transports peptides or polypeptides by quite different mechanisms. Finally, we suggest a putative structure for the Hly-translocon, HlyB, the multijointed HlyD, and the TolC exit.
Collapse
|
25
|
Zhang S, Liang M, Naqvi NI, Lin C, Qian W, Zhang LH, Deng YZ. Phototrophy and starvation-based induction of autophagy upon removal of Gcn5-catalyzed acetylation of Atg7 in Magnaporthe oryzae. Autophagy 2017; 13:1318-1330. [PMID: 28594263 PMCID: PMC5584857 DOI: 10.1080/15548627.2017.1327103] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Magnaporthe oryzae, the ascomycete fungus that causes rice blast disease, initiates conidiation in response to light when grown on Prune-Agar medium containing both carbon and nitrogen sources. Macroautophagy/autophagy was shown to be essential for M. oryzae conidiation and induced specifically upon exposure to light but is undetectable in the dark. Therefore, it is inferred that autophagy is naturally induced by light, rather than by starvation during M. oryzae conidiation. However, the signaling pathway(s) involved in such phototropic induction of autophagy remains unknown. We identified an M. oryzae ortholog of GCN5 (MGG_03677), encoding a histone acetyltransferase (HAT) that negatively regulates light- and nitrogen-starvation-induced autophagy, by acetylating the autophagy protein Atg7. Furthermore, we unveiled novel regulatory mechanisms on Gcn5 at both transcriptional and post-translational levels, governing its function associated with the unique phototropic response of autophagy in this pathogenic fungus. Thus, our study depicts a signaling network and regulatory mechanism underlying the autophagy induction by important environmental clues such as light and nutrients.
Collapse
Affiliation(s)
- Shulin Zhang
- a Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture , South China Agricultural University , Guangzhou , China.,b Guangdong Province Key Laboratory of Microbial Signals and Disease Control, and Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou , China
| | - Meiling Liang
- a Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture , South China Agricultural University , Guangzhou , China.,b Guangdong Province Key Laboratory of Microbial Signals and Disease Control, and Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou , China
| | - Naweed I Naqvi
- c Temasek Life Sciences Laboratory, and Department of Biological Sciences , National University of Singapore , Singapore
| | - Chaoxiang Lin
- a Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture , South China Agricultural University , Guangzhou , China.,b Guangdong Province Key Laboratory of Microbial Signals and Disease Control, and Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou , China
| | - Wanqiang Qian
- d The New Countryside Development Institute of South China Agricultural University , Guangzhou , China
| | - Lian-Hui Zhang
- a Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture , South China Agricultural University , Guangzhou , China.,b Guangdong Province Key Laboratory of Microbial Signals and Disease Control, and Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou , China
| | - Yi Zhen Deng
- a Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture , South China Agricultural University , Guangzhou , China.,b Guangdong Province Key Laboratory of Microbial Signals and Disease Control, and Integrative Microbiology Research Centre , South China Agricultural University , Guangzhou , China
| |
Collapse
|
26
|
Favrot L, Blanchard JS, Vergnolle O. Bacterial GCN5-Related N-Acetyltransferases: From Resistance to Regulation. Biochemistry 2016; 55:989-1002. [PMID: 26818562 DOI: 10.1021/acs.biochem.5b01269] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The GCN5-related N-acetyltransferases family (GNAT) is an important family of proteins that includes more than 100000 members among eukaryotes and prokaryotes. Acetylation appears as a major regulatory post-translational modification and is as widespread as phosphorylation. N-Acetyltransferases transfer an acetyl group from acetyl-CoA to a large array of substrates, from small molecules such as aminoglycoside antibiotics to macromolecules. Acetylation of proteins can occur at two different positions, either at the amino-terminal end (αN-acetylation) or at the ε-amino group (εN-acetylation) of an internal lysine residue. GNAT members have been classified into different groups on the basis of their substrate specificity, and in spite of a very low primary sequence identity, GNAT proteins display a common and conserved fold. This Current Topic reviews the different classes of bacterial GNAT proteins, their functions, their structural characteristics, and their mechanism of action.
Collapse
Affiliation(s)
- Lorenza Favrot
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - John S Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Olivia Vergnolle
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| |
Collapse
|