1
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Yagi H, Takagi K, Kato K. Exploring domain architectures of human glycosyltransferases: Highlighting the functional diversity of non-catalytic add-on domains. Biochim Biophys Acta Gen Subj 2024; 1868:130687. [PMID: 39097174 DOI: 10.1016/j.bbagen.2024.130687] [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: 06/21/2024] [Revised: 07/17/2024] [Accepted: 07/30/2024] [Indexed: 08/05/2024]
Abstract
Human glycosyltransferases (GTs) play crucial roles in glycan biosynthesis, exhibiting diverse domain architectures. This study explores the functional diversity of "add-on" domains within human GTs, using data from the AlphaFold Protein Structure Database. Among 215 annotated human GTs, 74 contain one or more add-on domains in addition to their catalytic domain. These domains include lectin folds, fibronectin type III, and thioredoxin-like domains and contribute to substrate specificity, oligomerization, and consequent enzymatic activity. Notably, certain GTs possess dual enzymatic functions due to catalytic add-on domains. The analysis highlights the importance of add-on domains in enzyme functionality and disease implications, such as congenital disorders of glycosylation. This comprehensive overview enhances our understanding of GT domain organization, providing insights into glycosylation mechanisms and potential therapeutic targets.
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Affiliation(s)
- Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan; Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Japan
| | - Katsuki Takagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan; Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Japan.
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2
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Graham LA, Hansen T, Yang Y, Sherik M, Ye Q, Soares BP, Kinrade B, Guo S, Davies PL. Adhesin domains responsible for binding bacteria to surfaces they colonize project outwards from companion split domains. Proteins 2024; 92:933-945. [PMID: 38591850 DOI: 10.1002/prot.26689] [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: 01/09/2024] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/10/2024]
Abstract
Bacterial adhesins attach their hosts to surfaces that the bacteria will colonize. This surface adhesion occurs through specific ligand-binding domains located towards the distal end of the long adhesin molecules. However, recognizing which of the many adhesin domains are structural and which are ligand binding has been difficult up to now. Here we have used the protein structure modeling program AlphaFold2 to predict structures for these giant 0.2- to 1.5-megadalton proteins. Crystal structures previously solved for several adhesin regions are in good agreement with the models. Whereas most adhesin domains are linked in a linear fashion through their N- and C-terminal ends, ligand-binding domains can be recognized by budding out from a companion core domain so that their ligand-binding sites are projected away from the axis of the adhesin for maximal exposure to their targets. These companion domains are "split" in their continuity by projecting the ligand-binding domain outwards. The "split domains" are mostly β-sandwich extender modules, but other domains like a β-solenoid can serve the same function. Bioinformatic analyses of Gram-negative bacterial sequences revealed wide variety ligand-binding domains are used in their Repeats-in-Toxin adhesins. The ligands for many of these domains have yet to be identified but known ligands include various cell-surface glycans, proteins, and even ice. Recognizing the ligands to which the adhesins bind could lead to ways of blocking colonization by bacterial pathogens. Engineering different ligand-binding domains into an adhesin has the potential to change the surfaces to which bacteria bind.
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Affiliation(s)
- Laurie A Graham
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Thomas Hansen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Yanzhi Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mustafa Sherik
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Qilu Ye
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Blake P Soares
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Brett Kinrade
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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3
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Sevdalis SE, Varney KM, Cook ME, Gillespie JJ, Pozharski E, Weber DJ. Structural and Functional Insights into the Delivery Systems of Bacillus and Clostridial Binary Toxins. Toxins (Basel) 2024; 16:330. [PMID: 39195740 PMCID: PMC11359772 DOI: 10.3390/toxins16080330] [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: 06/07/2024] [Revised: 07/04/2024] [Accepted: 07/19/2024] [Indexed: 08/29/2024] Open
Abstract
Pathogenic Bacillus and clostridial (i.e., Clostridium and Clostridioides) bacteria express a diverse repertoire of effector proteins to promote disease. This includes production of binary toxins, which enter host epithelial cells and seriously damage the intestinal tracts of insects, animals, and humans. In particular, binary toxins form an AB-type complex composed of a catalytic subunit that is toxic (A) and an oligomeric cell-binding and delivery subunit (B), where upon delivery of A into the cytoplasm of the host cell it catalytically ADP-ribosylates actin and rapidly induces host cell death. In this review, binary toxins expressed by Bacillus thuringiensis, Clostridioides difficile, and Clostridium perfringens will be discussed, with particular focus placed upon the structural elucidations of their respective B subunits and how these findings help to deconvolute how toxic enzyme delivery into target host cells is achieved by these deadly bacteria.
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Affiliation(s)
- Spiridon E. Sevdalis
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.M.V.); (M.E.C.); (E.P.)
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kristen M. Varney
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.M.V.); (M.E.C.); (E.P.)
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary E. Cook
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.M.V.); (M.E.C.); (E.P.)
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.M.V.); (M.E.C.); (E.P.)
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David J. Weber
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.M.V.); (M.E.C.); (E.P.)
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
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4
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Tokoro Y, Nagae M, Nakano M, Harduin-Lepers A, Kizuka Y. LacdiNAc synthase B4GALNT3 has a unique PA14 domain and suppresses N-glycan capping. J Biol Chem 2024; 300:107450. [PMID: 38844136 PMCID: PMC11254600 DOI: 10.1016/j.jbc.2024.107450] [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: 04/05/2024] [Revised: 05/17/2024] [Accepted: 05/30/2024] [Indexed: 06/28/2024] Open
Abstract
Structural variation of N-glycans is essential for the regulation of glycoprotein functions. GalNAcβ1-4GlcNAc (LacdiNAc or LDN), a unique subterminal glycan structure synthesized by B4GALNT3 or B4GALNT4, is involved in the clearance of N-glycoproteins from the blood and maintenance of cell stemness. Such regulation of glycoprotein functions by LDN is largely different from that by the dominant subterminal structure, N-acetyllactosamine (Galβ1-4GlcNAc, LacNAc). However, the mechanisms by which B4GALNT activity is regulated and how LDN plays different roles from LacNAc remain unclear. Here, we found that B4GALNT3 and four have unique domain organization containing a noncatalytic PA14 domain, which is a putative glycan-binding module. A mutant lacking this domain dramatically decreases the activity toward various substrates, such as N-glycan, O-GalNAc glycan, and glycoproteins, indicating that this domain is essential for enzyme activity and forms part of the catalytic region. In addition, to clarify the mechanism underlying the functional differences between LDN and LacNAc, we examined the effects of LDN on the maturation of N-glycans, focusing on the related glycosyltransferases upstream and downstream of B4GALNT. We revealed that, unlike LacNAc synthesis, prior formation of bisecting GlcNAc in N-glycan almost completely inhibits LDN synthesis by B4GALNT3. Moreover, the presence of LDN negatively impacted the actions of many glycosyltransferases for terminal modifications, including sialylation, fucosylation, and human natural killer-1 synthesis. These findings demonstrate that LDN has significant impacts on N-glycan maturation in a completely different way from LacNAc, which could contribute to obtaining a comprehensive overview of the system regulating complex N-glycan biosynthesis.
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Affiliation(s)
- Yuko Tokoro
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Masamichi Nagae
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan; Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka University, Suita, Japan
| | - Miyako Nakano
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Anne Harduin-Lepers
- University of Lille, CNRS, UMR 8576 -UGSF- Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Yasuhiko Kizuka
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan.
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5
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St John FJ, Bynum L, Tauscheck DA, Crooks C. Use of xylosidase 3C from Segatella baroniae to discriminate xylan non-reducing terminus substitution characteristics. BMC Res Notes 2024; 17:175. [PMID: 38915023 PMCID: PMC11197168 DOI: 10.1186/s13104-024-06835-3] [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: 09/15/2023] [Accepted: 06/17/2024] [Indexed: 06/26/2024] Open
Abstract
OBJECTIVE New characterized carbohydrate-active enzymes are needed for use as tools to discriminate complex carbohydrate structural features. Fungal glycoside hydrolase family 3 (GH3) β-xylosidases have been shown to be useful for the structural elucidation of glucuronic acid (GlcA) and arabinofuranose (Araf) substituted oligoxylosides. A homolog of these GH3 fungal enzymes from the bacterium Segatella baroniae (basonym Prevotella bryantii), Xyl3C, has been previously characterized, but those studies did not address important functional specificity features. In an interest to utilize this enzyme for laboratory methods intended to discriminate the structure of the non-reducing terminus of substituted xylooligosaccharides, we have further characterized this GH3 xylosidase. RESULTS In addition to verification of basic functional characteristics of this xylosidase we have determined its mode of action as it relates to non-reducing end xylose release from GlcA and Araf substituted oligoxylosides. Xyl3C cleaves xylose from the non-reducing terminus of β-1,4-xylan until occurrence of a penultimate substituted xylose. If this substitution is O2 linked, then Xyl3C removes the non-reducing xylose to leave the substituted xylose as the new non-reducing terminus. However, if the substitution is O3 linked, Xyl3C does not hydrolyze, thus leaving the substitution one-xylose (penultimate) from the non-reducing terminus. Hence, Xyl3C enables discrimination between O2 and O3 linked substitutions on the xylose penultimate to the non-reducing end. These findings are contrasted using a homologous enzyme also from S. baroniae, Xyl3B, which is found to yield a penultimate substituted nonreducing terminus regardless of which GlcA or Araf substitution exists.
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Affiliation(s)
- Franz J St John
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA.
| | - Loreen Bynum
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
| | - Dante A Tauscheck
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
| | - Casey Crooks
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Dr, Madison, WI, 53726, USA
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6
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Bennink S, Pradel G. The Multiple Roles of LCCL Domain-Containing Proteins for Malaria Parasite Transmission. Microorganisms 2024; 12:279. [PMID: 38399683 PMCID: PMC10892792 DOI: 10.3390/microorganisms12020279] [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: 12/16/2023] [Revised: 01/18/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Multi-protein complexes are crucial for various essential biological processes of the malaria parasite Plasmodium, such as protein synthesis, host cell invasion and adhesion. Especially during the sexual phase of the parasite, which takes place in the midgut of the mosquito vector, protein complexes are required for fertilization, sporulation and ultimately for the successful transmission of the parasite. Among the most noticeable protein complexes of the transmission stages are the ones formed by the LCCL domain-containing protein family that play critical roles in the generation of infective sporozoites. The six members of this protein family are characterized by numerous adhesive modules and domains typically found in secreted proteins. This review summarizes the findings of expression and functional studies on the LCCL domain-containing proteins of the human pathogenic P. falciparum and the rodent-infecting P. berghei and discusses the common features and differences of the homologous proteins.
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Affiliation(s)
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany;
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7
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Bannell TAK, Cockburn JJB. The molecular structure and function of fibrocystin, the key gene product implicated in autosomal recessive polycystic kidney disease (ARPKD). Ann Hum Genet 2024; 88:58-75. [PMID: 37905714 DOI: 10.1111/ahg.12535] [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: 07/11/2023] [Revised: 09/14/2023] [Accepted: 10/03/2023] [Indexed: 11/02/2023]
Abstract
Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single-pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin-like plexin-transcription factor domains, a protective antigen 14 domain, a tandem G8-TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective.
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Affiliation(s)
- Travis A K Bannell
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Joseph J B Cockburn
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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8
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Edrington T, Wang R, McKinnon L, Kessenich C, Hodge-Bell K, Li W, Tan J, Brown G, Wang C, Li B, Giddings K. Food and feed safety of the Bacillus thuringiensis derived protein Vpb4Da2, a novel protein for control of western corn rootworm. PLoS One 2022; 17:e0272311. [PMID: 35921368 PMCID: PMC9348738 DOI: 10.1371/journal.pone.0272311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022] Open
Abstract
Western corn rootworm (WCR), Diabrotica virgifera virgifera, LeConte, is an insect pest that poses a significant threat to the productivity of modern agriculture, causing significant economic and crop losses. The development of genetically modified (GM) crops expressing one or more proteins that confer tolerance to specific insect pests, such as WCR, was a historic breakthrough in agricultural biotechnology and continues to serve as an invaluable tool in pest management. Despite this, evolving resistance to existing insect control proteins expressed in current generation GM crops requires continued identification of new proteins with distinct modes of action while retaining targeted insecticidal efficacy. GM crops expressing insecticidal proteins must undergo extensive safety assessments prior to commercialization to ensure that they pose no increased risk to the health of humans or other animals relative to their non-GM conventional counterparts. As part of these safety evaluations, a weight of evidence approach is utilized to assess the safety of the expressed insecticidal proteins to evaluate any potential risk in the context of dietary exposure. This study describes the food and feed safety assessment of Vpb4Da2, a new Bacillus thuringiensis insecticidal protein that confers in planta tolerance to WCR. Vpb4Da2 exhibits structural and functional similarities to other insect control proteins expressed in commercialized GM crops. In addition, the lack of homology to known toxins or allergens, a lack of acute toxicity in mice, inactivation by conditions commonly experienced in the human gut or during cooking/food processing, and the extremely low expected dietary exposure to Vpb4Da2 provide a substantial weight of evidence to demonstrate that the Vpb4Da2 protein poses no indication of a risk to the health of humans or other animals.
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Affiliation(s)
| | - Rong Wang
- Bayer Crop Science, Chesterfield, MO, United States of America
- * E-mail:
| | - Lucas McKinnon
- Bayer Crop Science, Chesterfield, MO, United States of America
| | | | | | - Wenze Li
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Jianguo Tan
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Gregory Brown
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Cunxi Wang
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Bin Li
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, MO, United States of America
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9
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Ozubek S, Alzan HF, Bastos RG, Laughery JM, Suarez CE. Identification of CCp5 and FNPA as Novel Non-canonical Members of the CCp Protein Family in Babesia bovis. Front Vet Sci 2022; 9:833183. [PMID: 35242841 PMCID: PMC8886879 DOI: 10.3389/fvets.2022.833183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Bovine babesiosis, caused by Babesia bovis, is an economically significant tick-borne disease that imposes restrictions to livestock production worldwide. Current methods to control bovine babesiosis have severe limitations and novel approaches, including transmission-blocking vaccines, are needed. Members of the widely conserved CCp family are multidomain adhesion proteins containing LCCL motifs, which are differentially expressed on gametocytes of apicomplexans, including Babesia spp. and Plasmodium spp. While Plasmodium parasites contain 6 distinct CCp genes, only three members (CCp 1-3) were previously identified in B. bovis. In this study, we describe the identification and characterization of two novel non-canonical members of the CCp gene family in B. bovis, named CCp5 and FNPA. The genes were identified in silico by TBLASTN using P. falciparum CCp family domains as queries. Unlike CCp1-3, the B. bovis CCp5 and FNPA proteins lack the LCCL canonical domain but contain other typical multidomain adhesion motifs which are present in classical CCp proteins. In addition, the B. bovis CCp5 and FNPA are in synteny with known CCp genes in related apicomplexans. Sequence analysis of these two proteins demonstrated high sequence conservation among B. bovis different isolates. Transcription, immunoblot, and immunofluorescence analyses demonstrated expression of CCp5 and FNPA in blood and in vitro induced sexual stages of B. bovis. The FNPA, in contrast to CCp5, has a predicted transmembrane domain, suggesting that it might be expressed in the surface of sexual stage parasites. Altogether, finding of this study support FNPA as a possible target of a transmission-blocking vaccine against B. bovis.
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Affiliation(s)
- Sezayi Ozubek
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elâzig, Turkey
- *Correspondence: Sezayi Ozubek ;
| | - Heba F. Alzan
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Parasitology and Animal Diseases Department, Veterinary Research Institute, National Research Center, Giza, Egypt
| | - Reginaldo G. Bastos
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Jacob M. Laughery
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Carlos E. Suarez
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, United States
- Carlos E. Suarez
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10
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Kouadio JL, Zheng M, Aikins M, Duda D, Duff S, Chen D, Zhang J, Milligan J, Taylor C, Mamanella P, Rydel T, Kessenich C, Panosian T, Yin Y, Moar W, Giddings K, Park Y, Jerga A, Haas J. Structural and functional insights into the first Bacillus thuringiensis vegetative insecticidal protein of the Vpb4 fold, active against western corn rootworm. PLoS One 2021; 16:e0260532. [PMID: 34928980 PMCID: PMC8687597 DOI: 10.1371/journal.pone.0260532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/11/2021] [Indexed: 01/09/2023] Open
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major maize pest in the United States causing significant economic loss. The emergence of field-evolved resistant WCR to Bacillus thuringiensis (Bt) traits has prompted the need to discover and deploy new insecticidal proteins in transgenic maize. In the current study we determined the crystal structure and mode of action (MOA) of the Vpb4Da2 protein (formerly known as Vip4Da2) from Bt, the first identified insecticidal Vpb4 protein with commercial level control against WCR. The Vpb4Da2 structure exhibits a six-domain architecture mainly comprised of antiparallel β-sheets organized into β-sandwich layers. The amino-terminal domains 1-3 of the protein share structural homology with the protective antigen (PA) PA14 domain and encompass a long β-pore forming loop as in the clostridial binary-toxB module. Domains 5 and 6 at the carboxyl-terminal half of Vpb4Da2 are unique as this extension is not observed in PA or any other structurally-related protein other than Vpb4 homologs. These unique Vpb4 domains adopt the topologies of carbohydrate-binding modules known to participate in receptor-recognition. Functional assessment of Vpb4Da2 suggests that domains 4-6 comprise the WCR receptor binding region and are key in conferring the observed insecticidal activity against WCR. The current structural analysis was complemented by in vitro and in vivo characterizations, including immuno-histochemistry, demonstrating that Vpb4Da2 follows a MOA that is consistent with well-characterized 3-domain Bt insecticidal proteins despite significant structural differences.
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Affiliation(s)
| | - Meiying Zheng
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Michael Aikins
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - David Duda
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Stephen Duff
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Christina Taylor
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Timothy Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Colton Kessenich
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Timothy Panosian
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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11
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Willaert RG, Kayacan Y, Devreese B. The Flo Adhesin Family. Pathogens 2021; 10:pathogens10111397. [PMID: 34832553 PMCID: PMC8621652 DOI: 10.3390/pathogens10111397] [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: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 12/14/2022] Open
Abstract
The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.
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Affiliation(s)
- Ronnie G. Willaert
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Correspondence: ; Tel.: +32-2629-1846
| | - Yeseren Kayacan
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bart Devreese
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Laboratory for Microbiology, Gent University (UGent), 9000 Gent, Belgium
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12
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Vieira PS, Bonfim IM, Araujo EA, Melo RR, Lima AR, Fessel MR, Paixão DAA, Persinoti GF, Rocco SA, Lima TB, Pirolla RAS, Morais MAB, Correa JBL, Zanphorlin LM, Diogo JA, Lima EA, Grandis A, Buckeridge MS, Gozzo FC, Benedetti CE, Polikarpov I, Giuseppe PO, Murakami MT. Xyloglucan processing machinery in Xanthomonas pathogens and its role in the transcriptional activation of virulence factors. Nat Commun 2021; 12:4049. [PMID: 34193873 PMCID: PMC8245568 DOI: 10.1038/s41467-021-24277-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/07/2021] [Indexed: 02/06/2023] Open
Abstract
Xyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.
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Affiliation(s)
- Plinio S. Vieira
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Isabela M. Bonfim
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.411087.b0000 0001 0723 2494Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, São Paulo Brazil
| | - Evandro A. Araujo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.452567.70000 0004 0445 0877Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Ricardo R. Melo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Augusto R. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Melissa R. Fessel
- grid.418514.d0000 0001 1702 8585Butantan Institute, Butantan Foundation, São Paulo, São Paulo Brazil
| | - Douglas A. A. Paixão
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Gabriela F. Persinoti
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Silvana A. Rocco
- grid.452567.70000 0004 0445 0877Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Tatiani B. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Renan A. S. Pirolla
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Mariana A. B. Morais
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Jessica B. L. Correa
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Leticia M. Zanphorlin
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Jose A. Diogo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.411087.b0000 0001 0723 2494Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, São Paulo Brazil
| | - Evandro A. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Adriana Grandis
- grid.11899.380000 0004 1937 0722Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Marcos S. Buckeridge
- grid.11899.380000 0004 1937 0722Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Fabio C. Gozzo
- grid.411087.b0000 0001 0723 2494Institute of Chemistry, University of Campinas, Campinas, São Paulo Brazil
| | - Celso E. Benedetti
- grid.452567.70000 0004 0445 0877Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Igor Polikarpov
- grid.11899.380000 0004 1937 0722São Carlos Institute of Physics, University of São Paulo, São Carlos, São Paulo Brazil
| | - Priscila O. Giuseppe
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Mario T. Murakami
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
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13
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Essen LO, Vogt MS, Mösch HU. Diversity of GPI-anchored fungal adhesins. Biol Chem 2021; 401:1389-1405. [PMID: 33035180 DOI: 10.1515/hsz-2020-0199] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/21/2020] [Indexed: 12/28/2022]
Abstract
Selective adhesion of fungal cells to one another and to foreign surfaces is fundamental for the development of multicellular growth forms and the successful colonization of substrates and host organisms. Accordingly, fungi possess diverse cell wall-associated adhesins, mostly large glycoproteins, which present N-terminal adhesion domains at the cell surface for ligand recognition and binding. In order to function as robust adhesins, these glycoproteins must be covalently linkedto the cell wall via C-terminal glycosylphosphatidylinositol (GPI) anchors by transglycosylation. In this review, we summarize the current knowledge on the structural and functional diversity of so far characterized protein families of adhesion domains and set it into a broad context by an in-depth bioinformatics analysis using sequence similarity networks. In addition, we discuss possible mechanisms for the membrane-to-cell wall transfer of fungal adhesins by membrane-anchored Dfg5 transglycosidases.
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Affiliation(s)
- Lars-Oliver Essen
- Department of Biochemistry, Faculty of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043Marburg, Germany.,Center for Synthetic Microbiology, Philipps-Universität Marburg, Karl-von-Frisch-Str. 6, D-35043Marburg, Germany
| | - Marian Samuel Vogt
- Department of Biochemistry, Faculty of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043Marburg, Germany
| | - Hans-Ulrich Mösch
- Department of Genetics, Philipps-Universität Marburg, Karl-von-Frisch-Str. 8, D-35043Marburg, Germany.,Center for Synthetic Microbiology, Philipps-Universität Marburg, Karl-von-Frisch-Str. 6, D-35043Marburg, Germany
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14
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Structural Basis of Ligand Selectivity by a Bacterial Adhesin Lectin Involved in Multispecies Biofilm Formation. mBio 2021; 12:mBio.00130-21. [PMID: 33824212 PMCID: PMC8092209 DOI: 10.1128/mbio.00130-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Bacterial adhesins are key virulence factors that are essential for the pathogen-host interaction and biofilm formation that cause most infections. Many of the adhesin-driven cell-cell interactions are mediated by lectins. Carbohydrate recognition by lectins governs critical host-microbe interactions. MpPA14 (Marinomonas primoryensis PA14 domain) lectin is a domain of a 1.5-MDa adhesin responsible for a symbiotic bacterium-diatom interaction in Antarctica. Here, we show that MpPA14 binds various monosaccharides, with l-fucose and N-acetylglucosamine being the strongest ligands (dissociation constant [Kd], ∼150 μM). High-resolution structures of MpPA14 with 15 different sugars bound elucidated the molecular basis for the lectin’s apparent binding promiscuity but underlying selectivity. MpPA14 mediates strong Ca2+-dependent interactions with the 3,4-diols of l-fucopyranose and glucopyranoses, and it binds other sugars via their specific minor isomers. Thus, MpPA14 only binds polysaccharides like branched glucans and fucoidans with these free end groups. Consistent with our findings, adhesion of MpPA14 to diatom cells was selectively blocked by l-fucose, but not by N-acetyl galactosamine. The MpPA14 lectin homolog present in a Vibrio cholerae adhesin was produced and was shown to have the same sugar binding preferences as MpPA14. The pathogen’s lectin was unable to effectively bind the diatom in the presence of fucose, thus demonstrating the antiadhesion strategy of blocking infection via ligand-based antagonists.
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15
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The Buzz about ADP-Ribosylation Toxins from Paenibacillus larvae, the Causative Agent of American Foulbrood in Honey Bees. Toxins (Basel) 2021; 13:toxins13020151. [PMID: 33669183 PMCID: PMC7919650 DOI: 10.3390/toxins13020151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 11/26/2022] Open
Abstract
The Gram-positive, spore-forming bacterium Paenibacillus larvae is the etiological agent of American Foulbrood, a highly contagious and often fatal honey bee brood disease. The species P. larvae comprises five so-called ERIC-genotypes which differ in virulence and pathogenesis strategies. In the past two decades, the identification and characterization of several P. larvae virulence factors have led to considerable progress in understanding the molecular basis of pathogen-host-interactions during P. larvae infections. Among these virulence factors are three ADP-ribosylating AB-toxins, Plx1, Plx2, and C3larvin. Plx1 is a phage-born toxin highly homologous to the pierisin-like AB-toxins expressed by the whites-and-yellows family Pieridae (Lepidoptera, Insecta) and to scabin expressed by the plant pathogen Streptomyces scabiei. These toxins ADP-ribosylate DNA and thus induce apoptosis. While the presumed cellular target of Plx1 still awaits final experimental proof, the classification of the A subunits of the binary AB-toxins Plx2 and C3larvin as typical C3-like toxins, which ADP-ribosylate Rho-proteins, has been confirmed experimentally. Normally, C3-exoenzymes do not occur together with a B subunit partner, but as single domain toxins. Interestingly, the B subunits of the two P. larvae C3-like toxins are homologous to the B-subunits of C2-like toxins with striking structural similarity to the PA-63 protomer of Bacillus anthracis.
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16
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Bellas CM, Schroeder DC, Edwards A, Barker G, Anesio AM. Flexible genes establish widespread bacteriophage pan-genomes in cryoconite hole ecosystems. Nat Commun 2020; 11:4403. [PMID: 32879312 PMCID: PMC7468147 DOI: 10.1038/s41467-020-18236-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/10/2020] [Indexed: 12/20/2022] Open
Abstract
Bacteriophage genomes rapidly evolve via mutation and horizontal gene transfer to counter evolving bacterial host defenses; such arms race dynamics should lead to divergence between phages from similar, geographically isolated ecosystems. However, near-identical phage genomes can reoccur over large geographical distances and several years apart, conversely suggesting many are stably maintained. Here, we show that phages with near-identical core genomes in distant, discrete aquatic ecosystems maintain diversity by possession of numerous flexible gene modules, where homologous genes present in the pan-genome interchange to create new phage variants. By repeatedly reconstructing the core and flexible regions of phage genomes from different metagenomes, we show a pool of homologous gene variants co-exist for each module in each location, however, the dominant variant shuffles independently in each module. These results suggest that in a natural community, recombination is the largest contributor to phage diversity, allowing a variety of host recognition receptors and genes to counter bacterial defenses to co-exist for each phage. Bacteriophages and their hosts are involved in a constant evolutionary arms race that should lead to divergence between phage genes over time. Here, the authors recruit metagenomic reads to virus reference genomes and genome fragments in samples from cryoconite holes and show that phages with near-identical core genomes maintain diversity by possession of numerous flexible gene modules, where homologous genes present in the pan-genome interchange to create new phage variants.
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Affiliation(s)
- Christopher M Bellas
- Department of Ecology, Lake and Glacier Ecology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria.
| | - Declan C Schroeder
- Department of Veterinary Population Medicine, University of Minnesota, 1333 Gortner Avenue, St. Paul, MN, 55108, USA.,School of Biological Sciences, University of Reading, Reading, UK
| | - Arwyn Edwards
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3EE, UK
| | - Gary Barker
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Alexandre M Anesio
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
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17
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Alameh S, Bartolo G, O’Brien S, Henderson EA, Gonzalez LO, Hartmann S, Klimko CP, Shoe JL, Cote CK, Grill LK, Levitin A, Martchenko Shilman M. Anthrax toxin component, Protective Antigen, protects insects from bacterial infections. PLoS Pathog 2020; 16:e1008836. [PMID: 32866212 PMCID: PMC7458312 DOI: 10.1371/journal.ppat.1008836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/24/2020] [Indexed: 01/23/2023] Open
Abstract
Anthrax is a major zoonotic disease of wildlife, and in places like West Africa, it can be caused by Bacillus anthracis in arid nonsylvatic savannahs, and by B. cereus biovar anthracis (Bcbva) in sylvatic rainforests. Bcbva-caused anthrax has been implicated in as much as 38% of mortality in rainforest ecosystems, where insects can enhance the transmission of anthrax-causing bacteria. While anthrax is well-characterized in mammals, its transmission by insects points to an unidentified anthrax-resistance mechanism in its vectors. In mammals, a secreted anthrax toxin component, 83 kDa Protective Antigen (PA83), binds to cell-surface receptors and is cleaved by furin into an evolutionary-conserved PA20 and a pore-forming PA63 subunits. We show that PA20 increases the resistance of Drosophila flies and Culex mosquitoes to bacterial challenges, without directly affecting the bacterial growth. We further show that the PA83 loop known to be cleaved by furin to release PA20 from PA63 is, in part, responsible for the PA20-mediated protection. We found that PA20 binds directly to the Toll activating peptidoglycan-recognition protein-SA (PGRP-SA) and that the Toll/NF-κB pathway is necessary for the PA20-mediated protection of infected flies. This effect of PA20 on innate immunity may also exist in mammals: we show that PA20 binds to human PGRP-SA ortholog. Moreover, the constitutive activity of Imd/NF-κB pathway in MAPKK Dsor1 mutant flies is sufficient to confer the protection from bacterial infections in a manner that is independent of PA20 treatment. Lastly, Clostridium septicum alpha toxin protects flies from anthrax-causing bacteria, showing that other pathogens may help insects resist anthrax. The mechanism of anthrax resistance in insects has direct implications on insect-mediated anthrax transmission for wildlife management, and with potential for applications, such as reducing the sensitivity of pollinating insects to bacterial pathogens.
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Affiliation(s)
- Saleem Alameh
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Gloria Bartolo
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Summer O’Brien
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Elizabeth A. Henderson
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Leandra O. Gonzalez
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Stella Hartmann
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Christopher P. Klimko
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Jennifer L. Shoe
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Christopher K. Cote
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Laurence K. Grill
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Anastasia Levitin
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
| | - Mikhail Martchenko Shilman
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
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18
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Reinmets K, Dehkharghani A, Guasto JS, Fuchs SM. Microfluidic quantification and separation of yeast based on surface adhesion. LAB ON A CHIP 2019; 19:3481-3489. [PMID: 31524206 DOI: 10.1039/c9lc00275h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fungal adhesion is fundamental to processes ranging from infections to food production to bioengineering. Yet, robust, population-scale quantification methods for yeast surface adhesion are lacking. We developed a microfluidic assay to discriminate and separate genetically-related yeast strains based on adhesion strength, and to quantify effects of ionic strength and substrate hydrophobicity on adhesion. This approach will enable the rapid screening and fractionation of yeast based on adhesive properties for genetic protein engineering, anti-fouling surfaces, and a host of other applications.
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19
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Vance TDR, Guo S, Assaie-Ardakany S, Conroy B, Davies PL. Structure and functional analysis of a bacterial adhesin sugar-binding domain. PLoS One 2019; 14:e0220045. [PMID: 31335890 PMCID: PMC6650083 DOI: 10.1371/journal.pone.0220045] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 07/08/2019] [Indexed: 01/17/2023] Open
Abstract
Bacterial adhesins attach their hosts to surfaces through one or more ligand-binding domains. In RTX adhesins, which are localized to the outer membrane of many Gram-negative bacteria via the type I secretion system, we see several examples of a putative sugar-binding domain. Here we have recombinantly expressed one such ~20-kDa domain from the ~340-kDa adhesin found in Marinobacter hydrocarbonoclasticus, an oil-degrading bacterium. The sugar-binding domain was purified from E. coli with a yield of 100 mg/L of culture. Circular dichroism analysis showed that the protein was rich in beta-structure, was moderately heat resistant, and required Ca2+ for proper folding. A crystal structure was obtained in Ca2+ at 1.2-Å resolution, which showed the presence of three Ca2+ ions, two of which were needed for structural integrity and one for binding sugars. Glucose was soaked into the crystal, where it bound to the sugar's two vicinal hydroxyl groups attached to the first and second (C1 and C2) carbons in the pyranose ring. This attraction to glucose caused the protein to bind certain polysaccharide-based column matrices and was used in a simple competitive binding assay to assess the relative affinity of sugars for the protein's ligand-binding site. Fucose, glucose and N-acetylglucosamine bound most tightly, and N-acetylgalactosamine hardly bound at all. Isothermal titration calorimetry was used to determine specific binding affinities, which lie in the 100-μM range. Glycan arrays were tested to expand the range of ligand sugars assayed, and showed that MhPA14 bound preferentially to branched polymers containing terminal sugars highlighted as strong binders in the competitive binding assay. Some of these binders have vicinal hydroxyl groups attached to the C3 and C4 carbons that are sterically equivalent to those presented by the C1 and C2 carbons of glucose.
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Affiliation(s)
- Tyler D. R. Vance
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Shayan Assaie-Ardakany
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Brigid Conroy
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Peter L. Davies
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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20
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Grinberg IR, Yaniv O, de Ora LO, Muñoz-Gutiérrez I, Hershko A, Livnah O, Bayer EA, Borovok I, Frolow F, Lamed R, Voronov-Goldman M. Distinctive ligand-binding specificities of tandem PA14 biomass-sensory elements from Clostridium thermocellum and Clostridium clariflavum. Proteins 2019; 87:917-930. [PMID: 31162722 PMCID: PMC6852018 DOI: 10.1002/prot.25753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 05/26/2019] [Accepted: 05/30/2019] [Indexed: 11/25/2022]
Abstract
Cellulolytic clostridia use a highly efficient cellulosome system to degrade polysaccharides. To regulate genes encoding enzymes of the multi‐enzyme cellulosome complex, certain clostridia contain alternative sigma I (σI) factors that have cognate membrane‐associated anti‐σI factors (RsgIs) which act as polysaccharide sensors. In this work, we analyzed the structure‐function relationship of the extracellular sensory elements of Clostridium (Ruminiclostridium) thermocellum and Clostridium clariflavum (RsgI3 and RsgI4, respectively). These elements were selected for comparison, as each comprised two tandem PA14‐superfamily motifs. The X‐ray structures of the PA14 modular dyads from the two bacterial species were determined, both of which showed a high degree of structural and sequence similarity, although their binding preferences differed. Bioinformatic approaches indicated that the DNA sequence of promoter of sigI/rsgI operons represents a strong signature, which helps to differentiate binding specificity of the structurally similar modules. The σI4‐dependent C. clariflavum promoter sequence correlates with binding of RsgI4_PA14 to xylan and was identified in genes encoding xylanases, whereas the σI3‐dependent C. thermocellum promoter sequence correlates with RsgI3_PA14 binding to pectin and regulates pectin degradation‐related genes. Structural similarity between clostridial PA14 dyads to PA14‐containing proteins in yeast helped identify another crucial signature element: the calcium‐binding loop 2 (CBL2), which governs binding specificity. Variations in the five amino acids that constitute this loop distinguish the pectin vs xylan specificities. We propose that the first module (PA14A) is dominant in directing the binding to the ligand in both bacteria. The two X‐ray structures of the different PA14 dyads represent the first reported structures of tandem PA14 modules.
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Affiliation(s)
- Inna Rozman Grinberg
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel.,Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Oren Yaniv
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Lizett Ortiz de Ora
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel.,Department of Chemistry, University of California, Irvine, California
| | - Iván Muñoz-Gutiérrez
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.,Outreach Research Training and Minority Science Programs, School of Biological Sciences, University of California, Irvine, California
| | - Almog Hershko
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Oded Livnah
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Wolfson Centre for Applied Structural Biology, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, Jerusalem, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Milana Voronov-Goldman
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
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21
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Guo S, Vance TD, Stevens CA, Voets I, Davies PL. RTX Adhesins are Key Bacterial Surface Megaproteins in the Formation of Biofilms. Trends Microbiol 2019; 27:453-467. [DOI: 10.1016/j.tim.2018.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/13/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022]
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22
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Bernardi B, Kayacan Y, Wendland J. Expansion of a Telomeric FLO/ALS-Like Sequence Gene Family in Saccharomycopsis fermentans. Front Genet 2018; 9:536. [PMID: 30542368 PMCID: PMC6277891 DOI: 10.3389/fgene.2018.00536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/23/2018] [Indexed: 01/01/2023] Open
Abstract
Non-Saccharomyces species have been recognized for their beneficial contribution to fermented food and beverages based on their volatile compound formation and their ability to ferment glucose into ethanol. At the end of fermentation brewer's yeast flocculate which provides an easy means of separation of yeasts from green beer. Flocculation in Saccharomyces cerevisiae requires a set of flocculation genes. These FLO-genes, FLO1, FLO5, FLO9, FLO10, and FLO11, are located at telomeres and transcription of these adhesins is regulated by Flo8 and Mss11. Here, we show that Saccharomycopsis fermentans, an ascomycete yeast distantly related to S. cerevisiae, possesses a very large FLO/ALS-like Sequence (FAS) family encompassing 34 genes. Fas proteins are variable in size and divergent in sequence and show similarity to the Flo1/5/9 family. Fas proteins show the general build with a signal peptide, an N-terminal carbohydrate binding PA14 domain, a central region differing by the number of repeats and a C-terminus with a consensus sequence for GPI-anchor attachment. Like FLO genes in S. cerevisiae, FAS genes are mostly telomeric with several paralogs at each telomere. We term such genes that share evolutionary conserved telomere localization "telologs" and provide several other examples. Adhesin expression in S. cerevisiae and filamentation in Candida albicans is regulated by Flo8 and Mss11. In Saccharomycopsis we identified only a single protein with similarity to Flo8 based on sequence similarity and the presence of a LisH domain.
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Affiliation(s)
- Beatrice Bernardi
- Department of Bioengineering Sciences, Research Group of Microbiology, Functional Yeast Genomics, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Yeseren Kayacan
- Department of Bioengineering Sciences, Research Group of Microbiology, Functional Yeast Genomics, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jürgen Wendland
- Department of Bioengineering Sciences, Research Group of Microbiology, Functional Yeast Genomics, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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Wielgoss S, Fiegna F, Rendueles O, Yu YTN, Velicer GJ. Kin discrimination and outer membrane exchange in Myxococcus xanthus: A comparative analysis among natural isolates. Mol Ecol 2018; 27:3146-3158. [PMID: 29924883 DOI: 10.1111/mec.14773] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 01/05/2023]
Abstract
Genetically similar cells of the soil bacterium Myxococcus xanthus cooperate at multiple social behaviours, including motility and multicellular development. Another social interaction in this species is outer membrane exchange (OME), a behaviour of unknown primary benefit in which cells displaying closely related variants of the outer membrane protein TraA transiently fuse and exchange membrane contents. Functionally incompatible TraA variants do not mediate OME, which led to the proposal that TraA incompatibilities determine patterns of intercellular cooperation in nature, but how this might occur remains unclear. Using natural isolates from a centimetre-scale patch of soil, we analyse patterns of TraA diversity and ask whether relatedness at TraA is causally related to patterns of kin discrimination in the form of both colony-merger incompatibilities (CMIs) and interstrain antagonisms. A large proportion of TraA functional diversity documented among global isolates is predicted to be contained within this cm-scale population. We find evidence of balancing selection on the highly variable PA14-portion of TraA and extensive transfer of traA alleles across genomic backgrounds. CMIs are shown to be common among strains identical at TraA, suggesting that CMIs are not generally caused by TraA dissimilarity. Finally, it has been proposed that interstrain antagonisms might be caused by OME-mediated toxin transfer. However, we predict that most strain pairs previously shown to exhibit strong antagonisms are incapable of OME due to TraA dissimilarity. Overall, our results suggest that most documented patterns of kin discrimination in a natural population of M. xanthus are not causally related to the TraA sequences of interactants.
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Affiliation(s)
| | - Francesca Fiegna
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Olaya Rendueles
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.,Microbial Evolutionary Genomics Unit, Institut Pasteur, Paris, France
| | - Yuen-Tsu N Yu
- Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
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Timmermans B, De Las Peñas A, Castaño I, Van Dijck P. Adhesins in Candida glabrata. J Fungi (Basel) 2018; 4:E60. [PMID: 29783771 PMCID: PMC6023314 DOI: 10.3390/jof4020060] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 12/31/2022] Open
Abstract
The human fungal pathogen Candida glabrata is causing more and more problems in hospitals, as this species shows an intrinsic antifungal drug resistance or rapidly becomes resistant when challenged with antifungals. C. glabrata only grows in the yeast form, so it is lacking a yeast-to-hyphae switch, which is one of the main virulence factors of C. albicans. An important virulence factor of C. glabrata is its capacity to strongly adhere to many different substrates. To achieve this, C. glabrata expresses a large number of adhesin-encoding genes and genome comparisons with closely related species, including the non-pathogenic S. cerevisiae, which revealed a correlation between the number of adhesin-encoding genes and pathogenicity. The adhesins are involved in the first steps during an infection; they are the first point of contact with the host. For several of these adhesins, their importance in adherence to different substrates and subsequent biofilm formation was demonstrated in vitro or in vivo. In this review, we provide an overview of the role of C. glabrata adhesins during adhesion and biofilm formation both, under in vitro and in vivo conditions.
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Affiliation(s)
- Bea Timmermans
- KU Leuven, Laboratory of Molecular Cell Biology, Kasteelpark Arenberg 31 bus 2438, 3001 Leuven, Belgium.
- VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium.
| | - Alejandro De Las Peñas
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P., San Luis Potosí 78216 San Luis Potosí, Mexico.
| | - Irene Castaño
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P., San Luis Potosí 78216 San Luis Potosí, Mexico.
| | - Patrick Van Dijck
- KU Leuven, Laboratory of Molecular Cell Biology, Kasteelpark Arenberg 31 bus 2438, 3001 Leuven, Belgium.
- VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium.
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25
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Guo S, Stevens CA, Vance TDR, Olijve LLC, Graham LA, Campbell RL, Yazdi SR, Escobedo C, Bar-Dolev M, Yashunsky V, Braslavsky I, Langelaan DN, Smith SP, Allingham JS, Voets IK, Davies PL. Structure of a 1.5-MDa adhesin that binds its Antarctic bacterium to diatoms and ice. SCIENCE ADVANCES 2017; 3:e1701440. [PMID: 28808685 PMCID: PMC5550230 DOI: 10.1126/sciadv.1701440] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/11/2017] [Indexed: 05/20/2023]
Abstract
Bacterial adhesins are modular cell-surface proteins that mediate adherence to other cells, surfaces, and ligands. The Antarctic bacterium Marinomonas primoryensis uses a 1.5-MDa adhesin comprising over 130 domains to position it on ice at the top of the water column for better access to oxygen and nutrients. We have reconstructed this 0.6-μm-long adhesin using a "dissect and build" structural biology approach and have established complementary roles for its five distinct regions. Domains in region I (RI) tether the adhesin to the type I secretion machinery in the periplasm of the bacterium and pass it through the outer membrane. RII comprises ~120 identical immunoglobulin-like β-sandwich domains that rigidify on binding Ca2+ to project the adhesion regions RIII and RIV into the medium. RIII contains ligand-binding domains that join diatoms and bacteria together in a mixed-species community on the underside of sea ice where incident light is maximal. RIV is the ice-binding domain, and the terminal RV domain contains several "repeats-in-toxin" motifs and a noncleavable signal sequence that target proteins for export via the type I secretion system. Similar structural architecture is present in the adhesins of many pathogenic bacteria and provides a guide to finding and blocking binding domains to weaken infectivity.
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Affiliation(s)
- Shuaiqi Guo
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
- Laboratory of Macromolecular and Organic Chemistry of Department of Chemical Engineering and Chemistry, and Laboratory of Physical Chemistry of Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
| | - Corey A. Stevens
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Tyler D. R. Vance
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Luuk L. C. Olijve
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
- Laboratory of Macromolecular and Organic Chemistry of Department of Chemical Engineering and Chemistry, and Laboratory of Physical Chemistry of Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
| | - Laurie A. Graham
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Robert L. Campbell
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Saeed R. Yazdi
- Faculty of Engineering and Applied Science and Department of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Carlos Escobedo
- Faculty of Engineering and Applied Science and Department of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Maya Bar-Dolev
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Victor Yashunsky
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Ido Braslavsky
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - David N. Langelaan
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Steven P. Smith
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - John S. Allingham
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Ilja K. Voets
- Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
- Laboratory of Macromolecular and Organic Chemistry of Department of Chemical Engineering and Chemistry, and Laboratory of Physical Chemistry of Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MD Eindhoven, Netherlands
| | - Peter L. Davies
- Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- Corresponding author.
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26
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Matsunaga E, Higuchi Y, Mori K, Yairo N, Toyota S, Oka T, Tashiro K, Takegawa K. Characterization of a PA14 domain-containing galactofuranose-specific β-d-galactofuranosidase from Streptomyces sp. Biosci Biotechnol Biochem 2017; 81:1314-1319. [DOI: 10.1080/09168451.2017.1300518] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
As a constituent of polysaccharides and glycoconjugates, β-d-galactofuranose (Galf) exists in several pathogenic microorganisms. Although we recently identified a β-d-galactofuranosidase (Galf-ase) gene, ORF1110, in the Streptomyces strain JHA19, very little is known about the Galf-ase gene. Here, we characterized a strain, named JHA26, in the culture supernatant of which exhibited Galf-ase activity for 4-nitrophenyl β-d-galactofuranoside (pNP-β-d-Galf) as a substrate. Draft genome sequencing of the JHA26 strain revealed a putative gene, termed ORF0643, that encodes Galf-ase containing a PA14 domain, which is thought to function in substrate recognition. The recombinant protein expressed in Escherichia coli showed the Galf-specific Galf-ase activity and also released galactose residue of the polysaccharide galactomannan prepared from Aspergillus fumigatus, suggesting that this enzyme is an exo-type Galf-ase. BLAST searches using the amino acid sequences of ORF0643 and ORF1110 Galf-ases revealed two types of Galf-ases in Actinobacteria, suggesting that Galf-specific Galf-ases may exhibit discrete substrate specificities.
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Affiliation(s)
- Emiko Matsunaga
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Yujiro Higuchi
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Kazuki Mori
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Nao Yairo
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Saki Toyota
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Takuji Oka
- Faculty of Biotechnology and Life Science, Department of Applied Microbial Technology, Sojo University, Kumamoto, Japan
| | - Kosuke Tashiro
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
| | - Kaoru Takegawa
- Faculty of Agriculture, Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan
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27
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Larsbrink J, Tuveng TR, Pope PB, Bulone V, Eijsink VG, Brumer H, McKee LS. Proteomic insights into mannan degradation and protein secretion by the forest floor bacterium Chitinophaga pinensis. J Proteomics 2017; 156:63-74. [DOI: 10.1016/j.jprot.2017.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/13/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
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28
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Chandonia JM, Fox NK, Brenner SE. SCOPe: Manual Curation and Artifact Removal in the Structural Classification of Proteins - extended Database. J Mol Biol 2016; 429:348-355. [PMID: 27914894 DOI: 10.1016/j.jmb.2016.11.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 12/23/2022]
Abstract
SCOPe (Structural Classification of Proteins-extended, http://scop.berkeley.edu) is a database of relationships between protein structures that extends the Structural Classification of Proteins (SCOP) database. SCOP is an expert-curated ordering of domains from the majority of proteins of known structure in a hierarchy according to structural and evolutionary relationships. SCOPe classifies the majority of protein structures released since SCOP development concluded in 2009, using a combination of manual curation and highly precise automated tools, aiming to have the same accuracy as fully hand-curated SCOP releases. SCOPe also incorporates and updates the ASTRAL compendium, which provides several databases and tools to aid in the analysis of the sequences and structures of proteins classified in SCOPe. SCOPe continues high-quality manual classification of new superfamilies, a key feature of SCOP. Artifacts such as expression tags are now separated into their own class, in order to distinguish them from the homology-based annotations in the remainder of the SCOPe hierarchy. SCOPe 2.06 contains 77,439 Protein Data Bank entries, double the 38,221 structures classified in SCOP.
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Affiliation(s)
- John-Marc Chandonia
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Naomi K Fox
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Steven E Brenner
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
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29
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Huber RJ, O'Day DH. Extracellular matrix dynamics and functions in the social amoeba Dictyostelium: A critical review. Biochim Biophys Acta Gen Subj 2016; 1861:2971-2980. [PMID: 27693486 DOI: 10.1016/j.bbagen.2016.09.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/19/2016] [Accepted: 09/26/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND The extracellular matrix (ECM) is a dynamic complex of glycoproteins, proteoglycans, carbohydrates, and collagen that serves as an interface between mammalian cells and their extracellular environment. Essential for normal cellular homeostasis, physiology, and events that occur during development, it is also a key functionary in a number of human diseases including cancer. The social amoeba Dictyostelium discoideum secretes an ECM during multicellular development that regulates multicellularity, cell motility, cell differentiation, and morphogenesis, and provides structural support and protective layers to the resulting differentiated cell types. Proteolytic processing within the Dictyostelium ECM leads to specific bioactive factors that regulate cell motility and differentiation. SCOPE OF REVIEW Here we review the structure and functions of the Dictyostelium ECM and its role in regulating multicellular development. The questions and challenges that remain and how they can be answered are also discussed. MAJOR CONCLUSIONS The Dictyostelium ECM shares many of the features of mammalian and plant ECM, and thus presents an excellent system for studying the structure and function of the ECM. GENERAL SIGNIFICANCE As a genetically tractable model organism, Dictyostelium offers the potential to further elucidate ECM functions, and to possibly reveal previously unknown roles for the ECM.
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Affiliation(s)
- Robert J Huber
- Department of Biology, Trent University, Peterborough, Ontario, Canada.
| | - Danton H O'Day
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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30
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Recent structural insights into the enzymology of the ubiquitous plant cell wall glycan xyloglucan. Curr Opin Struct Biol 2016; 40:43-53. [PMID: 27475238 DOI: 10.1016/j.sbi.2016.07.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 01/03/2023]
Abstract
The xyloglucans (XyGs) constitute a family of highly decorated β(1→4)-glucans whose members are widespread and abundant across the plant kingdom. As such, XyGs constitute a significant reserve of metabolically accessible monosaccharides for diverse phytopathogenic, saprophytic, and gut symbiotic micro-organisms. To overcome the intrinsic stability of the diverse glycosidic bonds in XyGs, bacteria and fungi have evolved extensive repertoires of xyloglucan-active enzymes from manifold families, whose exquisitely adapted tertiary structures are recently coming to light.
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31
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Lectin-Glycan Interaction Network-Based Identification of Host Receptors of Microbial Pathogenic Adhesins. mBio 2016; 7:mBio.00584-16. [PMID: 27406561 PMCID: PMC4958244 DOI: 10.1128/mbio.00584-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The first step in the infection of humans by microbial pathogens is their adherence to host tissue cells, which is frequently based on the binding of carbohydrate-binding proteins (lectin-like adhesins) to human cell receptors that expose glycans. In only a few cases have the human receptors of pathogenic adhesins been described. A novel strategy—based on the construction of a lectin-glycan interaction (LGI) network—to identify the potential human binding receptors for pathogenic adhesins with lectin activity was developed. The new approach is based on linking glycan array screening results of these adhesins to a human glycoprotein database via the construction of an LGI network. This strategy was used to detect human receptors for virulent Escherichia coli (FimH adhesin), and the fungal pathogens Candida albicans (Als1p and Als3p adhesins) and C. glabrata (Epa1, Epa6, and Epa7 adhesins), which cause candidiasis. This LGI network strategy allows the profiling of potential adhesin binding receptors in the host with prioritization, based on experimental binding data, of the most relevant interactions. New potential targets for the selected adhesins were predicted and experimentally confirmed. This methodology was also used to predict lectin interactions with envelope glycoproteins of human-pathogenic viruses. It was shown that this strategy was successful in revealing that the FimH adhesin has anti-HIV activity. Microbial pathogens may express a wide range of carbohydrate-specific adhesion proteins that mediate adherence to host tissues. Pathogen attachment to host cells is achieved through the binding of these lectin-like adhesins to glycans on human glycoproteins. In only a few cases have the human receptors of pathogenic adhesins been described. We developed a new strategy to predict these interacting receptors. Therefore, we developed a novel LGI network that would allow the mapping of potential adhesin binding receptors in the host with prioritization, based on the experimental binding data, of the most relevant interactions. New potential targets for the selected adhesins (bacterial uroepithelial FimH from E. coli and fungal Epa and Als adhesins from C. glabrata and C. albicans) were predicted and experimentally confirmed. This methodology was also used to predict lectin interactions with human-pathogenic viruses and to discover whether FimH adhesin has anti-HIV activity.
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Decoding Biomass-Sensing Regulons of Clostridium thermocellum Alternative Sigma-I Factors in a Heterologous Bacillus subtilis Host System. PLoS One 2016; 11:e0146316. [PMID: 26731480 PMCID: PMC4711584 DOI: 10.1371/journal.pone.0146316] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/15/2015] [Indexed: 11/25/2022] Open
Abstract
The Gram-positive, anaerobic, cellulolytic, thermophile Clostridium (Ruminiclostridium) thermocellum secretes a multi-enzyme system called the cellulosome to solubilize plant cell wall polysaccharides. During the saccharolytic process, the enzymatic composition of the cellulosome is modulated according to the type of polysaccharide(s) present in the environment. C. thermocellum has a set of eight alternative RNA polymerase sigma (σ) factors that are activated in response to extracellular polysaccharides and share sequence similarity to the Bacillus subtilis σI factor. The aim of the present work was to demonstrate whether individual C. thermocellum σI-like factors regulate specific cellulosomal genes, focusing on C. thermocellum σI6 and σI3 factors. To search for putative σI6- and σI3-dependent promoters, bioinformatic analysis of the upstream regions of the cellulosomal genes was performed. Because of the limited genetic tools available for C. thermocellum, the functionality of the predicted σI6- and σI3-dependent promoters was studied in B. subtilis as a heterologous host. This system enabled observation of the activation of 10 predicted σI6-dependent promoters associated with the C. thermocellum genes: sigI6 (itself, Clo1313_2778), xyn11B (Clo1313_0522), xyn10D (Clo1313_0177), xyn10Z (Clo1313_2635), xyn10Y (Clo1313_1305), cel9V (Clo1313_0349), cseP (Clo1313_2188), sigI1 (Clo1313_2174), cipA (Clo1313_0627), and rsgI5 (Clo1313_0985). Additionally, we observed the activation of 4 predicted σI3-dependent promoters associated with the C. thermocellum genes: sigI3 (itself, Clo1313_1911), pl11 (Clo1313_1983), ce12 (Clo1313_0693) and cipA. Our results suggest possible regulons of σI6 and σI3 in C. thermocellum, as well as the σI6 and σI3 promoter consensus sequences. The proposed -35 and -10 promoter consensus elements of σI6 are CNNAAA and CGAA, respectively. Additionally, a less conserved CGA sequence next to the C in the -35 element and a highly conserved AT sequence three bases downstream of the -10 element were also identified as important nucleotides for promoter recognition. Regarding σI3, the proposed -35 and -10 promoter consensus elements are CCCYYAAA and CGWA, respectively. The present study provides new clues for understanding these recently discovered alternative σI factors.
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33
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Diderrich R, Kock M, Maestre-Reyna M, Keller P, Steuber H, Rupp S, Essen LO, Mösch HU. Structural Hot Spots Determine Functional Diversity of the Candida glabrata Epithelial Adhesin Family. J Biol Chem 2015; 290:19597-613. [PMID: 26105055 PMCID: PMC4528126 DOI: 10.1074/jbc.m115.655654] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/20/2015] [Indexed: 11/06/2022] Open
Abstract
For host colonization, the human fungal pathogen Candida glabrata is known to utilize a large family of highly related surface-exposed cell wall proteins, the lectin-like epithelial adhesins (Epas). To reveal the structure-function relationships within the entire Epa family, we have performed a large scale functional analysis of the adhesion (A) domains of 17 Epa paralogs in combination with three-dimensional structural studies of selected members with cognate ligands. Our study shows that most EpaA domains exert lectin-like functions and together recognize a wide variety of glycans with terminal galactosides for conferring epithelial cell adhesion. We further identify several conserved and variable structural features within the diverse Epa ligand binding pockets, which affect affinity and specificity. These features rationalize why mere phylogenetic relationships within the Epa family are weak indicators for functional classification and explain how Epa-like adhesins have evolved in C. glabrata and related fungal species.
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Affiliation(s)
| | - Michael Kock
- Biochemistry, Philipps-Universität, 35043 Marburg, Germany
| | | | - Petra Keller
- the Fraunhofer-Institut für Grenzflächen und Bioverfahrenstechnik, 70569 Stuttgart, Germany, and
| | - Holger Steuber
- Biochemistry, Philipps-Universität, 35043 Marburg, Germany
| | - Steffen Rupp
- the Fraunhofer-Institut für Grenzflächen und Bioverfahrenstechnik, 70569 Stuttgart, Germany, and the Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart, 70569 Stuttgart, Germany
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34
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Molecular mechanism of flocculation self-recognition in yeast and its role in mating and survival. mBio 2015; 6:mBio.00427-15. [PMID: 25873380 PMCID: PMC4453552 DOI: 10.1128/mbio.00427-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We studied the flocculation mechanism at the molecular level by determining the atomic structures of N-Flo1p and N-Lg-Flo1p in complex with their ligands. We show that they have similar ligand binding mechanisms but distinct carbohydrate specificities and affinities, which are determined by the compactness of the binding site. We characterized the glycans of Flo1p and their role in this binding process and demonstrate that glycan-glycan interactions significantly contribute to the cell-cell adhesion mechanism. Therefore, the extended flocculation mechanism is based on the self-interaction of Flo proteins and this interaction is established in two stages, involving both glycan-glycan and protein-glycan interactions. The crucial role of calcium in both types of interaction was demonstrated: Ca2+ takes part in the binding of the carbohydrate to the protein, and the glycans aggregate only in the presence of Ca2+. These results unify the generally accepted lectin hypothesis with the historically first-proposed “Ca2+-bridge” hypothesis. Additionally, a new role of cell flocculation is demonstrated; i.e., flocculation is linked to cell conjugation and mating, and survival chances consequently increase significantly by spore formation and by introduction of genetic variability. The role of Flo1p in mating was demonstrated by showing that mating efficiency is increased when cells flocculate and by differential transcriptome analysis of flocculating versus nonflocculating cells in a low-shear environment (microgravity). The results show that a multicellular clump (floc) provides a uniquely organized multicellular ultrastructure that provides a suitable microenvironment to induce and perform cell conjugation and mating. Yeast cells can form multicellular clumps under adverse growth conditions that protect cells from harsh environmental stresses. The floc formation is based on the self-interaction of Flo proteins via an N-terminal PA14 lectin domain. We have focused on the flocculation mechanism and its role. We found that carbohydrate specificity and affinity are determined by the accessibility of the binding site of the Flo proteins where the external loops in the ligand-binding domains are involved in glycan recognition specificity. We demonstrated that, in addition to the Flo lectin-glycan interaction, glycan-glycan interactions also contribute significantly to cell-cell recognition and interaction. Additionally, we show that flocculation provides a uniquely organized multicellular ultrastructure that is suitable to induce and accomplish cell mating. Therefore, flocculation is an important mechanism to enhance long-term yeast survival.
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Liu Z, Li R, Dong Q, Bian L, Li X, Yuan S. Characterization of the non-sexual flocculation of fission yeast cells that results from the deletion of ribosomal protein L32. Yeast 2015; 32:439-49. [DOI: 10.1002/yea.3070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 12/25/2014] [Accepted: 02/12/2015] [Indexed: 11/11/2022] Open
Affiliation(s)
- Zhonghua Liu
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
| | - Rongpeng Li
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
| | - Qing Dong
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
| | - Lezhi Bian
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
| | - Xuesong Li
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
| | - Sheng Yuan
- Jiangsu Key Laboratory for Microbes and Functional Genetics, Jiangsu Engineering and Technology Research Centre for Industrialization of Microbial Resources, College of Life Science; Nanjing Normal University; People's Republic of China
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Taylor ME, Drickamer K. Convergent and divergent mechanisms of sugar recognition across kingdoms. Curr Opin Struct Biol 2014; 28:14-22. [PMID: 25102772 PMCID: PMC4444583 DOI: 10.1016/j.sbi.2014.07.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/23/2014] [Accepted: 07/16/2014] [Indexed: 12/03/2022]
Abstract
Protein modules that bind specific oligosaccharides are found across all kingdoms of life from single-celled organisms to man. Different, overlapping and evolving designations for sugar-binding domains in proteins can sometimes obscure common features that often reflect convergent solutions to the problem of distinguishing sugars with closely similar structures and binding them with sufficient affinity to achieve biologically meaningful results. Structural and functional analysis has revealed striking parallels between protein domains with widely different structures and evolutionary histories that employ common solutions to the sugar recognition problem. Recent studies also demonstrate that domains descended from common ancestors through divergent evolution appear more widely across the kingdoms of life than had previously been recognized.
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Affiliation(s)
- Maureen E Taylor
- Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom.
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Ielasi FS, Verhaeghe T, Desmet T, Willaert RG. Engineering the carbohydrate-binding site of Epa1p from Candida glabrata: generation of adhesin mutants with different carbohydrate specificity. Glycobiology 2014; 24:1312-22. [DOI: 10.1093/glycob/cwu075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Rigden DJ, Eberhardt RY, Gilbert HJ, Xu Q, Chang Y, Godzik A. Structure- and context-based analysis of the GxGYxYP family reveals a new putative class of glycoside hydrolase. BMC Bioinformatics 2014; 15:196. [PMID: 24938123 PMCID: PMC4071793 DOI: 10.1186/1471-2105-15-196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 06/10/2014] [Indexed: 01/24/2023] Open
Abstract
Background Gut microbiome metagenomics has revealed many protein families and domains found largely or exclusively in that environment. Proteins containing the GxGYxYP domain are over-represented in the gut microbiota, and are found in Polysaccharide Utilization Loci in the gut symbiont Bacteroides thetaiotaomicron, suggesting their involvement in polysaccharide metabolism, but little else is known of the function of this domain. Results Genomic context and domain architecture analyses support a role for the GxGYxYP domain in carbohydrate metabolism. Sparse occurrences in eukaryotes are the result of lateral gene transfer. The structure of the GxGYxYP domain-containing protein encoded by the BT2193 locus reveals two structural domains, the first composed of three divergent repeats with no recognisable homology to previously solved structures, the second a more familiar seven-stranded β/α barrel. Structure-based analyses including conservation mapping localise a presumed functional site to a cleft between the two domains of BT2193. Matching to a catalytic site template from a GH9 cellulase and other analyses point to a putative catalytic triad composed of Glu272, Asp331 and Asp333. Conclusions We suggest that GxGYxYP-containing proteins constitute a novel glycoside hydrolase family of as yet unknown specificity.
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Affiliation(s)
- Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
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Du J, Cui CH, Park SC, Kim JK, Yu HS, Jin FX, Sun C, Kim SC, Im WT. Identification and characterization of a ginsenoside-transforming β-glucosidase from Pseudonocardia sp. Gsoil 1536 and its application for enhanced production of minor ginsenoside Rg2(S). PLoS One 2014; 9:e96914. [PMID: 24911166 PMCID: PMC4049585 DOI: 10.1371/journal.pone.0096914] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/14/2014] [Indexed: 11/25/2022] Open
Abstract
The ginsenoside Rg2(S), which is one of the pharmaceutical components of ginseng, is known to have neuroprotective, anti-inflammation, and anti-diabetic effects. However, the usage of ginsenoside Rg2(S) is restricted owing to the small amounts found in white and red ginseng. To enhance the production of ginsenoside Rg2(S) as a 100 gram unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the recombinant glycoside hydrolase (BglPC28), which is a ginsenoside-transforming recombinant β-glucosidase from Pseudonocardia sp. strain Gsoil 1536. The gene, termed bglPC28, encoding β-glucosidase (BglPC28) belonging to the glycoside hydrolase family 3 was cloned. bglPC28 consists of 2,232 bp (743 amino acid residues) with a predicted molecular mass of 78,975 Da. This enzyme was overexpressed in Escherichia coli BL21(DE3) using a GST-fused pGEX 4T-1 vector system. The optimum conditions of the recombinant BglPC28 were pH 7.0 and 37°C. BglPC28 can effectively transform the ginsenoside Re to Rg2(S); the Km values of PNPG and Re were 6.36±1.10 and 1.42±0.13 mM, respectively, and the Vmax values were 40.0±2.55 and 5.62±0.21 µmol min−1 mg−1 of protein, respectively. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 7.0 and 30°C for 12 hours with a concentration of 20 mg/ml of ginsenoside Re from American ginseng roots. Finally, 113 g of Rg2(S) was produced from 150 g of Re with 84.0±1.1% chromatographic purity. These results suggest that this enzymatic method could be usefully exploited in the preparation of ginsenoside Rg2(S) in the cosmetics, functional food, and pharmaceutical industries.
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Affiliation(s)
- Juan Du
- KAIST Institute for Biocentury, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea
- College of Biotechnology, Dalian Polytechnic University, Ganjingzi-qu, Dalian, P. R. China
| | - Chang-Hao Cui
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea
| | - Sung Chul Park
- Intelligent Synthetic Biology Center, Yuseong-gu, Daejeon, Republic of Korea
| | - Jin-Kwang Kim
- KAIST Institute for Biocentury, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea
| | - Hong-Shan Yu
- College of Biotechnology, Dalian Polytechnic University, Ganjingzi-qu, Dalian, P. R. China
| | - Feng-Xie Jin
- College of Biotechnology, Dalian Polytechnic University, Ganjingzi-qu, Dalian, P. R. China
| | - Changkai Sun
- Institute for Brain Disorders, Dalian Medical University, Dalian, P.R. China
| | - Sun-Chang Kim
- KAIST Institute for Biocentury, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Republic of Korea
- Intelligent Synthetic Biology Center, Yuseong-gu, Daejeon, Republic of Korea
| | - Wan-Taek Im
- Department of Biotechnology, Hankyoung National University, Chungang-no Anseong-si, Republic of Korea
- * E-mail:
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Wall D. Molecular recognition in myxobacterial outer membrane exchange: functional, social and evolutionary implications. Mol Microbiol 2013; 91:209-20. [PMID: 24261719 DOI: 10.1111/mmi.12450] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2013] [Indexed: 01/12/2023]
Abstract
Through cooperative interactions, bacteria can build multicellular communities. To ensure that productive interactions occur, bacteria must recognize their neighbours and respond accordingly. Molecular recognition between cells is thus a fundamental behaviour, and in bacteria important discoveries have been made. This MicroReview focuses on a recently described recognition system in myxobacteria that is governed by a polymorphic cell surface receptor called TraA. TraA regulates outer membrane exchange (OME), whereby myxobacterial cells transiently fuse their OMs to efficiently transfer proteins and lipids between cells. Unlike other transport systems, OME is rather indiscriminate in what OM goods are transferred. In contrast, the recognition of partnering cells is discriminatory and only occurs between cells that bear identical or closely related TraA proteins. Therefore TraA functions in kin recognition and, in turn, OME helps regulate social interactions between myxobacteria. Here, I discuss and speculate on the social and evolutionary implications of OME and suggest it helps to guide their transition from free-living cells into coherent and functional populations.
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Affiliation(s)
- Daniel Wall
- Department of Molecular Biology, University of Wyoming, 1000 E. University Ave., Laramie, WY, 82071, USA
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Molecular recognition by a polymorphic cell surface receptor governs cooperative behaviors in bacteria. PLoS Genet 2013; 9:e1003891. [PMID: 24244178 PMCID: PMC3820747 DOI: 10.1371/journal.pgen.1003891] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/04/2013] [Indexed: 12/17/2022] Open
Abstract
Cell-cell recognition is a fundamental process that allows cells to coordinate multicellular behaviors. Some microbes, such as myxobacteria, build multicellular fruiting bodies from free-living cells. However, how bacterial cells recognize each other by contact is poorly understood. Here we show that myxobacteria engage in recognition through interactions between TraA cell surface receptors, which leads to the fusion and exchange of outer membrane (OM) components. OM exchange is shown to be selective among 17 environmental isolates, as exchange partners parsed into five major recognition groups. TraA is the determinant of molecular specificity because: (i) exchange partners correlated with sequence conservation within its polymorphic PA14-like domain and (ii) traA allele replacements predictably changed partner specificity. Swapping traA alleles also reprogrammed social interactions among strains, including the regulation of motility and conferred immunity from inter-strain killing. We suggest that TraA helps guide the transition of single cells into a coherent bacterial community, by a proposed mechanism that is analogous to mitochondrial fusion and fission cycling that mixes contents to establish a homogenous population. In evolutionary terms, traA functions as a rare greenbeard gene that recognizes others that bear the same allele to confer beneficial treatment.
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Fünfhaus A, Poppinga L, Genersch E. Identification and characterization of two novel toxins expressed by the lethal honey bee pathogen Paenibacillus larvae, the causative agent of American foulbrood. Environ Microbiol 2013; 15:2951-65. [PMID: 23992535 DOI: 10.1111/1462-2920.12229] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 07/16/2013] [Accepted: 07/28/2013] [Indexed: 11/28/2022]
Abstract
Paenibacillus larvae is a Gram-positive bacterial pathogen causing the epizootic American foulbrood in honey bee larvae. Four so-called enterobacterial repetitive intergenic consensus (ERIC) genotypes of P. larvae exist with P. larvae genotypes ERIC I and ERIC II being responsible for disease outbreaks all over the world. Very few molecular data on the pathogen, on pathogenesis or on virulence factors exist. We now identified two genomic loci in P. larvae ERIC I coding for two binary AB toxins, Plx1 and Plx2. In silico analyses revealed that Plx1 is the third member of an enigmatic family of AB toxins so far only comprising MTX1 of Lysinibacillus sphaericus and pierisin-like toxins expressed by several butterflies. Plx2 is also remarkable because the A-domain is highly similar to C3 exoenzymes, which normally are single domain proteins, while the B-domain is homologous to B-domains of C2-toxins. We constructed P. larvae mutants lacking expression of Plx1, Plx2 or both toxins and demonstrated that these toxins are important virulence factors for P. larvae ERIC I.
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Affiliation(s)
- Anne Fünfhaus
- Department of Molecular Microbiology and Bee Diseases, Institute for Bee Research, Friedrich-Engels-Str 32, 16540 Hohen Neuendorf, Germany
| | - Lena Poppinga
- Department of Molecular Microbiology and Bee Diseases, Institute for Bee Research, Friedrich-Engels-Str. 32, 16540, Hohen Neuendorf, Germany
| | - Elke Genersch
- Department of Molecular Microbiology and Bee Diseases, Institute for Bee Research, Friedrich-Engels-Str. 32, 16540, Hohen Neuendorf, Germany
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Andersson KM, Meerupati T, Levander F, Friman E, Ahrén D, Tunlid A. Proteome of the nematode-trapping cells of the fungus Monacrosporium haptotylum. Appl Environ Microbiol 2013; 79:4993-5004. [PMID: 23770896 PMCID: PMC3754708 DOI: 10.1128/aem.01390-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/07/2013] [Indexed: 01/08/2023] Open
Abstract
Many nematophagous fungi use morphological structures called traps to capture nematodes by adhesion or mechanically. To better understand the cellular functions of adhesive traps, the trap cell proteome of the fungus Monacrosporium haptotylum was characterized. The trap of M. haptotylum consists of a unicellular structure called a knob that develops at the apex of a hypha. Proteins extracted from knobs and mycelia were analyzed using SDS-PAGE and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The peptide sequences were matched against predicted gene models from the recently sequenced M. haptotylum genome. In total, 336 proteins were identified, with 54 expressed at significantly higher levels in the knobs than in the mycelia. The upregulated knob proteins included peptidases, small secreted proteins with unknown functions, and putative cell surface adhesins containing carbohydrate-binding domains, including the WSC domain. Phylogenetic analysis showed that all upregulated WSC domain proteins belonged to a large, expanded cluster of paralogs in M. haptotylum. Several peptidases and homologs of experimentally verified proteins in other pathogenic fungi were also upregulated in the knob proteome. Complementary profiling of gene expression at the transcriptome level showed poor correlation between the upregulation of knob proteins and their corresponding transcripts. We propose that the traps of M. haptotylum contain many of the proteins needed in the early stages of infection and that the trap cells can tightly control the translation and degradation of these proteins to minimize the cost of protein synthesis.
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Affiliation(s)
| | | | - Fredrik Levander
- Bioinformatics Infrastructure for Life Sciences, Department of Immunotechnology, Lund University, Lund, Sweden
| | - Eva Friman
- Microbial Ecology, Department of Biology, Lund University, Lund, Sweden
| | - Dag Ahrén
- Microbial Ecology, Department of Biology, Lund University, Lund, Sweden
- Bioinformatics Infrastructure for Life Sciences, Department of Biology, Lund University, Lund, Sweden
| | - Anders Tunlid
- Microbial Ecology, Department of Biology, Lund University, Lund, Sweden
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Ielasi FS, Goyal P, Sleutel M, Wohlkonig A, Willaert RG. The mannose-specific lectin domains of Flo1p from Saccharomyces cerevisiae and Lg-Flo1p from S. pastorianus: crystallization and preliminary X-ray diffraction analysis of the adhesin-carbohydrate complexes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:779-782. [PMID: 23832207 PMCID: PMC3702324 DOI: 10.1107/s1744309113015030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/31/2013] [Indexed: 06/02/2023]
Abstract
Flo1p and Lg-Flo1p are two cell-wall adhesins belonging to the Flo (flocculation) protein family from the yeasts Saccharomyces cerevisiae and S. pastorianus. The main function of these modular proteins endowed with calcium-dependent lectin activity is to mediate cell-cell adhesion events during yeast flocculation, a process which is well known at the cellular level but still not fully characterized from a molecular perspective. Recently, structural features of the N-terminal Flo lectin domains, including the N-terminal domain of Lg-Flo1p (N-Lg-Flo1p), and their interactions with carbohydrate molecules have been investigated. However, structural data concerning the N-terminal domain of Flo1p (N-Flo1p), which is the most specific among the Flo proteins, are missing and information about the N-Lg-Flo1p-carbohydrate interaction still lacks detailed structural insight. Here, the crystallization and preliminary X-ray characterization of the apo form and the mannose complex of N-Flo1p and X-ray analysis of N-Lg-Flo1p crystals soaked in α-1,2-mannobiose are reported. The N-Flo1p crystals diffracted to a resolution of 1.43 Å in the case of the apo form and to 2.12 Å resolution for the mannose complex. Both crystals were orthorhombic and belonged to space group P212121, with one molecule in the asymmetric unit. The N-Lg-Flo1p-α-1,2-mannobiose complex crystal diffracted to 1.73 Å resolution and belonged to the monoclinic space group P1211 with two molecules in the asymmetric unit.
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Affiliation(s)
- Francesco S Ielasi
- Structural Biology Brussels (SBB) - Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
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Zmudka MW, Thoden JB, Holden HM. The structure of DesR from Streptomyces venezuelae, a β-glucosidase involved in macrolide activation. Protein Sci 2013; 22:883-92. [PMID: 23225731 DOI: 10.1002/pro.2204] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 11/26/2012] [Indexed: 11/11/2022]
Abstract
Antibiotics have, indeed, altered the course of human history as is evidenced by the increase in human life expectancy since the 1940s. Many of these natural compounds are produced by bacteria that, by necessity, must have efficient self-resistance mechanisms. The methymycin/pikromycin producing species Streptomyces venezuelae, for example, utilizes β-glucosylation of its macrolide products to neutralize their effects within the confines of the cell. Once released into the environment, these compounds are activated by the removal of the glucose moiety. In S. venezuelae, the enzyme responsible for removal of the sugar from the parent compound is encoded by the desR gene and referred to as DesR. It is a secreted enzyme containing 828 amino acid residues, and it is known to be a retaining glycosidase. Here, we describe the structure of the DesR/D-glucose complex determined to 1.4-Å resolution. The overall architecture of the enzyme can be envisioned in terms of three regions: a catalytic core and two auxiliary domains. The catalytic core harbors the binding platform for the glucose ligand. The first auxiliary domain adopts a "PA14 fold," whereas the second auxiliary domain contains an immunoglobulin-like fold. Asp 273 and Glu 578 are in the proper orientation to function as the catalytic base and proton donor, respectively, required for catalysis. The overall fold of the core region places DesR into the GH3 glycoside hydrolase family of enzymes. Comparison of the DesR structure with the β-glucosidase from Kluyveromyces marxianus shows that their PA14 domains assume remarkably different orientations.
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Affiliation(s)
- Matthew W Zmudka
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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46
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Pathak DT, Wei X, Wall D. Myxobacterial tools for social interactions. Res Microbiol 2012; 163:579-91. [PMID: 23123306 DOI: 10.1016/j.resmic.2012.10.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
Myxobacteria exhibit complex social traits during which large populations of cells coordinate their behaviors. An iconic example is their response to starvation: thousands of cells move by gliding motility to build a fruiting body in which vegetative cells differentiate into spores. Here we review mechanisms that the model species Myxococcus xanthus uses for cell-cell interactions, with a focus on developmental signaling and social gliding motility. We also discuss a newly discovered cell-cell interaction whereby myxobacteria exchange their outer membrane (OM) proteins and lipids. The mechanism of OM transfer requires physical contact between aligned cells on a hard surface and is apparently mediated by OM fusion. The TraA and TraB proteins are required in both donor and recipient cells for transfer, suggesting bidirectional exchange, and TraA is thought to serve as a cell surface adhesin. OM exchange results in phenotypic changes that can alter gliding motility and development and is proposed to represent a novel microbial interacting platform to coordinate multicellular activities.
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Affiliation(s)
- Darshankumar T Pathak
- Department of Molecular Biology, University of Wyoming, 1000 E. University Ave., Laramie, WY 82071, USA.
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Structural basis for promiscuity and specificity during Candida glabrata invasion of host epithelia. Proc Natl Acad Sci U S A 2012; 109:16864-9. [PMID: 23035251 DOI: 10.1073/pnas.1207653109] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The human pathogenic yeast Candida glabrata harbors more than 20 surface-exposed, epithelial adhesins (Epas) for host cell adhesion. The Epa family recognizes host glycans and discriminates between target tissues by their adhesin (A) domains, but a detailed structural basis for ligand-binding specificity of Epa proteins has been lacking so far. In this study, we provide high-resolution crystal structures of the Epa1A domain in complex with different carbohydrate ligands that reveal how host cell mucin-type O-glycans are recognized and allow a structure-guided classification of the Epa family into specific subtypes. Further detailed structural and functional characterization of subtype-switched Epa1 variants shows that specificity is governed by two inner loops, CBL1 and CBL2, involved in calcium binding as well as by three outer loops, L1, L2, and L3. In summary, our study provides the structural basis for promiscuity and specificity of Epa adhesins, which might further contribute to developing anti-adhesive antimycotics and combating Candida colonization.
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Bojsen RK, Andersen KS, Regenberg B. Saccharomyces cerevisiae— a model to uncover molecular mechanisms for yeast biofilm biology. ACTA ACUST UNITED AC 2012; 65:169-82. [DOI: 10.1111/j.1574-695x.2012.00943.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 01/06/2012] [Accepted: 02/09/2012] [Indexed: 01/14/2023]
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Pathak DT, Wei X, Bucuvalas A, Haft DH, Gerloff DL, Wall D. Cell contact-dependent outer membrane exchange in myxobacteria: genetic determinants and mechanism. PLoS Genet 2012; 8:e1002626. [PMID: 22511878 PMCID: PMC3325183 DOI: 10.1371/journal.pgen.1002626] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 02/14/2012] [Indexed: 01/15/2023] Open
Abstract
Biofilms are dense microbial communities. Although widely distributed and medically important, how biofilm cells interact with one another is poorly understood. Recently, we described a novel process whereby myxobacterial biofilm cells exchange their outer membrane (OM) lipoproteins. For the first time we report here the identification of two host proteins, TraAB, required for transfer. These proteins are predicted to localize in the cell envelope; and TraA encodes a distant PA14 lectin-like domain, a cysteine-rich tandem repeat region, and a putative C-terminal protein sorting tag named MYXO-CTERM, while TraB encodes an OmpA-like domain. Importantly, TraAB are required in donors and recipients, suggesting bidirectional transfer. By use of a lipophilic fluorescent dye, we also discovered that OM lipids are exchanged. Similar to lipoproteins, dye transfer requires TraAB function, gliding motility and a structured biofilm. Importantly, OM exchange was found to regulate swarming and development behaviors, suggesting a new role in cell–cell communication. A working model proposes TraA is a cell surface receptor that mediates cell–cell adhesion for OM fusion, in which lipoproteins/lipids are transferred by lateral diffusion. We further hypothesize that cell contact–dependent exchange helps myxobacteria to coordinate their social behaviors. All cells interact with their environment, including other cells, to elicit cellular responses. Cell–cell interactions between eukaryotic cells are widely appreciated as large multicellular organisms coordinate cell behaviors for tissue and organ functions. In bacteria cell–cell interactions are not widely appreciated, as these organisms are relatively simple and are often depicted as single-cell entities. However, over the past decade, the concept of bacteria living in microbial communities or biofilms has received broad acceptance as a major lifestyle. As biofilm cells are packed in tight physical contact, there is an opportunity for cell–cell signaling to provide spatial and physiological clues of neighboring cells to elicit cellular responses. Although much has been learned about diffusible signals through quorum sensing, little is known about cell contact–dependent signaling in bacteria. In this report we describe a new mechanism where bacterial cells within structured biofilms form contacts that allow cellular material to be exchanged. This exchange elicits phenotypic changes, including in cell movements and development. We hypothesize that OM exchange involves kin recognition that bestows social benefits to myxobacterial populations.
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Affiliation(s)
- Darshankumar T. Pathak
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Xueming Wei
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Alex Bucuvalas
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Daniel H. Haft
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Dietlind L. Gerloff
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, United States of America
- * E-mail:
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Ielasi FS, Decanniere K, Willaert RG. The epithelial adhesin 1 (Epa1p) from the human-pathogenic yeast Candida glabrata: structural and functional study of the carbohydrate-binding domain. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:210-7. [PMID: 22349222 DOI: 10.1107/s0907444911054898] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 12/20/2011] [Indexed: 01/18/2023]
Abstract
The yeast Candida glabrata represents the second major cause of clinical candidiasis cases in the world. The ability of this opportunistic pathogen to adhere to human epithelial and endothelial cells relies on the Epa adhesins, a large set of cell-wall proteins whose N-terminal domains are endowed with a calcium-dependent lectin activity. This feature allows the yeast cells to adhere to host cells by establishing multiple interactions with the glycans expressed on their cell membrane. The ligand-binding domain of the Epa1p adhesin, which is one of the best characterized in the Epa family, was expressed in Escherichia coli, purified and crystallized in complex with lactose. Sequence identity with the domain of another yeast adhesin, the Flo5p flocculin from Saccharomyces cerevisiae, was exploited for molecular replacement and the structure of the domain was solved at a resolution of 1.65 Å. The protein is a member of the PA14 superfamily. It has a β-sandwich core and a DcisD calcium-binding motif, which is also present in the binding site of Flo5p. However, Epa1p differs from this homologue by the lack of a Flo5-like subdomain and by a significantly decreased accessibility of the solvent to the binding site, in which a calcium ion still plays an active role in the interactions with carbohydrates. This structural insight, together with fluorescence-assay data, confirms and explains the higher specificity of Epa1p adhesin for glycan molecules compared with the S. cerevisiae flocculins.
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Affiliation(s)
- Francesco S Ielasi
- Research Group Structural Biology Brussels (SBB), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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