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Mojica N, Kersten F, Montserrat-Canals M, Huhn III GR, Tislevoll AM, Cordara G, Teter K, Krengel U. Using Vibrio natriegens for High-Yield Production of Challenging Expression Targets and for Protein Perdeuteration. Biochemistry 2024; 63:587-598. [PMID: 38359344 PMCID: PMC10919088 DOI: 10.1021/acs.biochem.3c00612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 02/17/2024]
Abstract
Production of soluble proteins is essential for structure/function studies; however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium Vibrio natriegens emerged as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from V. natriegens (Vmax X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in Escherichia coli. These proteins include the cholera toxin (CT) and N-acetyl glucosamine-binding protein A (GbpA) from Vibrio cholerae, the heat-labile enterotoxin (LT) from E. coli and the fungal nematotoxin CCTX2 from Coprinopsis cinerea. CT, GbpA, and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in E. coli (6- to 26-fold increase). We also tested Vmax for protein perdeuteration using deuterated minimal media with deuterium oxide as solvent and achieved a 3-fold increase in yield compared to the equivalent protocol in E. coli. This is good news, since isotopic labeling is expensive and often ineffective but represents a necessary prerequisite for some structural biology techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein perdeuteration in amounts suitable for structural biology studies.
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Affiliation(s)
- Natalia Mojica
- Department
of Chemistry, University of Oslo, NO-0315 Blindern, Oslo, Norway
| | - Flore Kersten
- Department
of Chemistry, University of Oslo, NO-0315 Blindern, Oslo, Norway
- Centre
for Molecular Medicine Norway, University
of Oslo, NO-0318 Blindern, Oslo, Norway
| | - Mateu Montserrat-Canals
- Department
of Chemistry, University of Oslo, NO-0315 Blindern, Oslo, Norway
- Centre
for Molecular Medicine Norway, University
of Oslo, NO-0318 Blindern, Oslo, Norway
| | - G. Robb Huhn III
- Burnett
School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32816, United States
| | | | - Gabriele Cordara
- Department
of Chemistry, University of Oslo, NO-0315 Blindern, Oslo, Norway
| | - Ken Teter
- Burnett
School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32816, United States
| | - Ute Krengel
- Department
of Chemistry, University of Oslo, NO-0315 Blindern, Oslo, Norway
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2
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Heinzelbecker J, Fauskanger M, Jonson I, Krengel U, Løset GÅ, Munthe L, Tveita A. Chimeric antigen receptor T cells targeting the GM3(Neu5Gc) ganglioside. Front Immunol 2024; 15:1331345. [PMID: 38370401 PMCID: PMC10869436 DOI: 10.3389/fimmu.2024.1331345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/19/2024] [Indexed: 02/20/2024] Open
Abstract
Chimeric antigen receptor (CAR) T cell technology has ushered in a new era of immunotherapy, enabling the targeting of a broad range of surface antigens, surpassing the limitations of traditional T cell epitopes. Despite the wide range of non-protein tumor-associated antigens, the advancement in crafting CAR T cells for these targets has been limited. Owing to an evolutionary defect in the CMP-Neu5Ac hydroxylase (CMAH) that abolishes the synthesis of CMP-Neu5Gc from CMP-Neu5Ac, Neu5Gc is generally absent in human tissues. Despite this, Neu5Gc-containing antigens, including the ganglioside GM3(Neu5Gc) have consistently been observed on tumor cells across a variety of human malignancies. This restricted expression makes GM3(Neu5Gc) an appealing and highly specific target for immunotherapy. In this study, we designed and evaluated 14F7-28z CAR T cells, with a targeting unit derived from the GM3(Neu5Gc)-specific murine antibody 14F7. These cells exhibited exceptional specificity, proficiently targeting GM3(Neu5Gc)-expressing murine tumor cells in syngeneic mouse models, ranging from B cell malignancies to epithelial tumors, without compromising safety. Notably, human tumor cells enhanced with murine Cmah were effectively targeted and eliminated by the 14F7 CAR T cells. Nonetheless, despite the detectable presence of GM3(Neu5Gc) in unmodified human tumor xenografts, the levels were insufficient to trigger a tumoricidal T-cell response with the current CAR T cell configuration. Overall, our findings highlight the potential of targeting the GM3(Neu5Gc) ganglioside using CAR T cells across a variety of cancers and set the stage for the optimization of 14F7-based therapies for future human clinical application.
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Affiliation(s)
- Julia Heinzelbecker
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
- K.G. Jebsen Centre for B cell malignancies, University of Oslo, Oslo, Norway
| | - Marte Fauskanger
- K.G. Jebsen Centre for B cell malignancies, University of Oslo, Oslo, Norway
| | - Ida Jonson
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Geir Åge Løset
- Department of Biosciences, Faculty of Mathematics and Natural Sciences University of Oslo, Oslo, Norway
- Nextera AS, Oslo, Norway
| | - Ludvig Munthe
- K.G. Jebsen Centre for B cell malignancies, University of Oslo, Oslo, Norway
| | - Anders Tveita
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway
- K.G. Jebsen Centre for B cell malignancies, University of Oslo, Oslo, Norway
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3
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Mojica N, Kersten F, Montserrat-Canals M, Huhn GR, Tislevoll AM, Cordara G, Teter K, Krengel U. Using Vibrio natriegens for high-yield production of challenging expression targets and for protein deuteration. bioRxiv 2023:2023.11.03.565449. [PMID: 37961550 PMCID: PMC10635113 DOI: 10.1101/2023.11.03.565449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Production of soluble proteins is essential for structure/function studies, however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium Vibrio natriegens appeared as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from V. natriegens (Vmax™ X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in Escherichia coli. These proteins include the cholera toxin (CT) and N-acetyl glucosamine binding protein A (GbpA) from Vibrio cholerae, the heat-labile enterotoxin (LT) from E. coli and the fungal nematotoxin CCTX2 from Coprinopsis cinerea. CT, GbpA and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted, and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in E. coli (6- to 26-fold increase). We also tested Vmax for protein deuteration using deuterated minimal media with deuterium oxide as solvent, and achieved a 3-fold increase in yield compared to the equivalent protocol in E. coli. This is good news since isotopic labeling is expensive and often ineffective, but represents a necessary prerequisite for some structural techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein deuteration in amounts suitable for structural biology studies.
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Affiliation(s)
- Natalia Mojica
- Department of Chemistry, University of Oslo, Blindern, Norway
| | - Flore Kersten
- Department of Chemistry, University of Oslo, Blindern, Norway
- Centre for Molecular Medicine Norway, University of Oslo, Blindern, Norway
| | - Mateu Montserrat-Canals
- Department of Chemistry, University of Oslo, Blindern, Norway
- Centre for Molecular Medicine Norway, University of Oslo, Blindern, Norway
| | - G. Robb Huhn
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, U.S.A
| | | | | | - Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, U.S.A
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Blindern, Norway
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4
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Stocker C, Khatanbaatar T, Bressan L, Würth-Roderer K, Cordara G, Krengel U, Kast P. Novel exported fusion enzymes with chorismate mutase and cyclohexadienyl dehydratase activity: Shikimate pathway enzymes teamed up in no man's land. J Biol Chem 2023; 299:105161. [PMID: 37586588 PMCID: PMC10520331 DOI: 10.1016/j.jbc.2023.105161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/29/2023] [Accepted: 08/11/2023] [Indexed: 08/18/2023] Open
Abstract
Chorismate mutase (CM) and cyclohexadienyl dehydratase (CDT) catalyze two subsequent reactions in the intracellular biosynthesis of l-phenylalanine (Phe). Here, we report the discovery of novel and extremely rare bifunctional fusion enzymes, consisting of fused CM and CDT domains, which are exported from the cytoplasm. Such enzymes were found in only nine bacterial species belonging to non-pathogenic γ- or β-Proteobacteria. In γ-proteobacterial fusion enzymes, the CM domain is N-terminal to the CDT domain, whereas the order is inverted in β-Proteobacteria. The CM domains share 15% to 20% sequence identity with the AroQγ class CM holotype of Mycobacterium tuberculosis (∗MtCM), and the CDT domains 40% to 60% identity with the exported monofunctional enzyme of Pseudomonas aeruginosa (PheC). In vitro kinetics revealed a Km <7 μM, much lower than for ∗MtCM, whereas kinetic parameters are similar for CDT domains and PheC. There is no feedback inhibition of CM or CDT by the pathway's end product Phe, and no catalytic benefit of the domain fusion compared with engineered single-domain constructs. The fusion enzymes of Aequoribacter fuscus, Janthinobacterium sp. HH01, and Duganella sacchari were crystallized and their structures refined to 1.6, 1.7, and 2.4 Å resolution, respectively. Neither the crystal structures nor the size-exclusion chromatography show evidence for substrate channeling or higher oligomeric structure that could account for the cooperation of CM and CDT active sites. The genetic neighborhood with genes encoding transporter and substrate binding proteins suggests that these exported bifunctional fusion enzymes may participate in signaling systems rather than in the biosynthesis of Phe.
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Affiliation(s)
- Christian Stocker
- Laboratory of Organic Chemistry, D-CHAB, ETH Zurich, Zurich, Switzerland
| | | | - Luca Bressan
- Laboratory of Organic Chemistry, D-CHAB, ETH Zurich, Zurich, Switzerland
| | | | | | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway.
| | - Peter Kast
- Laboratory of Organic Chemistry, D-CHAB, ETH Zurich, Zurich, Switzerland.
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5
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Sørensen HV, Montserrat-Canals M, Loose JSM, Fisher SZ, Moulin M, Blakeley MP, Cordara G, Bjerregaard-Andersen K, Krengel U. Perdeuterated GbpA Enables Neutron Scattering Experiments of a Lytic Polysaccharide Monooxygenase. ACS Omega 2023; 8:29101-29112. [PMID: 37599915 PMCID: PMC10433351 DOI: 10.1021/acsomega.3c02168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/14/2023] [Indexed: 08/22/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are surface-active redox enzymes that catalyze the degradation of recalcitrant polysaccharides, making them important tools for energy production from renewable sources. In addition, LPMOs are important virulence factors for fungi, bacteria, and viruses. However, many knowledge gaps still exist regarding their catalytic mechanism and interaction with their insoluble, crystalline substrates. Moreover, conventional structural biology techniques, such as X-ray crystallography, usually do not reveal the protonation state of catalytically important residues. In contrast, neutron crystallography is highly suited to obtain this information, albeit with significant sample volume requirements and challenges associated with hydrogen's large incoherent scattering signal. We set out to demonstrate the feasibility of neutron-based techniques for LPMOs using N-acetylglucosamine-binding protein A (GbpA) from Vibrio cholerae as a target. GbpA is a multifunctional protein that is secreted by the bacteria to colonize and degrade chitin. We developed an efficient deuteration protocol, which yields >10 mg of pure 97% deuterated protein per liter expression media, which was scaled up further at international facilities. The deuterated protein retains its catalytic activity and structure, as demonstrated by small-angle X-ray and neutron scattering studies of full-length GbpA and X-ray crystal structures of its LPMO domain (to 1.1 Å resolution), setting the stage for neutron scattering experiments with its substrate chitin.
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Affiliation(s)
- H. V. Sørensen
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | - Mateu Montserrat-Canals
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
- Centre
for Molecular Medicine Norway, University
of Oslo, NO-0318 Oslo, Norway
| | - Jennifer S. M. Loose
- Faculty
of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), NO-1340 Ås, Norway
| | - S. Zoë Fisher
- Science
Directorate, European Spallation Source
ERIC, P.O. Box 176, SE-221 00 Lund, Sweden
- Department
of Biology, Lund University, 35 Sölvegatan, SE-223 62 Lund, Sweden
| | - Martine Moulin
- Life Sciences
Group, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Cedex 9 Grenoble, France
| | - Matthew P. Blakeley
- Large-Scale
Structures Group, Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Gabriele Cordara
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | | | - Ute Krengel
- Department
of Chemistry, University of Oslo, NO-0315 Oslo, Norway
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6
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Askarian F, Tsai CM, Cordara G, Zurich RH, Bjånes E, Golten O, Vinther Sørensen H, Kousha A, Meier A, Chikwati E, Bruun JA, Ludviksen JA, Choudhury B, Trieu D, Davis S, Edvardsen PKT, Mollnes TE, Liu GY, Krengel U, Conrad DJ, Vaaje-Kolstad G, Nizet V. Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against Pseudomonas aeruginosa pneumonia. Proc Natl Acad Sci U S A 2023; 120:e2301538120. [PMID: 37459522 PMCID: PMC10372616 DOI: 10.1073/pnas.2301538120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/30/2023] [Indexed: 07/20/2023] Open
Abstract
Pseudomonas aeruginosa (PA) CbpD belongs to the lytic polysaccharide monooxygenases (LPMOs), a family of enzymes that cleave chitin or related polysaccharides. Here, we demonstrate a virulence role of CbpD in PA pneumonia linked to impairment of host complement function and opsonophagocytic clearance. Following intratracheal challenge, a PA ΔCbpD mutant was more easily cleared and produced less mortality than the wild-type parent strain. The x-ray crystal structure of the CbpD LPMO domain was solved to subatomic resolution (0.75Å) and its two additional domains modeled by small-angle X-ray scattering and Alphafold2 machine-learning algorithms, allowing structure-based immune epitope mapping. Immunization of naive mice with recombinant CbpD generated high IgG antibody titers that promoted human neutrophil opsonophagocytic killing, neutralized enzymatic activity, and protected against lethal PA pneumonia and sepsis. IgG antibodies generated against full-length CbpD or its noncatalytic M2+CBM73 domains were opsonic and protective, even in previously PA-exposed mice, while antibodies targeting the AA10 domain were not. Preexisting antibodies in PA-colonized cystic fibrosis patients primarily target the CbpD AA10 catalytic domain. Further exploration of LPMO family proteins, present across many clinically important and antibiotic-resistant human pathogens, may yield novel and effective vaccine antigens.
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Affiliation(s)
- Fatemeh Askarian
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Chih-Ming Tsai
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Gabriele Cordara
- Department of Chemistry, University of Oslo, N-0315 Oslo, Norway
| | - Raymond H Zurich
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Elisabet Bjånes
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Ole Golten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | | | - Armin Kousha
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Angela Meier
- Division of Critical Care, Department of Anesthesiology, University of California San Diego, La Jolla, CA 92037
| | - Elvis Chikwati
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Jack-Ansgar Bruun
- Proteomics and Metabolomics Core Facility, Department of Medical Biology, The Arctic University of Norway, N-9037 Tromsø, Norway
| | | | - Biswa Choudhury
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093
| | - Desmond Trieu
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
- School of Pharmacy, University of California San Francisco, San Francisco, CA 94143
| | - Stanley Davis
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | | | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, N-8005 Bodø, Norway
- Department of Immunology, University of Oslo Hospital, N-0424 Oslo, Norway
- Center of Molecular Inflammation Research, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - George Y Liu
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
| | - Ute Krengel
- Department of Chemistry, University of Oslo, N-0315 Oslo, Norway
| | - Douglas J Conrad
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, CA 92037
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA 92093
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
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7
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Thorbjørnsrud H, Bressan L, Khatanbaatar T, Carrer M, Würth-Roderer K, Cordara G, Kast P, Cascella M, Krengel U. What Drives Chorismate Mutase to Top Performance? Insights from a Combined In Silico and In Vitro Study. Biochemistry 2023; 62:782-796. [PMID: 36705397 PMCID: PMC9910054 DOI: 10.1021/acs.biochem.2c00635] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Unlike typical chorismate mutases, the enzyme from Mycobacterium tuberculosis (MtCM) has only low activity on its own. Remarkably, its catalytic efficiency kcat/Km can be boosted more than 100-fold by complex formation with a partner enzyme. Recently, an autonomously fully active MtCM variant was generated using directed evolution, and its structure was solved by X-ray crystallography. However, key residues were involved in crystal contacts, challenging the functional interpretation of the structural changes. Here, we address these challenges by microsecond molecular dynamics simulations, followed up by additional kinetic and structural analyses of selected sets of specifically engineered enzyme variants. A comparison of wild-type MtCM with naturally and artificially activated MtCMs revealed the overall dynamic profiles of these enzymes as well as key interactions between the C-terminus and the active site loop. In the artificially evolved variant of this model enzyme, this loop is preorganized and stabilized by Pro52 and Asp55, two highly conserved residues in typical, highly active chorismate mutases. Asp55 stretches across the active site and helps to appropriately position active site residues Arg18 and Arg46 for catalysis. The role of Asp55 can be taken over by another acidic residue, if introduced at position 88 close to the C-terminus of MtCM, as suggested by molecular dynamics simulations and confirmed by kinetic investigations of engineered variants.
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Affiliation(s)
- Helen
V. Thorbjørnsrud
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway
| | - Luca Bressan
- Laboratory
of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Tamjidmaa Khatanbaatar
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway
| | - Manuel Carrer
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway
| | | | - Gabriele Cordara
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway
| | - Peter Kast
- Laboratory
of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland,
| | - Michele Cascella
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway,
| | - Ute Krengel
- Department
of Chemistry, University of Oslo, Oslo 0315, NO, Norway,Hylleraas
Centre for Quantum Molecular Sciences, University
of Oslo, Oslo 0315, NO, Norway,
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8
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Bousquet PA, Manna D, Sandvik JA, Arntzen MØ, Moreno E, Sandvig K, Krengel U. SILAC-based quantitative proteomics and microscopy analysis of cancer cells treated with the N-glycolyl GM3-specific anti-tumor antibody 14F7. Front Immunol 2022; 13:994790. [DOI: 10.3389/fimmu.2022.994790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/20/2022] [Indexed: 11/10/2022] Open
Abstract
Cancer immunotherapy represents a promising approach to specifically target and treat cancer. The most common mechanisms by which monoclonal antibodies kill cells include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity and apoptosis, but also other mechanisms have been described. 14F7 is an antibody raised against the tumor-associated antigen NeuGc GM3, which was previously reported to kill cancer cells without inducing apoptotic pathways. The antibody was reported to induce giant membrane lesions in tumor cells, with apparent changes in the cytoskeleton. Here, we investigated the effect of humanized 14F7 on HeLa cells using stable isotope labeling with amino acids in cell culture (SILAC) in combination with LC-MS and live cell imaging. 14F7 did not kill the HeLa cells, however, it caused altered protein expression (MS data are available via ProteomeXchange with identifier PXD024320). Several cytoskeletal and nucleic-acid binding proteins were found to be strongly down-regulated in response to antibody treatment, suggesting how 14F7 may induce membrane lesions in cells that contain higher amounts of NeuGc GM3. The altered expression profile identified in this study thus contributes to an improved understanding of the unusual killing mechanism of 14F7.
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9
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Skåne A, Edvardsen PK, Cordara G, Loose JSM, Leitl KD, Krengel U, Sørum H, Askarian F, Vaaje-Kolstad G. Chitinolytic enzymes contribute to the pathogenicity of Aliivibrio salmonicida LFI1238 in the invasive phase of cold-water vibriosis. BMC Microbiol 2022; 22:194. [PMID: 35941540 PMCID: PMC9361615 DOI: 10.1186/s12866-022-02590-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/27/2022] [Indexed: 11/26/2022] Open
Abstract
Background Aliivibrio salmonicida is the causative agent of cold-water vibriosis in salmonids (Oncorhynchus mykiss and Salmo salar L.) and gadidae (Gadus morhua L.). Virulence-associated factors that are essential for the full spectrum of A. salmonicida pathogenicity are largely unknown. Chitin-active lytic polysaccharide monooxygenases (LPMOs) have been indicated to play roles in both chitin degradation and virulence in a variety of pathogenic bacteria but are largely unexplored in this context. Results In the present study we investigated the role of LPMOs in the pathogenicity of A. salmonicida LFI238 in Atlantic salmon (Salmo salar L.). In vivo challenge experiments using isogenic deletion mutants of the two LPMOs encoding genes AsLPMO10A and AsLPMO10B, showed that both LPMOs, and in particular AsLPMO10B, were important in the invasive phase of cold-water vibriosis. Crystallographic analysis of the AsLPMO10B AA10 LPMO domain (to 1.4 Å resolution) revealed high structural similarity to viral fusolin, an LPMO known to enhance the virulence of insecticidal agents. Finally, exposure to Atlantic salmon serum resulted in substantial proteome re-organization of the A. salmonicida LPMO deletion variants compared to the wild type strain, indicating the struggle of the bacterium to adapt to the host immune components in the absence of the LPMOs. Conclusion The present study consolidates the role of LPMOs in virulence and demonstrates that such enzymes may have more than one function.
Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02590-2.
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Affiliation(s)
- Anna Skåne
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Per Kristian Edvardsen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Gabriele Cordara
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Jennifer Sarah Maria Loose
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kira Daryl Leitl
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Henning Sørum
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Fatemeh Askarian
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, School of Medicine, UC San Diego, La Jolla, San Diego, CA, USA.
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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10
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Bousquet PA, Sandvik JA, Edin NFJ, Krengel U. Corrigendum to: Hypothesis: Hypoxia induces de novo synthesis of NeuGc gangliosides in humans through CMAH domain substitute. Biochem Biophys Res Commun 2022; 587:166. [PMID: 34865824 DOI: 10.1016/j.bbrc.2021.11.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Paula A Bousquet
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315, Oslo, Norway.
| | - Joe Alexander Sandvik
- Department of Physics, University of Oslo, P.O. Box 1048, Blindern, NO-0315, Oslo, Norway
| | - Nina F Jeppesen Edin
- Department of Physics, University of Oslo, P.O. Box 1048, Blindern, NO-0315, Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315, Oslo, Norway
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11
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Bjerregaard-Andersen K, Abraha F, Johannesen H, Oscarson S, Moreno E, Krengel U. Key role of a structural water molecule for the specificity of 14F7-An antitumor antibody targeting the NeuGc GM3 ganglioside. Glycobiology 2021; 31:1500-1509. [PMID: 34735569 PMCID: PMC8684480 DOI: 10.1093/glycob/cwab076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/19/2021] [Accepted: 06/28/2021] [Indexed: 12/22/2022] Open
Abstract
Tumor-associated glycolipids such as NeuGc GM3 are auspicious molecular targets in antineoplastic therapies and vaccine strategies. 14F7 is a monoclonal IgG1 with high clinical potential in cancer immunotherapy as it displays extraordinary specificity for NeuGc GM3, while it does not recognize the very similar, ubiquitous NeuAc GM3. Here we present the 2.3 Å crystal structure of the 14F7 antigen-binding domain (14F7 scFv) in complex with the NeuGc GM3 trisaccharide. Modeling analysis and previous mutagenesis data suggest that 14F7 may also bind to an alternative NeuGc GM3 conformation, not observed in the crystal structure. The most intriguing finding, however, was that a water molecule centrally placed in the complementarity-determining region directly mediates the specificity of 14F7 to NeuGc GM3. This has profound impact on the complexity of engineering in the binding site and provides an excellent example of the importance in understanding the water structure in antibody-antigen interactions.
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Affiliation(s)
| | - Fana Abraha
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.,Recipharm OT Chemistry, Uppsala, Sweden
| | - Hedda Johannesen
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway.,Department of Biosciences, University of Oslo, NO-0316 Oslo, Norway
| | - Stefan Oscarson
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ernesto Moreno
- Facultad de Ciencias Básicas, Universidad de Medellín, Medellín 050026, Colombia
| | - Ute Krengel
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway
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12
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Askarian F, Uchiyama S, Masson H, Sørensen HV, Golten O, Bunæs AC, Mekasha S, Røhr ÅK, Kommedal E, Ludviksen JA, Arntzen MØ, Schmidt B, Zurich RH, van Sorge NM, Eijsink VGH, Krengel U, Mollnes TE, Lewis NE, Nizet V, Vaaje-Kolstad G. The lytic polysaccharide monooxygenase CbpD promotes Pseudomonas aeruginosa virulence in systemic infection. Nat Commun 2021; 12:1230. [PMID: 33623002 PMCID: PMC7902821 DOI: 10.1038/s41467-021-21473-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 01/29/2021] [Indexed: 12/20/2022] Open
Abstract
The recently discovered lytic polysaccharide monooxygenases (LPMOs), which cleave polysaccharides by oxidation, have been associated with bacterial virulence, but supporting functional data is scarce. Here we show that CbpD, the LPMO of Pseudomonas aeruginosa, is a chitin-oxidizing virulence factor that promotes survival of the bacterium in human blood. The catalytic activity of CbpD was promoted by azurin and pyocyanin, two redox-active virulence factors also secreted by P. aeruginosa. Homology modeling, molecular dynamics simulations, and small angle X-ray scattering indicated that CbpD is a monomeric tri-modular enzyme with flexible linkers. Deletion of cbpD rendered P. aeruginosa unable to establish a lethal systemic infection, associated with enhanced bacterial clearance in vivo. CbpD-dependent survival of the wild-type bacterium was not attributable to dampening of pro-inflammatory responses by CbpD ex vivo or in vivo. Rather, we found that CbpD attenuates the terminal complement cascade in human serum. Studies with an active site mutant of CbpD indicated that catalytic activity is crucial for virulence function. Finally, profiling of the bacterial and splenic proteomes showed that the lack of this single enzyme resulted in substantial re-organization of the bacterial and host proteomes. LPMOs similar to CbpD occur in other pathogens and may have similar immune evasive functions.
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Affiliation(s)
- Fatemeh Askarian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
| | - Satoshi Uchiyama
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Helen Masson
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA, USA
| | | | - Ole Golten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anne Cathrine Bunæs
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Sophanit Mekasha
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Åsmund Kjendseth Røhr
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Eirik Kommedal
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Benjamin Schmidt
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Raymond H Zurich
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Netherlands Reference Laboratory for Bacterial Meningitis, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, Bodø, Norway
- K.G. Jebsen TREC, Faculty of Health Sciences, UiT- The Arctic University of Norway, Tromsø, Norway
- Department of Immunology, Oslo University Hospital, and K.G. Jebsen IRC, University of Oslo, Oslo, Norway
- Center of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nathan E Lewis
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA, USA
- Novo Nordisk Foundation Center for Biosustainability at UC San Diego, University of California, San Diego, School of Medicine, La Jolla, CA, USA
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA.
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, CA, USA.
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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13
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Fahrig-Kamarauskait J, Würth-Roderer K, Thorbjørnsrud HV, Mailand S, Krengel U, Kast P. Evolving the naturally compromised chorismate mutase from Mycobacterium tuberculosis to top performance. J Biol Chem 2020; 295:17514-17534. [PMID: 33453995 PMCID: PMC7762937 DOI: 10.1074/jbc.ra120.014924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/08/2020] [Indexed: 11/06/2022] Open
Abstract
Chorismate mutase (CM), an essential enzyme at the branch-point of the shikimate pathway, is required for the biosynthesis of phenylalanine and tyrosine in bacteria, archaea, plants, and fungi. MtCM, the CM from Mycobacterium tuberculosis, has less than 1% of the catalytic efficiency of a typical natural CM and requires complex formation with 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase for high activity. To explore the full potential of MtCM for catalyzing its native reaction, we applied diverse iterative cycles of mutagenesis and selection, thereby raising kcat/Km 270-fold to 5 × 105m−1s−1, which is even higher than for the complex. Moreover, the evolutionarily optimized autonomous MtCM, which had 11 of its 90 amino acids exchanged, was stabilized compared with its progenitor, as indicated by a 9 °C increase in melting temperature. The 1.5 Å crystal structure of the top-evolved MtCM variant reveals the molecular underpinnings of this activity boost. Some acquired residues (e.g. Pro52 and Asp55) are conserved in naturally efficient CMs, but most of them lie beyond the active site. Our evolutionary trajectories reached a plateau at the level of the best natural enzymes, suggesting that we have exhausted the potential of MtCM. Taken together, these findings show that the scaffold of MtCM, which naturally evolved for mediocrity to enable inter-enzyme allosteric regulation of the shikimate pathway, is inherently capable of high activity.
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Affiliation(s)
| | | | | | - Susanne Mailand
- Laboratory of Organic Chemistry, ETH Zurich, Zurich, Switzerland
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway.
| | - Peter Kast
- Laboratory of Organic Chemistry, ETH Zurich, Zurich, Switzerland.
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14
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Manna D, Cordara G, Krengel U. Crystal structure of MOA in complex with a peptide fragment: A protease caught in flagranti. Curr Res Struct Biol 2020; 2:56-67. [PMID: 34235469 PMCID: PMC8244254 DOI: 10.1016/j.crstbi.2020.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/28/2020] [Accepted: 04/06/2020] [Indexed: 11/20/2022] Open
Abstract
The Marasmius oreades agglutinin (MOA) is the holotype of an emerging family of fungal chimerolectins and an active Ca2+/Mn2+-dependent protease, which exhibits a unique papain-like fold with special active site features. Here we investigated the functional significance of the structural elements differentiating MOA from other papain-like cysteine proteases. X-ray crystal structures of MOA co-crystallized with two synthetic substrates reveal cleaved peptides bound to the catalytic site, corresponding to the final products of the proteolytic reaction. Anomalous diffraction data on crystals grown in the presence of calcium and manganese, cadmium or zinc resolve the calcium/manganese preference of MOA and elucidate the inhibitory roles of zinc and cadmium towards papain-like cysteine proteases in general. The reported structures, together with activity data of MOA active site variants, point to a conservation of the general proteolysis mechanism established for papain. Ultimately, the findings suggest that papain and the papain-like domain of MOA are the product of convergent evolution.
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Affiliation(s)
- Dipankar Manna
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315, Oslo, Norway
| | - Gabriele Cordara
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315, Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315, Oslo, Norway
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15
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Johannesen H, Bjerregaard-Andersen K, Heggelund J, Løset GÅ, Krengel U. Crystal structure of an anti-tumour antibody in complex with a tumour-specific antigen. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s2053273319095007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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16
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Abstract
Fungi and plants do not have an adaptive immune system. Innate immunity serves as their sole defense, often based on carbohydrate recognition by lectins. In a twist of nature, as revealed by Sommer et al. (2018) in this issue of Structure, a conserved fungal immunoprotein adopts the shape of a miniature virus.
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Affiliation(s)
- Gabriele Cordara
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220 Oulu, Finland
| | | | - Ute Krengel
- Department of Chemistry, University of Oslo, 0315 Oslo, Norway.
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17
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Krengel U. Cholera toxin: molecular mechanisms and drug design. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318097520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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18
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Bjerregaard-Andersen K, Johannesen H, Abdel-Rahman N, Heggelund JE, Hoås HM, Abraha F, Bousquet PA, Høydahl LS, Burschowsky D, Rojas G, Oscarson S, Løset GÅ, Krengel U. Crystal structure of an L chain optimised 14F7 anti-ganglioside Fv suggests a unique tumour-specificity through an unusual H-chain CDR3 architecture. Sci Rep 2018; 8:10836. [PMID: 30022069 PMCID: PMC6052152 DOI: 10.1038/s41598-018-28918-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/28/2018] [Indexed: 12/13/2022] Open
Abstract
Targeted cancer immunotherapy offers increased efficacy concomitantly with reduced side effects. One antibody with promising clinical potential is 14F7, which specifically recognises the NeuGc GM3 ganglioside. This antigen is found in the plasma membrane of a range of tumours, but is essentially absent from healthy human cells. 14F7 can discriminate NeuGc GM3 from the very similar NeuAc GM3, a common component of cell membranes. The molecular basis for this unique specificity is poorly understood. Here we designed and expressed 14F7-derived single-chain Fvs (scFvs), which retained the specificity of the parent antibody. Detailed expression and purification protocols are described as well as the synthesis of the NeuGc GM3 trisaccharide. The most successful scFv construct, which comprises an alternative variable light chain (VLA), allowed structure determination to 2.2 Å resolution. The structure gives insights into the conformation of the important CDR H3 loop and the suspected antigen binding site. Furthermore, the presence of VLA instead of the original VL elucidates how this subdomain indirectly stabilises the CDR H3 loop. The current work may serve as a guideline for the efficient production of scFvs for structure determination.
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Affiliation(s)
| | - Hedda Johannesen
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | - Noha Abdel-Rahman
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway.,Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Julie Elisabeth Heggelund
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway.,School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | | | - Fana Abraha
- School of Chemistry, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Paula A Bousquet
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway
| | - Lene Støkken Høydahl
- Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital, NO-0372 Oslo, Norway
| | - Daniel Burschowsky
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway.,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, LE1 7HB, UK
| | - Gertrudis Rojas
- Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, La Habana, CP, 11300, Cuba
| | - Stefan Oscarson
- School of Chemistry, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Geir Åge Løset
- Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital, NO-0372 Oslo, Norway. .,Department of Biosciences, University of Oslo, NO-0316 Oslo, Norway. .,Nextera AS, NO-0349 Oslo, Norway.
| | - Ute Krengel
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway.
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19
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Burschowsky D, Thorbjørnsrud HV, Heim JB, Fahrig-Kamarauskaitė JR, Würth-Roderer K, Kast P, Krengel U. Inter-Enzyme Allosteric Regulation of Chorismate Mutase in Corynebacterium glutamicum: Structural Basis of Feedback Activation by Trp. Biochemistry 2017; 57:557-573. [PMID: 29178787 DOI: 10.1021/acs.biochem.7b01018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Corynebacterium glutamicum is widely used for the industrial production of amino acids, nucleotides, and vitamins. The shikimate pathway enzymes DAHP synthase (CgDS, Cg2391) and chorismate mutase (CgCM, Cgl0853) play a key role in the biosynthesis of aromatic compounds. Here we show that CgCM requires the formation of a complex with CgDS to achieve full activity, and that both CgCM and CgDS are feedback regulated by aromatic amino acids binding to CgDS. Kinetic analysis showed that Phe and Tyr inhibit CgCM activity by inter-enzyme allostery, whereas binding of Trp to CgDS strongly activates CgCM. Mechanistic insights were gained from crystal structures of the CgCM homodimer, tetrameric CgDS, and the heterooctameric CgCM-CgDS complex, refined to 1.1, 2.5, and 2.2 Å resolution, respectively. Structural details from the allosteric binding sites reveal that DAHP synthase is recruited as the dominant regulatory platform to control the shikimate pathway, similar to the corresponding enzyme complex from Mycobacterium tuberculosis.
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Affiliation(s)
| | | | - Joel B Heim
- Department of Chemistry, University of Oslo , NO-0315 Oslo, Norway
| | | | | | - Peter Kast
- Laboratory of Organic Chemistry, ETH Zurich , CH-8093 Zurich, Switzerland
| | - Ute Krengel
- Department of Chemistry, University of Oslo , NO-0315 Oslo, Norway
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20
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Bousquet PA, Sandvik JA, Jeppesen Edin NF, Krengel U. Hypothesis: Hypoxia induces de novo synthesis of NeuGc gangliosides in humans through CMAH domain substitute. Biochem Biophys Res Commun 2017; 495:1562-1566. [PMID: 29196263 DOI: 10.1016/j.bbrc.2017.11.183] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 11/28/2017] [Indexed: 12/27/2022]
Abstract
Immunotherapy is a growing field in cancer research. A privileged tumor-associated antigen that has received much attention is N-glycolyl (NeuGc) GM3. This ganglioside is present in several types of cancer, but is almost undetectable in human healthy tissues. However, its non-hydroxylated variant, NeuAc GM3, is abundant in all mammals. Due to a deletion in the human gene encoding the key enzyme for synthesis of NeuGc, humans, in contrast to other mammals, cannot synthesize NeuGc GM3. Therefore the presence of this ganglioside in human cancer cells represents an enigma. It has been shown that hypoxic conditions trigger the expression of NeuGc gangliosides, which not only serve as attractive targets for cancer therapy, but also as diagnostic and prognostic tumor marker. Here, we confirm hypoxia-induced expression of the NeuGc GM3 ganglioside also in HeLa cells and reveal several candidate proteins, in particular GM3 synthase and subunit B of respiratory complex II (SDHB), that may be involved in the generation of NeuGc GM3 by SILAC-based proteome analysis. These findings have the potential to significantly advance our understanding of how this enigmatic tumor-associated antigen is produced in humans, and also suggest a possible mechanism of action of anti-tumor antibodies that recognize hypoxia markers, such as 14F7.
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Affiliation(s)
- Paula A Bousquet
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway.
| | - Joe Alexander Sandvik
- Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0315 Oslo, Norway
| | - Nina F Jeppesen Edin
- Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0315 Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway.
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21
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Affiliation(s)
- Gabriele Cordara
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Dipankar Manna
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
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22
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Heggelund JE, Mackenzie A, Martinsen T, Heim JB, Cheshev P, Bernardi A, Krengel U. Towards new cholera prophylactics and treatment: Crystal structures of bacterial enterotoxins in complex with GM1 mimics. Sci Rep 2017; 7:2326. [PMID: 28539625 PMCID: PMC5443773 DOI: 10.1038/s41598-017-02179-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/07/2017] [Indexed: 01/08/2023] Open
Abstract
Cholera is a life-threatening disease in many countries, and new drugs are clearly needed. C-glycosidic antagonists may serve such a purpose. Here we report atomic-resolution crystal structures of three such compounds in complexes with the cholera toxin. The structures give unprecedented atomic details of the molecular interactions and show how the inhibitors efficiently block the GM1 binding site. These molecules are well suited for development into low-cost prophylactic drugs, due to their relatively easy synthesis and their resistance to glycolytic enzymes. One of the compounds links two toxin B-pentamers in the crystal structure, which may yield improved inhibition through the formation of toxin aggregates. These structures can spark the improved design of GM1 mimics, either alone or as multivalent inhibitors connecting multiple GM1-binding sites. Future developments may further include compounds that link the primary and secondary binding sites. Serving as decoys, receptor mimics may lessen symptoms while avoiding the use of antibiotics.
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Affiliation(s)
- Julie Elisabeth Heggelund
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315, Blindern, Norway. .,School of Biomedical Sciences, University of Leeds, LS2 9JT Leeds, UK and School of Pharmacy, University of Oslo, P.O. Box 1068, NO-0316, Blindern, Norway.
| | - Alasdair Mackenzie
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315, Blindern, Norway.,Alere Technologies AS, Kjelsåsveien 161, NO-0884, Oslo, Norway
| | - Tobias Martinsen
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315, Blindern, Norway
| | - Joel Benjamin Heim
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315, Blindern, Norway
| | - Pavel Cheshev
- Universita' degli Studi di Milano, Dipartimento di Chimica, via Golgi 19, 20133, Milano, Italy.,Skolkovo innovation center, Office 229, OC Technopark bld. 2, Lugovaya str. 4, 143026, Moscow, Russia
| | - Anna Bernardi
- Universita' degli Studi di Milano, Dipartimento di Chimica, via Golgi 19, 20133, Milano, Italy
| | - Ute Krengel
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315, Blindern, Norway.
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23
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Heggelund JE, Varrot A, Imberty A, Krengel U. Histo-blood group antigens as mediators of infections. Curr Opin Struct Biol 2017; 44:190-200. [PMID: 28544984 DOI: 10.1016/j.sbi.2017.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 01/07/2023]
Abstract
The critical first step of a microbial infection is usually the attachment of pathogens to host cell glycans. Targets on host tissues are in particular the histo-blood group antigens (HBGAs), which are present in rich diversity in the mucus layer and on the underlying mucosa. Recent structural and functional studies have revealed significant new insight into the molecular mechanisms, explaining why individuals with certain blood groups are at increased risk of some infections. The most prominent example of blood-group-associated diseases is cholera, caused by infection with Vibrio cholerae. Many other microbial pathogens, for example Pseudomonas aeruginosa infecting the airways, and enterotoxigenic Escherichia coli (ETEC) causing traveler's diarrhea, also bind to histo-blood group antigens, but show a less clear correlation with blood group phenotype. Yet other pathogens, for example norovirus and Helicobacter pylori, recognize HBGAs differently depending on the strain. In all cases, milk oligosaccharides can aid the hosts' defenses, acting as natural receptor decoys, and anti-infectious therapy can be designed along similar strategies. In this review, we focus on important infections of humans, but the molecular mechanisms are of general relevance to a broad range of microbial infections of humans and animals.
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Affiliation(s)
- Julie E Heggelund
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315 Blindern, Norway
| | - Annabelle Varrot
- Centre de Recherches sur les Macromolécules Végétales (CERMAV), CNRS and Université Grenoble Alpes, 38000 Grenoble, France
| | - Anne Imberty
- Centre de Recherches sur les Macromolécules Végétales (CERMAV), CNRS and Université Grenoble Alpes, 38000 Grenoble, France
| | - Ute Krengel
- Department of Chemistry, University of Oslo, P.O. Box 1033, NO-0315 Blindern, Norway.
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24
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Burschowsky D, Krengel U, Uggerud E, Balcells D. Quantum chemical modeling of the reaction path of chorismate mutase based on the experimental substrate/product complex. FEBS Open Bio 2017; 7:789-797. [PMID: 28593134 PMCID: PMC5458464 DOI: 10.1002/2211-5463.12224] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 02/26/2017] [Accepted: 03/22/2017] [Indexed: 11/10/2022] Open
Abstract
Chorismate mutase is a well-known model enzyme, catalyzing the Claisen rearrangement of chorismate to prephenate. Recent high-resolution crystal structures along the reaction coordinate of this enzyme enabled computational analyses at unprecedented detail. Using quantum chemical simulations, we investigated how the catalytic reaction mechanism is affected by electrostatic and hydrogen-bond interactions. Our calculations showed that the transition state (TS) was mainly stabilized electrostatically, with Arg90 playing the leading role. The effect was augmented by selective hydrogen-bond formation to the TS in the wild-type enzyme, facilitated by a small-scale local induced fit. We further identified a previously underappreciated water molecule, which separates the negative charges during the reaction. The analysis includes the wild-type enzyme and a non-natural enzyme variant, where the catalytic arginine was replaced with an isosteric citrulline residue.
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Affiliation(s)
- Daniel Burschowsky
- Department of Chemistry University of Oslo Norway.,Present address: Leicester Institute of Structural and Chemical Biology University of Leicester Leicester UK
| | - Ute Krengel
- Department of Chemistry University of Oslo Norway
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Hatlem D, Heggelund JE, Burschowsky D, Krengel U, Kristiansen PE. 1H, 13C, 15N backbone assignment of the human heat-labile enterotoxin B-pentamer and chemical shift mapping of neolactotetraose binding. Biomol NMR Assign 2017; 11:99-104. [PMID: 28243889 DOI: 10.1007/s12104-017-9728-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/16/2017] [Indexed: 06/06/2023]
Abstract
The major virulence factor of enterotoxigenic Escherichia coli is the heat-labile enterotoxin (LT), an AB5 toxin closely related to the cholera toxin. LT consists of six subunits, the catalytically active A-subunit and five B-subunits arranged as a pentameric ring (LTB), which enable the toxin to bind to the epithelial cells in the intestinal lumen. LTB has two recognized binding sites; the primary binding site is responsible for anchoring the toxin to its main receptor, the GM1-ganglioside, while the secondary binding site recognizes blood group antigens. Herein, we report the 1H, 13C, 15N main chain assignment of LTB from human isolates (hLTB; 103 a.a. per subunit, with a total molecular mass of 58.5 kDa). The secondary structure was predicted based on 13C', 13Cα, 13Cβ, 1HN and 15N chemical shifts and compared to a published crystal structure of LTB. Neolactotetraose (NEO) was titrated to hLTB and chemical shift perturbations were measured. The chemical shift perturbations were mapped onto the crystal structure, confirming that NEO binds to the primary binding site of hLTB and competes with GM1-binding. Our new data further lend support to the hypothesis that binding at the primary binding site is transmitted to the secondary binding site of the toxin, where it may influence the binding to blood group antigens.
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Affiliation(s)
- Daniel Hatlem
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, 0315, Oslo, Norway
- Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, 0316, Oslo, Norway
| | - Julie E Heggelund
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, 0315, Oslo, Norway
- School of Pharmacy, University of Oslo, Blindern, P.O. Box 1068, 0316, Oslo, Norway
| | - Daniel Burschowsky
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, 0315, Oslo, Norway
- Department of Molecular and Cell Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, 0315, Oslo, Norway.
| | - Per E Kristiansen
- Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, 0316, Oslo, Norway.
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Manna D, Pust S, Torgersen ML, Cordara G, Künzler M, Krengel U, Sandvig K. Polyporus squamosus Lectin 1a (PSL1a) Exhibits Cytotoxicity in Mammalian Cells by Disruption of Focal Adhesions, Inhibition of Protein Synthesis and Induction of Apoptosis. PLoS One 2017; 12:e0170716. [PMID: 28114329 PMCID: PMC5256987 DOI: 10.1371/journal.pone.0170716] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/09/2017] [Indexed: 11/18/2022] Open
Abstract
PSL1a is a lectin from the mushroom Polyporus squamosus that binds to sialylated glycans and glycoconjugates with high specificity and selectivity. In addition to its N-terminal carbohydrate-binding domain, PSL1a possesses a Ca2+-dependent proteolytic activity in the C-terminal domain. In the present study, we demonstrate that PSL1a has cytotoxic effects on mammalian cancer cells, and we show that the cytotoxicity is dependent on the cysteine protease activity. PSL1a treatment leads to cell rounding and detachment from the substratum, concomitant with disruption of vinculin complexes in focal adhesions. We also demonstrate that PSL1a inhibits protein synthesis and induces apoptosis in HeLa cells, in a time- and concentration-dependent manner.
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Affiliation(s)
- Dipankar Manna
- Department of Chemistry, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Sascha Pust
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Maria L. Torgersen
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | | | - Markus Künzler
- Institute of Microbiology, ETH Zürich, Zürich, Switzerland
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway
- * E-mail: (UK); (KS)
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
- * E-mail: (UK); (KS)
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Cordara G, van Eerde A, Grahn EM, Winter HC, Goldstein IJ, Krengel U. An Unusual Member of the Papain Superfamily: Mapping the Catalytic Cleft of the Marasmius oreades agglutinin (MOA) with a Caspase Inhibitor. PLoS One 2016; 11:e0149407. [PMID: 26901797 PMCID: PMC4764322 DOI: 10.1371/journal.pone.0149407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/01/2016] [Indexed: 11/18/2022] Open
Abstract
Papain-like cysteine proteases (PLCPs) constitute the largest group of thiol-based protein degrading enzymes and are characterized by a highly conserved fold. They are found in bacteria, viruses, plants and animals and involved in a number of physiological and pathological processes, parasitic infections and host defense, making them interesting targets for drug design. The Marasmius oreades agglutinin (MOA) is a blood group B-specific fungal chimerolectin with calcium-dependent proteolytic activity. The proteolytic domain of MOA presents a unique structural arrangement, yet mimicking the main structural elements in known PLCPs. Here we present the X-ray crystal structure of MOA in complex with Z-VAD-fmk, an irreversible caspase inhibitor known to cross-react with PLCPs. The structural data allow modeling of the substrate binding geometry and mapping of the fundamental enzyme-substrate interactions. The new information consolidates MOA as a new, yet strongly atypical member of the papain superfamily. The reported complex is the first published structure of a PLCP in complex with the well characterized caspase inhibitor Z-VAD-fmk.
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Affiliation(s)
- Gabriele Cordara
- Department of Chemistry, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | | | - Elin M. Grahn
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Harry C. Winter
- Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Irwin J. Goldstein
- Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway
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Burschowsky D, Balcells D, Uggerud E, Kast P, Krengel U. The effects of electrostatic interactions and side-chain stabilization during chorismate mutase-catalyzed Claisen rearrangements. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315096874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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van Eerde A, Grahn EM, Winter HC, Goldstein IJ, Krengel U. Atomic-resolution structure of the -galactosyl binding Lyophyllum decastes lectin reveals a new protein family found in both fungi and plants. Glycobiology 2014; 25:492-501. [DOI: 10.1093/glycob/cwu136] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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31
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Abstract
Gangliosides are sialic-acid-containing glycosphingolipids expressed on all vertebrate cells. They are primarily positioned in the plasma membrane with the ceramide part anchored in the membrane and the glycan part exposed on the surface of the cell. These lipids have highly diverse structures, not the least with respect to their carbohydrate chains, with N-acetylneuraminic acid (NeuAc) and N-glycolylneuraminic acid (NeuGc) being the two most common sialic-acid residues in mammalian cells. Generally, human healthy tissue is deficient in NeuGc, but this molecule is expressed in tumors and in human fetal tissues, and was hence classified as an onco-fetal antigen. Gangliosides perform important functions through carbohydrate-specific interactions with proteins, for example, as receptors in cell–cell recognition, which can be exploited by viruses and other pathogens, and also by regulating signaling proteins, such as the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor receptor (VEGFR), through lateral interaction in the membrane. Through both mechanisms, tumor-associated gangliosides may affect malignant progression, which makes them attractive targets for cancer immunotherapies. In this review, we describe how proteins recognize gangliosides, focusing on the molecular recognition of gangliosides associated with cancer immunotherapy, and discuss the importance of these molecules in cancer research.
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Affiliation(s)
- Ute Krengel
- Department of Chemistry, University of Oslo , Oslo , Norway
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Vasile F, Reina JJ, Potenza D, Heggelund JE, Mackenzie A, Krengel U, Bernardi A. Comprehensive analysis of blood group antigen binding to classical and El Tor cholera toxin B-pentamers by NMR. Glycobiology 2014; 24:766-78. [PMID: 24829308 DOI: 10.1093/glycob/cwu040] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cholera is a diarrheal disease responsible for the deaths of thousands, possibly even hundreds of thousands of people every year, and its impact is predicted to further increase with climate change. It has been known for decades that blood group O individuals suffer more severe symptoms of cholera compared with individuals with other blood groups (A, B and AB). The observed blood group dependence is likely to be caused by the major virulence factor of Vibrio cholerae, the cholera toxin (CT). Here, we investigate the binding of ABH blood group determinants to both classical and El Tor CTB-pentamers using saturation transfer difference NMR and show that all three blood group determinants bind to both toxin variants. Although the details of the interactions differ, we see no large differences between the two toxin genotypes and observe very similar binding constants. We also show that the blood group determinants bind to a site distinct from that of the primary receptor, GM1. Transferred NOESY data confirm that the conformations of the blood group determinants in complex with both toxin variants are similar to those of reported X-ray and solution structures. Taken together, this detailed analysis provides a framework for the interpretation of the epidemiological data linking the severity of cholera infection and an individual's blood group, and brings us one step closer to understanding the molecular basis of cholera blood group dependence.
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Affiliation(s)
- Francesca Vasile
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - José J Reina
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - Donatella Potenza
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - Julie E Heggelund
- Department of Chemistry, University of Oslo, PO Box 1033, Blindern NO-0315, Norway
| | - Alasdair Mackenzie
- Department of Chemistry, University of Oslo, PO Box 1033, Blindern NO-0315, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, PO Box 1033, Blindern NO-0315, Norway
| | - Anna Bernardi
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
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Cordara G, Winter HC, Goldstein IJ, Krengel U, Sandvig K. The fungal chimerolectin MOA inhibits protein and DNA synthesis in NIH/3T3 cells and may induce BAX-mediated apoptosis. Biochem Biophys Res Commun 2014; 447:586-9. [PMID: 24747075 DOI: 10.1016/j.bbrc.2014.04.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 04/08/2014] [Indexed: 01/23/2023]
Abstract
The Marasmius oreades mushroom agglutinin (MOA) is a blood group B-specific lectin carrying an active proteolytic domain. Its enzymatic activity has recently been shown to be critical for toxicity of MOA toward the fungivorous soil nematode Caenorhabditis elegans. Here we present evidence that MOA also induces cytotoxicity in a cellular model system (murine NIH/3T3 cells), by inhibiting protein synthesis, and that cytotoxicity correlates, at least in part, with proteolytic activity. A peptide-array screen identified the apoptosis mediator BAX as a potential proteolytic substrate and further suggests a variety of bacterial and fungal peptides as potential substrates. These findings are in line with the suggestion that MOA and related proteases may play a role for host defense.
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Affiliation(s)
- Gabriele Cordara
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway; Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Harry C Winter
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-0606, USA
| | - Irwin J Goldstein
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109-0606, USA
| | - Ute Krengel
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway.
| | - Kirsten Sandvig
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway; Department of Biosciences, University of Oslo, PO Box 1041 Blindern, 0316 Oslo, Norway; Centre for Cancer Biomedicine, University of Oslo, Norway.
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Rojas G, Pupo A, Gómez S, Krengel U, Moreno E. Engineering the binding site of an antibody against N-glycolyl GM3: from functional mapping to novel anti-ganglioside specificities. ACS Chem Biol 2013; 8:376-86. [PMID: 23138862 DOI: 10.1021/cb3003754] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The structurally related gangliosides N-glycolyl GM3 and N-acetyl GM3 are potential targets for tumor immunotherapy. 14F7 is a monoclonal antibody able to discriminate the tumor-specific antigen N-glycolyl GM3 from the closely related N-acetyl GM3 on the basis of the presence of a single additional hydroxyl group in the former. A combinatorial phage display strategy, based on the screening of a large library followed by refined mutagenesis, allowed a thorough exploration of the binding chemistry of this unique antibody. Three essential features of the heavy chain variable region were identified: two aromatic rings (in positions 33 and 100D) contributing to the binding site architecture and an arginine residue (position 98) critical for recognition. Directed evolution of 14F7 resulted in novel variants that cross-react with the tumor-associated antigen N-acetyl GM3 and display recurrent replacements: the substitution W33Q and the appearance of additional arginine residues at several positions of CDR H1. Successful conversion of such engineered variable regions into whole cross-reactive anti-GM3 immunoglobulins validated our phage-based approach to study and modify the lead antibody 14F7. The resulting family of closely related antibodies offers new tools to study the mechanisms of cell death induced by antibodies targeting gangliosides. In vitro directed evolution was useful to overcome the technical limitations to obtain anti-ganglioside antibodies. The case of 14F7 illustrates the power of combining library screening with focused site-directed randomization for a comprehensive scanning of protein interactions.
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Affiliation(s)
- Gertrudis Rojas
- Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, PO Box
16040, La Habana CP 11600, Cuba
| | - Amaury Pupo
- Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, PO Box
16040, La Habana CP 11600, Cuba
| | - Silvia Gómez
- Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, PO Box
16040, La Habana CP 11600, Cuba
| | - Ute Krengel
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, NO-0315 Oslo,
Norway
| | - Ernesto Moreno
- Center of Molecular Immunology, Calle 216 esq 15, Atabey, Playa, PO Box
16040, La Habana CP 11600, Cuba
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Munack S, Leroux V, Roderer K, Ökvist M, van Eerde A, Gundersen LL, Krengel U, Kast P. When Inhibitors Do Not Inhibit: Critical Evaluation of Rational Drug Design Targeting Chorismate Mutase fromMycobacterium tuberculosis. Chem Biodivers 2012; 9:2507-27. [DOI: 10.1002/cbdv.201200322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Indexed: 12/16/2022]
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Cordara G, Goldstein IJ, Sandvig K, Krengel U. Structure–function studies on the proteolytic activity of the Marasmius oreadesagglutinin (MOA), a cytotoxic lectin. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312096808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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37
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Munack S, Roderer K, Kamarauskaite J, van Eerde A, Kast P, Krengel U. Enzyme inhibitors as tuberculosis drugs – a structure guided approach. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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38
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Heggelund JE, Haugen E, Lygren B, Mackenzie A, Holmner Å, Vasile F, Reina J, Bernardi A, Krengel U. Molecular basis of cholera blood group dependence. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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39
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Burschowsky D, van Eerde A, Ökvist M, Kienhöfer A, Kast P, Hilvert D, Krengel U. Reaction mechanism of chorismate mutase, a model enzyme for pericyclic reactions, finally resolved. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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40
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Heggelund JE, Haugen E, Lygren B, Mackenzie A, Holmner Å, Vasile F, Reina JJ, Bernardi A, Krengel U. Both El Tor and classical cholera toxin bind blood group determinants. Biochem Biophys Res Commun 2012; 418:731-5. [PMID: 22305717 DOI: 10.1016/j.bbrc.2012.01.089] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 01/24/2023]
Abstract
Cholera is a disease which shows a clear blood group profile, with blood group O individuals experiencing the most severe symptoms. For a long time, the cholera toxin has been suspected to be the main culprit of this blood group dependence. Here, we show that both El Tor and classical cholera toxin B-pentamers do indeed bind blood group determinants (with equal affinities), using Surface Plasmon Resonance and NMR spectroscopy. Together with previous structural data, this confirms our earlier hypothesis as to the molecular basis of cholera blood group dependence, with an interesting twist: the shorter blood group H-determinant characteristic of blood group O individuals binds with similar binding affinity compared to the A-determinant, however, with different kinetics.
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Affiliation(s)
- Julie E Heggelund
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
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41
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Talavera A, Friemann R, Gómez-Puerta S, Martinez-Fleites C, Garrido G, Rabasa A, Lopez-Requena A, Pupo A, Johansen RF, Sánchez O, Krengel U, Moreno E. Structure and molecular interactions of an anti-tumor antibody specific for EGFR. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311092695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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42
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Cordara G, Egge-Jacobsen W, Johansen HT, Winter HC, Goldstein IJ, Sandvig K, Krengel U. Marasmius oreades agglutinin (MOA) is a chimerolectin with proteolytic activity. Biochem Biophys Res Commun 2011; 408:405-10. [PMID: 21513701 DOI: 10.1016/j.bbrc.2011.04.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 04/07/2011] [Indexed: 10/18/2022]
Abstract
The Marasmius oreades mushroom lectin (MOA) is well known for its exquisite binding specificity for blood group B antigens. In addition to its N-terminal carbohydrate-binding domain, MOA possesses a C-terminal domain with unknown function, which structurally resembles hydrolytic enzymes. Here we show that MOA indeed has catalytic activity. It is a calcium-dependent cysteine protease resembling papain-like cysteine proteases, with Cys215 being the catalytic nucleophile. The possible importance of MOA's proteolytic activity for mushroom defense against pathogens is discussed.
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Affiliation(s)
- Gabriele Cordara
- Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway.
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43
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Holmner A, Mackenzie A, Okvist M, Jansson L, Lebens M, Teneberg S, Krengel U. Crystal structures exploring the origins of the broader specificity of escherichia coli heat-labile enterotoxin compared to cholera toxin. J Mol Biol 2010; 406:387-402. [PMID: 21168418 DOI: 10.1016/j.jmb.2010.11.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/26/2010] [Accepted: 11/30/2010] [Indexed: 11/28/2022]
Abstract
Cholera toxin (CT) and Escherichia coli heat-labile enterotoxin (LT) are structurally and functionally related and share the same primary receptor, the GM1 ganglioside. Despite their extensive similarities, these two toxins exhibit distinct ligand specificities, with LT being more promiscuous than CT. Here, we have attempted to rationalize the broader binding specificity of LT and the subtle differences between the binding characteristics of LTs from human and porcine origins (mediated by their B subunit pentamers, hLTB and pLTB, respectively). The analysis is based on two crystal structures of pLTB in complexes with the pentasaccharide of its primary ligand, GM1, and with neolactotetraose, the carbohydrate determinant of a typical secondary ligand of LTs, respectively. Important molecular determinants underlying the different binding specificities of LTB and CTB are found to be contributed by Ser95, Tyr18 and Thr4 (or Ser4 of hLTB), which together prestabilize the binding site by positioning Lys91, Glu51 and the adjacent loop region (50-61) containing Ile58 for ligand binding. Glu7 and Ala1 may also play an important role. Many of these residues are closely connected with a recently identified second binding site, and there appears to be cross-talk between the two sites. Binding to N-acetyllactosamine-terminated receptors is further augmented by Arg13 (present in pLT and some hLT variants), as previously predicted.
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Affiliation(s)
- Asa Holmner
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway.
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Holmner A, Mackenzie A, Krengel U. Molecular basis of cholera blood-group dependence and implications for a world characterized by climate change. FEBS Lett 2010; 584:2548-55. [PMID: 20417206 DOI: 10.1016/j.febslet.2010.03.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/04/2010] [Indexed: 11/17/2022]
Abstract
Climate change has the potential to increase the threat of water-borne diseases, through rises in temperature and sea-level, and precipitation variability. Cholera poses a particular threat, and the need to develop better intervention tools is imminent. Cholera infections are particularly severe for blood group O individuals, who are less protected by the current vaccines. Here we derive a hypothesis as to the molecular origins of blood-group dependence of this disease, based on relevant epidemiological, clinical and molecular data, and give suggestions on how to plan prevention strategies, and develop novel and improved pharmaceuticals.
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Affiliation(s)
- Asa Holmner
- Department of Biomedical Engineering and Informatics, Västerbotten County Council, Umeå, Sweden
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45
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Okvist M, Sasso S, Roderer K, Kast P, Krengel U. A novel noncovalent complex of chorismate mutase and DAHP synthase from Mycobacterium tuberculosis: protein purification, crystallization and X-ray diffraction analysis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:1048-52. [PMID: 19851019 DOI: 10.1107/s1744309109035878] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 09/04/2009] [Indexed: 11/10/2022]
Abstract
Chorismate mutase catalyzes a key step in the shikimate-biosynthetic pathway and hence is an essential enzyme in bacteria, plants and fungi. Mycobacterium tuberculosis contains two chorismate mutases, a secreted and an intracellular one, the latter of which (MtCM; Rv0948c; 90 amino-acid residues; 10 kDa) is the subject of this work. Here are reported the gene expression, purification and crystallization of MtCM alone and of its complex with another shikimate-pathway enzyme, DAHP synthase (MtDS; Rv2178c; 472 amino-acid residues; 52 kDa), which has been shown to enhance the catalytic efficiency of MtCM. The MtCM-MtDS complex represents the first noncovalent enzyme complex from the common shikimate pathway to be structurally characterized. Soaking experiments with a transition-state analogue are also reported. The crystals of MtCM and the MtCM-MtDS complex diffracted to 1.6 and 2.1 A resolution, respectively.
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Affiliation(s)
- Mats Okvist
- Department of Chemistry, University of Oslo, NO-0315 Oslo, Norway
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46
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Talavera A, Eriksson A, Okvist M, López-Requena A, Fernández-Marrero Y, Pérez R, Moreno E, Krengel U. Crystal structure of an anti-ganglioside antibody, and modelling of the functional mimicry of its NeuGc-GM3 antigen by an anti-idiotypic antibody. Mol Immunol 2009; 46:3466-75. [PMID: 19748674 DOI: 10.1016/j.molimm.2009.07.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/24/2009] [Accepted: 07/28/2009] [Indexed: 11/19/2022]
Abstract
N-Glycolylated (NeuGc) gangliosides are tumor-specific antigens and as such represent attractive targets for cancer immunotherapy. The chimeric antibody chP3 selectively recognizes a broad variety of NeuGc gangliosides, showing no cross-reactivity to the highly similar N-acetylated (NeuAc) gangliosides that are common cellular antigens in humans. Here, we report the crystal structure of the chP3 Fab and its computer-docking model with the trisaccharide NeuGcalpha3Galbeta4Glcbeta, which represents the carbohydrate moiety of the tumor-antigen NeuGc-GM3. The interaction involves only the heavy chain of the chP3 antibody. The modelled complex is consistent with all available experimental data and shows good surface complementarity. The negatively charged sialic acid residue NeuGc is buried in a pocket flanked by two arginine residues, VH Arg31 and VH Arg100A. We have further investigated the interaction of chP3 with its anti-idiotypic antibody, 1E10 (also known as Racotumomab), currently in clinical trials as a cancer vaccine. While many of the chP3 residues predicted to interact with the NeuGc ganglioside also feature prominently in the modelled complex of chP3 and 1E10, we do not observe structural mimicry. Rather, we suspect that the anti-idiotype 1E10 may serve as an imprint of the structural characteristics of the chP3 idiotype and, consequently, give rise to antibodies with P3-like properties upon immunization.
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47
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Talavera A, Friemann R, Gómez-Puerta S, Martinez-Fleites C, Garrido G, Rabasa A, López-Requena A, Pupo A, Johansen RF, Sánchez O, Krengel U, Moreno E. Nimotuzumab, an antitumor antibody that targets the epidermal growth factor receptor, blocks ligand binding while permitting the active receptor conformation. Cancer Res 2009; 69:5851-9. [PMID: 19584289 DOI: 10.1158/0008-5472.can-08-4518] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Overexpression of the epidermal growth factor (EGF) receptor (EGFR) in cancer cells correlates with tumor malignancy and poor prognosis for cancer patients. For this reason, the EGFR has become one of the main targets of anticancer therapies. Structural data obtained in the last few years have revealed the molecular mechanism for ligand-induced EGFR dimerization and subsequent signal transduction, and also how this signal is blocked by either monoclonal antibodies or small molecules. Nimotuzumab (also known as h-R3) is a humanized antibody that targets the EGFR and has been successful in the clinics. In this work, we report the crystal structure of the Fab fragment of Nimotuzumab, revealing some unique structural features in the heavy variable domain. Furthermore, competition assays show that Nimotuzumab binds to domain III of the extracellular region of the EGFR, within an area that overlaps with both the surface patch recognized by Cetuximab (another anti-EGFR antibody) and the binding site for EGF. A computer model of the Nimotuzumab-EGFR complex, constructed by docking and molecular dynamics simulations and supported by mutagenesis studies, unveils a novel mechanism of action, with Nimotuzumab blocking EGF binding while still allowing the receptor to adopt its active conformation, hence warranting a basal level of signaling.
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48
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Sasso S, Okvist M, Roderer K, Gamper M, Codoni G, Krengel U, Kast P. Structure and function of a complex between chorismate mutase and DAHP synthase: efficiency boost for the junior partner. EMBO J 2009; 28:2128-42. [PMID: 19556970 DOI: 10.1038/emboj.2009.165] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 05/26/2009] [Indexed: 11/09/2022] Open
Abstract
Chorismate mutase catalyzes a key step in the shikimate biosynthetic pathway towards phenylalanine and tyrosine. Curiously, the intracellular chorismate mutase of Mycobacterium tuberculosis (MtCM; Rv0948c) has poor activity and lacks prominent active-site residues. However, its catalytic efficiency increases >100-fold on addition of DAHP synthase (MtDS; Rv2178c), another shikimate-pathway enzyme. The 2.35 A crystal structure of the MtCM-MtDS complex bound to a transition-state analogue shows a central core formed by four MtDS subunits sandwiched between two MtCM dimers. Structural comparisons imply catalytic activation to be a consequence of the repositioning of MtCM active-site residues on binding to MtDS. The mutagenesis of the C-terminal extrusion of MtCM establishes conserved residues as part of the activation machinery. The chorismate-mutase activity of the complex, but not of MtCM alone, is inhibited synergistically by phenylalanine and tyrosine. The complex formation thus endows the shikimate pathway of M. tuberculosis with an important regulatory feature. Experimental evidence suggests that such non-covalent enzyme complexes comprising an AroQ(delta) subclass chorismate mutase like MtCM are abundant in the bacterial order Actinomycetales.
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Affiliation(s)
- Severin Sasso
- Laboratory of Organic Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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49
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Grahn E, Askarieh G, Holmner Å, Tateno H, Winter HC, Goldstein IJ, Krengel U. Crystal Structure of the Marasmius Oreades Mushroom Lectin in Complex with a Xenotransplantation Epitope. J Mol Biol 2007; 369:710-21. [DOI: 10.1016/j.jmb.2007.03.016] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 03/02/2007] [Accepted: 03/03/2007] [Indexed: 11/25/2022]
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Holmner A, Askarieh G, Okvist M, Krengel U. Blood group antigen recognition by Escherichia coli heat-labile enterotoxin. J Mol Biol 2007; 371:754-64. [PMID: 17586525 DOI: 10.1016/j.jmb.2007.05.064] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 05/16/2007] [Accepted: 05/18/2007] [Indexed: 11/18/2022]
Abstract
In a number of bacterial infections, such as Helicobacter pylori, Campylobacter jejuni and Vibrio cholerae infections, a correlation between the severity of disease and blood group phenotype of infected individuals has been observed. In the present investigation, we have studied the molecular basis of this effect for enterotoxigenic Escherichia coli (ETEC) infections. ETEC are non-invasive bacteria, which act through second messenger pathways to cause diarrhea. It has been suggested that the major virulence factor of ETEC from human isolates, i.e. the human heat-labile enterotoxin (hLT), recognizes certain blood group epitopes, although the molecular basis of blood group antigen recognition is unknown. The 2.5 A crystal structure of the receptor-binding B-subunit of hLT in complex with the blood group A antigen analog GalNAcalpha3(Fucalpha2)Galbeta4(Fucalpha3)Glcbeta provides evidence of a previously unknown binding site in the native toxin. The structure reveals the molecular interactions underlying blood group antigen recognition and suggests how this protein can discriminate between different blood group epitopes. These results support the previously debated role of hLT in the blood group dependence of ETEC infections. Similar observations regarding the closely related cholera toxin in V. cholera infections are also discussed.
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Affiliation(s)
- Asa Holmner
- Department of Chemistry and Bioscience, Chalmers University of Technology, PO box 462, SE-40530 Göteborg, Sweden
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