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Pawaskar GM, Raval R. Development of a fluorescence-based excipient screening for improved stability and shelf-life of recombinant chitin deacetylase. Biochem Biophys Rep 2024; 38:101718. [PMID: 38708424 PMCID: PMC11066597 DOI: 10.1016/j.bbrep.2024.101718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 04/19/2024] [Indexed: 05/07/2024] Open
Abstract
Chitin deacetylase (CDA) modifies chitin into chitosan by removing acetyl groups, but its inherent instability poses a challenge for successful crystallisation. Despite limited successes in crystallizing CDAs, prior attempts with recombinant chitin deacetylase (BaCDA) failed due to poor stability. To address this, we propose an enzyme buffer formulation as a cost-effective strategy to enhance stability, prolong shelf life, and increase the likelihood of crystallisation. Utilizing the high-throughput screening technique FTSA, we developed a screening method correlating BaCDA stability with its activity. The optimised formulation comprises 50 mM Tris-HCl buffer pH 7, 1 M NaCl, 20 % glycerol, and 1 mM Mg2+ as excipients. This formulation significantly improves BaCDA's thermostability (140.47 % increase) and enzyme activity (2.9-fold enhancement). BaCDA remains stable in the formulated buffer at -20 °C and -80 °C for 30 days and at 4 °C for 15 days. The current study has designed a high-throughput screening method approach to assess the stability of CDA enzyme formulations. The results of this study could contribute to the exploration of formulation elements that enhance the structural stability of CDA, thereby facilitating investigations into the enzyme's structure-function relationships.
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Affiliation(s)
- Goutam Mohan Pawaskar
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal, 576104, India
| | - Ritu Raval
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal, 576104, India
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2
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Hu S, Xu L, Xie C, Hong J. Structural Insights into the Catalytic Activity of Cyclobacterium marinum N-Acetylglucosamine Deacetylase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:783-793. [PMID: 38141024 DOI: 10.1021/acs.jafc.3c06146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
N-Acetylglucosamine deacetylase from Cyclobacterium marinum (CmCBDA) is a highly effective and selective biocatalyst for the production of d-glucosamine (GlcN) from N-acetylglucosamine (GlcNAc). However, the underlying catalytic mechanism remains elusive. Here, we show that CmCBDA is a metalloenzyme with a preference for Ni2+ over Mn2+. Crystal structures of CmCBDA in complex with Ni2+ and Mn2+ revealed slight remodeling of the CmCBDA active site by the metal ions. We also demonstrate that CmCBDA exists as a mixture of homodimers and monomers in solution, and dimerization is indispensable for catalytic activity. A mutagenesis analysis also indicated that the active site residues Asp22, His72, and His143 as well as the residues involved in dimerization, Pro52, Trp53, and Tyr55, are essential for catalytic activity. Furthermore, a mutation on the protein surface, Lys219Glu, resulted in a 2.3-fold improvement in the deacetylation activity toward GlcNAc. Mechanistic insights obtained here may facilitate the development of CmCBDA variants with higher activities.
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Affiliation(s)
- Shenglin Hu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Science at the Microscale, Hefei, Anhui 230026, China
- College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, Anhui 230027, China
| | - Li Xu
- Institute of Biotechnology and Health, Beijing Academy of Science and Technology, Beijing 100089, China
| | - Changlin Xie
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Science at the Microscale, Hefei, Anhui 230026, China
| | - Jiong Hong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Science at the Microscale, Hefei, Anhui 230026, China
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3
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Yin L, Wang Q, Sun J, Mao X. Expression and Molecular Modification of Chitin Deacetylase from Streptomyces bacillaris. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010113. [PMID: 36615307 PMCID: PMC9822392 DOI: 10.3390/molecules28010113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Chitin deacetylase can be used in the green and efficient preparation of chitosan from chitin. Herein, a novel chitin deacetylase SbCDA from Streptomyces bacillaris was heterologously expressed and comprehensively characterized. SbDNA exhibits its highest deacetylation activity at 35 °C and pH 8.0. The enzyme activity is enhanced by Mn2+ and prominently inhibited by Zn2+, SDS, and EDTA. SbCDA showed better deacetylation activity on colloidal chitin, (GlcNAc)5, and (GlcNAc)6 than other forms of the substrate. Molecular modification of SbCDA was conducted based on sequence alignment and homology modeling. A mutant SbCDA63G with higher activity and better temperature stability was obtained. The deacetylation activity of SbCDA63G was increased by 133% compared with the original enzyme, and the optimal reaction temperature increased from 35 to 40 °C. The half-life of SbCDA63G at 40 °C is 15 h, which was 5 h longer than that of the original enzyme. The improved characteristics of the chitin deacetylase SbCDA63G make it a potential candidate to industrially produce chitosan from chitin.
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Affiliation(s)
- Lili Yin
- Qingdao Key Laboratory of Food Biotechnology, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
- Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, China
| | - Qi Wang
- Qingdao Key Laboratory of Food Biotechnology, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
- Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, China
| | - Jianan Sun
- Qingdao Key Laboratory of Food Biotechnology, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
- Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, China
- Correspondence: (J.S.); (X.M.); Tel.: +86-532-82031360 (J.S.); +86-532-82032660 (X.M.)
| | - Xiangzhao Mao
- Qingdao Key Laboratory of Food Biotechnology, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China
- Key Laboratory of Biological Processing of Aquatic Products, China National Light Industry, Qingdao 266404, China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Correspondence: (J.S.); (X.M.); Tel.: +86-532-82031360 (J.S.); +86-532-82032660 (X.M.)
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4
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Vandana, Das S. Genetic regulation, biosynthesis and applications of extracellular polysaccharides of the biofilm matrix of bacteria. Carbohydr Polym 2022; 291:119536. [DOI: 10.1016/j.carbpol.2022.119536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 11/02/2022]
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Identification of Potential Insect Growth Inhibitor against Aedes aegypti: A Bioinformatics Approach. Int J Mol Sci 2022; 23:ijms23158218. [PMID: 35897792 PMCID: PMC9332482 DOI: 10.3390/ijms23158218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/30/2022] [Accepted: 07/11/2022] [Indexed: 02/04/2023] Open
Abstract
Aedes aegypti is the main vector that transmits viral diseases such as dengue, hemorrhagic dengue, urban yellow fever, zika, and chikungunya. Worldwide, many cases of dengue have been reported in recent years, showing significant growth. The best way to manage diseases transmitted by Aedes aegypti is to control the vector with insecticides, which have already been shown to be toxic to humans; moreover, insects have developed resistance. Thus, the development of new insecticides is considered an emergency. One way to achieve this goal is to apply computational methods based on ligands and target information. In this study, sixteen compounds with acceptable insecticidal activities, with 100% larvicidal activity at low concentrations (2.0 to 0.001 mg·L−1), were selected from the literature. These compounds were used to build up and validate pharmacophore models. Pharmacophore model 6 (AUC = 0.78; BEDROC = 0.6) was used to filter 4793 compounds from the subset of lead-like compounds from the ZINC database; 4142 compounds (dG < 0 kcal/mol) were then aligned to the active site of the juvenile hormone receptor Aedes aegypti (PDB: 5V13), 2240 compounds (LE < −0.40 kcal/mol) were prioritized for molecular docking from the construction of a chitin deacetylase model of Aedes aegypti by the homology modeling of the Bombyx mori species (PDB: 5ZNT), which aligned 1959 compounds (dG < 0 kcal/mol), and 20 compounds (LE < −0.4 kcal/mol) were predicted for pharmacokinetic and toxicological prediction in silico (Preadmet, SwissADMET, and eMolTox programs). Finally, the theoretical routes of compounds M01, M02, M03, M04, and M05 were proposed. Compounds M01−M05 were selected, showing significant differences in pharmacokinetic and toxicological parameters in relation to positive controls and interaction with catalytic residues among key protein sites reported in the literature. For this reason, the molecules investigated here are dual inhibitors of the enzymes chitin synthase and juvenile hormonal protein from insects and humans, characterizing them as potential insecticides against the Aedes aegypti mosquito.
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Abstract
Microbes are hardly seen as planktonic species and are most commonly found as biofilm communities in cases of chronic infections. Biofilms are regarded as a biological condition, where a large group of microorganisms gets adhered to a biotic or abiotic surface. In this context, Pseudomonas aeruginosa, a Gram-negative nosocomial pathogen is the main causative organism responsible for life-threatening and persistent infections in individuals affected with cystic fibrosis and other lung ailments. The bacteria can form a strong biofilm structure when it adheres to a surface suitable for the development of a biofilm matrix. These bacterial biofilms pose higher natural resistance to conventional antibiotic therapy due to their multiple tolerance mechanisms. This prevailing condition has led to an increasing rate of treatment failures associated with P. aeruginosa biofilm infections. A better understanding of the effect of a diverse group of antibiotics on established biofilms would be necessary to avoid inappropriate treatment strategies. Hence, the search for other alternative strategies as effective biofilm treatment options has become a growing area of research. The current review aims to give an overview of the mechanisms governing biofilm formation and the different strategies employed so far in the control of biofilm infections caused by P. aeruginosa. Moreover, this review can also help researchers to search for new antibiofilm agents to tackle the effect of biofilm infections that are currently imprudent to conventional antibiotics.
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Abstract
Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.
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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] [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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9
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Li Y, Liu L, Yang J, Yang Q. An overall look at insect chitin deacetylases: Promising molecular targets for developing green pesticides. JOURNAL OF PESTICIDE SCIENCE 2021; 46:43-52. [PMID: 33746545 PMCID: PMC7953033 DOI: 10.1584/jpestics.d20-085] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
Chitin deacetylase (CDA) is a key enzyme involved in the modification of chitin and plays critical roles in molting and pupation, which catalyzes the removal of acetyl groups from N-acetyl-D-glucosamine residues in chitin to form chitosan and release acetic acid. Defects in the CDA genes or their expression may lead to stunted insect development and even death. Therefore, CDA can be used as a potential pest control target. However, there are no effective pesticides known to target CDA. Although there has been some exciting research progress on bacterial or fungal CDAs, insect CDA characteristics are less understood. This review summarizes the current understanding of insect CDAs, especially very recent advances in our understanding of crystal structures and the catalytic mechanism. Progress in developing small-molecule CDA inhibitors is also summarized. We hope the information included in this review will help facilitate new pesticide development through a novel action mode, such as targeting CDA.
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Affiliation(s)
- Yingchen Li
- School of Bioengineering, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Lin Liu
- School of Bioengineering, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Jun Yang
- School of Bioengineering, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Qing Yang
- School of Bioengineering, Dalian University of Technology, Dalian, Liaoning 116024, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection and Shenzhen Agricultural Genome Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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10
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Evolutionary analysis and protein family classification of chitin deacetylases in Cryptococcus neoformans. J Microbiol 2020; 58:805-811. [PMID: 32870486 DOI: 10.1007/s12275-020-0288-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/15/2020] [Accepted: 07/23/2020] [Indexed: 10/23/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen causing cryptococcal meningoencephalitis. Interestingly, the cell wall of C. neoformans contains chitosan, which is critical for its virulence and persistence in the mammalian host. C. neoformans (H99) has three chitin deacetylases (CDAs), which convert chitin to chitosan. Herein, the classification of the chitin-related protein (CRP) family focused on cryptococcal CDAs was analyzed by phylogenetics, evolutionary pressure (dN/dS), and 3D modeling. A phylogenetic tree of 110 CRPs revealed that they can be divided into two clades, CRP I and II with bootstrap values (> 99%). CRP I clade comprises five groups (Groups 1-5) with a total of 20 genes, while CRP II clade comprises sixteen groups (Groups 6-21) with a total of 90 genes. CRP I comprises only fungal CDAs, including all three C. neoformans CDAs, whereas CRP II comprises diverse CDAs from fungi, bacteria, and amoeba, along with other carbohydrate esterase 4 family proteins. All CDAs have the signal peptide, except those from group 11. Notably, CDAs with the putative O-gycosylation site possess either the glycosylphosphatidylinositol (GPI)-anchor motif for CRP I or the chitin-binding domain (CBD) for CRP II, respectively. This evolutionary conservation strongly indicates that the O-glycosylation modification and the presence of either the GPI-anchor motif or the chitin-binding domain is important for fungal CDAs to function efficiently at the cell surface. This study reveals that C. neoformans CDAs carrying GPI anchors have evolved divergently from fungal and bacterial CDAs, providing new insights into evolution and classification of CRP family.
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Liu L, Zhou Y, Qu M, Qiu Y, Guo X, Zhang Y, Liu T, Yang J, Yang Q. Structural and biochemical insights into the catalytic mechanisms of two insect chitin deacetylases of the carbohydrate esterase 4 family. J Biol Chem 2019; 294:5774-5783. [PMID: 30755482 PMCID: PMC6463723 DOI: 10.1074/jbc.ra119.007597] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/08/2019] [Indexed: 12/15/2022] Open
Abstract
Insect chitin deacetylases (CDAs) catalyze the removal of acetyl groups from chitin and modify this polymer during its synthesis and reorganization. CDAs are essential for insect survival and therefore represent promising targets for insecticide development. However, the structural and biochemical characteristics of insect CDAs have remained elusive. Here, we report the crystal structures of two insect CDAs from the silk moth Bombyx mori: BmCDA1, which may function in cuticle modification, and BmCDA8, which may act in modifying peritrophic membranes in the midgut. Both enzymes belong to the carbohydrate esterase 4 (CE4) family. Comparing their overall structures at 1.98–2.4 Å resolution with those from well-studied microbial CDAs, we found that two unique loop regions in BmCDA1 and BmCDA8 contribute to the distinct architecture of their substrate-binding clefts. These comparisons revealed that both BmCDA1 and BmCDA8 possess a much longer and wider substrate-binding cleft with a very open active site in the center than the microbial CDAs, including VcCDA from Vibrio cholerae and ArCE4A from Arthrobacter species AW19M34-1. Biochemical analyses indicated that BmCDA8 is an active enzyme that requires its substrates to occupy subsites 0, +1, and +2 for catalysis. In contrast, BmCDA1 also required accessory proteins for catalysis. To the best of our knowledge, our work is the first to unveil the structural and biochemical features of insect proteins belonging to the CE4 family.
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Affiliation(s)
- Lin Liu
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Yong Zhou
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Mingbo Qu
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Yu Qiu
- Department of Protein Engineering, Biologics Research, Sanofi, Bridgewater, New Jersey 08807
| | - Xingming Guo
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Yuebin Zhang
- the Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116024, China
| | - Tian Liu
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Jun Yang
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China
| | - Qing Yang
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, China; the State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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12
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Bürger M, Chory J. Structural and chemical biology of deacetylases for carbohydrates, proteins, small molecules and histones. Commun Biol 2018; 1:217. [PMID: 30534609 PMCID: PMC6281622 DOI: 10.1038/s42003-018-0214-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/31/2018] [Indexed: 01/02/2023] Open
Abstract
Deacetylation is the removal of an acetyl group and occurs on a plethora of targets and for a wide range of biological reasons. Several pathogens deacetylate their surface carbohydrates to evade immune response or to support biofilm formation. Furthermore, dynamic acetylation/deacetylation cycles govern processes from chromatin remodeling to posttranslational modifications that compete with phosphorylation. Acetylation usually occurs on nitrogen and oxygen atoms and are referred to as N- and O-acetylation, respectively. This review discusses the structural prerequisites that enzymes must have to catalyze the deacetylation reaction, and how they adapted by formation of specific substrate and metal binding sites. Marco Bürger and Joanne Chory discuss the structural requirements for enzymes carrying out deacetylation reactions for various functions across phyla. They explore how these enzymes have adapted to and achieved specificity on a large number of target molecules.
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Affiliation(s)
- Marco Bürger
- 1Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Joanne Chory
- 1Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037 USA.,2Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037 USA
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13
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Substrate Recognition and Specificity of Chitin Deacetylases and Related Family 4 Carbohydrate Esterases. Int J Mol Sci 2018; 19:ijms19020412. [PMID: 29385775 PMCID: PMC5855634 DOI: 10.3390/ijms19020412] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 12/27/2022] Open
Abstract
Carbohydrate esterases family 4 (CE4 enzymes) includes chitin and peptidoglycan deacetylases, acetylxylan esterases, and poly-N-acetylglucosamine deacetylases that act on structural polysaccharides, altering their physicochemical properties, and participating in diverse biological functions. Chitin and peptidoglycan deacetylases are not only involved in cell wall morphogenesis and remodeling in fungi and bacteria, but they are also used by pathogenic microorganisms to evade host defense mechanisms. Likewise, biofilm formation in bacteria requires partial deacetylation of extracellular polysaccharides mediated by poly-N-acetylglucosamine deacetylases. Such biological functions make these enzymes attractive targets for drug design against pathogenic fungi and bacteria. On the other side, acetylxylan esterases deacetylate plant cell wall complex xylans to make them accessible to hydrolases, making them attractive biocatalysts for biomass utilization. CE4 family members are metal-dependent hydrolases. They are highly specific for their particular substrates, and show diverse modes of action, exhibiting either processive, multiple attack, or patterned deacetylation mechanisms. However, the determinants of substrate specificity remain poorly understood. Here, we review the current knowledge on the structure, activity, and specificity of CE4 enzymes, focusing on chitin deacetylases and related enzymes active on N-acetylglucosamine-containing oligo and polysaccharides.
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Structure and function of a CE4 deacetylase isolated from a marine environment. PLoS One 2017; 12:e0187544. [PMID: 29107991 PMCID: PMC5673215 DOI: 10.1371/journal.pone.0187544] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/20/2017] [Indexed: 11/30/2022] Open
Abstract
Chitin, a polymer of β(1–4)-linked N-acetylglucosamine found in e.g. arthropods, is a valuable resource that may be used to produce chitosan and chitooligosaccharides, two compounds with considerable industrial and biomedical potential. Deacetylating enzymes may be used to tailor the properties of chitin and its derived products. Here, we describe a novel CE4 enzyme originating from a marine Arthrobacter species (ArCE4A). Crystal structures of this novel deacetylase were determined, with and without bound chitobiose [(GlcNAc)2], and refined to 2.1 Å and 1.6 Å, respectively. In-depth biochemical characterization showed that ArCE4A has broad substrate specificity, with higher activity against longer oligosaccharides. Mass spectrometry-based sequencing of reaction products generated from a fully acetylated pentamer showed that internal sugars are more prone to deacetylation than the ends. These enzyme properties are discussed in the light of the structure of the enzyme-ligand complex, which adds valuable information to our still rather limited knowledge on enzyme-substrate interactions in the CE4 family.
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Patel S, Rauf A, Meher BR. In silico analysis of ChtBD3 domain to find its role in bacterial pathogenesis and beyond. Microb Pathog 2017; 110:519-526. [PMID: 28760454 DOI: 10.1016/j.micpath.2017.07.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022]
Abstract
Chitin binding domain 3, known by the acronym ChtBD3, is a domain in the enzymes and proteins of several pathogenic virus, bacteria and fungi. As this domain is evolutionarily-conserved in virulence factors of these infectious agents, its detailed investigation is of clinical interest. In this regard, the current in silico study analyzed ChtBD3 domain distribution in bacterial proteins present in publicly-available SMART (simple modular architecture research tool) database. Also, the co-occurring domains of ChtBD3 in the studied proteins were mapped to understand positional rearrangement of the domain and consequent functional diversity. Custom-made scripts were used to interpret the data and to derive patterns. As expected, interesting results were obtained. ChtBD3 domain co-occurred with other critical domains like peptidase, glycol_hydrolase, kinase, hemagglutinin-acting, collagen-binding, among others. The findings are expected to be of clinical relevance.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego, 92182, USA.
| | - Abdur Rauf
- Department of Chemistry, University of Swabi, Anbar, 23561, Khyber Pakhtunkhwa, Pakistan.
| | - Biswa Ranjan Meher
- Centre for Life Sciences, Central University of Jharkhand, Brambe, Ranchi, 835205, Jharkhand, India
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16
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Desoubeaux G, Piqueras MDC, Pantin A, Bhattacharya SK, Peschke R, Joachim A, Cray C. Application of mass spectrometry to elucidate the pathophysiology of Encephalitozoon cuniculi infection in rabbits. PLoS One 2017; 12:e0177961. [PMID: 28723944 PMCID: PMC5516978 DOI: 10.1371/journal.pone.0177961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/05/2017] [Indexed: 11/30/2022] Open
Abstract
Encephalitozoon cuniculi is a microsporidian species which can induce subclinical to serious disease in mammals including rabbits, a definitive natural host. The pathophysiology of infection has not been comprehensively elucidated. In this exploratory study, we utilized two mass spectrometry approaches: first, the analysis of the humoral response by profiling the microsporidian antigens as revealed by Western blot screening, and second, implementing the iTRAQ®-labeling protocol to focus on the changes within the host proteome during infection. Seven E. cuniculi proteins were identified at one-dimensional gel regions where specific seropositive reaction was observed by Western blot, including polar tube protein 3, polar tube protein 2, and for the first time reported: heat shock related 70kDa protein, polysaccharide deacetylase domain-containing protein, zinc finger protein, spore wall and anchoring disk complex protein EnP1, and translation elongation factor 1 alpha. In addition, there was a significant increase of nine host proteins in blood samples from E. cuniculi-diseased rabbits in comparison with non-diseased control subjects undergoing various inflammatory processes. This included serum paraoxonase, alpha-1-antiproteinase F precursor and alpha-1-antiproteinase S-1 which have presumptive catalytic activity likely related to infection control, and cystatin fetuin-B-type, an enzyme regulator that has been poorly studied to date. Notably, 11 proteins were found to be statistically increased in rabbits with neurological versus renal clinical presentation of E. cuniculi infection. Overall, this novel analysis based on mass spectrometry has provided new insights on the inflammatory and humoral responses during E. cuniculi infection in rabbits.
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Affiliation(s)
- Guillaume Desoubeaux
- University of Miami - Miller School of Medicine, Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, Miami, Florida, United States of America
- CHU de Tours, Service de Parasitologie – Mycologie – Médecine tropicale, Tours, France
- Université François-Rabelais, Faculté de Médecine, CEPR - INSERM U1100 / Équipe 3, Tours, France
| | - Maria del Carmen Piqueras
- University of Miami, Mass Spectrometry Core Facility, Miller School of Medicin–, Miami, Florida, United States of America
| | - Ana Pantin
- University of Miami - Miller School of Medicine, Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, Miami, Florida, United States of America
| | - Sanjoy K. Bhattacharya
- University of Miami, Mass Spectrometry Core Facility, Miller School of Medicin–, Miami, Florida, United States of America
| | - Roman Peschke
- University of Veterinary Medicine, Institute of Parasitology, Department of Pathobiology, Vienna, Austria
| | - Anja Joachim
- University of Veterinary Medicine, Institute of Parasitology, Department of Pathobiology, Vienna, Austria
| | - Carolyn Cray
- University of Miami - Miller School of Medicine, Division of Comparative Pathology, Department of Pathology & Laboratory Medicine, Miami, Florida, United States of America
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18
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Adesioye FA, Makhalanyane TP, Biely P, Cowan DA. Phylogeny, classification and metagenomic bioprospecting of microbial acetyl xylan esterases. Enzyme Microb Technol 2016; 93-94:79-91. [DOI: 10.1016/j.enzmictec.2016.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/18/2016] [Accepted: 07/01/2016] [Indexed: 02/06/2023]
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19
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010. MASS SPECTROMETRY REVIEWS 2015; 34:268-422. [PMID: 24863367 PMCID: PMC7168572 DOI: 10.1002/mas.21411] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 05/07/2023]
Abstract
This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.
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Affiliation(s)
- David J. Harvey
- Department of BiochemistryOxford Glycobiology InstituteUniversity of OxfordOxfordOX1 3QUUK
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20
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Andrés E, Albesa-Jové D, Biarnés X, Moerschbacher BM, Guerin ME, Planas A. Structural Basis of Chitin Oligosaccharide Deacetylation. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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21
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Andrés E, Albesa-Jové D, Biarnés X, Moerschbacher BM, Guerin ME, Planas A. Structural basis of chitin oligosaccharide deacetylation. Angew Chem Int Ed Engl 2014; 53:6882-7. [PMID: 24810719 DOI: 10.1002/anie.201400220] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/02/2014] [Indexed: 01/28/2023]
Abstract
Cell signaling and other biological activities of chitooligosaccharides (COSs) seem to be dependent not only on the degree of polymerization, but markedly on the specific de-N-acetylation pattern. Chitin de-N-acetylases (CDAs) catalyze the hydrolysis of the acetamido group in GlcNAc residues of chitin, chitosan, and COS. A major challenge is to understand how CDAs specifically define the distribution of GlcNAc and GlcNH2 moieties in the oligomeric chain. We report the crystal structure of the Vibrio cholerae CDA in four relevant states of its catalytic cycle. The two enzyme complexes with chitobiose and chitotriose represent the first 3D structures of a CDA with its natural substrates in a productive mode for catalysis, thereby unraveling an induced-fit mechanism with a significant conformational change of a loop closing the active site. We propose that the deacetylation pattern exhibited by different CDAs is governed by critical loops that shape and differentially block accessible subsites in the binding cleft of CE4 enzymes.
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Affiliation(s)
- Eduardo Andrés
- Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta 390, 08017 Barcelona (Spain)
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The genome of Spraguea lophii and the basis of host-microsporidian interactions. PLoS Genet 2013; 9:e1003676. [PMID: 23990793 PMCID: PMC3749934 DOI: 10.1371/journal.pgen.1003676] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/12/2013] [Indexed: 11/19/2022] Open
Abstract
Microsporidia are obligate intracellular parasites with the smallest known eukaryotic genomes. Although they are increasingly recognized as economically and medically important parasites, the molecular basis of microsporidian pathogenicity is almost completely unknown and no genetic manipulation system is currently available. The fish-infecting microsporidian Spraguea lophii shows one of the most striking host cell manipulations known for these parasites, converting host nervous tissue into swollen spore factories known as xenomas. In order to investigate the basis of these interactions between microsporidian and host, we sequenced and analyzed the S. lophii genome. Although, like other microsporidia, S. lophii has lost many of the protein families typical of model eukaryotes, we identified a number of gene family expansions including a family of leucine-rich repeat proteins that may represent pathogenicity factors. Building on our comparative genomic analyses, we exploited the large numbers of spores that can be obtained from xenomas to identify potential effector proteins experimentally. We used complex-mix proteomics to identify proteins released by the parasite upon germination, resulting in the first experimental isolation of putative secreted effector proteins in a microsporidian. Many of these proteins are not related to characterized pathogenicity factors or indeed any other sequences from outside the Microsporidia. However, two of the secreted proteins are members of a family of RICIN B-lectin-like proteins broadly conserved across the phylum. These proteins form syntenic clusters arising from tandem duplications in several microsporidian genomes and may represent a novel family of conserved effector proteins. These computational and experimental analyses establish S. lophii as an attractive model system for understanding the evolution of host-parasite interactions in microsporidia and suggest an important role for lineage-specific innovations and fast evolving proteins in the evolution of the parasitic microsporidian lifecycle. Microsporidia are unusual intracellular parasites that infect a broad range of animal cells. In comparison to their fungal relatives, microsporidian genomes have shrunk during evolution, encoding as few as 2000 proteins. This minimal molecular repertoire makes them a reduced model system for understanding host-parasite interactions. A number of microsporidian genomes have now been sequenced, but the lack of a system for genetic manipulation makes it difficult to translate these data into a better understanding of microsporidian biology. Here we present a deep sequencing project of Spraguea lophii, a fish-infecting microsporidian that is abundantly available from environmental samples. We use our sequence data combined with germination protocols and complex-mix proteomics to identify proteins released by the cell at the earliest stage of germination, representing potential pathogenicity factors. We profile the RNA expression pattern of germinating cells and identify a set of highly transcribed hypothetical genes. Our study provides new insight into the importance of uncharacterized, lineage-specific and/or fast evolving proteins in microsporidia and provides new leads for the investigation of virulence factors in these enigmatic parasites.
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Little DJ, Poloczek J, Whitney JC, Robinson H, Nitz M, Howell PL. The structure- and metal-dependent activity of Escherichia coli PgaB provides insight into the partial de-N-acetylation of poly-β-1,6-N-acetyl-D-glucosamine. J Biol Chem 2012; 287:31126-37. [PMID: 22810235 DOI: 10.1074/jbc.m112.390005] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Exopolysaccharides are required for the development and integrity of biofilms produced by a wide variety of bacteria. In Escherichia coli, partial de-N-acetylation of the exopolysaccharide poly-β-1,6-N-acetyl-D-glucosamine (PNAG) by the periplasmic protein PgaB is required for polysaccharide intercellular adhesin-dependent biofilm formation. To understand the molecular basis for PNAG de-N-acetylation, the structure of PgaB in complex with Ni(2+) and Fe(3+) have been determined to 1.9 and 2.1 Å resolution, respectively, and its activity on β-1,6-GlcNAc oligomers has been characterized. The structure of PgaB reveals two (β/α)(x) barrel domains: a metal-binding de-N-acetylase that is a member of the family 4 carbohydrate esterases (CE4s) and a domain structurally similar to glycoside hydrolases. PgaB displays de-N-acetylase activity on β-1,6-GlcNAc oligomers but not on the β-1,4-(GlcNAc)(4) oligomer chitotetraose and is the first CE4 member to exhibit this substrate specificity. De-N-acetylation occurs in a length-dependent manor, and specificity is observed for the position of de-N-acetylation. A key aspartic acid involved in de-N-acetylation, normally seen in other CE4s, is missing in PgaB, suggesting that the activity of PgaB is attenuated to maintain the low levels of de-N-acetylation of PNAG observed in vivo. The metal dependence of PgaB is different from most CE4s, because PgaB shows increased rates of de-N-acetylation with Co(2+) and Ni(2+) under aerobic conditions, and Co(2+), Ni(2+) and Fe(2+) under anaerobic conditions, but decreased activity with Zn(2+). The work presented herein will guide inhibitor design to combat biofilm formation by E. coli and potentially a wide range of medically relevant bacteria producing polysaccharide intercellular adhesin-dependent biofilms.
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Affiliation(s)
- Dustin J Little
- Program in Molecular Structure & Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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24
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Wong E, Vaaje-Kolstad G, Ghosh A, Hurtado-Guerrero R, Konarev PV, Ibrahim AFM, Svergun DI, Eijsink VGH, Chatterjee NS, van Aalten DMF. The Vibrio cholerae colonization factor GbpA possesses a modular structure that governs binding to different host surfaces. PLoS Pathog 2012; 8:e1002373. [PMID: 22253590 PMCID: PMC3257281 DOI: 10.1371/journal.ppat.1002373] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 09/27/2011] [Indexed: 02/06/2023] Open
Abstract
Vibrio cholerae is a bacterial pathogen that colonizes the chitinous exoskeleton of zooplankton as well as the human gastrointestinal tract. Colonization of these different niches involves an N-acetylglucosamine binding protein (GbpA) that has been reported to mediate bacterial attachment to both marine chitin and mammalian intestinal mucin through an unknown molecular mechanism. We report structural studies that reveal that GbpA possesses an unusual, elongated, four-domain structure, with domains 1 and 4 showing structural homology to chitin binding domains. A glycan screen revealed that GbpA binds to GlcNAc oligosaccharides. Structure-guided GbpA truncation mutants show that domains 1 and 4 of GbpA interact with chitin in vitro, whereas in vivo complementation studies reveal that domain 1 is also crucial for mucin binding and intestinal colonization. Bacterial binding studies show that domains 2 and 3 bind to the V. cholerae surface. Finally, mouse virulence assays show that only the first three domains of GbpA are required for colonization. These results explain how GbpA provides structural/functional modular interactions between V. cholerae, intestinal epithelium and chitinous exoskeletons. Vibrio cholerae is the bacterium that causes cholera, a disease endemic in developing countries with poor sanitation. The bacterium colonizes aquatic organisms that serve as a reservoir of transmission to humans. Our work has focused on GbpA, a protein that is secreted by V. cholerae and appears to facilitate growth of the bacteria both in the human intestine and on the exoskeletons of marine organisms. We show that the protein possesses an unusual three-dimensional structure consisting of four separate domains. Two of the domains are similar to proteins that are known to bind chitin, an exoskeleton biopolymer, and our data show that these domains indeed harbour the chitin binding properties of GbpA. One of these domains is also capable of binding intestinal mucus. The two remaining domains are required for interacting with the bacterium itself, creating a stable interface between the bacterium and the human/marine host, facilitating colonization. Finally, work with a cholera mouse model shows that only the first three domains of GbpA are required for colonization. These results show how GbpA provides structural/functional modular interactions between V. cholerae, the intestinal epithelium and chitinous exoskeletons.
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Affiliation(s)
- Edmond Wong
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Gustav Vaaje-Kolstad
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Avishek Ghosh
- Division of Biochemistry, National Institute of Cholera and Enteric Diseases, Scheme XM, Beliaghata, Kolkata, India
| | - Ramon Hurtado-Guerrero
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Peter V. Konarev
- European Molecular Biology Laboratory (EMBL), Outstation Hamburg at DESY, Hamburg, Germany
| | - Adel F. M. Ibrahim
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL), Outstation Hamburg at DESY, Hamburg, Germany
| | - Vincent G. H. Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Nabendu S. Chatterjee
- Division of Biochemistry, National Institute of Cholera and Enteric Diseases, Scheme XM, Beliaghata, Kolkata, India
| | - Daan M. F. van Aalten
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
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Franklin MJ, Nivens DE, Weadge JT, Howell PL. Biosynthesis of the Pseudomonas aeruginosa Extracellular Polysaccharides, Alginate, Pel, and Psl. Front Microbiol 2011; 2:167. [PMID: 21991261 PMCID: PMC3159412 DOI: 10.3389/fmicb.2011.00167] [Citation(s) in RCA: 327] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 07/19/2011] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas aeruginosa thrives in many aqueous environments and is an opportunistic pathogen that can cause both acute and chronic infections. Environmental conditions and host defenses cause differing stresses on the bacteria, and to survive in vastly different environments, P. aeruginosa must be able to adapt to its surroundings. One strategy for bacterial adaptation is to self-encapsulate with matrix material, primarily composed of secreted extracellular polysaccharides. P. aeruginosa has the genetic capacity to produce at least three secreted polysaccharides; alginate, Psl, and Pel. These polysaccharides differ in chemical structure and in their biosynthetic mechanisms. Since alginate is often associated with chronic pulmonary infections, its biosynthetic pathway is the best characterized. However, alginate is only produced by a subset of P. aeruginosa strains. Most environmental and other clinical isolates secrete either Pel or Psl. Little information is available on the biosynthesis of these polysaccharides. Here, we review the literature on the alginate biosynthetic pathway, with emphasis on recent findings describing the structure of alginate biosynthetic proteins. This information combined with the characterization of the domain architecture of proteins encoded on the Psl and Pel operons allowed us to make predictive models for the biosynthesis of these two polysaccharides. The results indicate that alginate and Pel share certain features, including some biosynthetic proteins with structurally or functionally similar properties. In contrast, Psl biosynthesis resembles the EPS/CPS capsular biosynthesis pathway of Escherichia coli, where the Psl pentameric subunits are assembled in association with an isoprenoid lipid carrier. These models and the environmental cues that cause the cells to produce predominantly one polysaccharide over the others are subjects of current investigation.
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