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Sharma P, Vaiwala R, Gopinath AK, Chockalingam R, Ayappa KG. Structure of the Bacterial Cell Envelope and Interactions with Antimicrobials: Insights from Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7791-7811. [PMID: 38451026 DOI: 10.1021/acs.langmuir.3c03474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Bacteria have evolved over 3 billion years, shaping our intrinsic and symbiotic coexistence with these single-celled organisms. With rising populations of drug-resistant strains, the search for novel antimicrobials is an ongoing area of research. Advances in high-performance computing platforms have led to a variety of molecular dynamics simulation strategies to study the interactions of antimicrobial molecules with different compartments of the bacterial cell envelope of both Gram-positive and Gram-negative species. In this review, we begin with a detailed description of the structural aspects of the bacterial cell envelope. Simulations concerned with the transport and associated free energy of small molecules and ions through the outer membrane, peptidoglycan, inner membrane and outer membrane porins are discussed. Since surfactants are widely used as antimicrobials, a section is devoted to the interactions of surfactants with the cell wall and inner membranes. The review ends with a discussion on antimicrobial peptides and the insights gained from the molecular simulations on the free energy of translocation. Challenges involved in developing accurate molecular models and coarse-grained strategies that provide a trade-off between atomic details with a gain in sampling time are highlighted. The need for efficient sampling strategies to obtain accurate free energies of translocation is also discussed. Molecular dynamics simulations have evolved as a powerful tool that can potentially be used to design and develop novel antimicrobials and strategies to effectively treat bacterial infections.
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Affiliation(s)
- Pradyumn Sharma
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Amar Krishna Gopinath
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rajalakshmi Chockalingam
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
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de Melo MIA, da Silva Cunha P, Ferreira IM, de Andrade ASR. DNA aptamers selection for Staphylococcus aureus cells by SELEX and Cell-SELEX. Mol Biol Rep 2023; 50:157-165. [PMID: 36315328 DOI: 10.1007/s11033-022-07991-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND Staphylococcus aureus is the most common bacteria found in skin, soft tissues, bone, and bone prostheses infections. The aim of this study was to select DNA aptamers for S. aureus to be applied in the diagnosis of bacteria. METHODS AND RESULTS We used SELEX (Systematic Evolution of Ligands by EXponencial Enrichment) for peptidoglycan followed by cell-SELEX with S. aureus cells as target. Four sequences showed significantly higher binding to S. aureus distinguishing it from the control cells of other significant microbial species: Escherichia coli, Candida albicans, Streptococcus pyogenes and Streptococcus pneumoniae. In particular, ApSA1 (Kd = 62.7 ± 5.6 nM) and ApSA3 (Kd = 43.3 ± 3.0 nM) sequences combined high affinity and specificity for S. aureus, considering all microorganisms tested. CONCLUSIONS Our results demonstrated that these aptamers were able to identify peptidoglycan in the S. aureus surface and have great potential for use in the development of radiopharmaceuticals capable to identify S. aureus infectious foci, as well as in other aptamer-based methodologies for bacteria diagnosis.
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Affiliation(s)
| | - Pricila da Silva Cunha
- Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, 31270-901, Belo Horizonte, MG, Brazil.,Instituto Federal de Educação, Ciência e Tecnologia do Sudeste de Minas Gerais, 36884-036, Muriaé, MG, Brazil
| | - Iêda Mendes Ferreira
- Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, 31270-901, Belo Horizonte, MG, Brazil
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Yahashiri A, Kaus GM, Popham DL, Houtman JCD, Weiss DS. Comparative Study of Bacterial SPOR Domains Identifies Functionally Important Differences in Glycan Binding Affinity. J Bacteriol 2022; 204:e0025222. [PMID: 36005810 PMCID: PMC9487507 DOI: 10.1128/jb.00252-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/05/2022] [Indexed: 11/20/2022] Open
Abstract
Bacterial SPOR domains target proteins to the divisome by binding septal peptidoglycan (PG) at sites where cell wall amidases have removed stem peptides. These PG structures are referred to as denuded glycans. Although all characterized SPOR domains bind denuded glycans, whether there are differences in affinity is not known. Here, we use isothermal titration calorimetry (ITC) to determine the relative PG glycan binding affinity (<i>K</i><sub>d</sub>) of four Escherichia coli SPOR domains and one Cytophaga hutchinsonii SPOR domain. We found that the <i>K</i><sub>d</sub> values ranged from approximately 1 μM for E. coli DamX<sup>SPOR</sup> and <i>C. hutchinsonii</i> CHU2221<sup>SPOR</sup> to about 10 μM for E. coli FtsN<sup>SPOR</sup>. To investigate whether these differences in PG binding affinity are important for SPOR domain protein function, we constructed and characterized a set of DamX and FtsN "swap" proteins. As expected, all SPOR domain swap proteins localized to the division site, and, in the case of FtsN, all of the heterologous SPOR domains supported cell division. However, for DamX, only the high-affinity SPOR domain from CHU2221 supported normal function in cell division. In summary, different SPOR domains bind denuded PG glycans with different affinities, which appears to be important for the functions of some SPOR domain proteins (e.g., DamX) but not for the functions of others (e.g., FtsN). <b>IMPORTANCE</b> SPOR domain proteins are prominent components of the cell division apparatus in a wide variety of bacteria. The primary function of SPOR domains is targeting proteins to the division site, which they accomplish by binding to septal peptidoglycan. However, whether SPOR domains have any functions beyond septal targeting is unknown. Here, we show that SPOR domains vary in their PG binding affinities and that, at least in the case of the E. coli cell division protein DamX, having a high-affinity SPOR domain contributes to proper function.
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Affiliation(s)
- Atsushi Yahashiri
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Gabriela M. Kaus
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - David L. Popham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Jon C. D. Houtman
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - David S. Weiss
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
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Ker YB, Wu HL, Chen KC, Peng RY. Nutrient composition of Chenopodium formosanum Koidz. bran: Fractionation and bioactivity of its soluble active polysaccharides. PeerJ 2022; 10:e13459. [PMID: 35637713 PMCID: PMC9147384 DOI: 10.7717/peerj.13459] [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: 09/13/2021] [Accepted: 04/27/2022] [Indexed: 01/14/2023] Open
Abstract
Background Chenopodium formosanum Koidz. Amaranthaceae-also known as Djulis or red quinoa (RQ)-is a cereal plant indigenous to Taiwan, known for its high nutrient value. However, its bran is considered a waste product and the nutrient value has never been analyzed. Methods In this study, we examined the proximate composition of RQ bran, specifically its soluble polysaccharide fractions. Results RQ bran exhibited high contents of protein (16.56%), ash (7.10%), carbohydrate (60.45%), total polyphenolics (1.85%), betaxanthin (9.91 mg/100 g of RQ bran), and indicaxanthin (7.27 mg/100 g of RQ bran). Specifically, it was rich in polyunsaturated fatty acids (PUFAs; 39.24%)-with an n-6/n-3 and PUFA/saturated fatty acid (SFA) ratio of 18.137 and 0.743, respectively. Four soluble polysaccharide fractions were also obtained: CF-1, CF-2, CF-3, and CF-4, with yields of 3.90%, 6.74%, 22.28%, and 0.06%, respectively, and molecular weights of 32.54, 24.93, 72.39, and 55.45 kDa, respectively. CF-1, CF-2, CF-3, and CF-4 had respectively 15.67%, 42.41%, 5.44%, and 14.52% peptide moiety content and 38.92%, 50.70%, 93.76%, and 19.80% carbohydrate moiety. In CF-2, the glucose content was 95.86 mol% and that of leucine was 16.23%, implicating the presence of a typical leucinoglucan. All four polysaccharide fractions lacked glutamic acid and hydroxyproline. The IC50 of CF-1, CF-2, and CF-3 was respectively 12.05, 3.98, and 14.5 mg/mL for DPPH free radical-scavenging ability; 5.77, 4.10, and 7.03 mg/mL for hydrogen peroxide-scavenging capability; 0.26, 0.05, and 0.19 mg/mL for O2 - free radical-scavenging capability; and 100.41, 28.12, and 29.73 mg/mL for Fe2+ chelation. Conclusion Our results indicated that RQ bran has a large amount of nutrient compounds, and a cost-efficient process for their extraction is needed. Their biomedical application as nutraceuticals also warrants further investigation.
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Affiliation(s)
- Yaw-Bee Ker
- Department of Food and Applied Technology, Hungkuang University, Taichung City, Taiwan
| | - Hui-Ling Wu
- Department of Food and Applied Technology, Hungkuang University, Taichung City, Taiwan
| | - Kuan-Chou Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan,Department of Urology, Taipei Medical University Shuang-Ho Hospital, Taipei, Taiwan,TMU-Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan
| | - Robert Y. Peng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Lu Q, Zhang W, Fang J, Zheng J, Dong C, Xiong S. Mycobacterium tuberculosis Rv1096, facilitates mycobacterial survival by modulating the NF-κB/MAPK pathway as peptidoglycan N-deacetylase. Mol Immunol 2020; 127:47-55. [PMID: 32927163 DOI: 10.1016/j.molimm.2020.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 07/15/2020] [Accepted: 08/13/2020] [Indexed: 01/06/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that can infect and replicate in macrophages. Peptidoglycan (PGN) is a major component of the mycobacterial cell wall and is recognized by host pattern recognition receptors (PRRs). Many bacteria modulate and evade the immune defenses of their hosts through PGN deacetylation. Rv1096 was previously characterized as a PGN N-deacetylase gene in Mtb. However, the underlying mechanism by which Rv1096 regulates host immune defenses during macrophage infection remains unclear. In the present study, we investigated the role of Rv1096 in evading host immunity using a recombinant M. smegmatis expressing exogenous Rv1096 and Rv1096-deleted Mtb strain H37Rv mutant. We found that Rv1096 promoted intracellular bacillary survival and inhibited the inflammatory response in M. smegmatis- or Mtb-infected macrophages. The inhibition of mycobacteria-induced inflammatory response in macrophages was at least partially due to NF-κB and MAPK activation downstream of TLR and NOD signaling pathways. Furthermore, we found that Rv1096 inhibitory effect on inflammatory response was associated with TLR2, TLR4 and NOD2. Finally, we demonstrated the PGN deacetylase activity of Rv1096 by Fourier transform IR and Rv1096 NODB deficient mutant. Our findings suggest that Rv1096 may deacetylate PGNs to evade PRRs recognition, thus protecting Mtb from host immune surveillance and clearance in macrophages.
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Affiliation(s)
- Qian Lu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China
| | - Wei Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China
| | - Jun Fang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China
| | - Jianjian Zheng
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China
| | - Chunsheng Dong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China.
| | - Sidong Xiong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, China.
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Brott AS, Clarke AJ. Peptidoglycan O-Acetylation as a Virulence Factor: Its Effect on Lysozyme in the Innate Immune System. Antibiotics (Basel) 2019; 8:E94. [PMID: 31323733 PMCID: PMC6783866 DOI: 10.3390/antibiotics8030094] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/11/2019] [Accepted: 07/13/2019] [Indexed: 11/16/2022] Open
Abstract
The peptidoglycan sacculus of both Gram-positive and Gram-negative bacteria acts as a protective mesh and provides structural support around the entirety of the cell. The integrity of this structure is of utmost importance for cell viability and so naturally is the first target for attack by the host immune system during bacterial infection. Lysozyme, a muramidase and the first line of defense of the innate immune system, targets the peptidoglycan sacculus hydrolyzing the β-(1→4) linkage between repeating glycan units, causing lysis and the death of the invading bacterium. The O-acetylation of N-acetylmuramoyl residues within peptidoglycan precludes the productive binding of lysozyme, and in doing so renders it inactive. This modification has been shown to be an important virulence factor in pathogens such as Staphylococcus aureus and Neisseria gonorrhoeae and is currently being investigated as a novel target for anti-virulence therapies. This article reviews interactions made between peptidoglycan and the host immune system, specifically with respect to lysozyme, and how the O-acetylation of the peptidoglycan interrupts these interactions, leading to increased pathogenicity.
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Affiliation(s)
- Ashley S Brott
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Anthony J Clarke
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Porfírio S, Carlson RW, Azadi P. Elucidating Peptidoglycan Structure: An Analytical Toolset. Trends Microbiol 2019; 27:607-622. [DOI: 10.1016/j.tim.2019.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/16/2019] [Accepted: 01/29/2019] [Indexed: 01/04/2023]
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8
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Extracellular electron transfer features of Gram-positive bacteria. Anal Chim Acta 2019; 1076:32-47. [PMID: 31203962 DOI: 10.1016/j.aca.2019.05.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/23/2019] [Accepted: 05/05/2019] [Indexed: 12/20/2022]
Abstract
Electroactive microorganisms possess the unique ability to transfer electrons to or from solid phase electron conductors, e.g., electrodes or minerals, through various physiological mechanisms. The processes are commonly known as extracellular electron transfer and broadly harnessed in microbial electrochemical systems, such as microbial biosensors, microbial electrosynthesis, or microbial fuel cells. Apart from a few model microorganisms, the nature of the microbe-electrode conductive interaction is poorly understood for most of the electroactive species. The interaction determines the efficiency and a potential scaling up of bioelectrochemical systems. Gram-positive bacteria generally have a thick electron non-conductive cell wall and are believed to exhibit weak extracellular electron shuttling activity. This review highlights reported research accomplishments on electroactive Gram-positive bacteria. The use of electron-conducting polymers as mediators is considered as one promising strategy to enhance the electron transfer efficiency up to application scale. In view of the recent progress in understanding the molecular aspects of the extracellular electron transfer mechanisms of Enterococcus faecalis, the electron transfer properties of this bacterium are especially focused on. Fundamental knowledge on the nature of microbial extracellular electron transfer and its possibilities can provide insight in interspecies electron transfer and biogeochemical cycling of elements in nature. Additionally, a comprehensive understanding of cell-electrode interactions may help in overcoming insufficient electron transfer and restricted operational performance of various bioelectrochemical systems and facilitate their practical applications.
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Gokulan K, Varughese KI. Drug resistance in Mycobacterium tuberculosis
and targeting the l,d
-transpeptidase enzyme. Drug Dev Res 2018; 80:11-18. [DOI: 10.1002/ddr.21455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/26/2018] [Accepted: 07/28/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Kuppan Gokulan
- The Department of Physiology & Biophysics; University of Arkansas for Medical Sciences; Little Rock Arkansas
- The Division of Microbiology; National Center for Toxicological Research, US-FDA; Jefferson Arkansas
| | - Kottayil I. Varughese
- The Department of Physiology & Biophysics; University of Arkansas for Medical Sciences; Little Rock Arkansas
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Mikoulinskaia GV, Chernyshov SV, Shavrina MS, Molochkov NV, Lysanskaya VY, Zimin AA. Two novel thermally resistant endolysins encoded by pseudo T-even bacteriophages RB43 and RB49. J Gen Virol 2018; 99:402-415. [DOI: 10.1099/jgv.0.001014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Galina V. Mikoulinskaia
- Branch of Shemyakin & Ovchinnikov’s Institute of Bioorganic Chemistry RAS, Pushchino, Moscow region 142290, Russia
| | - Sergei V. Chernyshov
- Branch of Shemyakin & Ovchinnikov’s Institute of Bioorganic Chemistry RAS, Pushchino, Moscow region 142290, Russia
| | - Maria S. Shavrina
- Branch of Shemyakin & Ovchinnikov’s Institute of Bioorganic Chemistry RAS, Pushchino, Moscow region 142290, Russia
| | - Nikolai V. Molochkov
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow region 142290, Russia
| | - Valentina Ya. Lysanskaya
- Skryabin’s Institute of Biochemistry and Physiology of Micro-organisms RAS, Pushchino, Moscow region 142290, Russia
| | - Andrei A. Zimin
- Skryabin’s Institute of Biochemistry and Physiology of Micro-organisms RAS, Pushchino, Moscow region 142290, Russia
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Desvaux M, Candela T, Serror P. Surfaceome and Proteosurfaceome in Parietal Monoderm Bacteria: Focus on Protein Cell-Surface Display. Front Microbiol 2018; 9:100. [PMID: 29491848 PMCID: PMC5817068 DOI: 10.3389/fmicb.2018.00100] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/16/2018] [Indexed: 12/12/2022] Open
Abstract
The cell envelope of parietal monoderm bacteria (archetypal Gram-positive bacteria) is formed of a cytoplasmic membrane (CM) and a cell wall (CW). While the CM is composed of phospholipids, the CW is composed at least of peptidoglycan (PG) covalently linked to other biopolymers, such as teichoic acids, polysaccharides, and/or polyglutamate. Considering the CW is a porous structure with low selective permeability contrary to the CM, the bacterial cell surface hugs the molecular figure of the CW components as a well of the external side of the CM. While the surfaceome corresponds to the totality of the molecules found at the bacterial cell surface, the proteinaceous complement of the surfaceome is the proteosurfaceome. Once translocated across the CM, secreted proteins can either be released in the extracellular milieu or exposed at the cell surface by associating to the CM or the CW. Following the gene ontology (GO) for cellular components, cell-surface proteins at the CM can either be integral (GO: 0031226), i.e., the integral membrane proteins, or anchored to the membrane (GO: 0046658), i.e., the lipoproteins. At the CW (GO: 0009275), cell-surface proteins can be covalently bound, i.e., the LPXTG-proteins, or bound through weak interactions to the PG or wall polysaccharides, i.e., the cell wall binding proteins. Besides monopolypeptides, some proteins can associate to each other to form supramolecular protein structures of high molecular weight, namely the S-layer, pili, flagella, and cellulosomes. After reviewing the cell envelope components and the different molecular mechanisms involved in protein attachment to the cell envelope, perspectives in investigating the proteosurfaceome in parietal monoderm bacteria are further discussed.
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Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRA, UMR454 MEDiS, Clermont-Ferrand, France
| | - Thomas Candela
- EA4043 Unité Bactéries Pathogènes et Santé, Châtenay-Malabry, France
| | - Pascale Serror
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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Squeglia F, Ruggiero A, Berisio R. Chemistry of Peptidoglycan in Mycobacterium tuberculosis
Life Cycle: An off-the-wall Balance of Synthesis and Degradation. Chemistry 2017; 24:2533-2546. [DOI: 10.1002/chem.201702973] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Flavia Squeglia
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
| | - Alessia Ruggiero
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
| | - Rita Berisio
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
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Pérez de Nanclares M, Trudeau M, Hansen J, Mydland L, Urriola P, Shurson G, Piercey Åkesson C, Kjos N, Arntzen M, Øverland M. High-fiber rapeseed co-product diet for Norwegian Landrace pigs: Effect on digestibility. Livest Sci 2017. [DOI: 10.1016/j.livsci.2017.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Peptidoglycan (murein) is a vital component of the cell wall of nearly all bacteria, composed of sugars linked by short peptides. This protocol describes the purification of macromolecular peptidoglycan from cultured bacteria and the analysis of enzyme-digested peptidoglycan fragments using high performance liquid chromatography (HPLC). Digested peptidoglycan fragments can be identified by mass spectrometry, or predicted by comparing retention times with other published chromatograms. The quantitative nature of this method allows for the measurement of changes to peptidoglycan composition between different species of bacteria, growth conditions, or mutations. This method can determine the overall architecture of peptidoglycan, such as peptide stem length, the extent of cross-linking, and modifications. Muropeptide analysis has been used to study the function of peptidoglycan-associated proteins and the mechanisms by which bacteria acquire antibiotic resistance.
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Affiliation(s)
- Ryan E Schaub
- Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, USA
| | - Joseph P Dillard
- Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, USA
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15
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Abstract
Gram-positive organisms, including the pathogens Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis, have dynamic cell envelopes that mediate interactions with the environment and serve as the first line of defense against toxic molecules. Major components of the cell envelope include peptidoglycan (PG), which is a well-established target for antibiotics, teichoic acids (TAs), capsular polysaccharides (CPS), surface proteins, and phospholipids. These components can undergo modification to promote pathogenesis, decrease susceptibility to antibiotics and host immune defenses, and enhance survival in hostile environments. This chapter will cover the structure, biosynthesis, and important functions of major cell envelope components in gram-positive bacteria. Possible targets for new antimicrobials will be noted.
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Abstract
Peptidoglycan (PG) is the major structural component of the bacterial cell wall. Bacteria have autolytic PG hydrolases that allow the cell to grow and divide. A well-studied group of PG hydrolase enzymes are the bacteriophage endolysins. Endolysins are PG-degrading proteins that allow the phage to escape from the bacterial cell during the phage lytic cycle. The endolysins, when purified and exposed to PG externally, can cause "lysis from without." Numerous publications have described how this phenomenon can be used therapeutically as an effective antimicrobial against certain pathogens. Endolysins have a characteristic modular structure, often with multiple lytic and/or cell wall-binding domains (CBDs). They degrade the PG with glycosidase, amidase, endopeptidase, or lytic transglycosylase activities and have been shown to be synergistic with fellow PG hydrolases or a range of other antimicrobials. Due to the coevolution of phage and host, it is thought they are much less likely to invoke resistance. Endolysin engineering has opened a range of new applications for these proteins from food safety to environmental decontamination to more effective antimicrobials that are believed refractory to resistance development. To put phage endolysin work in a broader context, this chapter includes relevant studies of other well-characterized PG hydrolase antimicrobials.
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17
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Forster BM, Marquis H. Protein transport across the cell wall of monoderm Gram-positive bacteria. Mol Microbiol 2012; 84:405-13. [PMID: 22471582 DOI: 10.1111/j.1365-2958.2012.08040.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In monoderm (single-membrane) Gram-positive bacteria, the majority of secreted proteins are first translocated across the cytoplasmic membrane into the inner wall zone. For a subset of these proteins, final destination is within the cell envelope as either membrane-anchored or cell wall-anchored proteins, whereas another subset of proteins is destined to be transported across the cell wall into the extracellular milieu. Although the cell wall is a porous structure, there is evidence that, for some proteins, transport is a regulated process. This review aims at describing what is known about the mechanisms that regulate the transport of proteins across the cell wall of monoderm Gram-positive bacteria.
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Affiliation(s)
- Brian M Forster
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
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Wheeler R, Mesnage S, Boneca IG, Hobbs JK, Foster SJ. Super-resolution microscopy reveals cell wall dynamics and peptidoglycan architecture in ovococcal bacteria. Mol Microbiol 2011; 82:1096-109. [PMID: 22059678 DOI: 10.1111/j.1365-2958.2011.07871.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cell morphology and viability in Eubacteria is dictated by the architecture of peptidoglycan, the major and essential structural component of the cell wall. Although the biochemical composition of peptidoglycan is well understood, how the peptidoglycan architecture can accommodate the dynamics of growth and division while maintaining cell shape remains largely unknown. Here, we elucidate the peptidoglycan architecture and dynamics of bacteria with ovoid cell shape (ovococci), which includes a number of important pathogens, by combining biochemical analyses with atomic force and super-resolution microscopies. Atomic force microscopy analysis showed preferential orientation of the peptidoglycan network parallel to the short axis of the cell, with distinct architectural features associated with septal and peripheral wall synthesis. Super-resolution three-dimensional structured illumination fluorescence microscopy was applied for the first time in bacteria to unravel the dynamics of peptidoglycan assembly in ovococci. The ovococci have a unique peptidoglycan architecture and growth mode not observed in other model organisms.
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Affiliation(s)
- Richard Wheeler
- Krebs Institute, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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Mikoulinskaia GV, Odinokova IV, Zimin AA, Lysanskaya VY, Feofanov SA, Stepnaya OA. Identification and characterization of the metal ion-dependent l-alanoyl-d-glutamate peptidase encoded by bacteriophage T5. FEBS J 2009; 276:7329-42. [DOI: 10.1111/j.1742-4658.2009.07443.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The bacterial cell wall is essential for viability and shape determination. Cell wall structural dynamics allowing growth and division, while maintaining integrity is a basic problem governing the life of bacteria. The polymer peptidoglycan is the main structural component for most bacteria and is made up of glycan strands that are cross-linked by peptide side chains. Despite study and speculation over many years, peptidoglycan architecture has remained largely elusive. Here, we show that the model rod-shaped bacterium Bacillus subtilis has glycan strands up to 5 microm, longer than the cell itself and 50 times longer than previously proposed. Atomic force microscopy revealed the glycan strands to be part of a peptidoglycan architecture allowing cell growth and division. The inner surface of the cell wall has a regular macrostructure with approximately 50 nm-wide peptidoglycan cables [average 53 +/- 12 nm (n = 91)] running basically across the short axis of the cell. Cross striations with an average periodicity of 25 +/- 9 nm (n = 96) along each cable are also present. The fundamental cabling architecture is also maintained during septal development as part of cell division. We propose a coiled-coil model for peptidoglycan architecture encompassing our data and recent evidence concerning the biosynthetic machinery for this essential polymer.
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Affiliation(s)
- Waldemar Vollmer
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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Plomp M, Leighton TJ, Wheeler KE, Hill HD, Malkin AJ. In vitro high-resolution structural dynamics of single germinating bacterial spores. Proc Natl Acad Sci U S A 2007; 104:9644-9. [PMID: 17535925 PMCID: PMC1877984 DOI: 10.1073/pnas.0610626104] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Although significant progress has been achieved in understanding the genetic and biochemical bases of the spore germination process, the structural basis for breaking the dormant spore state remains poorly understood. We have used atomic force microscopy (AFM) to probe the high-resolution structural dynamics of single Bacillus atrophaeus spores germinating under native conditions. Here, we show that AFM can reveal previously unrecognized germination-induced alterations in spore coat architecture and topology as well as the disassembly of outer spore coat rodlet structures. These results and previous studies in other microorganisms suggest that the spore coat rodlets are structurally similar to amyloid fibrils. AFM analysis of the nascent surface of the emerging germ cell revealed a porous network of peptidoglycan fibers. The results are consistent with a honeycomb model structure for synthetic peptidoglycan oligomers determined by NMR. AFM is a promising experimental tool for investigating the morphogenesis of spore germination and cell wall peptidoglycan structure.
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Affiliation(s)
- Marco Plomp
- *Department of Chemistry, Materials and Life Sciences, Lawrence Livermore National Laboratory, L-234, Livermore, CA 94551
| | | | | | - Haley D. Hill
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208
| | - Alexander J. Malkin
- *Department of Chemistry, Materials and Life Sciences, Lawrence Livermore National Laboratory, L-234, Livermore, CA 94551
- To whom correspondence should be addressed at:
Department of Chemistry, Materials, and Life Sciences, L-234, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551. E-mail:
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23
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Scheffers DJ, Pinho MG. Bacterial cell wall synthesis: new insights from localization studies. Microbiol Mol Biol Rev 2006; 69:585-607. [PMID: 16339737 PMCID: PMC1306805 DOI: 10.1128/mmbr.69.4.585-607.2005] [Citation(s) in RCA: 414] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to maintain shape and withstand intracellular pressure, most bacteria are surrounded by a cell wall that consists mainly of the cross-linked polymer peptidoglycan (PG). The importance of PG for the maintenance of bacterial cell shape is underscored by the fact that, for various bacteria, several mutations affecting PG synthesis are associated with cell shape defects. In recent years, the application of fluorescence microscopy to the field of PG synthesis has led to an enormous increase in data on the relationship between cell wall synthesis and bacterial cell shape. First, a novel staining method enabled the visualization of PG precursor incorporation in live cells. Second, penicillin-binding proteins (PBPs), which mediate the final stages of PG synthesis, have been localized in various model organisms by means of immunofluorescence microscopy or green fluorescent protein fusions. In this review, we integrate the knowledge on the last stages of PG synthesis obtained in previous studies with the new data available on localization of PG synthesis and PBPs, in both rod-shaped and coccoid cells. We discuss a model in which, at least for a subset of PBPs, the presence of substrate is a major factor in determining PBP localization.
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Affiliation(s)
- Dirk-Jan Scheffers
- Department of Molecular Microbiology, Institute of Molecular Cell Biology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
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24
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Deutsch SM, Guezenec S, Piot M, Foster S, Lortal S. Mur-LH, the broad-spectrum endolysin of Lactobacillus helveticus temperate bacteriophage phi-0303. Appl Environ Microbiol 2004; 70:96-103. [PMID: 14711630 PMCID: PMC321252 DOI: 10.1128/aem.70.1.96-103.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Accepted: 09/28/2003] [Indexed: 11/20/2022] Open
Abstract
phi-0303 is a temperate bacteriophage isolated from Lactobacillus helveticus CNRZ 303 strain after mitomycin C induction. In this work, the gene coding for a lytic protein of this bacteriophage was cloned using a library of phi-0303 in Escherichia coli DH5alpha. The lytic activity was detected by its expression, using whole cells of the sensitive strain L. helveticus CNRZ 892 as the substrate. The lysin gene was within a 4.1-kb DNA fragment of phi-0303 containing six open reading frames (ORFs) and two truncated ORFs. No sequence homology with holin genes was found within the cloned fragment. An integrase-encoding gene was also present in the fragment, but it was transcribed in a direction opposite that of the lysin gene. The lysin-encoding lys gene was verified by PCR amplification from the total phage DNA and subcloned. The lys gene is a 1,122-bp sequence encoding a protein of 373 amino acids (Mur-LH), whose product had a deduced molecular mass of 40,207 Da. Comparisons with sequences in sequence databases showed homology with numerous endolysins of other bacteriophages. Mur-LH was expressed in E. coli BL21, and by renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis with L. helveticus CNRZ 892 as the substrate, the recombinant protein showed an apparent molecular mass of 40 kDa. The N-terminal sequence of the protein confirmed the start codon. Hydrolysis of cell walls of L. helveticus CNRZ 303 by the endolysin and biochemical analysis of the residues produced demonstrated that Mur-LH has N-acetylmuramidase activity. Last, the endolysin exhibited a broad spectrum of lytic activity, as it was active on different species, mainly thermophilic lactobacilli but also lactococci, pediococci, Bacillus subtilis, Brevibacterium linens, and Enterococcus faecium.
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Affiliation(s)
- Stéphanie-Marie Deutsch
- Laboratoire de Recherches de Technologie Laitière, Institut National de la Recherche Agronomique, 35042 Rennes Cédex, France.
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Boneca IG, Huang ZH, Gage DA, Tomasz A. Characterization of Staphylococcus aureus cell wall glycan strands, evidence for a new beta-N-acetylglucosaminidase activity. J Biol Chem 2000; 275:9910-8. [PMID: 10744664 DOI: 10.1074/jbc.275.14.9910] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Using sequential digestion with the glycyl-glycine endopeptidase lysostaphin followed by the pneumococcal N-acetylmuramyl-L-alanine amidase (amidase), the glycan strands of the peptidoglycan of Staphylococcus aureus were purified and analyzed by a combination of reverse-phase-high pressure liquid chromatography (HPLC) and mass spectrometry. Reverse-phase-HPLC resolved the glycan strands to a family of major peaks, which represented oligosaccharides composed of repeating disaccharide units (N-acetylglucosamine-[beta-1, 4]-N-acetylmuramic acid) with different degrees of polymerization and terminating with N-acetylmuramic acid residues at the reducing ends. The method allowed separation of strands up to 23-26 disaccharide units with a predominant length between 3 and 10 and an average degree of polymerization of approximately 6. Glycan strands with a higher degree of polymerization (>26 disaccharide units) represented 10-15% of the total UV absorbing glycan material. A unique feature of the staphylococcal glycan strands was the presence of minor satellite peaks that were present throughout the HPLC elution profile eluting either just prior or shortly after the major oligosaccharide peaks. A number of observations including mass spectrometric analysis suggest that the satellites are the products of an N-acetylglucosaminidase activity that differs from the atl gene product and that appears to be involved with modification of the glycan strand structure.
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Affiliation(s)
- I G Boneca
- Laboratory of Microbiology, The Rockefeller University, New York, New York 10021, USA
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26
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García P, Paz González M, García E, García JL, López R. The molecular characterization of the first autolytic lysozyme of Streptococcus pneumoniae reveals evolutionary mobile domains. Mol Microbiol 1999; 33:128-38. [PMID: 10411730 DOI: 10.1046/j.1365-2958.1999.01455.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A biochemical approach to identify proteins with high affinity for choline-containing pneumococcal cell walls has allowed the localization, cloning and sequencing of a gene (lytC ) coding for a protein that degrades the cell walls of Streptococcus pneumoniae. The lytC gene is 1506 bp long and encodes a protein (LytC) of 501 amino acid residues with a predicted M r of 58 682. LytC has a cleavable signal peptide, as demonstrated when the mature protein (about 55 kDa) was purified from S. pneumoniae. Biochemical analyses of the pure, mature protein proved that LytC is a lysozyme. Combined cell fractionation and Western blot analysis showed that the unprocessed, primary product of the lytC gene is located in the pneumococcal cytoplasm whereas the processed, active form of LytC is tightly bound to the cell envelope. In vivo experiments demonstrated that this lysozyme behaves as a pneumococcal autolytic enzyme at 30 degrees C. The DNA region encoding the 253 C-terminal amino acid residues of LytC has been cloned and expressed in Escherichia coli. The truncated protein exhibits a low, but significant, choline-independent lysozyme activity, which suggests that this polypeptide adopts an active conformation. Self-alignment of the N-terminal part of the deduced amino acid sequence of LytC revealed the presence of 11 repeated motifs. These results strongly suggest that the lysozyme reported here has changed the general building plan characteristic of the choline-binding proteins of S. pneumoniae and its bacteriophages, i.e. the choline-binding domain and the catalytic domain are located, respectively, at the N-terminal and the C-terminal moieties of LytC. This work illustrates the natural versatility exhibited by the pneumococcal genes coding for choline-binding proteins to fuse separated catalytic and substrate-binding domains and create new and functional mature proteins.
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Affiliation(s)
- P García
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Velázquez 144, 28006 Madrid, Spain
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Vasala A, Välkkilä M, Caldentey J, Alatossava T. Genetic and biochemical characterization of the Lactobacillus delbrueckii subsp. lactis bacteriophage LL-H lysin. Appl Environ Microbiol 1995; 61:4004-11. [PMID: 8526515 PMCID: PMC167708 DOI: 10.1128/aem.61.11.4004-4011.1995] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
LL-H, a virulent phage of Lactobacillus delbrueckii subsp. lactis, produces a peptidoglycan-degrading enzyme, Mur, that is effective on L. delbrueckii, Lactobacillus acidophilus, Lactobacillus helveticus, and Pediococcus damnosus cell walls. In this study, the LL-H gene mur was cloned into Escherichia coli, its nucleotide sequence was determined, and the enzyme produced in E. coli was purified and biochemically characterized. Mur was purified 112-fold by means of ammonium sulfate precipitation and cation-exchange chromatography. The cell wall-hydrolyzing activity was found to be associated with a 34-kDa protein. The C-terminal domain of Mur is not essential for catalytic activity since it can be removed without destroying the lytic activity. The N-terminal sequence of the purified lysin was identical to that deduced from the nucleotide sequence, but the first methionine is absent from the mature protein. The N-terminal part of this 297-amino-acid protein had homology with several Chalaropsis-type lysozymes. Reduction of purified and Mur-digested L. delbrueckii cell wall material with labeled NaB3H4 indicated that the enzyme is a muramidase. The temperature optimum of purified Mur is between 30 and 40 degrees C, and the pH optimum is around 5.0. The LL-H lysin Mur is stable at temperatures below 60 degrees C.
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Affiliation(s)
- A Vasala
- Department of Genetics, University of Oulu, Finland
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28
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Caldentey J, Hänninen AL, Bamford DH. Gene XV of bacteriophage PRD1 encodes a lytic enzyme with muramidase activity. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 225:341-6. [PMID: 7925454 DOI: 10.1111/j.1432-1033.1994.00341.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacteriophage PRD1 is a lipid-containing virus that infects a variety of Gram-negative bacteria, including Escherichia coli. The phage lyses its host by virtue of a virally-encoded lytic enzyme, the synthesis of which has been assigned to gene XV on the basis of complementation analysis and experiments with mutant phages. We report here the cloning of gene XV into an expression plasmid and the purification of its product, protein P15, to near homogeneity. The purified protein P15, identified by N-terminal sequence analysis, showed a strong lytic activity against chloroform-treated Gram-negative cells. No activity against Gram-positive bacterial species could be detected. The pH optimum of the enzyme was between 7.0-8.0. Protein P15 was readily inactivated at temperatures above 4 degrees C, as well as by increasing the ionic strength of the buffers. The analysis of cell wall digests indicated that P15 is a glycosidase that cleaves the beta (1-4) linkage between N-acetylmuramic acid and N-acetylglucosamine, thus displaying muramidase activity.
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Affiliation(s)
- J Caldentey
- Institute of Biotechnology, University of Helsinki, Finland
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29
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Abstract
The capsular polysaccharide released from the bacterial surface by cell wall turnover during growth exhibited less size heterogeneity and a higher average molecular mass than the polysaccharide extracted from the cell by treatment with lysostaphin or low pH. Treatment of turnover polysaccharide, radiolabelled by growth of the bacteria in the presence of N-acetyl-[3H]-glucosamine, with muramidase B from Chalaropsis released a low molecular weight product chromatographically identical to the peptidoglycan degradation products released from the peptidoglycan-teichoic acid complex by the same treatment. It is concluded that some or all of the capsular polysaccharide released into the culture fluid during growth is derived from peptidoglycan-linked capsular material, solubilised by cell wall turnover.
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Affiliation(s)
- S A Havaei
- Department of Microbiology, Medical School, University of Newcastle, UK
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30
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Caldentey J, Bamford DH. The lytic enzyme of the Pseudomonas phage phi 6. Purification and biochemical characterization. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1159:44-50. [PMID: 1390911 DOI: 10.1016/0167-4838(92)90073-m] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The lytic enzyme of the lipid-containing bacteriophage phi 6, protein P5, has been purified to apparent homogeneity from disrupted viral particles. The enzyme is a monomer with a molecular mass of approx. 24 kDa. The optimal pH for P5 activity is 8.5 and the protein is readily inactivated at temperatures above 20 degrees C. Protein P5 is active against several Gram-negative bacteria, but no activity against Gram-positive species was detected. Analysis of cell wall digests indicates that P5 is not a glycosidase, but an endopeptidase splitting the peptide bridge formed by meso-diaminopimelic acid and D-alanine.
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Affiliation(s)
- J Caldentey
- Department of Genetics, University of Helsinki, Finland
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31
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Characterization of cross-linking of cell walls of Bacillus subtilis by a combination of magic-angle spinning NMR and gas chromatography-mass spectrometry of both intact and hydrolyzed 13C- and 15N-labeled cell-wall peptidoglycan. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54254-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Dolinger DL, Daneo-Moore L, Shockman GD. The second peptidoglycan hydrolase of Streptococcus faecium ATCC 9790 covalently binds penicillin. J Bacteriol 1989; 171:4355-61. [PMID: 2753858 PMCID: PMC210212 DOI: 10.1128/jb.171.8.4355-4361.1989] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A second peptidoglycan hydrolase (muramidase-2) of Streptococcus faecium ATCC 9790 (Enterococcus hirae) has been purified to apparent homogeneity. The enzyme has been shown to be a beta-1,4-N-acetylmuramoylhydrolase (muramidase; EC 3.2.1.17) and to differ in substrate specificity from a previously isolated muramidase. Purified enzyme appears as two protein staining bands with molecular masses of 125 and 75 kilodaltons (kDa) on polyacrylamide gels after sodium dodecyl sulfate electrophoresis. Elution and renaturation of protein bands from sodium dodecyl sulfate-polyacrylamide gels showed that both proteins have muramidase-2 activity. Both proteins have been shown to bind radioactive benzylpenicillin and have the same electrophoretic mobilities as penicillin-binding proteins 1 and 5 present in membrane preparations of this organism, respectively. Incubation of a [14C]penicillin G-labeled 125-kDa form of the enzyme with crude alkaline extracts from S. faecium (which did not contain added proteinase inhibitors) showed the endogenous conversion of the radiolabeled 125-kDa form to the radiolabeled 75-kDa form of the enzyme.
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Affiliation(s)
- D L Dolinger
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania 19140
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33
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García P, García JL, García E, López R. Purification and characterization of the autolytic glycosidase of Streptococcus pneumoniae. Biochem Biophys Res Commun 1989; 158:251-6. [PMID: 2492193 DOI: 10.1016/s0006-291x(89)80205-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A new lytic enzyme isolated from Streptococcus pneumoniae has been purified to electrophoretical homogeneity. The enzyme, showing a Mr of 64000, has been characterized as an endo-beta-1,4-N-acetylglucosaminidase that requires choline in the teichoic acid of the cell wall substrate for catalytic activity. In vivo experiments demonstrate that the glucosaminidase behaves as an autolytic enzyme.
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Affiliation(s)
- P García
- Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain
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McDowell TD, Lemanski CL. Absence of autolytic activity (peptidoglycan nicking) in penicillin-induced nonlytic death in a group A streptococcus. J Bacteriol 1988; 170:1783-8. [PMID: 3280551 PMCID: PMC211031 DOI: 10.1128/jb.170.4.1783-1788.1988] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The extent of sublytic autolysin activity (peptidoglycan [PG] nicking) after exposure of exponentially growing cultures of a group A streptococcus (GAS) to benzylpenicillin (PenG) was studied by determining changes in the glycan chain length of PG polymers. The average PG chain length in isolated cell walls was estimated by calculating the ratio of the total hexosamine content (Morgan-Elson-reactive material) to reducing-end group content established via quantitation of [3H]borohydride reduction products. Comparison of the average PG chain length obtained from untreated control cultures of GAS with those obtained after exposure to a saturating dose of PenG revealed no decrease over a time interval equivalent to four mass doublings of the control cultures. Exposure to this concentration of PenG for a time equivalent to only two mass doublings resulted in approximately 90% loss of viability. In contrast, exposure of the lytic bacterium, Streptococcus faecium ATCC 9790, to a 50% growth inhibitory dose of PenG produced a 20% reduction in the average PG chain length concomitant with only a 65% loss of viability. Preliminary characterization of the autolytic system of GAS indicated that this streptococcus has a hexosaminidase-type autolysin. The results presented indicate the lack of autolytic activity in PenG-induced nonlytic death.
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Affiliation(s)
- T D McDowell
- Department of Microbiology, University of New Mexico, School of Medicine, Albuquerque 87131
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35
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García JL, García E, Arrarás A, García P, Ronda C, López R. Cloning, purification, and biochemical characterization of the pneumococcal bacteriophage Cp-1 lysin. J Virol 1987; 61:2573-80. [PMID: 3298686 PMCID: PMC255702 DOI: 10.1128/jvi.61.8.2573-2580.1987] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cp-1, a small virulent bacteriophage infecting Streptococcus pneumoniae, encodes its own lytic enzyme (CPL). A fragment of Cp-1 DNA containing the gene cpl coding for CPL was cloned and expressed in high amounts in Escherichia coli. CPL was purified to electrophoretic homogeneity by using affinity chromatography on choline-Sepharose (T. Briese and R. Hakenbeck, Eur. J. Biochem. 146:417-427, 1985), and the enzyme showing a Mr of 39,000 was characterized as a muramidase. This muramidase required for in vivo and in vitro activity the presence of choline in the teichoic acids of the pneumococcal cell walls. Free choline or lipoteichoic acid noncompetitively inhibited the activity of CPL.
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36
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Foster SJ, Johnstone K. Purification and properties of a germination-specific cortex-lytic enzyme from spores of Bacillus megaterium KM. Biochem J 1987; 242:573-9. [PMID: 3109395 PMCID: PMC1147743 DOI: 10.1042/bj2420573] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Two peptidoglycan-lytic enzyme activities were isolated from spores of Bacillus megaterium KM. Surface-bound lytic enzyme was extracted from dormant spores and hydrolysed a variety of peptidoglycan substrates including isolated spore cortex, but did not cause refractility changes in permeabilized spores. Germination-specific lytic enzyme activity appeared early in germination and had minimal activity on isolated peptidoglycan substrates, but caused refractility changes in permeabilized spores of several Bacillus isolated peptidoglycan substrates, but caused refractility changes in permeabilized spores of several Bacillus species. The germination-specific lytic enzyme was shown to be a heat-sensitive 29 kDa protein with maximal activity at pH 6.5. It catalysed post-commitment muramic acid delta-lactam synthesis and displayed an inhibitor profile similar to that for post-commitment A600 loss. The relationship of the germination-specific enzyme to a recently proposed model of spore germination is discussed.
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37
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Seligman SJ, Pincus MR. A model for the three-dimensional structure of peptidoglycan in staphylococci. J Theor Biol 1987; 124:275-92. [PMID: 3657196 DOI: 10.1016/s0022-5193(87)80116-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although the monomeric units of peptidoglycan in Staphylococcus aureus and other staphylococci are well known, the complete structure of the peptidoglycan has not been elucidated. The peptidoglycan monomeric unit may be divided into three parts: (1) glycan chain piece, consisting of N-acetylglucosaminyl-N-acetylmuramic acid; (2) connecting peptide extending from L-alanine to the alpha-amino group of L-lysine; (3) peptide chain piece, consisting of D-alanine, the remainder of L-lysine not included in the connecting peptide, and pentaglycine (S. aureus) or mixed glycine and serine residues (other staphylococci) attached to the epsilon amino group of lysine. The deformation of cross wall into hemisphere in the course of cell division, the distensibility of peptidoglycan, and the appearance of circular (? spiral) lines in the cross wall and on the surface of the newly-formed hemisphere are clues to the structure of peptidoglycan. In the proposed model, cross wall is formed as a linear spiral with 20 turns extending in a plane from periphery to center of the cell. During cell division, the cross wall is bisected. The cross wall spiral becomes a spiral forming the peripheral wall of a new hemisphere. The width of the spiral on the cell surface is maintained by rigid glycan chains and by covalent bonds linking turns of the spiral. The length of the spiral is about 30 times the diameter of the cell. Flexible polypeptide sheets consisting of parallel polypeptide chains run along the length of the spiral. Individual polypeptides contain an average of ten peptide chain pieces. The glycan chain is a helix with two disaccharide residues per turn; consequently consecutive connecting peptides project in opposite directions and are perpendicular both to the glycan chain and to the peptide chain. In cross wall, hydrogen bonding between polypeptide chains enables the polypeptide sheet to transmit changes in tension. The deformation of cross wall into peripheral wall requires doubling of the external surface area of the peptidoglycan. A change in the angle of the glycan chain with respect to the peptide chain results in an increase of the distance between peptide chains, causing the doubling of surface area. Implications of the model include explanations for the initiation of cell division and for the existence of osmotically growth-dependent staphylococci.
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Affiliation(s)
- S J Seligman
- Department of Medicine, SUNY Health Science Center at Brooklyn 11203
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Doyle RJ, Koch AL. The functions of autolysins in the growth and division of Bacillus subtilis. Crit Rev Microbiol 1987; 15:169-222. [PMID: 3123142 DOI: 10.3109/10408418709104457] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Some bacteria, such as streptococci, exhibit growth from discrete and well-defined zones. In Streptococcus faecalis, growth zones can be observed in the electron microscope, and the position of the zone can be used as a marker for cell cycle events. Growth of the cell surface of Bacillus subtilis appears to be by a much different mechanism from that of streptococci. Cell elongation takes place by the insertion at many sites in the cell cylinder of peptidoglycan components. The insertion occurs on the inner face of the wall, and upon cross linking, the new wall material becomes stress bearing and older wall is pushed to the surface. When old wall reaches the surface, it becomes susceptible to excision by autolysins, resulting in wall turnover; cell elongation, due to the stretching of the cross-linked peptidoglycan, therefore, accompanies turnover and does not require a specialized growth zone.
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Affiliation(s)
- R J Doyle
- Department of Microbiology and Immunology, University of Louisville Health Sciences Center, Kentucky
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Cheung HY, Freese E. Monovalent cations enable cell wall turnover of the turnover-deficient lyt-15 mutant of Bacillus subtilis. J Bacteriol 1985; 161:1222-5. [PMID: 3918987 PMCID: PMC215031 DOI: 10.1128/jb.161.3.1222-1225.1985] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A lyt-15 mutant reported to be unable to turn over the cell wall exhibited the same rate of wall turnover as the standard strain if the medium contained 0.2 M NaCl, which did not affect growth. Cell wall autolysis was also optimal at 0.2 M NaCl.
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Abstract
Several lines of evidence suggest that Gram-positive bacterial cell surface polymers are synthesized by stepwise addition of polymer subunits to an amphipathic acceptor. In the case of membrane-bound lipopolymers such as mannan and lipoteichoic acid, the finished product may be covalently linked to a lipid anchor. In the case of polymers that are transferred into preexisting cell wall, such as teichoic acid and peptidoglycan, two alternative fates might be possible: (1) transfer into wall with concomitant or later cleavage of the lipid anchor, with recycling of the lipid anchor or secretion of the lipid anchor into the growth medium, and (2) transfer into wall without cleavage of the lipid anchor, resulting in maintenance of the covalent relationship between lipid anchor and polymer chain. In the latter case, a close relationship should be established between the cell wall and the plasma membrane. A number of Gram-positive bacteria have been shown to be resistant to plasmolysis. Therefore, a model for the assembly of the Gram-positive cell wall is proposed which takes into account a role for lipopolymeric intermediates and which views the establishment of resistance to plasmolysis as the natural consequence of such a mechanism.
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Johnstone K, Ellar DJ. The role of cortex hydrolysis in the triggering of germination of Bacillus megaterium KM endospores. Biochim Biophys Acta Gen Subj 1982. [DOI: 10.1016/0304-4165(82)90323-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Thorpe SJ, Perkins HR. Deoxycholate enhancement of an intermediate of peptidoglycan synthesis in Micrococcus luteus. FEBS Lett 1979; 105:151-4. [PMID: 488338 DOI: 10.1016/0014-5793(79)80906-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Schindler M, Mirelman D, Schwarz U. Quantitative determination of N-acetylglucosamine residues at the non-reducing ends of peptidoglycan chains by enzymic attachment of [14C]-D-galactose. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 71:131-4. [PMID: 1009945 DOI: 10.1111/j.1432-1033.1976.tb11098.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The ability of human milk galactosyltransferase to attach D-galactose residues quantitatively to the C-4 of N-acetylglucosamine moieties at the ends of oligosaccharides has been utilized for the specific labeling and quantitative determination of the chain length of the glycan moiety of the bacterial cell wall. The average polysaccharide chain length of the soluble, uncrosslinked peptidoglycan secreted by Micrococcus luteus cells on incubation with penicillin G was studied with this technique and found to be approximately 70 hexosamines long. Furthermore, the peptidoglycan chain length of Escherichia coli sacculi of different cell shapes and dimensions was determined both in rod-shaped cells and in filaments induced by temperature shift of a division mutant or by addition of cephalexin or nalidixic acid. The average chain length found in most of these sacculi was between 70 and 100 hexosamines long. Small spherical 'mini' cells had chain lengths similar to those of the isogenic rod-like cells.
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Verwer RW, Nanninga N. Electron microscopy of isolated cell walls of Bacillus subtilis var. niger. Arch Microbiol 1976; 109:195-7. [PMID: 822796 DOI: 10.1007/bf00425135] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Isolated cell walls of Bacillus subtilis have astriated appearance in the electron microscope. The structure persists when teichoic acids are removed. It is inferred that the structure bears on the arrangement of the peptidoglycan chains.
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