1
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Vasileiadis S, Perruchon C, Scheer B, Adrian L, Steinbach N, Trevisan M, Plaza-Bolaños P, Agüera A, Chatzinotas A, Karpouzas DG. Nutritional inter-dependencies and a carbazole-dioxygenase are key elements of a bacterial consortium relying on a Sphingomonas for the degradation of the fungicide thiabendazole. Environ Microbiol 2022; 24:5105-5122. [PMID: 35799498 DOI: 10.1111/1462-2920.16116] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/28/2022]
Abstract
Thiabendazole (TBZ), is a persistent fungicide/anthelminthic and a serious environmental threat. We previously enriched a TBZ-degrading bacterial consortium and provided first evidence for a Sphingomonas involvement in TBZ transformation. Here, using a multi-omic approach combined with DNA-stable isotope probing (SIP) we verified the key degrading role of Sphingomonas and identify potential microbial interactions governing consortium functioning. SIP and amplicon sequencing analysis of the heavy and light DNA fraction of cultures grown on 13 C-labelled versus 12 C-TBZ showed that 66% of the 13 C-labelled TBZ was assimilated by Sphingomonas. Metagenomic analysis retrieved 18 metagenome-assembled genomes with the dominant belonging to Sphingomonas, Sinobacteriaceae, Bradyrhizobium, Filimonas and Hydrogenophaga. Meta-transcriptomics/-proteomics and non-target mass spectrometry suggested TBZ transformation by Sphingomonas via initial cleavage by a carbazole dioxygenase (car) to thiazole-4-carboxamidine (terminal compound) and catechol or a cleaved benzyl ring derivative, further transformed through an ortho-cleavage (cat) pathway. Microbial co-occurrence and gene expression networks suggested strong interactions between Sphingomonas and a Hydrogenophaga. The latter activated its cobalamin biosynthetic pathway and Sphingomonas its cobalamin salvage pathway to satisfy its B12 auxotrophy. Our findings indicate microbial interactions aligning with the 'black queen hypothesis' where Sphingomonas (detoxifier, B12 recipient) and Hydrogenophaga (B12 producer, enjoying detoxification) act as both helpers and beneficiaries.
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Affiliation(s)
- Sotirios Vasileiadis
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis, Greece
| | - Chiara Perruchon
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis, Greece
| | - Benjamin Scheer
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Lorenz Adrian
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.,Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany
| | - Nicole Steinbach
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Marco Trevisan
- Department of Sustainable Food Process, Universitá Cattolica del Sacro Cuore, Piacenza, Italy
| | - Patricia Plaza-Bolaños
- Solar Energy Research Centre (CIESOL), Joint Center University of Almería-CIEMAT, Almeria, Spain
| | - Ana Agüera
- Solar Energy Research Centre (CIESOL), Joint Center University of Almería-CIEMAT, Almeria, Spain
| | - Antonis Chatzinotas
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.,Institute of Biology, Leipzig University, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Dimitrios G Karpouzas
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis, Greece
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2
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Zhang N, Li K, Xie BB, Chen XL, Zhou BC, Su HN, Zhang YZ. Fluorescence recovery after photobleaching: analyses of cyanobacterial phycobilisomes reveal intrinsic fluorescence recovery. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:427-433. [PMID: 37073268 PMCID: PMC10077209 DOI: 10.1007/s42995-021-00104-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 04/08/2021] [Indexed: 05/03/2023]
Abstract
Fluorescence recovery after photobleaching (FRAP) has been used to study the dynamics of the cyanobacterial photosynthesis apparatus since 1997. Fluorescence recovery of cyanobacteria during FRAP was conventionally interpreted as a result of phycobilisome (PBS) diffusion on the surface of the thylakoid membrane. The mechanism of state transition in cyanobacteria has been widely attributed to PBS diffusion. However, in red algae, another PBS-containing group, the intrinsic photoprocess was found to contribute greatly to the fluorescence recovery of PBS, which raises questions concerning the role of FRAP in red algal PBS. Therefore, it is important to re-evaluate the nature of PBS fluorescence recovery in cyanobacteria. In the present study, four cyanobacterial strains with different phenotypes and PBS compositions were used to investigate their FRAP characteristics. Fluorescence recovery of PBS was observed in wholly photobleached cells in all four cyanobacterial strains, in which the contribution of PBS diffusion to the fluorescence recovery was not possible. Moreover, the fluorescence recovered in isolated PBSs and PBS-thylakoid membranes after photobleaching further demonstrated the intrinsic photoprocess nature of fluorescence recovery. These findings suggest that the intrinsic photoprocess contributed to the fluorescence recovery following photobleaching when measured by the FRAP method.
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Affiliation(s)
- Nan Zhang
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
- College of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353 China
| | - Kang Li
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Bin-Bin Xie
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
| | - Bai-Cheng Zhou
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
| | - Hai-Nan Su
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, 266237 China
- College of Marine Life Sciences, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266237 China
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3
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Current knowledge and recent advances in understanding metabolism of the model cyanobacterium Synechocystis sp. PCC 6803. Biosci Rep 2021; 40:222317. [PMID: 32149336 PMCID: PMC7133116 DOI: 10.1042/bsr20193325] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
Cyanobacteria are key organisms in the global ecosystem, useful models for studying metabolic and physiological processes conserved in photosynthetic organisms, and potential renewable platforms for production of chemicals. Characterizing cyanobacterial metabolism and physiology is key to understanding their role in the environment and unlocking their potential for biotechnology applications. Many aspects of cyanobacterial biology differ from heterotrophic bacteria. For example, most cyanobacteria incorporate a series of internal thylakoid membranes where both oxygenic photosynthesis and respiration occur, while CO2 fixation takes place in specialized compartments termed carboxysomes. In this review, we provide a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in Synechocystis sp. PCC 6803 (Synechocystis) involved in biosynthesis of sugar-based metabolites, amino acids, nucleotides, lipids, cofactors, vitamins, isoprenoids, pigments and cell wall components, in addition to the proteins involved in metabolite transport. While some pathways are conserved between model cyanobacteria, such as Synechocystis, and model heterotrophic bacteria like Escherichia coli, many enzymes and/or pathways involved in the biosynthesis of key metabolites in cyanobacteria have not been completely characterized. These include pathways required for biosynthesis of chorismate and membrane lipids, nucleotides, several amino acids, vitamins and cofactors, and isoprenoids such as plastoquinone, carotenoids, and tocopherols. Moreover, our understanding of photorespiration, lipopolysaccharide assembly and transport, and degradation of lipids, sucrose, most vitamins and amino acids, and haem, is incomplete. We discuss tools that may aid our understanding of cyanobacterial metabolism, notably CyanoSource, a barcoded library of targeted Synechocystis mutants, which will significantly accelerate characterization of individual proteins.
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4
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Bose P, Harit AK, Das R, Sau S, Iyer AK, Kashaw SK. Tuberculosis: current scenario, drug targets, and future prospects. Med Chem Res 2021. [DOI: 10.1007/s00044-020-02691-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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5
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Haranahalli K, Tong S, Kim S, Awwa M, Chen L, Knudson SE, Slayden RA, Singleton E, Russo R, Connell N, Ojima I. Structure-activity relationship studies on 2,5,6-trisubstituted benzimidazoles targeting Mtb-FtsZ as antitubercular agents. RSC Med Chem 2021; 12:78-94. [PMID: 34046600 PMCID: PMC8132993 DOI: 10.1039/d0md00256a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/14/2020] [Indexed: 11/21/2022] Open
Abstract
Filamenting temperature sensitive protein Z (FtsZ) is an essential bacterial cell division protein and a promising target for the development of new antibacterial therapeutics. As a part of our ongoing SAR studies on 2,5,6-trisubstituted benzimidazoles as antitubercular agents targeting Mtb-FtsZ, a new library of compounds with modifications at the 2 position was designed, synthesized and evaluated for their activity against Mtb-H37Rv. This new library of trisubstituted benzimidazoles exhibited MIC values in the range of 0.004-50 μg mL-1. Compounds 6b, 6c, 20f and 20g showed excellent growth inhibitory activities ranging from 0.004-0.08 μg mL-1. This SAR study has led to the discovery of a remarkably potent compound 20g (MIC 0.0039 μg mL-1; normalized MIC 0.015 μg mL-1). Our 3DQSAR model predicted 20g as the most potent compound in the library.
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Affiliation(s)
- Krupanandan Haranahalli
- Institute of Chemical Biology and Drug Discovery, Stony Brook University Stony Brook NY USA
- Department of Chemistry, Stony Brook University Stony Brook NY USA
| | - Simon Tong
- Department of Chemistry, Stony Brook University Stony Brook NY USA
| | - Saerom Kim
- Department of Chemistry, Stony Brook University Stony Brook NY USA
| | - Monaf Awwa
- Department of Chemistry, Stony Brook University Stony Brook NY USA
| | - Lei Chen
- Department of Chemistry, Stony Brook University Stony Brook NY USA
| | - Susan E Knudson
- Department of Microbiology, Immunology and Pathology, Colorado State University Fort Collins Colorado 80523-1682 USA
| | - Richard A Slayden
- Department of Microbiology, Immunology and Pathology, Colorado State University Fort Collins Colorado 80523-1682 USA
| | - Eric Singleton
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University Newark New Jersey 07103 USA
| | - Riccardo Russo
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University Newark New Jersey 07103 USA
| | - Nancy Connell
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University Newark New Jersey 07103 USA
- Department of Physiology, Rutgers University Newark New Jersey 07103 USA
| | - Iwao Ojima
- Institute of Chemical Biology and Drug Discovery, Stony Brook University Stony Brook NY USA
- Department of Chemistry, Stony Brook University Stony Brook NY USA
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6
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Springstein BL, Nürnberg DJ, Weiss GL, Pilhofer M, Stucken K. Structural Determinants and Their Role in Cyanobacterial Morphogenesis. Life (Basel) 2020; 10:E355. [PMID: 33348886 PMCID: PMC7766704 DOI: 10.3390/life10120355] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/04/2020] [Accepted: 12/09/2020] [Indexed: 12/16/2022] Open
Abstract
Cells have to erect and sustain an organized and dynamically adaptable structure for an efficient mode of operation that allows drastic morphological changes during cell growth and cell division. These manifold tasks are complied by the so-called cytoskeleton and its associated proteins. In bacteria, FtsZ and MreB, the bacterial homologs to tubulin and actin, respectively, as well as coiled-coil-rich proteins of intermediate filament (IF)-like function to fulfil these tasks. Despite generally being characterized as Gram-negative, cyanobacteria have a remarkably thick peptidoglycan layer and possess Gram-positive-specific cell division proteins such as SepF and DivIVA-like proteins, besides Gram-negative and cyanobacterial-specific cell division proteins like MinE, SepI, ZipN (Ftn2) and ZipS (Ftn6). The diversity of cellular morphologies and cell growth strategies in cyanobacteria could therefore be the result of additional unidentified structural determinants such as cytoskeletal proteins. In this article, we review the current advances in the understanding of the cyanobacterial cell shape, cell division and cell growth.
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Affiliation(s)
- Benjamin L. Springstein
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Dennis J. Nürnberg
- Department of Physics, Biophysics and Biochemistry of Photosynthetic Organisms, Freie Universität Berlin, 14195 Berlin, Germany;
| | - Gregor L. Weiss
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Martin Pilhofer
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Karina Stucken
- Department of Food Engineering, Universidad de La Serena, La Serena 1720010, Chile;
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7
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Zhang M, Qiao C, Luan G, Luo Q, Lu X. Systematic Identification of Target Genes for Cellular Morphology Engineering in Synechococcus elongatus PCC7942. Front Microbiol 2020; 11:1608. [PMID: 32754143 PMCID: PMC7381316 DOI: 10.3389/fmicb.2020.01608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/19/2020] [Indexed: 11/24/2022] Open
Abstract
Cyanobacteria are serving as promising microbial platforms for development of photosynthetic cell factories. For enhancing the economic competitiveness of the photosynthetic biomanufacturing technology, comprehensive improvements on industrial properties of the cyanobacteria chassis cells and engineered strains are required. Cellular morphology engineering is an up-and-coming strategy for development of microbial cell factories fitting the requirements of industrial application. In this work, we performed systematic evaluation of potential genes for cyanobacterial cellular morphology engineering. Twelve candidate genes participating in cell morphogenesis of an important model cyanobacteria strain, Synechococcus elongatus PCC7942, were knocked out/down and overexpressed, respectively, and the influences on cell sizes and cell shapes were imaged and calculated. Targeting the selected genes with potentials for cellular morphology engineering, the controllable cell lengthening machinery was also explored based on the application of sRNA approaches. The findings in this work not only provided many new targets for cellular morphology engineering in cyanobacteria, but also helped to further understand the cell division process and cell elongation process of Synechococcus elongatus PCC7942.
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Affiliation(s)
- Mingyi Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cuncun Qiao
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guodong Luan
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Quan Luo
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China.,Dalian National Laboratory for Clean Energy, Dalian, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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8
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Synthesis, screening and docking analysis of novel benzimidazolium compounds as potent anti microbial agents targeting FtsZ protein. Microb Pathog 2018; 124:258-265. [PMID: 30149132 DOI: 10.1016/j.micpath.2018.08.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 07/19/2018] [Accepted: 08/23/2018] [Indexed: 02/02/2023]
Abstract
The dominance of multi drug resistance in the clinically significant bacteria led to urgency in the development of new antibiotics with novel mechanism of action. Among the biochemical targets explored for selective toxicity, molecular mechanisms involving cell division remained focal point for novel antimicrobial drug discovery. For this purpose we have performed in-silico studies of FtsZ protein and obtained benzimidazolium compounds as potential hits. These molecules obtained in the dock results were synthesized via reacting benzimidazoles with appropriate benzyl halides. The structures of the synthesized compounds were confirmed by their 1H NMR, 13C NMR, IR and mass spectral data. These were evaluated for anti-microbial activity. Among the tested compounds B14, B15 and B20 have shown highest activity (MIC 5 μg/mL) against Staphylococcus aureus, Macrococcus caseolyticus, Escherichia coli and Pseudomonas aeruginosa. . Microscopic examination of drug-treated cultures of Staphylococcus aureus and Pseudomonas aeruginosa showed rod-shaped filamentous growth of the dividing cells, which is a characteristic feature of FtsZ inhibition.
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9
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Haranahalli K, Tong S, Ojima I. Recent advances in the discovery and development of antibacterial agents targeting the cell-division protein FtsZ. Bioorg Med Chem 2016; 24:6354-6369. [PMID: 27189886 PMCID: PMC5157688 DOI: 10.1016/j.bmc.2016.05.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 01/21/2023]
Abstract
With the emergence of multidrug-resistant bacterial strains, there is a dire need for new drug targets for antibacterial drug discovery and development. Filamentous temperature sensitive protein Z (FtsZ), is a GTP-dependent prokaryotic cell division protein, sharing less than 10% sequence identity with the eukaryotic cell division protein, tubulin. FtsZ forms a dynamic Z-ring in the middle of the cell, leading to septation and subsequent cell division. Inhibition of the Z-ring blocks cell division, thus making FtsZ a highly attractive target. Various groups have been working on natural products and synthetic small molecules as inhibitors of FtsZ. This review summarizes the recent advances in the development of FtsZ inhibitors, focusing on those in the last 5years, but also includes significant findings in previous years.
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Affiliation(s)
| | - Simon Tong
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Iwao Ojima
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA; Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, USA.
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10
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Abstract
Filamenting temperature-sensitive mutant Z (FtsZ), an essential cell division protein in bacteria, has recently emerged as an important and exploitable antibacterial target. Cytokinesis in bacteria is regulated by the assembly dynamics of this protein, which is ubiquitously present in eubacteria. The perturbation of FtsZ assembly has been found to have a deleterious effect on the cytokinetic machinery and, in turn, upon cell survival. FtsZ is highly conserved among prokaryotes, offering the possibility of broad-spectrum antibacterial agents, while its limited sequence homology with tubulin (an essential protein in eukaryotic mitosis) offers the possibility of selective toxicity. This review aims to summarize current knowledge regarding the mechanism of action of FtsZ, and to highlight existing attempts toward the development of clinically useful inhibitors.
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11
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Hurley KA, Santos TMA, Nepomuceno GM, Huynh V, Shaw JT, Weibel DB. Targeting the Bacterial Division Protein FtsZ. J Med Chem 2016; 59:6975-98. [DOI: 10.1021/acs.jmedchem.5b01098] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katherine A. Hurley
- Department of Pharmaceutical Sciences, University of Wisconsin—Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Thiago M. A. Santos
- Department
of Biochemistry, University of Wisconsin—Madison, 440 Henry Mall, Madison, Wisconsin 53706, United States
| | - Gabriella M. Nepomuceno
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Valerie Huynh
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Jared T. Shaw
- Department of Chemistry, University of California—Davis, One Shields Avenue, Davis, California 95616, United States
| | - Douglas B. Weibel
- Department
of Biochemistry, University of Wisconsin—Madison, 440 Henry Mall, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Department of Biomedical Engineering, University of Wisconsin—Madison, 1550 Engineering Drive, Madison, Wisconsin 53706, United States
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12
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Song D, Ma S. Recent Development of Benzimidazole-Containing Antibacterial Agents. ChemMedChem 2016; 11:646-59. [PMID: 26970352 DOI: 10.1002/cmdc.201600041] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 02/20/2016] [Indexed: 11/11/2022]
Abstract
Clinically significant antibiotic resistance is one of the greatest challenges of the twenty-first century. However, new antibacterial agents are currently being developed at a much slower pace than our growing need for such drugs. Given their diverse biological activities and clinical applications, many bioactive heterocyclic compounds containing a benzimidazole nucleus have been the focus of interest for many researchers. The benzimidazole nucleus is a structural isostere of naturally occurring nucleotides. This advantage allows benzimidazoles to readily interact with the various biopolymers found in living systems. In view of this situation, much attention has been given to the exploration of benzimidazole-based antibacterial agents, leading to the discovery of many new chemical entities with intriguing profiles. In this minireview we summarize novel benzimidazole derivatives active against various bacterial strains. In particular, we outline the relationship between the structures of variously modified benzimidazoles and their antibacterial activity.
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Affiliation(s)
- Di Song
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, Jinan, 250012, P.R. China
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, Jinan, 250012, P.R. China.
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13
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Ojima I, Kumar K, Awasthi D, Vineberg JG. Drug discovery targeting cell division proteins, microtubules and FtsZ. Bioorg Med Chem 2014; 22:5060-77. [PMID: 24680057 PMCID: PMC4156572 DOI: 10.1016/j.bmc.2014.02.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/25/2014] [Accepted: 02/18/2014] [Indexed: 12/16/2022]
Abstract
Eukaryotic cell division or cytokinesis has been a major target for anticancer drug discovery. After the huge success of paclitaxel and docetaxel, microtubule-stabilizing agents (MSAs) appear to have gained a premier status in the discovery of next-generation anticancer agents. However, the drug resistance caused by MDR, point mutations, and overexpression of tubulin subtypes, etc., is a serious issue associated with these agents. Accordingly, the discovery and development of new-generation MSAs that can obviate various drug resistances has a significant meaning. In sharp contrast, prokaryotic cell division has been largely unexploited for the discovery and development of antibacterial drugs. However, recent studies on the mechanism of bacterial cytokinesis revealed that the most abundant and highly conserved cell division protein, FtsZ, would be an excellent new target for the drug discovery of next-generation antibacterial agents that can circumvent drug-resistances to the commonly used drugs for tuberculosis, MRSA and other infections. This review describes an account of our research on these two fronts in drug discovery, targeting eukaryotic as well as prokaryotic cell division.
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Affiliation(s)
- Iwao Ojima
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA; Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, USA.
| | - Kunal Kumar
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Divya Awasthi
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Jacob G Vineberg
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
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14
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Singh D, Bhattacharya A, Rai A, Dhaked HPS, Awasthi D, Ojima I, Panda D. SB-RA-2001 inhibits bacterial proliferation by targeting FtsZ assembly. Biochemistry 2014; 53:2979-92. [PMID: 24749867 PMCID: PMC4020581 DOI: 10.1021/bi401356y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
FtsZ
has been recognized as a promising antimicrobial drug target
because of its vital role in bacterial cell division. In this work,
we found that a taxane SB-RA-2001 inhibited the proliferation of Bacillus subtilis 168 and Mycobacterium smegmatis cells with minimal inhibitory concentrations of 38 and 60 μM,
respectively. Cell lengths of these microorganisms increased remarkably
in the presence of SB-RA-2001, indicating that it inhibits bacterial
cytokinesis. SB-RA-2001 perturbed the formation of the FtsZ ring in B. subtilis 168 cells and also affected the localization
of the late cell division protein, DivIVA, at the midcell position.
Flow cytometric analysis of the SB-RA-2001-treated cells indicated
that the compound did not affect the duplication of DNA in B. subtilis 168 cells. Further, SB-RA-2001 treatment did
not affect the localization of the chromosomal partitioning protein,
Spo0J, along the two ends of the nucleoids and also had no discernible
effect on the nucleoid segregation in B. subtilis 168 cells. The agent also did not appear to perturb the membrane
potential of B. subtilis 168 cells. In vitro, SB-RA-2001 bound to FtsZ with modest affinity, promoted the assembly
and bundling of FtsZ protofilaments, and reduced the GTPase activity
of FtsZ. GTP did not inhibit the binding of SB-RA-2001 to FtsZ, suggesting
that it does not bind to the GTP binding site on FtsZ. A computational
analysis indicated that SB-RA-2001 binds to FtsZ in the cleft region
between the C-terminal domain and helix H7, and the binding site of
SB-RA-2001 on FtsZ resembled that of PC190723, a well-characterized
inhibitor of FtsZ. The findings collectively suggested that SB-RA-2001
inhibits bacterial proliferation by targeting the assembly dynamics
of FtsZ, and this can be exploited further to develop potent FtsZ-targeted
antimicrobials.
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Affiliation(s)
- Dipty Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay , Mumbai 400076, India
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15
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Park B, Awasthi D, Chowdhury SR, Melief EH, Kumar K, Knudson SE, Slayden RA, Ojima I. Design, synthesis and evaluation of novel 2,5,6-trisubstituted benzimidazoles targeting FtsZ as antitubercular agents. Bioorg Med Chem 2014; 22:2602-12. [PMID: 24726304 DOI: 10.1016/j.bmc.2014.03.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/12/2014] [Accepted: 03/21/2014] [Indexed: 11/17/2022]
Abstract
Filamenting temperature-sensitive protein Z (FtsZ), an essential cell division protein, is a promising target for the drug discovery of new-generation antibacterial agents against various bacterial pathogens. As a part of SAR studies on benzimidazoles, we have synthesized a library of 376 novel 2,5,6-trisubstituted benzimidazoles, bearing ether or thioether linkage at the 6-position. In a preliminary HTP screening against Mtb H37Rv, 108 compounds were identified as hits at a cut off concentration of 5 μg/mL. Among those hits, 10 compounds exhibited MIC values in the range of 0.63-12.5 μg/mL. Light scattering assay and TEM analysis with the most potent compound 5a clearly indicate that its molecular target is Mtb-FtsZ. Also, the Kd of 5a with Mtb-FtsZ was determined to be 1.32 μM.
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Affiliation(s)
- Bora Park
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Divya Awasthi
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Soumya R Chowdhury
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Eduard H Melief
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Kunal Kumar
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Susan E Knudson
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, United States
| | - Richard A Slayden
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, United States
| | - Iwao Ojima
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, United States.
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16
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Anderson DE, Kim MB, Moore JT, O’Brien TE, Sorto NA, Grove CI, Lackner LL, Ames JB, Shaw JT. Comparison of small molecule inhibitors of the bacterial cell division protein FtsZ and identification of a reliable cross-species inhibitor. ACS Chem Biol 2012; 7:1918-28. [PMID: 22958099 DOI: 10.1021/cb300340j] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
FtsZ is a guanosine triphosphatase (GTPase) that mediates cytokinesis in bacteria. FtsZ is homologous in structure to eukaryotic tubulin and polymerizes in a similar head-to-tail fashion. The study of tubulin's function in eukaryotic cells has benefited greatly from specific and potent small molecule inhibitors, including colchicine and taxol. Although many small molecule inhibitors of FtsZ have been reported, none has emerged as a generally useful probe for modulating bacterial cell division. With the goal of establishing a useful and reliable small molecule inhibitor of FtsZ, a broad biochemical cross-comparison of reported FtsZ inhibitors was undertaken. Several of these molecules, including phenolic natural products, are unselective inhibitors that seem to derive their activity from the formation of microscopic colloids or aggregates. Other compounds, including the natural product viriditoxin and the drug development candidate PC190723, exhibit no inhibition of GTPase activity using protocols in this work or under published conditions. Of the compounds studied, only zantrin Z3 exhibits good levels of inhibition, maintains activity under conditions that disrupt small molecule aggregates, and provides a platform for exploration of structure-activity relationships (SAR). Preliminary SAR studies have identified slight modifications to the two side chains of this structure that modulate the inhibitory activity of zantrin Z3. Collectively, these studies will help focus future investigations toward the establishment of probes for FtsZ that fill the roles of colchicine and taxol in studies of tubulin.
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Affiliation(s)
- David E. Anderson
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Michelle B. Kim
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Jared T. Moore
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Terrence E. O’Brien
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Nohemy A. Sorto
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Charles I. Grove
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Laura L. Lackner
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - James B. Ames
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
| | - Jared T. Shaw
- Department of Chemistry, University of California, One Shields Ave, Davis, California 95616,
United States
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Serbus LR, Landmann F, Bray WM, White PM, Ruybal J, Lokey RS, Debec A, Sullivan W. A cell-based screen reveals that the albendazole metabolite, albendazole sulfone, targets Wolbachia. PLoS Pathog 2012; 8:e1002922. [PMID: 23028321 PMCID: PMC3447747 DOI: 10.1371/journal.ppat.1002922] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 08/07/2012] [Indexed: 12/25/2022] Open
Abstract
Wolbachia endosymbionts carried by filarial nematodes give rise to the neglected diseases African river blindness and lymphatic filariasis afflicting millions worldwide. Here we identify new Wolbachia-disrupting compounds by conducting high-throughput cell-based chemical screens using a Wolbachia-infected, fluorescently labeled Drosophila cell line. This screen yielded several Wolbachia-disrupting compounds including three that resembled Albendazole, a widely used anthelmintic drug that targets nematode microtubules. Follow-up studies demonstrate that a common Albendazole metabolite, Albendazole sulfone, reduces intracellular Wolbachia titer both in Drosophila melanogaster and Brugia malayi, the nematode responsible for lymphatic filariasis. Significantly, Albendazole sulfone does not disrupt Drosophila microtubule organization, suggesting that this compound reduces titer through direct targeting of Wolbachia. Accordingly, both DNA staining and FtsZ immunofluorescence demonstrates that Albendazole sulfone treatment induces Wolbachia elongation, a phenotype indicative of binary fission defects. This suggests that the efficacy of Albendazole in treating filarial nematode-based diseases is attributable to dual targeting of nematode microtubules and their Wolbachia endosymbionts.
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Affiliation(s)
- Laura R Serbus
- Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, USA.
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18
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Ma S, Ma S. The Development of FtsZ Inhibitors as Potential Antibacterial Agents. ChemMedChem 2012; 7:1161-72. [DOI: 10.1002/cmdc.201200156] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/05/2012] [Indexed: 11/12/2022]
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Abstract
The emergence of multidrug-resistant Mycobacterium tuberculosis strains has made many of the currently available anti-tuberculosis (TB) drugs ineffective. Accordingly, there is a pressing need to identify new drug targets. Filamentous temperature-sensitive protein Z (FtsZ), a bacterial tubulin homologue, is an essential cell-division protein that polymerizes in a GTP-dependent manner, forming a highly dynamic cytokinetic ring, designated as the Z ring, at the septum site. Other cell-division proteins are recruited to the Z ring and, upon resolution of the septum, two daughter cells are produced. Since inactivation of FtsZ or alteration of FtsZ assembly results in the inhibition of Z-ring and septum formation, FtsZ is a very promising target for novel antimicrobial drug development. This review describes the function and dynamic behaviors of FtsZ and the recent development of FtsZ inhibitors as potential anti-TB agents.
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Koksharova OA, Babykin MM. Cyanobacterial cell division: Genetics and comparative genomics of cyanobacterial cell division. RUSS J GENET+ 2011. [DOI: 10.1134/s1022795411030070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Awasthi D, Kumar K, Ojima I. Therapeutic potential of FtsZ inhibition: a patent perspective. Expert Opin Ther Pat 2011; 21:657-79. [PMID: 21413908 DOI: 10.1517/13543776.2011.568483] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Filamentous temperature sensitive mutant Z (FtsZ), an essential protein for bacterial cell division, has emerged as an attractive therapeutic target for the development of efficacious antibacterial agents active against drug-sensitive and drug-resistant bacterial strains. Recently, FtsZ has garnered special attention in the antibacterial research field, which is evident by the amount of research papers and patents disclosed in the public domain. Because of the significance of FtsZ as a highly promising target for the development of novel antibacterial agents, it is timely to review the patents on this subject so far published to date. AREAS COVERED This review article covers the patent literature on FtsZ-targeting potential antibacterial agents up to November 2010, including their pharmacological findings. EXPERT OPINION Since FtsZ is well preserved in various bacteria, the FtsZ-targeting agents would act as novel broad-spectrum antibacterial drugs in addition to their use against particular bacteria, especially drug-resistant strains. Based on the increasing interest and advancement in this field of research, it looks almost certain that a good number of clinical candidates targeting FtsZ will emerge in the near future.
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Affiliation(s)
- Divya Awasthi
- State University of New York at Stony Brook, Department of Chemistry, Stony Brook, NY 11794-3400, USA
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Clément MJ, Kuoch BT, Ha-Duong T, Joshi V, Hamon L, Toma F, Curmi PA, Savarin P. The Stathmin-Derived I19L Peptide Interacts with FtsZ and Alters Its Bundling. Biochemistry 2009; 48:9734-44. [DOI: 10.1021/bi900556a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marie-Jeanne Clément
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Boï-trinh Kuoch
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Tap Ha-Duong
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, UMR/UEVE 8587, Evry, 91025 France
| | - Vandana Joshi
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Loïc Hamon
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Flavio Toma
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Patrick A. Curmi
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
| | - Philippe Savarin
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Evry, 91025 France
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23
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Loss of topological relationships in a Pleurocapsalean cyanobacterium (Chroococcidiopsis sp.) with partially inactivatedftsZ. ANN MICROBIOL 2009. [DOI: 10.1007/bf03178322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Mullineaux CW. FRAP analysis of photosynthetic membranes. JOURNAL OF EXPERIMENTAL BOTANY 2004; 55:1207-1211. [PMID: 15020635 DOI: 10.1093/jxb/erh106] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fluorescence Recovery after Photobleaching (FRAP) is a technique widely used in cell biology to observe the dynamics of biological systems, including the diffusion of membrane components. More information is needed on the dynamics of photosynthetic membranes in order to help to understand processes such as photosynthetic electron transport, regulation of light-harvesting, and biogenesis and turnover of the photosynthetic apparatus. FRAP has the potential to provide this information, although applying the technique to photosynthetic membranes is not always straightforward. This review explains the potential and the problems, and gives a brief guide to performing FRAP measurements and analysing the data.
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Affiliation(s)
- Conrad W Mullineaux
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
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25
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Sarcina M, Murata N, Tobin MJ, Mullineaux CW. Lipid diffusion in the thylakoid membranes of the cyanobacterium Synechococcus sp.: effect of fatty acid desaturation. FEBS Lett 2003; 553:295-8. [PMID: 14572639 DOI: 10.1016/s0014-5793(03)01031-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Thylakoid membranes are crucial to photosynthesis in cyanobacteria and plants. In cyanobacteria, genetic modification of membrane lipid composition strongly influences cold tolerance and susceptibility to photoinhibition. We have used fluorescence recovery after photobleaching to measure the diffusion of a lipid-soluble fluorescent marker in cells of the cyanobacterium Synechococcus sp. PCC 7942. We have compared the wild-type strain with a transformant with an increased level of fatty acid unsaturation. The transformant showed a six-fold increase in the diffusion coefficient for the fluorescent marker at growth temperature. This is the first direct measurement of lipid diffusion in a photosynthetic membrane.
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Affiliation(s)
- Mary Sarcina
- Department of Biology, University College London, Darwin Building, Gower Street, WC1E 6BT London, UK
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26
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Mullineaux CW, Sarcina M. Probing the dynamics of photosynthetic membranes with fluorescence recovery after photobleaching. TRENDS IN PLANT SCIENCE 2002; 7:237-240. [PMID: 12049914 DOI: 10.1016/s1360-1385(02)02283-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the past few years, there has been remarkable progress in knowledge of the structures and organization of the protein complexes of photosynthetic membranes. However, static structures do not tell the whole story. Photosynthetic membranes, like other biological membranes, are dynamic systems. Recent technological advances are making it increasingly easy to probe the dynamics of photosynthetic membranes using fluorescence recovery after photobleaching. Here we explain the potential and the limitations of the technique.
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27
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Sarcina M, Tobin MJ, Mullineaux CW. Diffusion of phycobilisomes on the thylakoid membranes of the cyanobacterium Synechococcus 7942. Effects of phycobilisome size, temperature, and membrane lipid composition. J Biol Chem 2001; 276:46830-4. [PMID: 11590154 DOI: 10.1074/jbc.m107111200] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A variant of fluorescence recovery after photobleaching allows us to observe the diffusion of photosynthetic complexes in cyanobacterial thylakoid membranes in vivo. The unicellular cyanobacterium Synechococcus sp. PCC7942 is a wonderful model organism for fluorescence recovery after photobleaching, because it has a favorable membrane geometry and is well characterized and transformable. In Synechococcus 7942 (as in other cyanobacteria) we find that photosystem II is immobile, but phycobilisomes diffuse rapidly on the membrane surface. The diffusion coefficient is 3 x 10(-10) cm(2) s(-1) at 30 degrees C. This shows that the association of phycobilisomes with reaction centers is dynamic; there are no stable phycobilisome-reaction center complexes in vivo. We report the effects of mutations that change the phycobilisome size and membrane lipid composition. 1) In a mutant with no phycobilisome rods, the phycobilisomes remain mobile with a slightly faster diffusion coefficient. This confirms that the diffusion we observe is of intact phycobilisomes rather than detached rod elements. The faster diffusion coefficient in the mutant indicates that the rate of diffusion is partly determined by the phycobilisome size. 2) The temperature dependence of the phycobilisome diffusion coefficient indicates that the phycobilisomes have no integral membrane domain. It is likely that association with the membrane is mediated by multiple weak interactions with lipid head groups. 3) Changing the lipid composition of the thylakoid membrane has a dramatic effect on phycobilisome mobility. The results cannot be explained in terms of changes in the fluidity of the membrane; they suggest that lipids play a role in controlling phycobilisome-reaction center interaction.
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Affiliation(s)
- M Sarcina
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, United Kingdom
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