1
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Kunz HH, Armbruster U, Mühlbauer S, de Vries J, Davis GA. Chloroplast ion homeostasis - what do we know and where should we go? THE NEW PHYTOLOGIST 2024. [PMID: 38515227 DOI: 10.1111/nph.19661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 02/01/2024] [Indexed: 03/23/2024]
Abstract
Plant yields heavily depend on proper macro- and micronutrient supply from the soil. In the leaf cells, nutrient ions fulfill specific roles in biochemical reactions, especially photosynthesis housed in the chloroplast. Here, a well-balanced ion homeostasis is maintained by a number of ion transport proteins embedded in the envelope and thylakoid membranes. Ten years ago, the first alkali metal transporters from the K+ EFFLUX ANTIPORTER family were discovered in the model plant Arabidopsis. Since then, our knowledge about the physiological importance of these carriers and their substrates has greatly expanded. New insights into the role of alkali ions in plastid gene expression and photoprotective mechanisms, both prerequisites for plant productivity in natural environments, were gained. The discovery of a Cl- channel in the thylakoid and several additional plastid alkali and alkali metal transport proteins have advanced the field further. Nevertheless, scientists still have long ways to go before a complete systemic understanding of the chloroplast's ion transportome will emerge. In this Tansley review, we highlight and discuss the achievements of the last decade. More importantly, we make recommendations on what areas to prioritize, so the field can reach the next milestones. One area, laid bare by our similarity-based comparisons among phototrophs is our lack of knowledge what ion transporters are used by cyanobacteria to buffer photosynthesis fluctuations.
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Affiliation(s)
- Hans-Henning Kunz
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Ute Armbruster
- Institute of Molecular Photosynthesis, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
- CEPLAS - Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Susanne Mühlbauer
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Jan de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, Goettingen Center for Molecular Biosciences (GZMB), Campus Institute Data Science (CIDAS), University of Goettingen, Goldschmidtstr. 1, D-37077, Göttingen, Germany
| | - Geoffry A Davis
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
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2
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Srivastava R, Singh N, Kanda T, Yadav S, Yadav S, Atri N. Cyanobacterial Proteomics: Diversity and Dynamics. J Proteome Res 2024. [PMID: 38470568 DOI: 10.1021/acs.jproteome.3c00779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Cyanobacteria (oxygenic photoautrophs) comprise a diverse group holding significance both environmentally and for biotechnological applications. The utilization of proteomic techniques has significantly influenced investigations concerning cyanobacteria. Application of proteomics allows for large-scale analysis of protein expression and function within cyanobacterial systems. The cyanobacterial proteome exhibits tremendous functional, spatial, and temporal diversity regulated by multiple factors that continuously modify protein abundance, post-translational modifications, interactions, localization, and activity to meet the dynamic needs of these tiny blue greens. Modern mass spectrometry-based proteomics techniques enable system-wide examination of proteome complexity through global identification and high-throughput quantification of proteins. These powerful approaches have revolutionized our understanding of proteome dynamics and promise to provide novel insights into integrated cellular behavior at an unprecedented scale. In this Review, we present modern methods and cutting-edge technologies employed for unraveling the spatiotemporal diversity and dynamics of cyanobacterial proteomics with a specific focus on the methods used to analyze post-translational modifications (PTMs) and examples of dynamic changes in the cyanobacterial proteome investigated by proteomic approaches.
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Affiliation(s)
| | - Nidhi Singh
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Tripti Kanda
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Sadhana Yadav
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Shivam Yadav
- Department of Botany, University of Allahabad, Allahabad 211002, India
| | - Neelam Atri
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
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3
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Santos-Merino M, Sakkos JK, Singh AK, Ducat DC. Coordination of carbon partitioning and photosynthesis by a two-component signaling network in Synechococcus elongatus PCC 7942. Metab Eng 2024; 81:38-52. [PMID: 37925065 DOI: 10.1016/j.ymben.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/26/2023] [Accepted: 11/02/2023] [Indexed: 11/06/2023]
Abstract
Photosynthetic organisms need to balance the rate of photosynthesis with the utilization of photosynthetic products by downstream reactions. While such "source/sink" pathways are well-interrogated in plants, analogous regulatory systems are unknown or poorly studied in single-celled algal and cyanobacterial species. Towards the identification of energy/sugar sensors in cyanobacteria, we utilized an engineered strain of Synechococcus elongatus PCC 7942 that allows experimental manipulation of carbon status. We conducted a screening of all two-component systems (TCS) and serine/threonine kinases (STKs) encoded in S. elongatus PCC 7942 by analyzing phenotypes consistent with sucrose-induced relaxation of sink inhibition. We narrowed the candidate sensor proteins by analyzing changes observed after sucrose feeding. We show that a clustered TCS network containing RpaA, CikB, ManS and NblS are involved in the regulation of genes related to photosynthesis, pigment synthesis, and Rubisco concentration in response to sucrose. Altogether, these results highlight a regulatory TCS group that may play under-appreciated functions in carbon partitioning and energy balancing in cyanobacteria.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Jonathan K Sakkos
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Amit K Singh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States
| | - Daniel C Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States.
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4
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Wang Y, Ge H, Xiao Z, Huang C, Wang G, Duan X, Zheng L, Dong J, Huang X, Zhang Y, An H, Xu W, Wang Y. Spatial Proteome Reorganization of a Photosynthetic Model Cyanobacterium in Response to Abiotic Stresses. J Proteome Res 2023; 22:1255-1269. [PMID: 36930737 DOI: 10.1021/acs.jproteome.2c00759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
Spatial proteome reorganization in response to a changing environment represents a different layer of adaptation mechanism in addition to differential expression of a subset of stress responsive genes in photosynthetic organisms. Profiling such reorganization events is critically important to extend our understanding how photosynthetic organisms adapt to adverse environments. Thus, we treated a unicellular photosynthetic model cyanobacterium, Synechocystis sp. PCC 6803 (hereafter referred to as Synechocystis), with five different types of abiotic stresses including nitrogen starvation, iron deficiency, cold, heat, and darkness, and systematically identified proteins showing stress-induced differential expression and/or redistribution between the membrane and the soluble fractions using a quantitative proteomics approach. A number of proteins showing such a redistribution in response to a single or multiple types of abiotic stresses were identified. These include 12 ribosomal proteins displaying unanimous cold-induced redistribution to the membrane and the protein FurA, a master regulator of iron acquisition, displaying iron deficiency- and nitrogen starvation-induced redistribution to the membrane. Such findings shed light on a novel regulatory mechanism underlying the corresponding stress responses, and establish the results in the present study as an important resource for future studies intended to understand how photosynthetic organisms cope with adverse environments.
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Affiliation(s)
- Yan Wang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Haitao Ge
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China
| | - Zhen Xiao
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Chengcheng Huang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Gaojie Wang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Xiaoxiao Duan
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Limin Zheng
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Jinghui Dong
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China
| | - Yuanya Zhang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China
| | - Hongyu An
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, United States
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Innovation Academy for Seed Design, CAS, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China
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5
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Burnap RL. Cyanobacterial Bioenergetics in Relation to Cellular Growth and Productivity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:25-64. [PMID: 36764956 DOI: 10.1007/10_2022_215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Cyanobacteria, the evolutionary originators of oxygenic photosynthesis, have the capability to convert CO2, water, and minerals into biomass using solar energy. This process is driven by intricate bioenergetic mechanisms that consist of interconnected photosynthetic and respiratory electron transport chains coupled. Over the last few decades, advances in physiochemical analysis, molecular genetics, and structural analysis have enabled us to gain a more comprehensive understanding of cyanobacterial bioenergetics. This includes the molecular understanding of the primary energy conversion mechanisms as well as photoprotective and other dissipative mechanisms that prevent photodamage when the rates of photosynthetic output, primarily in the form of ATP and NADPH, exceed the rates that cellular assimilatory processes consume these photosynthetic outputs. Despite this progress, there is still much to learn about the systems integration and the regulatory circuits that control expression levels for optimal cellular abundance and activity of the photosynthetic complexes and the cellular components that convert their products into biomass. With an improved understanding of these regulatory principles and mechanisms, it should be possible to optimally modify cyanobacteria for enhanced biotechnological purposes.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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6
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Lambertz J, Liauw P, Whitelegge JP, Nowaczyk MM. Mass spectrometry analysis of the photosystem II assembly factor Psb27 revealed variations in its lipid modification. PHOTOSYNTHESIS RESEARCH 2022; 152:305-316. [PMID: 34910272 PMCID: PMC9458691 DOI: 10.1007/s11120-021-00891-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
The assembly of large, multi-cofactor membrane protein complexes like photosystem II (PSII) requires a high level of coordination. The process is facilitated by a large network of auxiliary proteins that bind transiently to unassembled subunits, preassembled modules or intermediate states of PSII, which are comprised of a subset of subunits. However, analysis of these immature, partially assembled PSII complexes is hampered by their low abundance and intrinsic instability. In this study, PSII was purified from the thermophilic cyanobacterium Thermosynechococcus elongatus via Twin-Strep-tagged CP43 and further separated by ion exchange chromatography into mature and immature complexes. Mass spectrometry analysis of the immature Psb27-PSII intermediate revealed six different Psb27 proteoforms with distinct lipid modifications. The maturation and functional role of thylakoid localized lipoproteins are discussed.
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Affiliation(s)
- Jan Lambertz
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Bochum, Germany
| | - Pasqual Liauw
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Bochum, Germany
| | - Julian P Whitelegge
- The Pasarow Mass Spectrometry Laboratory, David Geffen School of Medicine, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, 90095, USA
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Bochum, Germany.
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7
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Muth-Pawlak D, Kreula S, Gollan PJ, Huokko T, Allahverdiyeva Y, Aro EM. Patterning of the Autotrophic, Mixotrophic, and Heterotrophic Proteomes of Oxygen-Evolving Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2022; 13:891895. [PMID: 35694301 PMCID: PMC9175036 DOI: 10.3389/fmicb.2022.891895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Proteomes of an oxygenic photosynthetic cyanobacterium, Synechocystis sp. PCC 6803, were analyzed under photoautotrophic (low and high CO2, assigned as ATLC and ATHC), photomixotrophic (MT), and light-activated heterotrophic (LAH) conditions. Allocation of proteome mass fraction to seven sub-proteomes and differential expression of individual proteins were analyzed, paying particular attention to photosynthesis and carbon metabolism–centered sub-proteomes affected by the quality and quantity of the carbon source and light regime upon growth. A distinct common feature of the ATHC, MT, and LAH cultures was low abundance of inducible carbon-concentrating mechanisms and photorespiration-related enzymes, independent of the inorganic or organic carbon source. On the other hand, these cells accumulated a respiratory NAD(P)H dehydrogenase I (NDH-11) complex in the thylakoid membrane (TM). Additionally, in glucose-supplemented cultures, a distinct NDH-2 protein, NdbA, accumulated in the TM, while the plasma membrane-localized NdbC and terminal oxidase decreased in abundance in comparison to both AT conditions. Photosynthetic complexes were uniquely depleted under the LAH condition but accumulated under the ATHC condition. The MT proteome displayed several heterotrophic features typical of the LAH proteome, particularly including the high abundance of ribosome as well as amino acid and protein biosynthesis machinery-related components. It is also noteworthy that the two equally light-exposed ATHC and MT cultures allocated similar mass fractions of the total proteome to the seven distinct sub-proteomes. Unique trophic condition-specific expression patterns were likewise observed among individual proteins, including the accumulation of phosphate transporters and polyphosphate polymers storing energy surplus in highly energetic bonds under the MT condition and accumulation under the LAH condition of an enzyme catalyzing cyanophycin biosynthesis. It is concluded that the rigor of cell growth in the MT condition results, to a great extent, by combining photosynthetic activity with high intracellular inorganic carbon conditions created upon glucose breakdown and release of CO2, besides the direct utilization of glucose-derived carbon skeletons for growth. This combination provides the MT cultures with excellent conditions for growth that often exceeds that of mere ATHC.
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8
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Wang J, Huang X, Ge H, Wang Y, Chen W, Zheng L, Huang C, Yang H, Li L, Sui N, Wang Y, Zhang Y, Lu D, Fang L, Xu W, Jiang Y, Huang F, Wang Y. The Quantitative Proteome Atlas of a Model Cyanobacterium. J Genet Genomics 2021; 49:96-108. [PMID: 34775074 DOI: 10.1016/j.jgg.2021.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 09/23/2021] [Accepted: 09/25/2021] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are a group of oxygenic photosynthetic bacteria with great potentials in biotechnological applications and advantages as models for photosynthesis research. The subcellular locations of the majority of proteins in any cyanobacteria remain undetermined, representing a major challenge in using cyanobacteria for both basic and industrial researches. Here, using label free quantitative proteomics we mapped 2027 proteins of Synechocystis sp. PCC6803, a model cyanobacterium, to different subcellular compartments, and generated a proteome atlas with such information. The atlas leads to numerous unexpected but important findings, including the predominant localization of the histidine kinases Hik33 and Hik27 on the thylakoid but not the plasma membrane. Such information completely changes the concept regarding how the two kinases are activated. Together, the atlas provides subcellular localization information for nearly 60% proteome of a model cyanobacterium, and will serve as an important resource for the cyanobacterial research community.
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Affiliation(s)
- Jinlong Wang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Haitao Ge
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Wang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiyang Chen
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Limin Zheng
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengcheng Huang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haomeng Yang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Bejing 100093, China
| | - Lingyu Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Bejing 100093, China
| | - Na Sui
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Science, Shandong Normal University, Jinan 250014, China
| | - Yu Wang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanya Zhang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Longfa Fang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Yuqiang Jiang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Huang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Bejing 100093, China.
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, The Innovative Academy of Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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9
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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: 31] [Impact Index Per Article: 10.3] [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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Dahlgren KK, Gates C, Lee T, Cameron JC. Proximity-based proteomics reveals the thylakoid lumen proteome in the cyanobacterium Synechococcus sp. PCC 7002. PHOTOSYNTHESIS RESEARCH 2021; 147:177-195. [PMID: 33280076 PMCID: PMC7880944 DOI: 10.1007/s11120-020-00806-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Cyanobacteria possess unique intracellular organization. Many proteomic studies have examined different features of cyanobacteria to learn about the intracellular structures and their respective functions. While these studies have made great progress in understanding cyanobacterial physiology, the conventional fractionation methods used to purify cellular structures have limitations; specifically, certain regions of cells cannot be purified with existing fractionation methods. Proximity-based proteomics techniques were developed to overcome the limitations of biochemical fractionation for proteomics. Proximity-based proteomics relies on spatiotemporal protein labeling followed by mass spectrometry of the labeled proteins to determine the proteome of the region of interest. We performed proximity-based proteomics in the cyanobacterium Synechococcus sp. PCC 7002 with the APEX2 enzyme, an engineered ascorbate peroxidase. We determined the proteome of the thylakoid lumen, a region of the cell that has remained challenging to study with existing methods, using a translational fusion between APEX2 and PsbU, a lumenal subunit of photosystem II. Our results demonstrate the power of APEX2 as a tool to study the cell biology of intracellular features and processes, including photosystem II assembly in cyanobacteria, with enhanced spatiotemporal resolution.
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Affiliation(s)
- Kelsey K Dahlgren
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA
- BioFrontiers Institute, University of Colorado, Boulder, CO, 80309, USA
- Interdisciplinary Quantitative Biology Program (IQ Biology), BioFrontiers Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Colin Gates
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Thomas Lee
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA.
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA.
- National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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11
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Oberleitner L, Poschmann G, Macorano L, Schott-Verdugo S, Gohlke H, Stühler K, Nowack ECM. The Puzzle of Metabolite Exchange and Identification of Putative Octotrico Peptide Repeat Expression Regulators in the Nascent Photosynthetic Organelles of Paulinella chromatophora. Front Microbiol 2020; 11:607182. [PMID: 33329499 PMCID: PMC7729196 DOI: 10.3389/fmicb.2020.607182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022] Open
Abstract
The endosymbiotic acquisition of mitochondria and plastids more than one billion years ago was central for the evolution of eukaryotic life. However, owing to their ancient origin, these organelles provide only limited insights into the initial stages of organellogenesis. The cercozoan amoeba Paulinella chromatophora contains photosynthetic organelles-termed chromatophores-that evolved from a cyanobacterium ∼100 million years ago, independently from plastids in plants and algae. Despite the more recent origin of the chromatophore, it shows tight integration into the host cell. It imports hundreds of nucleus-encoded proteins, and diverse metabolites are continuously exchanged across the two chromatophore envelope membranes. However, the limited set of chromatophore-encoded solute transporters appears insufficient for supporting metabolic connectivity or protein import. Furthermore, chromatophore-localized biosynthetic pathways as well as multiprotein complexes include proteins of dual genetic origin, suggesting that mechanisms evolved that coordinate gene expression levels between chromatophore and nucleus. These findings imply that similar to the situation in mitochondria and plastids, also in P. chromatophora nuclear factors evolved that control metabolite exchange and gene expression in the chromatophore. Here we show by mass spectrometric analyses of enriched insoluble protein fractions that, unexpectedly, nucleus-encoded transporters are not inserted into the chromatophore inner envelope membrane. Thus, despite the apparent maintenance of its barrier function, canonical metabolite transporters are missing in this membrane. Instead we identified several expanded groups of short chromatophore-targeted orphan proteins. Members of one of these groups are characterized by a single transmembrane helix, and others contain amphipathic helices. We hypothesize that these proteins are involved in modulating membrane permeability. Thus, the mechanism generating metabolic connectivity of the chromatophore fundamentally differs from the one for mitochondria and plastids, but likely rather resembles the poorly understood mechanism in various bacterial endosymbionts in plants and insects. Furthermore, our mass spectrometric analysis revealed an expanded family of chromatophore-targeted helical repeat proteins. These proteins show similar domain architectures as known organelle-targeted expression regulators of the octotrico peptide repeat type in algae and plants. Apparently these chromatophore-targeted proteins evolved convergently to plastid-targeted expression regulators and are likely involved in gene expression control in the chromatophore.
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Affiliation(s)
- Linda Oberleitner
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Gereon Poschmann
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Luis Macorano
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stephan Schott-Verdugo
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Faculty of Engineering, Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Talca, Chile
| | - Holger Gohlke
- Department of Pharmacy, Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Jülich Supercomputing Centre, John von Neumann Institute for Computing, Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Kai Stühler
- Medical Faculty, Institute for Molecular Medicine, Proteome Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Molecular Proteomics Laboratory, Biologisch-Medizinisches Forschungszentrum, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Eva C. M. Nowack
- Department of Biology, Institute of Microbial Cell Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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12
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Jeong Y, Cho SH, Lee H, Choi HK, Kim DM, Lee CG, Cho S, Cho BK. Current Status and Future Strategies to Increase Secondary Metabolite Production from Cyanobacteria. Microorganisms 2020; 8:E1849. [PMID: 33255283 PMCID: PMC7761380 DOI: 10.3390/microorganisms8121849] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/15/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022] Open
Abstract
Cyanobacteria, given their ability to produce various secondary metabolites utilizing solar energy and carbon dioxide, are a potential platform for sustainable production of biochemicals. Until now, conventional metabolic engineering approaches have been applied to various cyanobacterial species for enhanced production of industrially valued compounds, including secondary metabolites and non-natural biochemicals. However, the shortage of understanding of cyanobacterial metabolic and regulatory networks for atmospheric carbon fixation to biochemical production and the lack of available engineering tools limit the potential of cyanobacteria for industrial applications. Recently, to overcome the limitations, synthetic biology tools and systems biology approaches such as genome-scale modeling based on diverse omics data have been applied to cyanobacteria. This review covers the synthetic and systems biology approaches for advanced metabolic engineering of cyanobacteria.
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Affiliation(s)
- Yujin Jeong
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Sang-Hyeok Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Hookeun Lee
- Institute of Pharmaceutical Research, College of Pharmacy, Gachon University, Incheon 21999, Korea;
| | | | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Korea;
| | - Choul-Gyun Lee
- Department of Biological Engineering, Inha University, Incheon 22212, Korea;
| | - Suhyung Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Byung-Kwan Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
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13
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Russo DA, Zedler JAZ. Genomic insights into cyanobacterial protein translocation systems. Biol Chem 2020; 402:39-54. [PMID: 33544489 DOI: 10.1515/hsz-2020-0247] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023]
Abstract
Cyanobacteria are ubiquitous oxygenic photosynthetic bacteria with a versatile metabolism that is highly dependent on effective protein targeting. Protein sorting in diderm bacteria is not trivial and, in cyanobacteria, even less so due to the presence of a complex membrane system: the outer membrane, the plasma membrane and the thylakoid membrane. In cyanobacteria, protein import into the thylakoids is essential for photosynthesis, export to the periplasm fulfills a multifunctional role in maintaining cell homeostasis, and secretion mediates motility, DNA uptake and environmental interactions. Intriguingly, only one set of genes for the general secretory and the twin-arginine translocation pathways seem to be present. However, these systems have to operate in both plasma and thylakoid membranes. This raises the question of how substrates are recognized and targeted to their correct, final destination. Additional complexities arise when a protein has to be secreted across the outer membrane, where very little is known regarding the mechanisms involved. Given their ecological importance and biotechnological interest, a better understanding of protein targeting in cyanobacteria is of great value. This review will provide insights into the known knowns of protein targeting, propose hypotheses based on available genomic sequences and discuss future directions.
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Affiliation(s)
- David A Russo
- Bioorganic Analytics, Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Julie A Z Zedler
- Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Dornburgerstr. 159, D-07743 Jena, Germany
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14
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Pohland AC, Schneider D. Mg2+ homeostasis and transport in cyanobacteria - at the crossroads of bacterial and chloroplast Mg2+ import. Biol Chem 2020; 400:1289-1301. [PMID: 30913030 DOI: 10.1515/hsz-2018-0476] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/19/2019] [Indexed: 12/29/2022]
Abstract
Magnesium cation (Mg2+) is the most abundant divalent cation in living cells, where it is required for various intracellular functions. In chloroplasts and cyanobacteria, established photosynthetic model systems, Mg2+ is the central ion in chlorophylls, and Mg2+ flux across the thylakoid membrane is required for counterbalancing the light-induced generation of a ΔpH across the thylakoid membrane. Yet, not much is known about Mg2+ homoeostasis, transport and distribution within cyanobacteria. However, Mg2+ transport across membranes has been studied in non-photosynthetic bacteria, and first observations and findings are reported for chloroplasts. Cyanobacterial cytoplasmic membranes appear to contain the well-characterized Mg2+ channels CorA and/or MgtE, which both facilitate transmembrane Mg2+ flux down the electrochemical gradient. Both Mg2+ channels are typical for non-photosynthetic bacteria. Furthermore, Mg2+ transporters of the MgtA/B family are also present in the cytoplasmic membrane to mediate active Mg2+ import into the bacterial cell. While the cytoplasmic membrane of cyanobacteria resembles a 'classical' bacterial membrane, essentially nothing is known about Mg2+ channels and/or transporters in thylakoid membranes of cyanobacteria or chloroplasts. As discussed here, at least one Mg2+ channelling protein must be localized within thylakoid membranes. Thus, either one of the 'typical' bacterial Mg2+ channels has a dual localization in the cytoplasmic plus the thylakoid membrane, or another, yet unidentified channel is present in cyanobacterial thylakoid membranes.
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Affiliation(s)
- Anne-Christin Pohland
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
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15
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Baers LL, Breckels LM, Mills LA, Gatto L, Deery MJ, Stevens TJ, Howe CJ, Lilley KS, Lea-Smith DJ. Proteome Mapping of a Cyanobacterium Reveals Distinct Compartment Organization and Cell-Dispersed Metabolism. PLANT PHYSIOLOGY 2019; 181:1721-1738. [PMID: 31578229 PMCID: PMC6878006 DOI: 10.1104/pp.19.00897] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/11/2019] [Indexed: 05/23/2023]
Abstract
Cyanobacteria are complex prokaryotes, incorporating a Gram-negative cell wall and internal thylakoid membranes (TMs). However, localization of proteins within cyanobacterial cells is poorly understood. Using subcellular fractionation and quantitative proteomics, we produced an extensive subcellular proteome map of an entire cyanobacterial cell, identifying ∼67% of proteins in Synechocystis sp. PCC 6803, ∼1000 more than previous studies. Assigned to six specific subcellular regions were 1,712 proteins. Proteins involved in energy conversion localized to TMs. The majority of transporters, with the exception of a TM-localized copper importer, resided in the plasma membrane (PM). Most metabolic enzymes were soluble, although numerous pathways terminated in the TM (notably those involved in peptidoglycan monomer, NADP+, heme, lipid, and carotenoid biosynthesis) or PM (specifically, those catalyzing lipopolysaccharide, molybdopterin, FAD, and phylloquinol biosynthesis). We also identified the proteins involved in the TM and PM electron transport chains. The majority of ribosomal proteins and enzymes synthesizing the storage compound polyhydroxybuyrate formed distinct clusters within the data, suggesting similar subcellular distributions to one another, as expected for proteins operating within multicomponent structures. Moreover, heterogeneity within membrane regions was observed, indicating further cellular complexity. Cyanobacterial TM protein localization was conserved in Arabidopsis (Arabidopsis thaliana) chloroplasts, suggesting similar proteome organization in more developed photosynthetic organisms. Successful application of this technique in Synechocystis suggests it could be applied to mapping the proteomes of other cyanobacteria and single-celled organisms. The organization of the cyanobacterial cell revealed here substantially aids our understanding of these environmentally and biotechnologically important organisms.
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Affiliation(s)
- Laura L Baers
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Lisa M Breckels
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
- Computational Proteomics Unit, Cambridge Centre for Proteomics, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Lauren A Mills
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Laurent Gatto
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
- Computational Proteomics Unit, Cambridge Centre for Proteomics, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Michael J Deery
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Tim J Stevens
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH United Kingdom
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Kathryn S Lilley
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - David J Lea-Smith
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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16
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Lysine Propionylation is a Widespread Post-Translational Modification Involved in Regulation of Photosynthesis and Metabolism in Cyanobacteria. Int J Mol Sci 2019; 20:ijms20194792. [PMID: 31561603 PMCID: PMC6801645 DOI: 10.3390/ijms20194792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/31/2022] Open
Abstract
Lysine propionylation is a reversible and widely distributed post-translational modification that is known to play a regulatory role in both eukaryotes and prokaryotes. However, the extent and function of lysine propionylation in photosynthetic organisms remains unclear. Cyanobacteria are the most ancient group of Gram-negative bacteria capable of oxygenic photosynthesis, and are of great importance to global carbon and nitrogen cycles. Here, we carried out a systematic study of lysine propionylaiton in cyanobacteria where we used Synechocystis sp. PCC 6803 (Synechocystis) as a model. Combining high-affinity anti-propionyllysine pan antibodies with high-accuracy mass spectrometry (MS) analysis, we identified 111 unique lysine propionylation sites on 69 proteins in Synechocystis. Further bioinformatic analysis showed that a large fraction of the propionylated proteins were involved in photosynthesis and metabolism. The functional significance of lysine propionylation on the enzymatic activity of fructose-1,6-bisphosphatase (FbpI) was studied by site-directed mutagenesis and biochemical studies. Further functional studies revealed that the propionylation level of subunit II of photosystem I (PsaD) was obviously increased after high light (HL) treatment, suggesting that propionylation may be involved in high light adaption in Synechocystis. Thus, our findings provide novel insights into the range of functions regulated by propionylation and reveal that reversible propionylation is a functional modification with the potential to regulate photosynthesis and carbon metabolism in Synechocystis, as well as in other photosynthetic organisms.
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17
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Deng X, Zhen S, Liu D, Liu Y, Li M, Liu N, Yan Y. Integrated proteome analyses of wheat glume and awn reveal central drought response proteins under water deficit conditions. JOURNAL OF PLANT PHYSIOLOGY 2019; 232:270-283. [PMID: 30540969 DOI: 10.1016/j.jplph.2018.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Integrated proteome analyses revealed differentially accumulated proteins in the non-leaf green organs in wheat glume and awn that play important roles in photosynthesis and drought resistance. Two non-leaf green organs in wheat, glume and awn, have photosynthetic potential, contribute to grain yield, and also play roles in resistance to adverse conditions. We performed the first integrated proteome analysis of wheat glume and awn in response to water deficit. Water deficit caused a significant decrease in important agronomic traits and grain yield. A total of 120 and 77 differentially accumulated protein (DAP) spots, representing 100 and 67 unique proteins responsive to water deficit, were identified by two-dimensional difference gel electrophoresis (2D-DIGE) in glumes and awns, respectively, of the elite Chinese bread wheat cultivar Zhongmai 175. The DAPs of both organs showed similar functional classification and proportion and were mainly involved in photosynthesis, detoxification/defense, carbon/energy metabolism, and proteometabolism. Comparative proteome analyses revealed many more drought-responsive DAP spots in glumes than in awns, which indicate that glumes underwent more proteome changes in response to water deficit. The main DAPs involved in photosynthesis and carbon metabolism were significantly downregulated, whereas those related to detoxification/defense and energy metabolism were markedly upregulated under water deficit. The potential functions of the identified DAPs revealed an intricate interaction network that responds synergistically to drought stress during grain development. Our results from the proteome perspective illustrate the potential roles of wheat non-leaf green organs glume and awn in photosynthetic and defensive responses under drought stress.
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Affiliation(s)
- Xiong Deng
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Shoumin Zhen
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Dongmiao Liu
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Yue Liu
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Mengfei Li
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Nannan Liu
- College of Life Science, Capital Normal University, 100048, Beijing, China.
| | - Yueming Yan
- College of Life Science, Capital Normal University, 100048, Beijing, China.
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18
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Battchikova N, Muth-Pawlak D, Aro EM. Proteomics of cyanobacteria: current horizons. Curr Opin Biotechnol 2018; 54:65-71. [DOI: 10.1016/j.copbio.2018.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 12/01/2022]
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19
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Huokko T, Muth-Pawlak D, Battchikova N, Allahverdiyeva Y, Aro EM. Role of Type 2 NAD(P)H Dehydrogenase NdbC in Redox Regulation of Carbon Allocation in Synechocystis. PLANT PHYSIOLOGY 2017; 174:1863-1880. [PMID: 28533358 PMCID: PMC5490909 DOI: 10.1104/pp.17.00398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/19/2017] [Indexed: 05/21/2023]
Abstract
NAD(P)H dehydrogenases comprise type 1 (NDH-1) and type 2 (NDH-2s) enzymes. Even though the NDH-1 complex is a well-characterized protein complex in the thylakoid membrane of Synechocystis sp. PCC 6803 (hereafter Synechocystis), the exact roles of different NDH-2s remain poorly understood. To elucidate this question, we studied the function of NdbC, one of the three NDH-2s in Synechocystis, by constructing a deletion mutant (ΔndbC) for a corresponding protein and submitting the mutant to physiological and biochemical characterization as well as to comprehensive proteomics analysis. We demonstrate that the deletion of NdbC, localized to the plasma membrane, affects several metabolic pathways in Synechocystis in autotrophic growth conditions without prominent effects on photosynthesis. Foremost, the deletion of NdbC leads, directly or indirectly, to compromised sugar catabolism, to glycogen accumulation, and to distorted cell division. Deficiencies in several sugar catabolic routes were supported by severe retardation of growth of the ΔndbC mutant under light-activated heterotrophic growth conditions but not under mixotrophy. Thus, NdbC has a significant function in regulating carbon allocation between storage and the biosynthesis pathways. In addition, the deletion of NdbC increases the amount of cyclic electron transfer, possibly via the NDH-12 complex, and decreases the expression of several transporters in ambient CO2 growth conditions.
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Affiliation(s)
- Tuomas Huokko
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Dorota Muth-Pawlak
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Natalia Battchikova
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
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20
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Gandini C, Schmidt SB, Husted S, Schneider A, Leister D. The transporter SynPAM71 is located in the plasma membrane and thylakoids, and mediates manganese tolerance in Synechocystis PCC6803. THE NEW PHYTOLOGIST 2017; 215:256-268. [PMID: 28318016 DOI: 10.1111/nph.14526] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/19/2017] [Indexed: 05/24/2023]
Abstract
Manganese (Mn) is an essential constituent of photosystem II (PSII) and therefore indispensable for oxygenic photosynthesis. Very little is known about how Mn is transported, delivered and retained in photosynthetic cells. Recently, the thylakoid-localized transporter PAM71 has been linked to chloroplast Mn homeostasis in Arabidopsis thaliana. Here, we characterize the function of its homolog in Synechocystis (SynPAM71). We used a loss-of-function line (ΔSynPAM71), wild-type (WT) cells exposed to Mn stress and strains expressing a tagged variant of SynPAM71 to characterize the role of SynPAM71 in cyanobacterial Mn homeostasis. The ΔSynPAM71 strain displays an Mn-sensitive phenotype with reduced levels of chlorophyll and PSI accumulation, defects in PSII photochemistry and intracellular Mn enrichment, particularly in the thylakoid membranes. These effects are attributable to Mn toxicity, as very similar symptoms were observed in WT cells exposed to excess Mn. Moreover, CyanoP, which is involved in the early steps of PSII assembly, is massively upregulated in ΔSynPAM71. SynPAM71 was detected in both the plasma membrane and, to a lesser extent, the thylakoid membranes. Our results suggest that SynPAM71 is involved in the maintenance of Mn homeostasis through the export of Mn from the cytoplasm into the periplasmic and luminal compartments, where it can be stored without interfering with cytoplasmic metabolic processes.
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Affiliation(s)
- Chiara Gandini
- Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Martinsried, 82152, Germany
| | - Sidsel Birkelund Schmidt
- Department of Plant and Environmental Sciences and Copenhagen Plant Science Centre (CPSC), Faculty of Science, University of Copenhagen, Frederiksberg C, 1871, Denmark
| | - Søren Husted
- Department of Plant and Environmental Sciences and Copenhagen Plant Science Centre (CPSC), Faculty of Science, University of Copenhagen, Frederiksberg C, 1871, Denmark
| | - Anja Schneider
- Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Martinsried, 82152, Germany
| | - Dario Leister
- Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Martinsried, 82152, Germany
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21
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Brandenburg F, Schoffman H, Kurz S, Krämer U, Keren N, Weber APM, Eisenhut M. The Synechocystis Manganese Exporter Mnx Is Essential for Manganese Homeostasis in Cyanobacteria. PLANT PHYSIOLOGY 2017; 173:1798-1810. [PMID: 28153926 PMCID: PMC5338678 DOI: 10.1104/pp.16.01895] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/26/2017] [Indexed: 05/05/2023]
Abstract
The essential micronutrient manganese (Mn) functions as redox-active cofactor in active sites of enzymes and, thus, is involved in various physiological reactions. Moreover, in oxygenic photosynthetic organisms, Mn is of special importance, since it is central to the oxygen-evolving complex in photosystem II. Although Mn is an essential micronutrient, increased amounts are detrimental to the organism; thus, only a small window exists for beneficial concentrations. Accordingly, Mn homeostasis must be carefully maintained. In contrast to the well-studied uptake mechanisms in cyanobacteria, it is largely unknown how Mn is distributed to the different compartments inside the cell. We identified a protein with so far unknown function as a hypothetical Mn transporter in the cyanobacterial model strain Synechocystis sp. PCC 6803 and named this protein Mnx for Mn exporter. The knockout mutant Δmnx showed increased sensitivity toward externally supplied Mn and Mn toxicity symptoms, which could be linked to intracellular Mn accumulation. 54Mn chase experiments demonstrated that the mutant was not able to release Mn from the internal pool. Microscopic analysis of a Mnx::yellow fluorescent protein fusion showed that the protein resides in the thylakoid membrane. Heterologous expression of mnx suppressed the Mn-sensitive phenotype of the Saccharomyces cerevisiae mutant Δpmr1 Our results indicate that Mnx functions as a thylakoid Mn transporter and is a key player in maintaining Mn homeostasis in Synechocystis sp. PCC 6803. We propose that Mn export from the cytoplasm into the thylakoid lumen is crucial to prevent toxic cytoplasmic Mn accumulation and to ensure Mn provision to photosystem II.
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Affiliation(s)
- Fabian Brandenburg
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Hanan Schoffman
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Samantha Kurz
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Ute Krämer
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Nir Keren
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
| | - Marion Eisenhut
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science, Heinrich Heine University, 40225 Duesseldorf, Germany (F.B., S.K., A.P.M.W., M.E.)
- Department of Plant and Environmental Sciences, Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel (H.S., N.K.); and
- Department of Plant Physiology, Ruhr University, 44801 Bochum, Germany (U.K.)
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22
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Bhuiyan NH, Friso G, Rowland E, Majsec K, van Wijk KJ. The Plastoglobule-Localized Metallopeptidase PGM48 Is a Positive Regulator of Senescence in Arabidopsis thaliana. THE PLANT CELL 2016; 28:3020-3037. [PMID: 27895226 PMCID: PMC5240743 DOI: 10.1105/tpc.16.00745] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/08/2016] [Accepted: 11/19/2016] [Indexed: 05/18/2023]
Abstract
Plastoglobuli (PG) are thylakoid-associated monolayer lipid particles with a specific proteome of ∼30 PG core proteins and isoprenoid and neutral lipids. During senescence, PGs increase in size, reflecting their role in dismantling thylakoid membranes. Here, we show that the only PG-localized peptidase PGM48 positively regulates leaf senescence. We discovered that PGM48 is a member of the M48 peptidase family with PGM48 homologs, forming a clade (M48D) only found in photosynthetic organisms. Unlike the M48A, B, and C clades, members of M48D have no transmembrane domains, consistent with their unique subcellular location in the PG. In vitro assays showed Zn-dependent proteolytic activity and substrate cleavage upstream of hydrophobic residues. Overexpression of PGM48 accelerated natural leaf senescence, whereas suppression delayed senescence. Quantitative proteomics of PG from senescing rosettes of PGM48 overexpression lines showed a dramatically reduced level of CAROTENOID CLEAVAGE ENZYME4 (CCD4) and significantly increased levels of the senescence-induced ABC1 KINASE7 (ABC1K7) and PHYTYL ESTER SYNTHASE1 (PES1). Yeast two-hybrid experiments identified PG core proteins ABC1K3, PES1, and CCD4 as PGM48 interactors, whereas several other PG-localized proteins and chlorophyll degradation enzymes did not interact. We discuss mechanisms through which PGM48 could possibly accelerate the senescence process.
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Affiliation(s)
- Nazmul H Bhuiyan
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Giulia Friso
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Elden Rowland
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Kristina Majsec
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Klaas J van Wijk
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
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23
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Unique attributes of cyanobacterial metabolism revealed by improved genome-scale metabolic modeling and essential gene analysis. Proc Natl Acad Sci U S A 2016; 113:E8344-E8353. [PMID: 27911809 DOI: 10.1073/pnas.1613446113] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The model cyanobacterium, Synechococcus elongatus PCC 7942, is a genetically tractable obligate phototroph that is being developed for the bioproduction of high-value chemicals. Genome-scale models (GEMs) have been successfully used to assess and engineer cellular metabolism; however, GEMs of phototrophic metabolism have been limited by the lack of experimental datasets for model validation and the challenges of incorporating photon uptake. Here, we develop a GEM of metabolism in S. elongatus using random barcode transposon site sequencing (RB-TnSeq) essential gene and physiological data specific to photoautotrophic metabolism. The model explicitly describes photon absorption and accounts for shading, resulting in the characteristic linear growth curve of photoautotrophs. GEM predictions of gene essentiality were compared with data obtained from recent dense-transposon mutagenesis experiments. This dataset allowed major improvements to the accuracy of the model. Furthermore, discrepancies between GEM predictions and the in vivo dataset revealed biological characteristics, such as the importance of a truncated, linear TCA pathway, low flux toward amino acid synthesis from photorespiration, and knowledge gaps within nucleotide metabolism. Coupling of strong experimental support and photoautotrophic modeling methods thus resulted in a highly accurate model of S. elongatus metabolism that highlights previously unknown areas of S. elongatus biology.
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24
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MacCready JS, Schossau J, Osteryoung KW, Ducat DC. Robust Min-system oscillation in the presence of internal photosynthetic membranes in cyanobacteria. Mol Microbiol 2016; 103:483-503. [PMID: 27891682 DOI: 10.1111/mmi.13571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2016] [Indexed: 11/29/2022]
Abstract
The oscillatory Min system of Escherichia coli defines the cell division plane by regulating the site of FtsZ-ring formation and represents one of the best-understood examples of emergent protein self-organization in nature. The oscillatory patterns of the Min-system proteins MinC, MinD and MinE (MinCDE) are strongly dependent on the geometry of membranes they bind. Complex internal membranes within cyanobacteria could disrupt this self-organization by sterically occluding or sequestering MinCDE from the plasma membrane. Here, it was shown that the Min system in the cyanobacterium Synechococcus elongatus PCC 7942 oscillates from pole-to-pole despite the potential spatial constraints imposed by their extensive thylakoid network. Moreover, reaction-diffusion simulations predict robust oscillations in modeled cyanobacterial cells provided that thylakoid network permeability is maintained to facilitate diffusion, and suggest that Min proteins require preferential affinity for the plasma membrane over thylakoids to correctly position the FtsZ ring. Interestingly, in addition to oscillating, MinC exhibits a midcell localization dependent on MinD and the DivIVA-like protein Cdv3, indicating that two distinct pools of MinC are coordinated in S. elongatus. Our results provide the first direct evidence for Min oscillation outside of E. coli and have broader implications for Min-system function in bacteria and organelles with internal membrane systems.
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Affiliation(s)
- Joshua S MacCready
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Jory Schossau
- Department of Computer Science, Michigan State University, East Lansing, MI, 48824, USA
| | | | - Daniel C Ducat
- Department of Biochemistry, MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
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25
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Heinz S, Rast A, Shao L, Gutu A, Gügel IL, Heyno E, Labs M, Rengstl B, Viola S, Nowaczyk MM, Leister D, Nickelsen J. Thylakoid Membrane Architecture in Synechocystis Depends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins. THE PLANT CELL 2016; 28:2238-2260. [PMID: 27543090 PMCID: PMC5059811 DOI: 10.1105/tpc.16.00491] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/05/2016] [Accepted: 08/17/2016] [Indexed: 05/21/2023]
Abstract
Photosynthesis occurs in thylakoids, a highly specialized membrane system. In the cyanobacterium Synechocystis sp PCC 6803 (hereafter Synechocystis 6803), the thylakoids are arranged parallel to the plasma membrane and occasionally converge toward it to form biogenesis centers. The initial steps in PSII assembly are thought to take place in these regions, which contain a membrane subcompartment harboring the early assembly factor PratA and are referred to as PratA-defined membranes (PDMs). Loss of CurT, the Synechocystis 6803 homolog of Arabidopsis thaliana grana-shaping proteins of the CURVATURE THYLAKOID1 family, results in disrupted thylakoid organization and the absence of biogenesis centers. As a consequence, PSII is less efficiently assembled and accumulates to only 50% of wild-type levels. CurT induces membrane curvature in vitro and is distributed all over the thylakoids, with local concentrations at biogenesis centers. There it forms a sophisticated tubular network at the cell periphery, as revealed by live-cell imaging. CurT is part of several high molecular mass complexes, and Blue Native/SDS-PAGE and isoelectric focusing demonstrated that different isoforms associate with PDMs and thylakoids. Moreover, CurT deficiency enhances sensitivity to osmotic stress, adding a level of complexity to CurT function. We propose that CurT is crucial for the differentiation of membrane architecture, including the formation of PSII-related biogenesis centers, in Synechocystis 6803.
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Affiliation(s)
- Steffen Heinz
- Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Anna Rast
- Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Lin Shao
- Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Andrian Gutu
- Department of Molecular and Cellular Biology, FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Irene L Gügel
- Biochemie und Physiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Department of Chemistry and Biochemistry, 81377 Munich, Germany
| | - Eiri Heyno
- Biochemie der Pflanzen, Ruhr-Universität Bochum, 44801 Bochum, Germany
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim an der Ruhr, Germany
| | - Mathias Labs
- Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Birgit Rengstl
- Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Stefania Viola
- Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Marc M Nowaczyk
- Biochemie der Pflanzen, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Dario Leister
- Molekularbiologie der Pflanzen, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
| | - Jörg Nickelsen
- Molekulare Pflanzenwissenschaften, Ludwig-Maximilians-Universität München, Biozentrum, 82152 Planegg-Martinsried, Germany
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26
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Comparative Community Proteomics Demonstrates the Unexpected Importance of Actinobacterial Glycoside Hydrolase Family 12 Protein for Crystalline Cellulose Hydrolysis. mBio 2016; 7:mBio.01106-16. [PMID: 27555310 PMCID: PMC4999548 DOI: 10.1128/mbio.01106-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glycoside hydrolases (GHs) are key enzymes in the depolymerization of plant-derived cellulose, a process central to the global carbon cycle and the conversion of plant biomass to fuels and chemicals. A limited number of GH families hydrolyze crystalline cellulose, often by a processive mechanism along the cellulose chain. During cultivation of thermophilic cellulolytic microbial communities, substantial differences were observed in the crystalline cellulose saccharification activities of supernatants recovered from divergent lineages. Comparative community proteomics identified a set of cellulases from a population closely related to actinobacterium Thermobispora bispora that were highly abundant in the most active consortium. Among the cellulases from T. bispora, the abundance of a GH family 12 (GH12) protein correlated most closely with the changes in crystalline cellulose hydrolysis activity. This result was surprising since GH12 proteins have been predominantly characterized as enzymes active on soluble polysaccharide substrates. Heterologous expression and biochemical characterization of the suite of T. bispora hydrolytic cellulases confirmed that the GH12 protein possessed the highest activity on multiple crystalline cellulose substrates and demonstrated that it hydrolyzes cellulose chains by a predominantly random mechanism. This work suggests that the role of GH12 proteins in crystalline cellulose hydrolysis by cellulolytic microbes should be reconsidered. Cellulose is the most abundant organic polymer on earth, and its enzymatic hydrolysis is a key reaction in the global carbon cycle and the conversion of plant biomass to biofuels. The glycoside hydrolases that depolymerize crystalline cellulose have been primarily characterized from isolates. In this study, we demonstrate that adapting microbial consortia from compost to grow on crystalline cellulose generated communities whose soluble enzymes exhibit differential abilities to hydrolyze crystalline cellulose. Comparative proteomics of these communities identified a protein of glycoside hydrolase family 12 (GH12), a family of proteins previously observed to primarily hydrolyze soluble substrates, as a candidate that accounted for some of the differences in hydrolytic activities. Heterologous expression confirmed that the GH12 protein identified by proteomics was active on crystalline cellulose and hydrolyzed cellulose by a random mechanism, in contrast to most cellulases that act on the crystalline polymer in a processive mechanism.
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27
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Zhu Y, Liberton M, Pakrasi HB. A Novel Redoxin in the Thylakoid Membrane Regulates the Titer of Photosystem I. J Biol Chem 2016; 291:18689-99. [PMID: 27382055 DOI: 10.1074/jbc.m116.721175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Indexed: 11/06/2022] Open
Abstract
In photosynthetic organisms like cyanobacteria and plants, the main engines of oxygenic photosynthesis are the pigment-protein complexes photosystem I (PSI) and photosystem II (PSII) located in the thylakoid membrane. In the cyanobacterium Synechocystis sp. PCC 6803, the slr1796 gene encodes a single cysteine thioredoxin-like protein, orthologs of which are found in multiple cyanobacterial strains as well as chloroplasts of higher plants. Targeted inactivation of slr1796 in Synechocystis 6803 resulted in compromised photoautotrophic growth. The mutant displayed decreased chlorophyll a content. These changes correlated with a decrease in the PSI titer of the mutant cells, whereas the PSII content was unaffected. In the mutant, the transcript levels of genes for PSI structural and accessory proteins remained unaffected, whereas the levels of PSI structural proteins were severely diminished, indicating that Slr1796 acts at a posttranscriptional level. Biochemical analysis indicated that Slr1796 is an integral thylakoid membrane protein. We conclude that Slr1796 is a novel regulatory factor that modulates PSI titer.
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Affiliation(s)
- Yuehui Zhu
- From the Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Michelle Liberton
- From the Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Himadri B Pakrasi
- From the Department of Biology, Washington University, St. Louis, Missouri 63130
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