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Assembly of the Photosystem II Membrane-Protein Complex of Oxygenic Photosynthesis

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452330 Year: Pages: 315 DOI: 10.3389/978-2-88945-233-0 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2017-10-13 14:57:01
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Abstract

Photosystem II is a 700-kDa membrane-protein super-complex responsible for the light-driven splitting of water in oxygenic photosynthesis. The photosystem is comprised of two 350-kDa complexes each made of 20 different polypeptides and over 80 co-factors. While there have been major advances in understanding the mature structure of this photosystem many key protein factors involved in the assembly of the complex do not appear in the holoenzyme. The mechanism for assembling this super-complex is a very active area of research with newly discovered assembly factors and subcomplexes requiring characterization. Additionally the ability to split water is inseparable from light-induced photodamage that arises from radicals and reactive O2 species generated by Photosystem II chemistry. Consequently, to sustain water splitting, a “self repair” cycle has evolved whereby damaged protein is removed and replaced so as to extend the working life of the complex. Understanding how the biogenesis and repair processes are coordinated is among several important questions that remain to be answered. Other questions include: how and when are the inorganic cofactors inserted during the assembly and repair processes and how are the subcomplexes protected from photodamage during assembly? Evidence has also been obtained for Photosystem II biogenesis centers in cyanobacteria but do these also exist in plants? Do the molecular mechanisms associated with Photosystem II assembly shed fresh light on the assembly of other major energy-transducing complexes such as Photosystem I or the cytochrome b6/f complex or indeed other respiratory complexes? The contributions to this Frontiers in Plant Science Research Topic are likely to reveal new details applicable to the assembly of a range of membrane-protein complexes, including aspects of self-assembly and solar energy conversion that may be applied to artificial photosynthetic systems. In addition, a deeper understanding of Photosystem II assembly — particularly in response to changing environmental conditions — will provide new knowledge underpinning photosynthetic yields which may contribute to improved food production and long-term food security.

Thioredoxin and Glutaredoxin Systems

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ISBN: 9783038978367 / 9783038978374 Year: Pages: 280 DOI: 10.3390/books978-3-03897-837-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-06-26 08:44:06
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This Special Issue features recent data concerning thioredoxins and glutaredoxins from various biological systems, including bacteria, mammals, and plants. Four of the sixteen articles are review papers that deal with the regulation of development of the effect of hydrogen peroxide and the interactions between oxidants and reductants, the description of methionine sulfoxide reductases, detoxification enzymes that require thioredoxin or glutaredoxin, and the response of plants to cold stress, respectively. This is followed by eleven research articles that focus on a reductant of thioredoxin in bacteria, a thioredoxin reductase, and a variety of plant and bacterial thioredoxins, including the m, f, o, and h isoforms and their targets. Various parameters are studied, including genetic, structural, and physiological properties of these systems. The redox regulation of monodehydroascorbate reductase, aminolevulinic acid dehydratase, and cytosolic isocitrate dehydrogenase could have very important consequences in plant metabolism. Also, the properties of the mitochondrial o-type thioredoxins and their unexpected capacity to bind iron–sulfur center (ISC) structures open new developments concerning the redox mitochondrial function and possibly ISC assembly in mitochondria. The final paper discusses interesting biotechnological applications of thioredoxin for breadmaking.

Keywords

methionine --- methionine sulfoxide --- methionine sulfoxide reductase --- physiological function --- protein --- plant --- repair --- redox homeostasis --- signaling --- stress --- mitochondria --- thioredoxin --- iron–sulfur cluster --- redox regulation --- ALAD --- tetrapyrrole biosynthesis --- redox control --- thioredoxins --- posttranslational modification --- chlorophyll --- redox regulation --- thioredoxin --- ferredoxin-thioredoxin reductase --- chloroplast --- H2O2 --- redox signalling --- development --- regeneration --- adult stem cells --- metazoan --- cyanobacteria --- thioredoxin --- photosynthesis --- redox active site --- thioredoxin --- disulfide --- flavin --- NADPH --- X-ray crystallography --- SAXS --- methanoarchaea --- chilling stress --- cold temperature --- posttranslational modification --- regulation --- ROS --- thiol redox network --- thioredoxin --- thioredoxin --- Calvin-Benson cycle --- photosynthesis --- carbon fixation --- chloroplast --- macromolecular crystallography --- protein-protein recognition --- electrostatic surface --- Chlamydomonas reinhardtii --- thioredoxin --- glutaredoxin --- legume plant --- symbiosis --- redox homeostasis --- stress --- thioredoxin --- monodehydroascorbate reductase --- water stress --- protein oxidation --- antioxidants --- ascorbate --- glutathione --- wheat --- thioredoxin --- thioredoxin reductase --- baking --- redox --- dough rheology --- protein oxidation --- methionine oxidation --- methionine sulfoxide reductases --- oxidized protein repair --- ageing --- Chlamydomonas reinhardtii --- cysteine alkylation --- cysteine reactivity --- MALDI-TOF mass spectrometry --- thioredoxin --- X-ray crystallography --- Isocitrate dehydrogenase --- glutathionylation --- nitrosylation --- glutaredoxin --- Arabidopsis thaliana --- thioredoxins --- plastidial --- specificity --- function --- proteomic --- photosynthesis --- Calvin cycle --- n/a

Salinity Tolerance in Plants

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ISBN: 9783039210268 / 9783039210275 Year: Pages: 422 DOI: 10.3390/books978-3-03921-027-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Biochemistry
Added to DOAB on : 2019-06-26 10:09:00
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Salt stress is one of the most damaging abiotic stresses because most crop plants are susceptible to salinity to different degrees. According to the FAO, about 800 million Has of land are affected by salinity worldwide. Unfortunately, this situation will worsen in the context of climate change, where there will be an overall increase in temperature and a decrease in average annual rainfall worldwide. This Special Issue presents different research works and reviews on the response of plants to salinity, focused from different points of view: physiological, biochemical, and molecular levels. Although an important part of the studies on the response to salinity have been carried out with Arabidopsis plants, the use of other species with agronomic interest is also notable, including woody plants. Most of the conducted studies in this Special Issue were focused on the identification and characterization of candidate genes for salt tolerance in higher plants. This identification would provide valuable information about the molecular and genetic mechanisms involved in the salt tolerance response, and it also supplies important resources to breeding programs for salt tolerance in plants.

Keywords

Arabidopsis --- Brassica napus --- ion homeostasis --- melatonin --- NaCl stress --- nitric oxide --- redox homeostasis --- Chlamydomonas reinhardtii --- bZIP transcription factors --- salt stress --- transcriptional regulation --- photosynthesis --- lipid accumulation --- Apocyni Veneti Folium --- salt stress --- multiple bioactive constituents --- physiological changes --- multivariate statistical analysis --- banana (Musa acuminata L.) --- ROP --- genome-wide identification --- abiotic stress --- salt stress --- MaROP5g --- rice --- genome-wide association study --- salt stress --- germination --- natural variation --- Chlamydomonas reinhardtii --- salt stress --- transcriptome analysis --- impairment of photosynthesis --- underpinnings of salt stress responses --- chlorophyll fluorescence --- J8-1 plum line --- mandelonitrile --- Prunus domestica --- redox signalling --- salicylic acid --- salt-stress --- soluble nutrients --- Arabidopsis thaliana --- VOZ --- transcription factor --- salt stress --- transcriptional activator --- chlorophyll fluorescence --- lipid peroxidation --- Na+ --- photosynthesis --- photosystem --- RNA binding protein --- nucleolin --- salt stress --- photosynthesis --- light saturation point --- booting stage --- transcriptome --- grapevine --- salt stress --- ROS detoxification --- phytohormone --- transcription factors --- Arabidopsis --- CDPK --- ion homeostasis --- NMT --- ROS --- salt stress --- antioxidant enzymes --- Arabidopsis thaliana --- ascorbate cycle --- hydrogen peroxide --- reactive oxygen species --- salinity --- SnRK2 --- RNA-seq --- DEUs --- flax --- NaCl stress --- EST-SSR --- Salt stress --- Oryza sativa --- proteomics --- iTRAQ quantification --- cell membrane injury --- root activity --- antioxidant systems --- ion homeostasis --- melatonin --- salt stress --- signal pathway --- SsMAX2 --- Sapium sebiferum --- drought, osmotic stress --- salt stress --- redox homeostasis --- strigolactones --- ABA --- TGase --- photosynthesis --- salt stress --- polyamines --- cucumber --- abiotic stresses --- high salinity --- HKT1 --- halophytes --- glycophytes --- poplars (Populus) --- salt tolerance --- molecular mechanisms --- SOS --- ROS --- Capsicum annuum L. --- CaDHN5 --- salt stress --- osmotic stress --- dehydrin --- Gossypium arboretum --- salt tolerance --- single nucleotide polymorphisms --- association mapping. --- n/a

Carbonic Anhydrases and Metabolism

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ISBN: 9783038978008 9783038978015 Year: Pages: 184 DOI: 10.3390/books978-3-03897-801-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-04-25 16:37:17
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Carbonic anhydrases (CAs; EC 4.2.1.1) are metalloenzymes present in all kingdoms of life, as they equilibrate the reaction between three simple but essential chemical species: CO2, bicarbonate, and protons. Discovered more than 80 years ago, in 1933, these enzymes have been extensively investigated due to the biomedical application of their inhibitors, but also because they are an extraordinary example of convergent evolution, with seven genetically distinct CA families that evolved independently in Bacteria, Archaea, and Eukarya. CAs are also among the most efficient enzymes known in nature, due to the fact that the uncatalyzed hydration of CO2 is a very slow process and the physiological demands for its conversion to ionic, soluble species is very high. Inhibition of the CAs has pharmacological applications in many fields, such as antiglaucoma, anticonvulsant, antiobesity, and anticancer agents/diagnostic tools, but is also emerging for designing anti-infectives, i.e., antifungal, antibacterial, and antiprotozoan agents with a novel mechanism of action. Mitochondrial CAs are implicated in de novo lipogenesis, and thus selective inhibitors of such enzymes may be useful for the development of new antiobesity drugs. As tumor metabolism is diverse compared to that of normal cells, ultimately, relevant contributions on the role of the tumor-associated isoforms CA IX and XII in these phenomena have been published and the two isoforms have been validated as novel antitumor/antimetastatic drug targets, with antibodies and small-molecule inhibitors in various stages of clinical development. CAs also play a crucial role in other metabolic processes connected with urea biosynthesis, gluconeogenesis, and so on, since many carboxylation reactions catalyzed by acetyl-coenzyme A carboxylase or pyruvate carboxylase use bicarbonate, not CO2, as a substrate. In organisms other than mammals, e.g., plants, algae, and cyanobacteria, CAs are involved in photosynthesis, whereas in many parasites (fungi, protozoa), they are involved in the de novo synthesis of important metabolites (lipids, nucleic acids, etc.). The metabolic effects related to interference with CA activity, however, have been scarcely investigated. The present Special Issue of Metabolites aims to fill this gap by presenting the latest developments in the field of CAs and their role in metabolism.

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