Magnesium Chelatase of Hordeum Vulgare L. Is Not Activated by Light
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1 Introduction
Introduction 1 1 Introduction Tetrapyrroles belong to a group of molecules with a common structure. They are synthesized in a branched pathway, in which various end products are formed to different amounts. The most abundant cyclic tetrapyrroles are chlorophyll (Chl) and heme, which are characterized by a chelated magnesium and ferrous ion, respectively. Chlorophyll is involved in light absorption and energy transduction during photosynthesis. Heme is a cofactor of hemoglobin, cytochromes, P450 mixed-function oxygenases, and catalases. Other members of the class of tetrapyrroles include siroheme (the prosthetic group of nitrite and sulphite reductases) and phytochromobilin, the chromophore of phytochrome, which is involved in light perception. Tetrapyrrole biosynthesis has been the subject of numerous studies over several decades. But genetic and biochemical characterization of tetrapyrrole biosynthesis has progressed by using approaches to genetically dissect the tetrapyrrole biosynthetic pathway. Pigment-deficient mutants and antisense technology have proved to be useful for examining the mechanisms of metabolic control or for analyzing biochemically the enzymatic steps which are affected by the mutation or by the antisense RNA expression. Tetrapyrrole intermediates are highly photoreactive. They can easily be excited and transfer the energy or electrons to O2. Then reactive oxygen species (ROS) are produced upon exposure to light and oxygen. Under normal growth conditions the risk of photooxidative damage from intermediates in tetrapyrrole biosynthesis is low. Excessive accumulation of such intermediates is the result of deregulation of tetrapyrrole biosynthesis. Toxic effects of porphyrins are evident in human patients with deficiencies of one of the enzymes of heme biosynthesis. These patients are suffering from metabolic diseases, which are called porphyrias (Moore, 1993). -
The Gun4 Gene Is Essential for Cyanobacterial Porphyrin Metabolism
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector FEBS 28618 FEBS Letters 571 (2004) 119–123 The gun4 gene is essential for cyanobacterial porphyrin metabolism Annegret Wildea,*, Sandra Mikolajczyka, Ali Alawadyb, Heiko Loksteinb, Bernhard Grimmb aInstitut fu€r Biologie, Biochemie der Pflanzen, Humboldt-Universita€t zu Berlin, Chausseestr. 117, 10115 Berlin, Germany bInstitut fu€r Biologie, Pflanzenphysiologie, Humboldt-Universita€t zu Berlin, Philippstr. 13, 10115 Berlin, Germany Received 5 April 2004; revised 16 June 2004; accepted 17 June 2004 Available online 6 July 2004 Edited by Richard Cogdell norflurazon treatment and are characterized by deregulated Abstract Ycf53 is a hypothetical chloroplast open reading Gun4 frame with similarity to the Arabidopsis nuclear gene GUN4.In communication between plastids and nucleus [2]. carries plants, GUN4 is involved in tetrapyrrole biosynthesis. We a nuclear mutant gene, which encodes a putative regulatory demonstrate that one of the two Synechocystis sp. PCC 6803 protein that interacts with Mg chelatase and stimulates its ycf53 genes with similarity to GUN4 functions in chlorophyll activity [3]. Mg chelatase is a highly regulated tetrapyrrole (Chl) biosynthesis as well: cyanobacterial gun4 mutant cells biosynthesis enzyme which catalyzes insertion of Mg2þ into exhibit lower Chl contents, accumulate protoporphyrin IX and protoporphyrin IX (Proto) and thus, directs Proto into the show less activity not only of Mg chelatase but also of Fe chlorophyll (Chl) synthesizing pathway [4]. Mg chelatase is a chelatase. The possible role of Gun4 for the Mg as well as Fe protein complex consisting of three subunits, CHL I, CHL H porphyrin biosynthesis branches in Synechocystis sp. -
TION of BUCKWHEAT. It Has Been Known for a Long Time That Certain
PHOTOSENSITIZATION OF ANIMALS AFTER THE INGES- TION OF BUCKWHEAT. BY CHARLES SHEARD, PH.D., HAROLD D. CAYLOR, M.D., AND CARL SCHLOTTHAUER, D.V.M. (From tke Section on Pkysics and Biophysical Research, tke Section on Surgical Pathology, and the Division of Experimental Palhdogy and Surgery, Mayo Clinic and The Mayo Foundation, Rochester, Minnesota.) (Received for publication,~'March 1, 1928.) It has been known for a long time that certain animals, following the ingestion of various substances, are rendered sensitive to certain types of radiant energy. The present study covers biologic and physical observations on the degree of sensitization, the character of the sensitizing light and the nature of the photodynamic substance of buckwheat. White rabbits, mice, rats, goats, swine, dogs and varicolored guinea pigs were studied. Sunlight, carbon arc lamp (Efka or Hoffman) with Conradty-Norris vacuum carbon electrodes and quartz mercury vapor arcs (Victor X-Ray Corporation), both with and without various filters, were employed for irradiation. All of these sources contain infra-red, visible and ultra-violet radiations. I~SLr~ OF LITERATURE. Considerable literature, especially European, has appeared on the subject of diseases in animals and man brought about by optical sensitization. Somewhat detailed accounts of the contributions relative to diseases due to exogenous sensi- tization are to be found in the brochures by Hausmann and by Mayer. Years ago European stockmen found that in certain animals which had ingested buckwheat (plant or seed), erythema, itching, edema and convulsions developed and, in many cases, paralysis and death, on exposure to out-of-door sunshine. However, untoward symptoms did not arise if the animals were kept indoors or in partial darkness and they recovered from the sensitization induced by eating certain plants if they were removed from the light early in the onset of the symp- toms. -
Itraq-Based Quantitative Proteomics Analysis Reveals the Mechanism Underlying the Weakening of Carbon Metabolism in Chlorotic Tea Leaves
Article iTRAQ-Based Quantitative Proteomics Analysis Reveals the Mechanism Underlying the Weakening of Carbon Metabolism in Chlorotic Tea Leaves Fang Dong 1,2, Yuanzhi Shi 1,2, Meiya Liu 1,2, Kai Fan 1,2, Qunfeng Zhang 1,2,* and Jianyun Ruan 1,2 1 Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China; [email protected] (F.D.); [email protected] (Y.S.); [email protected] (M.L.); [email protected] (K.F.); [email protected] (J.R.) 2 Key Laboratory for Plant Biology and Resource Application of Tea, the Ministry of Agriculture, Hangzhou 310008, China * Correspondence: [email protected]; Tel.: +86-571-8527-0665 Received: 7 November 2018; Accepted: 5 December 2018; Published: 7 December 2018 Abstract: To uncover mechanism of highly weakened carbon metabolism in chlorotic tea (Camellia sinensis) plants, iTRAQ (isobaric tags for relative and absolute quantification)-based proteomic analyses were employed to study the differences in protein expression profiles in chlorophyll-deficient and normal green leaves in the tea plant cultivar “Huangjinya”. A total of 2110 proteins were identified in “Huangjinya”, and 173 proteins showed differential accumulations between the chlorotic and normal green leaves. Of these, 19 proteins were correlated with RNA expression levels, based on integrated analyses of the transcriptome and proteome. Moreover, the results of our analysis of differentially expressed proteins suggested that primary carbon metabolism (i.e., carbohydrate synthesis and transport) was inhibited in chlorotic tea leaves. The differentially expressed genes and proteins combined with photosynthetic phenotypic data indicated that 4-coumarate-CoA ligase (4CL) showed a major effect on repressing flavonoid metabolism, and abnormal developmental chloroplast inhibited the accumulation of chlorophyll and flavonoids because few carbon skeletons were provided as a result of a weakened primary carbon metabolism. -
Post-Translational Coordination of Chlorophyll Biosynthesis And
ARTICLE https://doi.org/10.1038/s41467-020-14992-9 OPEN Post-translational coordination of chlorophyll biosynthesis and breakdown by BCMs maintains chlorophyll homeostasis during leaf development ✉ ✉ Peng Wang 1 , Andreas S. Richter 1,3, Julius R.W. Kleeberg 2, Stefan Geimer2 & Bernhard Grimm1 Chlorophyll is indispensable for life on Earth. Dynamic control of chlorophyll level, determined by the relative rates of chlorophyll anabolism and catabolism, ensures optimal photosynthesis 1234567890():,; and plant fitness. How plants post-translationally coordinate these two antagonistic pathways during their lifespan remains enigmatic. Here, we show that two Arabidopsis paralogs of BALANCE of CHLOROPHYLL METABOLISM (BCM) act as functionally conserved scaffold proteins to regulate the trade-off between chlorophyll synthesis and breakdown. During early leaf development, BCM1 interacts with GENOMES UNCOUPLED 4 to stimulate Mg-chelatase activity, thus optimizing chlorophyll synthesis. Meanwhile, BCM1’s interaction with Mg- dechelatase promotes degradation of the latter, thereby preventing chlorophyll degradation. At the onset of leaf senescence, BCM2 is up-regulated relative to BCM1, and plays a con- served role in attenuating chlorophyll degradation. These results support a model in which post-translational regulators promote chlorophyll homeostasis by adjusting the balance between chlorophyll biosynthesis and breakdown during leaf development. 1 Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, -
Itraq-Based Proteome Profiling Revealed the Role of Phytochrome A
www.nature.com/scientificreports OPEN iTRAQ‑based proteome profling revealed the role of Phytochrome A in regulating primary metabolism in tomato seedling Sherinmol Thomas1, Rakesh Kumar2,3, Kapil Sharma2, Abhilash Barpanda1, Yellamaraju Sreelakshmi2, Rameshwar Sharma2 & Sanjeeva Srivastava1* In plants, during growth and development, photoreceptors monitor fuctuations in their environment and adjust their metabolism as a strategy of surveillance. Phytochromes (Phys) play an essential role in plant growth and development, from germination to fruit development. FR‑light (FR) insensitive mutant (fri) carries a recessive mutation in Phytochrome A and is characterized by the failure to de‑etiolate in continuous FR. Here we used iTRAQ‑based quantitative proteomics along with metabolomics to unravel the role of Phytochrome A in regulating central metabolism in tomato seedlings grown under FR. Our results indicate that Phytochrome A has a predominant role in FR‑mediated establishment of the mature seedling proteome. Further, we observed temporal regulation in the expression of several of the late response proteins associated with central metabolism. The proteomics investigations identifed a decreased abundance of enzymes involved in photosynthesis and carbon fxation in the mutant. Profound accumulation of storage proteins in the mutant ascertained the possible conversion of sugars into storage material instead of being used or the retention of an earlier profle associated with the mature embryo. The enhanced accumulation of organic sugars in the seedlings indicates the absence of photomorphogenesis in the mutant. Plant development is intimately bound to the external light environment. Light drives photosynthetic carbon fxa- tion and activates a set of signal-transducing photoreceptors that regulate plant growth and development. -
Chlorophyll Biosynthesis
Chlorophyll Biosynthesis: Various Chlorophyllides as Exogenous Substrates for Chlorophyll Synthetase Jürgen Benz and Wolfhart Rüdiger Botanisches Institut, Universität München, Menziger Str. 67, D-8000 München 19 Z. Naturforsch. 36 c, 51 -5 7 (1981); received October 10, 1980 Dedicated to Professor Dr. H. Merxmüller on the Occasion of His 60th Birthday Chlorophyllides a and b, Protochlorophyllide, Bacteriochlorophyllide a, 3-Acetyl-3-devinylchlo- rophyllide a, Pyrochlorophyllide a, Pheophorbide a The esterification of various chlorophyllides with geranylgeranyl diphosphate was investigated as catalyzed by the enzyme chlorophyll synthetase. The enzyme source was an etioplast membrane fraction from etiolated oat seedlings ( Avena sativa L.). The following chlorophyllides were prepared from the corresponding chlorophylls by the chlorophyllase reaction: chlorophyllide a (2) and b (4), bacteriochlorophyllide a (5), 3-acetyl-3-devinylchlorophyllide a (6), and pyro chlorophyllide a (7). The substrates were solubilized with cholate which reproducibly reduced the activity of chlorophyll synthetase by 40-50%. It was found that the following compounds were good substrates for chlorophyll synthetase: chlorophyllide a and b, 3-acetyl-3-devinylchloro- phyllide a, and pyrochlorophyllide a. Only a poor or no reaction was found with protochloro phyllide, pheophorbide a, and bacteriochlorophyllide. This difference of reactivity was not due to distribution differences of the substrates between solution and pelletable membrane fraction. Furthermore, no interference between good and poor substrate was detected. Structural features necessary for chlorophyll synthetase substrates were discussed. Introduction Therefore no exogenous 2 was applied. The only substrate was 2 formed by photoconversion of endo The last steps of chlorophyll a (Chi a) biosynthe genous Protochlide (1) in the etioplast membrane. -
Magnesium-Protoporphyrin Chelatase of Rhodobacter
Proc. Natl. Acad. Sci. USA Vol. 92, pp. 1941-1944, March 1995 Biochemistry Magnesium-protoporphyrin chelatase of Rhodobacter sphaeroides: Reconstitution of activity by combining the products of the bchH, -I, and -D genes expressed in Escherichia coli (protoporphyrin IX/tetrapyrrole/chlorophyll/bacteriochlorophyll/photosynthesis) LUCIEN C. D. GIBSON*, ROBERT D. WILLOWSt, C. GAMINI KANNANGARAt, DITER VON WETTSTEINt, AND C. NEIL HUNTER* *Krebs Institute for Biomolecular Research and Robert Hill Institute for Photosynthesis, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom; and tCarlsberg Laboratory, Department of Physiology, Gamle Carlsberg Vej 10, DK-2500 Copenhagen Valby, Denmark Contributed by Diter von Wettstein, November 14, 1994 ABSTRACT Magnesium-protoporphyrin chelatase lies at Escherichia coli and demonstrate that the extracts of the E. coli the branch point of the heme and (bacterio)chlorophyll bio- transformants can convert Mg-protoporphyrin IX to Mg- synthetic pathways. In this work, the photosynthetic bacte- protoporphyrin monomethyl ester (20, 21). Apart from posi- rium Rhodobacter sphaeroides has been used as a model system tively identifying bchM as the gene encoding the Mg- for the study of this reaction. The bchH and the bchI and -D protoporphyrin methyltransferase, this work opens up the genes from R. sphaeroides were expressed in Escherichia coli. possibility of extending this approach to other parts of the When cell-free extracts from strains expressing BchH, BchI, pathway. In this paper, we report the expression of the genes and BchD were combined, the mixture was able to catalyze the bchH, -I, and -D from R. sphaeroides in E. coli: extracts from insertion of Mg into protoporphyrin IX in an ATP-dependent these transformants, when combined in vitro, are highly active manner. -
Antibacterial Photosensitization Through Activation of PNAS PLUS Coproporphyrinogen Oxidase
Antibacterial photosensitization through activation of PNAS PLUS coproporphyrinogen oxidase Matthew C. Surdela, Dennis J. Horvath Jr.a, Lisa J. Lojeka, Audra R. Fullena, Jocelyn Simpsona, Brendan F. Dutterb,c, Kenneth J. Sallenga, Jeremy B. Fordd, J. Logan Jenkinsd, Raju Nagarajane, Pedro L. Teixeiraf, Matthew Albertollec,g, Ivelin S. Georgieva,e,h, E. Duco Jansend, Gary A. Sulikowskib,c, D. Borden Lacya,d, Harry A. Daileyi,j,k, and Eric P. Skaara,1 aDepartment of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232; bDepartment of Chemistry, Vanderbilt University, Nashville, TN 37232; cVanderbilt Institute for Chemical Biology, Nashville, TN 37232; dDepartment of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232; eVanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232; fBiomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37203; gDepartment of Biochemistry, Vanderbilt University, Nashville, TN 37232; hDepartment of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37232; iBiomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602; jDepartment of Microbiology, University of Georgia, Athens, GA 30602; and kDepartment of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 Edited by Ferric C. Fang, University of Washington School of Medicine, Seattle, WA, and accepted by Editorial Board Member Carl F. Nathan June 26, 2017 (received for review January 10, 2017) Gram-positive bacteria cause the majority of skin and soft tissue Small-molecule VU0038882 (‘882) was previously identified in infections (SSTIs), resulting in the most common reason for clinic a screen for activators of the S. aureus heme-sensing system two- visits in the United States. -
Surprising Roles for Bilins in a Green Alga Jean-David Rochaix1 Departments of Molecular Biology and Plant Biology, University of Geneva,1211 Geneva, Switzerland
COMMENTARY COMMENTARY Surprising roles for bilins in a green alga Jean-David Rochaix1 Departments of Molecular Biology and Plant Biology, University of Geneva,1211 Geneva, Switzerland It is well established that the origin of plastids which serves as chromophore of phyto- can be traced to an endosymbiotic event in chromes (Fig. 1). An intriguing feature of which a free-living photosynthetic prokaryote all sequenced chlorophyte genomes is that, invaded a eukaryotic cell more than 1 billion although they lack phytochromes, their years ago. Most genes from the intruder genomes encode two HMOXs, HMOX1 were gradually transferred to the host nu- andHMOX2,andPCYA.InPNAS,Duanmu cleus whereas a small number of these genes et al. (6) investigate the role of these genes in were maintained in the plastid and gave the green alga Chlamydomonas reinhardtii rise to the plastid genome with its associated and made unexpected findings. protein synthesizing system. The products of Duanmu et al. first show that HMOX1, many of the genes transferred to the nucleus HMOX2, and PCYA are catalytically active were then retargeted to the plastid to keep it and produce bilins in vitro (6). They also functional. Altogether, approximately 3,000 demonstrate in a very elegant way that these nuclear genes in plants and algae encode proteins are functional in vivo by expressing plastid proteins, whereas chloroplast ge- a cyanobacteriochrome in the chloroplast Fig. 1. Tetrapyrrole biosynthetic pathways. The heme nomes contain between 100 and 120 genes of C. reinhardtii, where, remarkably, the and chlorophyll biosynthetic pathways diverge at pro- (1). A major challenge for eukaryotic pho- photoreceptor is assembled with bound toporphyrin IX (ProtoIX). -
Kinetics of Metal Chelatase from Rat Liver Mitochondria
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Volume 13, number 2 FEBS LETTERS February 1971 KINETICS OF METAL CHELATASE FROM RAT LIVER MITOCHONDRIA H. BUGANY, L. FLOHE and U. WESER* Physiologisch-Chemisches Institut der Universitit Tiibingen, Germany Received 11 December 1970 1. Introduction and protoporphyrin IX served as the cosubstrate. This permitted assay of the metal chelatase activity The name metal chelatase has been deliberately much more precisely since anaerobic precautions chosen for the enzyme ferrochelatase (protohaem could be omitted. The maximum deviation of this ferro-lyase, EC 4.99.1 .l.). This enzyme preferentially assay did not exceed 7%. The experimental data pre- catalyses the insertion of Fe’+ ions into porphyrins sented in this report strongly suggest a random bin- to form haems. However, Co*+ and Zn*+ are almost ding of either substrate - i.e. Co*+ or protoporphyrin as active as Fe*+. Many divalent cations including IX - to the metal chelatase. The respective K, values Mg”, Ca*+, Ni*‘, Cd*‘, Pb*+ and Hg*+ inhibits this proved to be independent of the concentration of enzyme process [l-4] . The rate of non-enzymic the cosubstrate. The numerical K, values were 8 MM incorporation of metal ions under the same experi- for Co*+ and 3.6 PM for protoporphyrin IX. mental conditions is practically zero. Metal chelatase has a wide distribution in a great number of aerobic cells. Its purification, however, is 2. Materials and methods difficult and this was attributable to its chemical nature. Metal chelatase appears to be a structure- Female albino rats (Sprague-Dawley) weighing bound lipoprotein although a second water soluble 150 ? 30 g were kept under normal laboratory con- enzyme has been detected in Rhodopseudomonas ditions and were used without further treatment. -
Supplementary Information
Supplementary information (a) (b) Figure S1. Resistant (a) and sensitive (b) gene scores plotted against subsystems involved in cell regulation. The small circles represent the individual hits and the large circles represent the mean of each subsystem. Each individual score signifies the mean of 12 trials – three biological and four technical. The p-value was calculated as a two-tailed t-test and significance was determined using the Benjamini-Hochberg procedure; false discovery rate was selected to be 0.1. Plots constructed using Pathway Tools, Omics Dashboard. Figure S2. Connectivity map displaying the predicted functional associations between the silver-resistant gene hits; disconnected gene hits not shown. The thicknesses of the lines indicate the degree of confidence prediction for the given interaction, based on fusion, co-occurrence, experimental and co-expression data. Figure produced using STRING (version 10.5) and a medium confidence score (approximate probability) of 0.4. Figure S3. Connectivity map displaying the predicted functional associations between the silver-sensitive gene hits; disconnected gene hits not shown. The thicknesses of the lines indicate the degree of confidence prediction for the given interaction, based on fusion, co-occurrence, experimental and co-expression data. Figure produced using STRING (version 10.5) and a medium confidence score (approximate probability) of 0.4. Figure S4. Metabolic overview of the pathways in Escherichia coli. The pathways involved in silver-resistance are coloured according to respective normalized score. Each individual score represents the mean of 12 trials – three biological and four technical. Amino acid – upward pointing triangle, carbohydrate – square, proteins – diamond, purines – vertical ellipse, cofactor – downward pointing triangle, tRNA – tee, and other – circle.