scholarly journals The carbonic anhydrase CAH1 is an essential component of the carbon-concentrating mechanism in Nannochloropsis oceanica

2017 ◽  
Vol 114 (17) ◽  
pp. 4537-4542 ◽  
Author(s):  
Christopher W. Gee ◽  
Krishna K. Niyogi
Keyword(s):  
Carbonic Anhydrase ◽  
Molecular Mechanisms ◽  
Inorganic Carbon ◽  
Carbonic Anhydrases ◽  
Nannochloropsis Oceanica ◽  
Essential Component ◽  
Protein Levels ◽  
Photosynthetic Organisms ◽  
Carbon Concentrating Mechanisms ◽  
Carbonic Anhydrase 1

Aquatic photosynthetic organisms cope with low environmental CO2 concentrations through the action of carbon-concentrating mechanisms (CCMs). Known eukaryotic CCMs consist of inorganic carbon transporters and carbonic anhydrases (and other supporting components) that culminate in elevated [CO2] inside a chloroplastic Rubisco-containing structure called a pyrenoid. We set out to determine the molecular mechanisms underlying the CCM in the emerging model photosynthetic stramenopile, Nannochloropsis oceanica, a unicellular picoplanktonic alga that lacks a pyrenoid. We characterized CARBONIC ANHYDRASE 1 (CAH1) as an essential component of the CCM in N. oceanica CCMP1779. We generated insertions in this gene by directed homologous recombination and found that the cah1 mutant has severe defects in growth and photosynthesis at ambient CO2. We identified CAH1 as an α-type carbonic anhydrase, providing a biochemical role in CCM function. CAH1 was found to localize to the lumen of the epiplastid endoplasmic reticulum, with its expression regulated by the external inorganic carbon concentration at both the transcript and protein levels. Taken together, these findings show that CAH1 is an indispensable component of what may be a simple but effective and dynamic CCM in N. oceanica.

The carbonic anhydrase gene families of Chlamydomonas reinhardtii

2005 ◽  
Vol 83 (7) ◽  
pp. 780-795 ◽  
Author(s):  
Mautusi Mitra ◽  
Catherine B Mason ◽  
Ying Xiao ◽  
Ruby A Ynalvez ◽  
Scott M Lato ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Chlamydomonas Reinhardtii ◽  
Gene Families ◽  
Carbonic Anhydrases ◽  
Photosynthetic Organisms ◽  
Surrounding Environment ◽  
Concentrating Mechanism ◽  
Chloroplast Stroma ◽  
Carbonic Anhydrase Gene

Carbonic anhydrases (CAs) are zinc-containing metalloenzymes that catalyze the reversible interconversion of CO2 and HCO3–. Aquatic photosynthetic organisms have evolved different forms of CO2-concentrating mechanisms to aid Rubisco in capturing CO2 from the surrounding environment. One aspect of all CO2-concentrating mechanisms is the critical roles played by various specially localized extracellular and intracellular CAs. There are three evolutionarily unrelated CA families designated α-, β-, and γ-CA. In the green alga, Chlamydomonas reinhardtii Dangeard, eight CAs have now been identified, including three α-CAs and five β-CAs. In addition, C. reinhardtii has another CA-like gene, Glp1 that is similar to known γ-CAs. To characterize these different CA isoforms, some of the CA genes have been overexpressed to determine whether the proteins have CA activity and to generate antibodies for in vivo immunolocalization. The CA proteins Cah3, Cah6, and Cah8, and the γ-CA-like protein, Glp1, have been overexpressed. Cah3, Cah6, and Cah8 have CA activity, but Glp1 does not. At least two of these proteins, Cah3 and Cah6, are localized to the chloroplast. Using immunolocalization and sequence analyses, we have determined that Cah6 is located to the chloroplast stroma and confirmed that Cah3 is localized to the chloroplast thylakoid lumen. Activity assays show that Cah3 is 100 times more sensitive to sulfonamides than Cah6. We present a model on how these two chloroplast CAs might participate in the CO2-concentrating mechanism of C. reinhardtii. Key words: carbonic anhydrase, CO2-concentrating mechanism, Chlamydomonas, immunolocalization.

Carbonic anhydrase in eukaryotic algae: characterization, regulation, and possible function during photosynthesis

1998 ◽  
Vol 76 (6) ◽  
pp. 962-972 ◽  
Author(s):  
Dieter Sültemeyer
Keyword(s):  
Carbonic Anhydrase ◽  
Carbon Concentration ◽  
Inorganic Carbon ◽  
Molecular Level ◽  
Carbonic Anhydrases ◽  
Ph Values ◽  
Genes Encoding ◽  
Inorganic Carbon Concentration ◽  
Macro Algae ◽  
Made In

Carbonic anhydrase (CA) speeds up the equilibrium between CO2 and HCO3- at physiological pH values and has been detected in almost every species of the animal and plant kingdoms. Among eucaryotic micro- and macro-algae the enzyme is widely distributed and plays an important role in photosynthetic CO2 fixation. In some cases, different forms of carbonic anhydrases located extracellularly and intracellularly have been found to occur in the same cell. The expression of the genes encoding these CA isoforms are under the control of the inorganic carbon concentration in the medium, as the activities increase with decreasing the inorganic carbon content. Considerable progress has been made in recent years in isolating and characterizing the various forms of carbonic anhydrases on a biochemical and molecular level. Most of the data have been collected for microalgae like Chlamydomonas reinhardtii (Dangeard), while the situation in macroalgae is still descriptive. Therefore, this review summarizes the recent development with an emphasis on microalgae carbonic anhydrases.Key words: carbonic anhydrase, CO2 concentrating mechanism, macroalgae, microalgae, photosynthesis.

The acquisition of inorganic carbon by marine macroalgae

1991 ◽  
Vol 69 (5) ◽  
pp. 1123-1132 ◽  
Author(s):  
Andrew M. Johnston
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Carbon Assimilation ◽  
Carbon Accumulation ◽  
Compensation Point ◽  
Marine Macroalgae ◽  
Bicarbonate Ions ◽  
Sublittoral Zone ◽  
Carbon Concentrating Mechanisms

Marine macroalgae inhabit three different environments: the eulittoral zone, rock pools, and the sublittoral zone. Many macroalgae exhibit C4 gas exchange characteristics, i.e., low CO2 compensation point, high pH compensation point, photosynthesis insensitive to changes in oxygen changes below 21 kPa, and a high affinity for inorganic carbon. It is concluded that in general eulittoral and rock-pool species are more C4-like than the subtidal species though there are interesting exceptions. Experimental evidence points to the following mechanisms being involved in inorganic carbon acquisition by macroalgae. The role of β-carboxylation as the primary step in carbon fixation is only convincing in Udotea flabellum, while PGA is the first product of 14C fixation in most species. Direct evidence of inorganic carbon accumulation is only available for Ulva fasciata, whereas Chondrus crispus does not have this ability. Studies show that carbonic anhydrase is prominent in the mechanism of carbon acquisition by Ascophyllum nodosum, and when inhibited the alga is dependent on CO2, whereas U. fasciata retains some ability to use bicarbonate ions. It is concluded that macroalgae display a range of inorganic carbon assimilation mechanisms that are active to varying degrees. The relationships between these mechanisms, the different macroalgal habitats, and carbonic anhydrase is discussed. Key words: inorganic carbon concentrating mechanisms, macroalgae, carbonic anhydrase.

scholarly journals The roles of carbonic anhydrases in сarbon concentrating mechanisms of aquatic photoautotrophs

Algologia ◽  
2021 ◽  
Vol 31 (4) ◽  
pp. 337-352
Author(s):  
O.V. Polishchuk ◽  
Keyword(s):  
Lipid Bilayers ◽  
Inorganic Carbon ◽  
Multiple Roles ◽  
Co2 Production ◽  
Aquatic Environments ◽  
Carbonic Anhydrases ◽  
Inner Surface ◽  
Carbon Concentrating Mechanisms ◽  
Co2 Concentrating Mechanisms ◽  
Aquatic Angiosperms

The article surveys multiple roles of carbonic anhydrases (CAs) in inorganic carbon (Ci) acquisition by cyanobacteria, microalgae, and macrophytes under Ci limiting conditions. Slow Ci diffusion in aquatic environments imposes the need for carbon concentrating mechanisms (also named CO2 concentrating mechanisms, CCMs) in aquatic photoautotrophs to transport Ci against the gradient and ensure CO2 supply to photosynthesis. There are common requirements for efficient CCM functioning in cyanobacteria, algae, and aquatic angiosperms, including active transport of HCO3- to the Ci-concentrating compartment and CO2 generation from the HCO3- pool in the Rubisco-enriched subcompartment. Facilitating Ci diffusion in aqueous solutions and across lipid bilayers, CAs play essential roles in CCMs that are best studied in cyanobacteria, green algae, and diatoms. Roles of CAs in CCMs depend on their localization and include facilitation of active transmembrane Ci uptake by its supplying at the outer surface (Role 1) and removal at the inner surface (Role 2), as well as the acceleration of CO2 production from HCO3- near Rubisco (Role 3) in a special CO2-tight compartment, carboxysome in cyanobacteria or pyrenoid in microalgae. The compartmentalization of CAs is also critical because, if activated in the HCO3- –concentrating compartment, they can easily eliminate the Ci gradient created by CCMs.

Are Carbonic Anhydrases Suitable Targets to Fight Protozoan Parasitic Diseases?

2019 ◽  
Vol 25 (39) ◽  
pp. 5266-5278 ◽  
Author(s):  
Katia D'Ambrosio ◽  
Claudiu T. Supuran ◽  
Giuseppina De Simone
Keyword(s):  
Drug Resistance ◽  
Animal Models ◽  
Carbonic Anhydrase ◽  
Drug Target ◽  
Treatment Options ◽  
Parasitic Diseases ◽  
Carbonic Anhydrases ◽  
Extensive Drug Resistance ◽  
Protozoan Infections

Protozoans belonging to Plasmodium, Leishmania and Trypanosoma genera provoke widespread parasitic diseases with few treatment options and many of the clinically used drugs experiencing an extensive drug resistance phenomenon. In the last several years, the metalloenzyme Carbonic Anhydrase (CA, EC 4.2.1.1) was cloned and characterized in the genome of these protozoa, with the aim to search for a new drug target for fighting malaria, leishmaniasis and Chagas disease. P. falciparum encodes for a CA (PfCA) belonging to a novel genetic family, the η-CA class, L. donovani chagasi for a β-CA (LdcCA), whereas T. cruzi genome contains an α-CA (TcCA). These three enzymes were characterized in detail and a number of in vitro potent and selective inhibitors belonging to the sulfonamide, thiol, dithiocarbamate and hydroxamate classes were discovered. Some of these inhibitors were also effective in cell cultures and animal models of protozoan infections, making them of considerable interest for the development of new antiprotozoan drugs with a novel mechanism of action.

scholarly journals Synthesis and Human Carbonic Anhydrase I, II, IX, and XII Inhibition Studies of Sulphonamides Incorporating Mono-, Bi- and Tricyclic Imide Moieties

2021 ◽  
Vol 14 (7) ◽  
pp. 693
Author(s):  
Kalyan K. Sethi ◽  
KM Abha Mishra ◽  
Saurabh M. Verma ◽  
Daniela Vullo ◽  
Fabrizio Carta ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Carbonic Anhydrase ◽  
Docking Studies ◽  
Carbonic Anhydrases ◽  
Molecular Docking Studies ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Carbonic Anhydrase I ◽  
Human Carbonic Anhydrase ◽  
Inhibition Studies

New derivatives were synthesised by reaction of amino-containing aromatic sulphonamides with mono-, bi-, and tricyclic anhydrides. These sulphonamides were investigated as human carbonic anhydrases (hCAs, EC 4.2.1.1) I, II, IX, and XII inhibitors. hCA I was inhibited with inhibition constants (Kis) ranging from 49 to >10,000 nM. The physiologically dominant hCA II was significantly inhibited by most of the sulphonamide with the Kis ranging between 2.4 and 4515 nM. hCA IX and hCA XII were inhibited by these sulphonamides in the range of 9.7 to 7766 nM and 14 to 316 nM, respectively. The structure–activity relationships (SAR) are rationalised with the help of molecular docking studies.

Polypharmacology of epacadostat: a potent and selective inhibitor of the tumor associated carbonic anhydrases IX and XII

2019 ◽  
Vol 55 (40) ◽  
pp. 5720-5723 ◽  
Author(s):  
Andrea Angeli ◽  
Marta Ferraroni ◽  
Alessio Nocentini ◽  
Silvia Selleri ◽  
Paola Gratteri ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Selective Inhibitor ◽  
Carbonic Anhydrase Inhibitor ◽  
Carbonic Anhydrases ◽  
Indoleamine 2,3 Dioxygenase

Epacadostat (EPA), a selective indoleamine-2,3-dioxygenase 1 (IDO1) inhibitor, has been investigatedin vitroas a human (h) Carbonic Anhydrase Inhibitor (CAI).

scholarly journals Carbonic Anhydrases in Photosynthesizing Cells of C3 Higher Plants

Metabolites ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 73 ◽  
Author(s):  
Lyudmila Ignatova ◽  
Natalia Rudenko ◽  
Elena Zhurikova ◽  
Maria Borisova-Mubarakshina ◽  
Boris Ivanov
Keyword(s):  
Plasma Membrane ◽  
Carbonic Anhydrase ◽  
Environmental Conditions ◽  
Organic Molecules ◽  
Higher Plants ◽  
C3 Plants ◽  
Coherent System ◽  
Carbonic Anhydrases ◽  
Chloroplast Stroma ◽  
Different Parts

The review presents data on the location, nature, properties, number, and expression of carbonic anhydrase genes in the photosynthesizing cells of C3 plants. The available data about the presence of carbonic anhydrases in plasma membrane, cytoplasm, mitochondria, chloroplast stroma and thylakoids are scrutinized. Special attention was paid to the presence of carbonic anhydrase activities in the different parts of thylakoids, and on collation of sources of these activities with enzymes encoded by the established genes of carbonic anhydrases. The data are presented to show that the consistent incorporation of carbonic anhydrases belonging to different families of these enzymes forms a coherent system of CO2 molecules transport from air to chloroplasts in photosynthesizing cells, where they are included in organic molecules in the carboxylation reaction. It is discussed that the manifestation of the activity of a certain carbonic anhydrase depends on environmental conditions and the stage of ontogenesis.

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