scholarly journals Regulation of the Expression of Intracellular β-Carbonic Anhydrase in Response to CO2 and Light in the Marine Diatom Phaeodactylum tricornutum

2005 ◽  
Vol 139 (2) ◽  
pp. 1041-1050 ◽  
Author(s):  
Hisashi Harada ◽  
Daisuke Nakatsuma ◽  
Maki Ishida ◽  
Yusuke Matsuda
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Marine Diatom

Identification and characterization of a new carbonic anhydrase in the marine diatom Phaeodactylum tricornutum

2005 ◽  
Vol 83 (7) ◽  
pp. 909-916 ◽  
Author(s):  
Hisashi Harada ◽  
Yusuke Matsuda
Keyword(s):  
Amino Acid ◽  
Carbonic Anhydrase ◽  
Amino Acid Sequence ◽  
Phaeodactylum Tricornutum ◽  
Fold Increase ◽  
Marine Diatom ◽  
Porphyridium Purpureum ◽  
Mrna Accumulation ◽  
Reading Frame ◽  
Endoplasmic Reticulum Targeting

A cDNA encoding a new isoenzyme of β-type carbonic anhydrase (CA; EC 4.2.1.1) in the marine diatom Phaeodactylum tricornutum Bohlin has been cloned. The cDNA contained an open reading frame of 819 bp, which encodes a polypeptide of 273 amino acids. This gene, which is designated as ptca2, was found to be highly homologous (83% at the nucleotide level) to the previously isolated intracellular β-CA gene from Phaeodactylum tricornutum (ptca1). Comparison of the deduced amino acid sequence of ptca2 with β-CAs from other sources demonstrated that PtCA2 possesses the completely conserved zinc coordination residues of β-CA. The N-terminus 19 amino acid sequence of PtCA2 was predicted to be an endoplasmic reticulum-targeting signal, suggesting localization of the protein in an organelle or in the periplasmic space. Quantitative analysis of mRNA accumulation of ptca2 using real-time polymerase chain reaction revealed a significant level of mRNA accumulation even under 5% CO2 and a 3.5-fold increase in accumulation upon acclimation of the diatom to air. This indicates that ptca2 belongs to a constitutive class of enzyme that responds only weakly to the ambient CO2 concentration. The sequences of both ptca1 and ptca2 were shown to be grouped into a phylogeny that is composed of mixture of sequences from the eucarya and procarya domains, including sequences from the red alga Porphyridium purpureum, the green alga Coccomyxa, the red mold Neurospora crassa, and the yeast Saccharomyces cerevisiae.Key words: carbonic anhydrase, marine diatom, inorganic carbon concentrating mechanism (CCM), Phaeodactylum tricornutum.

scholarly journals Thylakoid luminal θ-carbonic anhydrase critical for growth and photosynthesis in the marine diatom Phaeodactylum tricornutum

2016 ◽  
Vol 113 (35) ◽  
pp. 9828-9833 ◽  
Author(s):  
Sae Kikutani ◽  
Kensuke Nakajima ◽  
Chikako Nagasato ◽  
Yoshinori Tsuji ◽  
Ai Miyatake ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Marine Diatom ◽  
Bisphosphate Carboxylase ◽  
Gfp Fusion Protein ◽  
Close Proximity ◽  
Esterase Activities

The algal pyrenoid is a large plastid body, where the majority of the CO2-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) resides, and it is proposed to be the hub of the algal CO2-concentrating mechanism (CCM) and CO2 fixation. The thylakoid membrane is often in close proximity to or penetrates the pyrenoid itself, implying there is a functional cooperation between the pyrenoid and thylakoid. Here, GFP tagging and immunolocalization analyses revealed that a previously unidentified protein, Pt43233, is targeted to the lumen of the pyrenoid-penetrating thylakoid in the marine diatom Phaeodactylum tricornutum. The recombinant Pt43233 produced in Escherichia coli cells had both carbonic anhydrase (CA) and esterase activities. Furthermore, a Pt43233:GFP-fusion protein immunoprecipitated from P. tricornutum cells displayed a greater specific CA activity than detected for the purified recombinant protein. In an RNAi-generated Pt43233 knockdown mutant grown in atmospheric CO2 levels, photosynthetic dissolved inorganic carbon (DIC) affinity was decreased and growth was constantly retarded; in contrast, overexpression of Pt43233:GFP yielded a slightly greater photosynthetic DIC affinity. The discovery of a θ-type CA localized to the thylakoid lumen, with an essential role in photosynthetic efficiency and growth, strongly suggests the existence of a common role for the thylakoid-luminal CA with respect to the function of diverse algal pyrenoids.

Regulation of the expressions of HCO3- uptake and intracellular carbonic anhydrase in response to CO2 concentration in the marine diatom Phaeodactylum sp.

2002 ◽  
Vol 29 (3) ◽  
pp. 279 ◽  
Author(s):  
Yusuke Matsuda ◽  
Keiichi Satoh ◽  
Hisashi Harada ◽  
Dan Satoh ◽  
Yasutaka Hiraoka ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Phaeodactylum Tricornutum ◽  
Marine Alga ◽  
Review Paper ◽  
Dissolved Inorganic Carbon ◽  
Co2 Concentration ◽  
Marine Diatom ◽  
Great Capacity ◽  
Low Co2 ◽  
Quantitative Analyses

The marine diatom, Phaeodactylum tricornutum Bohlin, is probably one of the most extensively studied marine alga with respect to carbon acquisition and assimilation mechanisms. However, quantitative analyses of HCO3-utilization and the detailed process of acclimation of cells from high CO2 to limited CO2 are yet to be done extensively. Suitable molecular markers for this acclimation process are not established, either. Recently, it became clear that the rate of CO2 formation in artificial seawater is about eight times slower than that in freshwater, and thatP. tricornutum cells utilize HCO3- quite efficiently. Despite their great capacity to take up HCO3-, the signal controlling photosynthetic affinity for dissolved inorganic carbon has been shown to be CO2 in the medium. Furthermore, light seems to be required for this process. Internal carbonic anhydrase (CA) activity has been shown to be crucial for high-affinity photosynthesis in a number of algae, including marine diatoms. Internal β-type CA, which has been isolated in one strain of P. tricornutum, was clearly shown to be a low-CO2 inducible enzyme. This review paper additionally includes data showing that this CA occurs generally in P. tricornutum species.

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