TY - JOUR
T1 - Identification and functional role of the carbonic anhydrase Cah3 in thylakoid membranes of pyrenoid of Chlamydomonas reinhardtii
AU - Sinetova, Maria A.
AU - Kupriyanova, Elena V.
AU - Markelova, Alexandra G.
AU - Allakhverdiev, Suleyman I.
AU - Pronina, Natalia A.
N1 - Funding Information:
We are very grateful to Prof. J. Moroney (Louisiana State University, USA) for generously providing the strain of C. reinhardtii 137mt + and CCM-mutant cia3 , which were presented to Culture Collection of the Institute of Plant Physiology (IPPAS); Prof. G. Samuelsson (Umea University, Sweden) who kindly supplied us with primary antibodies against recombinant Cah3 and Cah3-MBP fusion protein. We thank Prof. D.A. Los and Dr. N. L. Klyachko (Institute of Plant Physiology, Russia) for helpful discussions and advice at the stage of manuscript preparation. This work was supported by a grant from the Russian Foundation for Basic Research (no. 10-04-01463 ) to E.V.K., by a grant from the Presidium of Russian Academy of Sciences (program “Molecular and Cell Biology”), and by a grant from the Russian Ministry of Education and Science (no. 16.740.11.0176 ).
PY - 2012/8
Y1 - 2012/8
N2 - The distribution of the luminal carbonic anhydrase Cah3 associated with thylakoid membranes in the chloroplast and pyrenoid was studied in wild-type cells of Chlamydomonas reinhardtii and in its cia3 mutant deficient in the activity of the Cah3 protein. In addition, the effect of CO2 concentration on fatty acid composition of photosynthetic membranes was examined in wild-type cells and in the cia3 mutant. In the cia3 mutant, the rate of growth was lower as compared to wild-type, especially in the cells grown at 0.03% CO2. This might indicate a participation of thylakoid Cah3 in the CO2-concentrating mechanism (CCM) of chloroplast and reflect the dysfunction of the CCM in the cia3 mutant. In both strains, a decrease in the CO2 concentration from 2% to 0.03% caused an increase in the content of polyunsaturated fatty acids in membrane lipids. At the same time, in the cia3 mutant, the increase in the majority of polyunsaturated fatty acids was less pronounced as compared to wild-type cells, whereas the amount of 16:4ω3 did not increase at all. Immunoelectron microscopy demonstrated that luminal Cah3 is mostly located in the thylakoid membranes that pass through the pyrenoid. In the cells of CCM-mutant, cia3, the Cah3 protein was much less abundant, and it was evenly distributed throughout the pyrenoid matrix. The results support our hypothesis that CO2 might be generated from HCO3- by Cah3 in the thylakoid lumen with the following CO2 diffusion into the pyrenoid, where the CO2 fixing Rubisco is located. This ensures the maintenance of active photosynthesis under CO2-limiting conditions, and, as a result, the active growth of cells. The relationships between the induction of CCM and restructuring of the photosynthetic membranes, as well as the involvement of the Cah3 of the pyrenoid in these events, are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
AB - The distribution of the luminal carbonic anhydrase Cah3 associated with thylakoid membranes in the chloroplast and pyrenoid was studied in wild-type cells of Chlamydomonas reinhardtii and in its cia3 mutant deficient in the activity of the Cah3 protein. In addition, the effect of CO2 concentration on fatty acid composition of photosynthetic membranes was examined in wild-type cells and in the cia3 mutant. In the cia3 mutant, the rate of growth was lower as compared to wild-type, especially in the cells grown at 0.03% CO2. This might indicate a participation of thylakoid Cah3 in the CO2-concentrating mechanism (CCM) of chloroplast and reflect the dysfunction of the CCM in the cia3 mutant. In both strains, a decrease in the CO2 concentration from 2% to 0.03% caused an increase in the content of polyunsaturated fatty acids in membrane lipids. At the same time, in the cia3 mutant, the increase in the majority of polyunsaturated fatty acids was less pronounced as compared to wild-type cells, whereas the amount of 16:4ω3 did not increase at all. Immunoelectron microscopy demonstrated that luminal Cah3 is mostly located in the thylakoid membranes that pass through the pyrenoid. In the cells of CCM-mutant, cia3, the Cah3 protein was much less abundant, and it was evenly distributed throughout the pyrenoid matrix. The results support our hypothesis that CO2 might be generated from HCO3- by Cah3 in the thylakoid lumen with the following CO2 diffusion into the pyrenoid, where the CO2 fixing Rubisco is located. This ensures the maintenance of active photosynthesis under CO2-limiting conditions, and, as a result, the active growth of cells. The relationships between the induction of CCM and restructuring of the photosynthetic membranes, as well as the involvement of the Cah3 of the pyrenoid in these events, are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
KW - CCM-mutant cia3
KW - Carbonic anhydrase Cah3
KW - Chlamydomonas reinhardtii
KW - Fatty acids
KW - Immunocytochemical localization
KW - Pyrenoid
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U2 - 10.1016/j.bbabio.2012.02.014
DO - 10.1016/j.bbabio.2012.02.014
M3 - Article
C2 - 22709623
AN - SCOPUS:84862180540
VL - 1817
SP - 1248
EP - 1255
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 8
ER -