Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii.
Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.
Park
Y I
YI
Department of Biology, Chungnam National University, Taejon, South Korea. yipark@hanbat.chungnam.ac.kr
Karlsson
J
J
Rojdestvenski
I
I
Pronina
N
N
Klimov
V
V
Oquist
G
G
Samuelsson
G
G
D020418:Algal Proteins / Q000378:metabolism*; D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D001639:Bicarbonates / Q000378:metabolism; D015153:Blotting, Western; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D005016:Ethoxzolamide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008027:Light; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex
D020418:Algal Proteins; D016227:Benzoquinones; D001639:Bicarbonates; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D002245:Carbon Dioxide; C071926:2,6-dichlorobenzoquinone; D002244:Carbon; D002256:Carbonic Anhydrases; D010100:Oxygen; D005016:Ethoxzolamide