Plant Physiology Preview Published on April 30, 2004; 10.1104/pp.103.037283
Received December 4, 2003
Returned for revision January 23, 2004
Accepted January 23, 2004
Identification of a New Chloroplast Carbonic Anhydrase in Chlamydomonas reinhardtii
Mautusi Mitra , Scott M. Lato , Ruby A. Ynalvez , Ying Xiao , and James V. Moroney *
Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
* Corresponding author; email: btmoro{at}lsu.edu.
Carbonic anhydrases (CA) are zinc-containing metalloenzymes that catalyze the reversible hydration of CO2. The three evolutionarily unrelated families of CAs are designated -, -, and -CA. Aquatic photosynthetic organisms have evolved different forms of CO2 concentrating mechanisms (CCMs) to aid Rubisco in capturing CO2 from the surrounding environment. One aspect of all CCMs is the critical roles played by various specially localized extracellular and intracellular CAs. Five CAs have previously been identified in Chlamydomonas reinhardtii, a green alga with a well-studied CCM. Here we identify a sixth gene encoding a -type CA. This new -CA, designated Cah6, is distinct from the two mitochondrial -CAs in C. reinhardtii. Nucleotide sequence data show that the Cah6 cDNA contains an open reading frame encoding a polypeptide of 264 amino acids with a leader sequence likely targeting the protein to the chloroplast stroma. We have fused the Cah6 open reading frame to the coding sequence of maltose-binding protein in a pMal expression vector. The purified recombinant fusion protein is active and was used to partially characterize the Cah6 protein. The purified recombinant fusion protein was cleaved with protease Factor Xa to separate Cah6 from the maltose-binding protein and the purified Cah6 protein was used to raise an antibody. Western blots, immunolocalization studies, and northern blots collectively indicated that Cah6 is constitutively expressed in the stroma of chloroplasts. A possible role for Cah6 in the CCM of C. reinhardtii is proposed.
This article has been cited by other articles:

|
 |

|
 |
 
D. Duanmu, Y. Wang, and M. H. Spalding
Thylakoid Lumen Carbonic Anhydrase (CAH3) Mutation Suppresses Air-Dier Phenotype of LCIB Mutant in Chlamydomonas reinhardtii
Plant Physiology,
February 1, 2009;
149(2):
929 - 937.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. H. Spalding
Microalgal carbon-dioxide-concentrating mechanisms: Chlamydomonas inorganic carbon transporters
J. Exp. Bot.,
May 1, 2008;
59(7):
1463 - 1473.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. V. Moroney and R. A. Ynalvez
Proposed Carbon Dioxide Concentrating Mechanism in Chlamydomonas reinhardtii
Eukaryot. Cell,
August 1, 2007;
6(8):
1251 - 1259.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. Heinhorst, E. B. Williams, F. Cai, C. D. Murin, J. M. Shively, and G. C. Cannon
Characterization of the Carboxysomal Carbonic Anhydrase CsoSCA from Halothiobacillus neapolitanus
J. Bacteriol.,
December 1, 2006;
188(23):
8087 - 8094.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. R. Soto, H. Zheng, D. Shoemaker, J. Rodriguez, B. A. Read, and T. M. Wahlund
Identification and Preliminary Characterization of Two cDNAs Encoding Unique Carbonic Anhydrases from the Marine Alga Emiliania huxleyi
Appl. Envir. Microbiol.,
August 1, 2006;
72(8):
5500 - 5511.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Y. Tanaka, D. Nakatsuma, H. Harada, M. Ishida, and Y. Matsuda
Localization of Soluble {beta}-Carbonic Anhydrase in the Marine Diatom Phaeodactylum tricornutum. Sorting to the Chloroplast and Cluster Formation on the Girdle Lamellae
Plant Physiology,
May 1, 2005;
138(1):
207 - 217.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|