Subunit II of cytochrome c oxidase in chlamydomonad algae is a heterodimer encoded by two independent nuclear genes

被引:86
作者
Pérez-Martínez, X
Antaramian, A
Vázquez-Acevedo, M
Funes, S
Tolkunova, E
d'Alayer, J
Claros, MG
Davidson, E
King, MP
González-Halphen, D
机构
[1] Univ Nacl Autonoma Mexico, Dept Mol Genet, Inst Fisiol Celular, Mexico City 04510, DF, Mexico
[2] Thomas Jefferson Univ, Dept Biochem & Mol Pharmacol, Philadelphia, PA 19107 USA
[3] Inst Pasteur, Lab Microsequencage Proteines, Dept Biotechnol, F-75724 Paris 15, France
[4] Univ Malaga, Fac Ciencias, Dept Biol Mol & Bioquim, E-29071 Malaga, Spain
关键词
D O I
10.1074/jbc.M010244200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The mitochondrial genomes of Chlamydomonad algae lack the cox2 gene that encodes the essential subunit COX II of cytochrome c oxidase. COX II is normally a single polypeptide encoded by a single mitochondrial gene. In this work we cloned two nuclear genes encoding COX II from both Chlamydomonas reinhardtii and Polytomella sp. The cox2a gene encodes a protein, COX IIA, corresponding to the N-terminal portion of subunit II of cytochrome c oxidase, and the cox2b gene encodes COX IIB, corresponding to the C-terminal region. The cox2a and cox2b genes are located in the nucleus and are independently transcribed into mRNAs that are translated into separate polypeptides. These two proteins assemble with other cytochrome c oxidase subunits in the inner mitochondrial membrane to form the mature multi-subunit complex. We propose that during the evolution of the Chlorophyte algae, the cox2 gene was divided into two mitochondrial genes that were subsequently transferred to the nucleus. This event was evolutionarily distinct from the transfer of an intact cox2 gene to the nucleus in some members the Leguminosae plant family.
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页码:11302 / 11309
页数:8
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