Tetratricopeptide repeat protein protects photosystem I from oxidative disruption during assembly.
Proc Natl Acad Sci U S A
; 113(10): 2774-9, 2016 Mar 08.
Article
em En
| MEDLINE
| ID: mdl-26903622
ABSTRACT
A Chlamydomonas reinhardtii mutant lacking CGL71, a thylakoid membrane protein previously shown to be involved in photosystem I (PSI) accumulation, exhibited photosensitivity and highly reduced abundance of PSI under photoheterotrophic conditions. Remarkably, the PSI content of this mutant declined to nearly undetectable levels under dark, oxic conditions, demonstrating that reduced PSI accumulation in the mutant is not strictly the result of photodamage. Furthermore, PSI returns to nearly wild-type levels when the O2 concentration in the medium is lowered. Overall, our results suggest that the accumulation of PSI in the mutant correlates with the redox state of the stroma rather than photodamage and that CGL71 functions under atmospheric O2 conditions to allow stable assembly of PSI. These findings may reflect the history of the Earth's atmosphere as it transitioned from anoxic to highly oxic (1-2 billion years ago), a change that required organisms to evolve mechanisms to assist in the assembly and stability of proteins or complexes with O2-sensitive cofactors.
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MEDLINE
Assunto principal:
Chlamydomonas reinhardtii
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Proteínas de Algas
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Complexo de Proteína do Fotossistema I
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Proteínas de Cloroplastos
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Proteínas das Membranas dos Tilacoides
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2016
Tipo de documento:
Article