A small chloroplast-encoded protein as a novel architectural component of the light-harvesting antenna.
J Cell Biol
; 149(2): 369-78, 2000 Apr 17.
Article
em En
| MEDLINE
| ID: mdl-10769029
ABSTRACT
A small conserved open reading frame in the plastid genome, ycf9, encodes a putative membrane protein of 62 amino acids. To determine the function of this reading frame we have constructed a knockout allele for targeted disruption of ycf9. This allele was introduced into the tobacco plastid genome by biolistic transformation to replace the wild-type ycf9 allele. Homoplasmic ycf9 knockout plants displayed no phenotype under normal growth conditions. However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. We show that this phenotype is caused by the deficiency in a pigment-protein complex of the light-harvesting antenna of photosystem II and hence by a reduced efficiency of photon capture when light availability is limiting. Our results indicate that, in contrast to the current view, light-harvesting complexes do not only consist of the classical pigment-binding proteins, but may contain small structural subunits in addition. These subunits appear to be crucial architectural factors for the assembly and/or maintenance of stable light-harvesting complexes.
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Base de dados:
MEDLINE
Assunto principal:
Plantas Tóxicas
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Nicotiana
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Cloroplastos
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Fases de Leitura Aberta
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Plastídeos
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Complexo de Proteínas do Centro de Reação Fotossintética
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Proteínas de Membrana
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Alemanha