Organization, structure, and assembly of alpha-carboxysomes determined by electron cryotomography of intact cells.
J Mol Biol
; 396(1): 105-17, 2010 Feb 12.
Article
en En
| MEDLINE
| ID: mdl-19925807
Carboxysomes are polyhedral inclusion bodies that play a key role in autotrophic metabolism in many bacteria. Using electron cryotomography, we examined carboxysomes in their native states within intact cells of three chemolithoautotrophic bacteria. We found that carboxysomes generally cluster into distinct groups within the cytoplasm, often in the immediate vicinity of polyphosphate granules, and a regular lattice of density frequently connects granules to nearby carboxysomes. Small granular bodies were also seen within carboxysomes. These observations suggest a functional relationship between carboxysomes and polyphosphate granules. Carboxysomes exhibited greater size, shape, and compositional variability in cells than in purified preparations. Finally, we observed carboxysomes in various stages of assembly, as well as filamentous structures that we attribute to misassembled shell protein. Surprisingly, no more than one partial carboxysome was ever observed per cell. Based on these observations, we propose a model for carboxysome assembly in which the shell and the internal RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) lattice form simultaneously, likely guided by specific interactions between shell proteins and RuBisCOs.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Bacterias
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Tomografía
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Cuerpos de Inclusión
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Microscopía por Crioelectrón
Idioma:
En
Revista:
J Mol Biol
Año:
2010
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos