Spherical reconstruction: a method for structure determination of membrane proteins from cryo-EM images.
J Struct Biol
; 133(2-3): 119-31, 2001.
Article
em En
| MEDLINE
| ID: mdl-11472084
ABSTRACT
We propose a new method for single-particle reconstruction, which should be generally applicable to structure determination for membrane proteins. After reconstitution into a small spherical vesicle, a membrane protein takes a particular orientation relative to the membrane normal, and its position in the projected image of the vesicle directly defines two of its three Euler angles of orientation. The spherical constraint imposed by the vesicle effectively reduces the dimensionality of the alignment search from 5 to 3 and simplifies the detection of the particle. Projection images of particles in vesicles collectively take all possible orientations and therefore cover the whole Fourier space. Analysis of images of vesicles in ice showed that the vesicle density is well described by a simple model for membrane electron scattering density. In fitting this model we found that osmotically swollen vesicles remain nearly spherical through the freezing process. These results satisfy the basic experimental requirements for spherical reconstruction. A computer simulation of particles in vesicles showed that this method provides good estimates of the two Euler angles and thus may improve single-particle reconstruction and extend it to smaller membrane proteins.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Processamento de Imagem Assistida por Computador
/
Microscopia Crioeletrônica
/
Proteínas de Membrana
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Struct Biol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA