Fibrinogen structure in projection at 18 A resolution. Electron density by co-ordinated cryo-electron microscopy and X-ray crystallography.
J Mol Biol
; 222(1): 89-98, 1991 Nov 05.
Article
em En
| MEDLINE
| ID: mdl-1942070
ABSTRACT
Electron microscope images of frozen-hydrated crystals of a proteolytically modified fibrinogen show excellent preservation of the structure. An electron density map of the key centric projection of the crystal at 18 A resolution has been obtained by combining the phases derived from cryo-electron microscopy with X-ray amplitudes. Simulation methods developed in earlier studies have been used to interpret the map. In contrast to the earlier images, the map allows us to visualize the coiled-coil region of the molecule and possible substructure in the beta domains. The map also shows that there is a marked difference in density in the two regions corresponding to the molecular ends where the gamma domains interact. A possible interpretation of this finding is provided by assuming substructure in the gamma domains and the breaking of molecular symmetry where these domains interact. Some additional constraints useful for the determination of the three-dimensional structure were obtained from cryo-electron micrographs of a perpendicular view at 25 A resolution. Implications of this working model for the molecular length and contacts in the filaments in both the crystal and fibrin are described. The data used here will be valuable as a starting point for obtaining the three-dimensional structure.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fibrinogênio
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
1991
Tipo de documento:
Article