Architecture of native human alpha 2-macroglobulin studied by cryoelectron microscopy and three-dimensional reconstruction.
The architecture of the native human alpha 2-macroglobulin was studied by cryoelectron microscopy and image processing techniques. The lip, padlock, doughnut, and four-petaled flower views of this homotetrameric proteinase inhibitor were observed in the frozen-hydrated specimen, and a new view, termed eye view, was also characterized. The present three-dimensional reconstruction demonstrates that all these electron microscope views derive from a single three-dimensional structure. The molecule is composed of two horizontal bodies and of two oblique arches, which border a large central cavity. The polymorphism and the flexibility of the native alpha 2-macroglobulin are discussed.
Larquet
E
E
Laboratoire de Microscopie Cellulaire et Moléculaire, CNRS URA 147, Institut Gustave-Roussy, Villejuif, France.
Boisset
N
N
Pochon
F
F
Lamy
J
J
D005615:Freezing; D006801:Humans; D008854:Microscopy, Electron / Q000379:methods; D008961:Models, Structural; D015999:Multivariate Analysis; D011487:Protein Conformation; D000511:alpha-Macroglobulins / Q000737:chemistry* / Q000648:ultrastructure*
D000511:alpha-Macroglobulins