Three-dimensional structure of cytochrome c oxidase vesicle crystals in negative stain

1982 ◽  
Vol 158 (3) ◽  
pp. 487-499 ◽  
Author(s):  
J.F. Deatherage ◽  
R. Henderson ◽  
R.A. Capaldi
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Negative Stain

The Three-dimensional structure of frozen-hydrated nudaurelia capensis β virus

1987 ◽  
Vol 45 ◽  
pp. 650-651
Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry
Keyword(s):  
South African ◽  
Rna Virus ◽  
Carbon Film ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Electron Dose ◽  
Total Electron ◽  
Three Dimensional Structure ◽  
Negative Stain ◽  
Dimensional Reconstruction

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.

scholarly journals Three-Dimensional Structure of the Neisseria meningitidis Secretin PilQ Determined from Negative-Stain Transmission Electron Microscopy

2003 ◽  
Vol 185 (8) ◽  
pp. 2611-2617 ◽  
Author(s):  
Richard F. Collins ◽  
Robert C. Ford ◽  
Ashraf Kitmitto ◽  
Ranveig O. Olsen ◽  
Tone Tønjum ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Outer Membrane ◽  
Protein Complex ◽  
Rotational Symmetry ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Type Iv ◽  
Negative Stain ◽  
Dominant Feature

ABSTRACT The PilQ secretin from the pathogenic bacterium Neisseria meningitidis is an integral outer membrane protein complex which plays a crucial role in the biogenesis of type IV pili. We present here the first three-dimensional structure of this type of secretin at 2.5-nm resolution, obtained by single-particle averaging methods applied to the purified protein complex visualized in a negative stain. In projection, the PilQ complex is circular, with a donut-like appearance. When viewed from the side it has a rounded, conical profile. The complex was demonstrated to have 12-fold rotational symmetry, and this property was used to improve the quality of the density map by symmetry averaging. The dominant feature of the structure is a cavity, 10 nm deep, within the center of the molecule. The cavity is funnel-shaped in cross section, measures 6.5 nm in diameter at the top of the complex, and tapers to a closed point, effectively blocking formation of a continuous pore through the PilQ complex. These results suggest that the complex would have to undergo a conformational change in order to accommodate an assembled pilus fiber of diameter 6.5 nm running through the outer membrane.

scholarly journals tBID, a membrane-targeted death ligand, oligomerizes BAK to release cytochrome c

2000 ◽  
Vol 14 (16) ◽  
pp. 2060-2071 ◽  
Author(s):  
Michael C. Wei ◽  
Tullia Lindsten ◽  
Vamsi K. Mootha ◽  
Solly Weiler ◽  
Atan Gross ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Gene Disruption ◽  
Three Dimensional ◽  
Permeability Transition ◽  
Dimensional Structure ◽  
Cytochrome C Release ◽  
Allosteric Activation ◽  
Three Dimensional Structure ◽  
Bh3 Domain ◽  
Blocking Antibodies

TNFR1/Fas engagement results in the cleavage of cytosolic BID to truncated tBID, which translocates to mitochondria. Immunodepletion and gene disruption indicate BID is required for cytochrome c release. Surprisingly, the three-dimensional structure of this BH3 domain-only molecule revealed two hydrophobic α-helices suggesting tBID itself might be a pore-forming protein. Instead, we demonstrate that tBID functions as a membrane-targeted death ligand in which an intact BH3 domain is required for cytochrome c release, but not for targeting.Bak-deficient mitochondria and blocking antibodies reveal tBID binds to its mitochondrial partner BAK to release cytochrome c, a process independent of permeability transition. Activated tBID results in an allosteric activation of BAK, inducing its intramembranous oligomerization into a proposed pore for cytochrome c efflux, integrating the pathway from death receptors to cell demise.

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