scholarly journals Three-dimensional Structure of Acanthamoeba castellanii Myosin-IB (MIB) Determined by Cryoelectron Microscopy of Decorated Actin Filaments

1998 ◽  
Vol 141 (1) ◽  
pp. 155-162 ◽  
Author(s):  
James D. Jontes ◽  
E. Michael Ostap ◽  
Thomas D. Pollard ◽  
Ronald A. Milligan
Keyword(s):  
Actin Filaments ◽  
Catalytic Domain ◽  
Three Dimensional ◽  
Acanthamoeba Castellanii ◽  
Dimensional Structure ◽  
Cryoelectron Microscopy ◽  
Tail Domain ◽  
Three Dimensional Structure ◽  
Myosin I ◽  
Carboxy Terminal

The Acanthamoeba castellanii myosin-Is were the first unconventional myosins to be discovered, and the myosin-I class has since been found to be one of the more diverse and abundant classes of the myosin superfamily. We used two-dimensional (2D) crystallization on phospholipid monolayers and negative stain electron microscopy to calculate a projection map of a “classical” myosin-I, Acanthamoeba myosin-IB (MIB), at ∼18 Å resolution. Interpretation of the projection map suggests that the MIB molecules sit upright on the membrane. We also used cryoelectron microscopy and helical image analysis to determine the three-dimensional structure of actin filaments decorated with unphosphorylated (inactive) MIB. The catalytic domain is similar to that of other myosins, whereas the large carboxy-terminal tail domain differs greatly from brush border myosin-I (BBM-I), another member of the myosin-I class. These differences may be relevant to the distinct cellular functions of these two types of myosin-I. The catalytic domain of MIB also attaches to F-actin at a significantly different angle, ∼10°, than BBM-I. Finally, there is evidence that the tails of adjacent MIB molecules interact in both the 2D crystal and in the decorated actin filaments.

Three-dimensional Structure Prediction of the Human LMTK3 Catalytic Domain in DYG-in Conformation

2017 ◽  
Vol 06 (01) ◽  
Author(s):  
Loubna Allam ◽  
Wiame Lakhlili ◽  
Zineb Tarhda ◽  
Jihane Akachar ◽  
Fatima Ghrifi ◽  
...  
Keyword(s):  
Structure Prediction ◽  
Catalytic Domain ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure

scholarly journals Three-dimensional structure of actin filaments and of an actin gel made with actin-binding protein.

1983 ◽  
Vol 96 (5) ◽  
pp. 1400-1413 ◽  
Author(s):  
R Niederman ◽  
P C Amrein ◽  
J Hartwig
Keyword(s):  
Actin Filaments ◽  
Binding Protein ◽  
Three Dimensional ◽  
Actin Binding ◽  
Dimensional Structure ◽  
Molar Ratio ◽  
Computer Assisted ◽  
Three Dimensional Structure ◽  
Actin Binding Protein ◽  
Critical Point Drying

Purified muscle actin and mixtures of actin and actin-binding protein were examined in the transmission electron microscope after fixation, critical point drying, and rotary shadowing. The three-dimensional structure of the protein assemblies was analyzed by a computer-assisted graphic analysis applicable to generalized filament networks. This analysis yielded information concerning the frequency of filament intersections, the filament length between these intersections, the angle at which filaments branch at these intersections, and the concentration of filaments within a defined volume. Purified actin at a concentration of 1 mg/ml assembled into a uniform mass of long filaments which overlap at random angles between 0 degrees and 90 degrees. Actin in the presence of macrophage actin-binding protein assembled into short, straight filaments, organized in a perpendicular branching network. The distance between branch points was inversely related to the molar ratio of actin-binding protein to actin. This distance was what would be predicted if actin filaments grew at right angles off of nucleation sites on the two ends of actin-binding protein dimers, and then annealed. The results suggest that actin in combination with actin-binding protein self-assembles to form a three-dimensional network resembling the peripheral cytoskeleton of motile cells.

Three-Dimensional Structure of Keyhole Limpet Hemocyanin by Cryoelectron Microscopy and Angular Reconstitution

1995 ◽  
Vol 115 (3) ◽  
pp. 226-232 ◽  
Author(s):  
Prakash Dube ◽  
Elena V. Orlova ◽  
Friederich Zemlin ◽  
Marin van Heel ◽  
J.Robin Harris ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Keyhole Limpet Hemocyanin ◽  
Dimensional Structure ◽  
Cryoelectron Microscopy ◽  
Three Dimensional Structure

scholarly journals Three-Dimensional Structure of Vinculin Bound to Actin Filaments

2006 ◽  
Vol 21 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Mandy E.W. Janssen ◽  
Eldar Kim ◽  
Hongjun Liu ◽  
L. Miya Fujimoto ◽  
Andrey Bobkov ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure

scholarly journals Brush Border Myosin–I Structure and ADP-dependent Conformational Changes Revealed by Cryoelectron Microscopy and Image Analysis

1997 ◽  
Vol 139 (3) ◽  
pp. 683-693 ◽  
Author(s):  
James D. Jontes ◽  
Ronald A. Milligan
Keyword(s):  
Image Analysis ◽  
Conformational Changes ◽  
Light Chain ◽  
Brush Border ◽  
Actin Filaments ◽  
Catalytic Domain ◽  
Binding Domain ◽  
Cryoelectron Microscopy ◽  
Skeletal Muscle Myosin ◽  
Myosin I

Brush border myosin–I (BBM-I) is a single-headed myosin found in the microvilli of intestinal epithelial cells, where it forms lateral bridges connecting the core bundle of actin filaments to the plasma membrane. Extending previous observations (Jontes, J.D., E.M. Wilson-Kubalek, and R.A. Milligan. 1995. Nature [Lond.]. 378:751–753), we have used cryoelectron microscopy and helical image analysis to generate three-dimensional (3D) maps of actin filaments decorated with BBM-I in both the presence and absence of 1 mM MgADP. In the improved 3D maps, we are able to see the entire light chain–binding domain, containing density for all three calmodulin light chains. This has enabled us to model a high resolution structure of BBM-I using the crystal structures of the chicken skeletal muscle myosin catalytic domain and essential light chain. Thus, we are able to directly measure the full magnitude of the ADP-dependent tail swing. The ∼31° swing corresponds to ∼63 Å at the end of the rigid light chain–binding domain. Comparison of the behavior of BBM-I with skeletal and smooth muscle subfragments-1 suggests that there are substantial differences in the structure and energetics of the biochemical transitions in the actomyosin ATPase cycle.

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