Polymerization, three-dimensional structure and mechanical properties of Dictyostelium versus rabbit muscle actin filaments

2000 ◽  
Vol 303 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Michel O Steinmetz ◽  
Andreas Hoenger ◽  
Daniel Stoffler ◽  
Angelika A Noegel ◽  
Ueli Aebi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
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.

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 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 and micro-mechanical properties of iron ore sinter

2017 ◽  
Vol 24 (10) ◽  
pp. 998-1006 ◽  
Author(s):  
Wei Wang ◽  
Ming Deng ◽  
Run-sheng Xu ◽  
Wei-bo Xu ◽  
Ze-lin Ouyang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Iron Ore ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Iron Ore Sinter

scholarly journals Arrangement of filaments and cross-links in the bee flight muscle Z disk by image analysis of oblique sections.

1989 ◽  
Vol 108 (5) ◽  
pp. 1775-1782 ◽  
Author(s):  
J F Deatherage ◽  
N Q Cheng ◽  
B Bullard
Keyword(s):  
Actin Filaments ◽  
Flight Muscle ◽  
Three Dimensional ◽  
Thick Filament ◽  
Opposite Polarity ◽  
Dimensional Structure ◽  
Central Plane ◽  
Thin Sections ◽  
Three Dimensional Structure ◽  
Rotation Axes

Information from oblique thin sections and from three-dimensional reconstructions of tilted, transverse thin sections (Cheng, N., and J. F. Deatherage. 1989. J. Cell Biol. 108:1761-1774) has been combined to determine the three-dimensional structure of the honeybee flight muscle Z disk at 70-A resolution. The overall symmetry and structure of the Z disk and its relationship to the rest of the myofibril have been determined by tracing filaments and connecting elements on electron images of oblique sections which have been enhanced by a local crystallographic averaging technique. In the three-dimensional structure, the connecting density between actin filaments can be described as five compact, crystallographically nonequivalent domains. Features C1 and C2 are located on the transverse twofold rotation axes in the central plane of the Z disk. They are associated with the sides of actin filaments of opposite polarity. Features C3, C4, and C5 are present in two symmetry-related sets which are located on opposite sides of the central plane. C3 and C5 are each associated with two filaments of opposite polarity, interacting with the side of one filament and the end of the other filament. C3 and C5 may be involved in stabilizing actin filament ends inside the Z disk. The location of the threefold symmetric connection C4, relative to the thick filament of the adjacent sarcomere, is determined and its possible relationship to the C filament is considered.

scholarly journals Three-dimensional reconstruction of a simple Z-band in fish muscle.

1991 ◽  
Vol 113 (5) ◽  
pp. 1043-1055 ◽  
Author(s):  
P K Luther
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Rotational Symmetry ◽  
Three Dimensional ◽  
The Other ◽  
Dimensional Structure ◽  
Central Plane ◽  
Three Dimensional Structure ◽  
Proximal Site ◽  
Distal Site

The three-dimensional structure of the Z-band in fish white muscle has been investigated by electron microscopy. This Z-band is described as simple, since in longitudinal sections it has the appearance of a single zigzag pattern connecting the ends of actin filaments of opposite polarity from adjacent sarcomeres. The reconstruction shows two pairs of links, the Z-links, between one actin filament and the facing four actin filaments in the adjacent sarcomere. The members of each pair have nearly diametrically opposed origins. In relation to one actin filament, one pair of links appears to bind along the final 10 nm of the actin filament (proximal site) and the other pair binds along a region extending from 5 to 20 nm from the filament end (distal site). Between one pair and the other, there is a rotation of approximately 80 degrees round the filament axis. A Z-link with a proximal site at the end of one actin filament attaches at a distal site on the oppositely oriented actin filaments of the facing sarcomere and vice versa. The length of each Z-link is consistent with the length of an alpha-actinin molecule. An additional set of links located 10-15 nm from the center of the Z-band occurs between actin filaments of the same polarity. These polar links connect the actin filaments along the same direction on each side of the Z-band. The three-dimensional structure appears to have twofold screw symmetry about the central plane of the Z-band. Only approximate twofold rotational symmetry is observed in directions parallel to the actin filaments. Previous models of the Z-band in which four identical and rotationally symmetrical links emanate from the end of one actin filament and span across to the ends of four actin filaments in the adjacent sarcomere are therefore incorrect.

scholarly journals Intramolecular ionic interactions of lysine residues and a possible folding domain in fructose diphosphate aldolase

1977 ◽  
Vol 161 (1) ◽  
pp. 63-71 ◽  
Author(s):  
J M Lambert ◽  
R N Perham ◽  
J R Coggins
Keyword(s):  
Primary Structure ◽  
Protein Structures ◽  
Three Dimensional ◽  
Native Enzyme ◽  
Dimensional Structure ◽  
Ionic Interactions ◽  
Rabbit Muscle ◽  
Amino Groups ◽  
Three Dimensional Structure ◽  
Lysine Residues

1. Treatment with methyl acetimidate was used to probe the topography of the tetrameric fructose 1,6-diphosphate aldolase from ox liver. A single treatment with imido ester in the presence or absence of 20mM-fructose 1,6-diphosphate caused the number of amino groups in the enzyme to fall to approx. 30% of the starting number (assumed to be 30 per subunit). The catalytic activity of the aldolase modified in the presence of fructose 1,6-diphosphate was unaffected, whereas that of the enzyme modified in the absence of substrate fell by about 20%. 2. Use of methyl [1-14C]acetimidate and small-scale methods of protein chemistry showed that the amino group of lysine-27 (the numbering is that of the highly homologous rabbit muscle enzyme) is essentially unavailable for amidination in the native enzyme and is therefore predicted to be buried in a hydrophobic environment, probably in the form of an ion-pair with a negatively charged side-chain carboxyl group. All the other lysine residues that reacted poorly with methyl acetimidate in the native enzyme (a total of 7) were found to be within the primary structure bounded by lysine-107 and lysine-227. An important member of this group of lysine residues displaying aberrant reactivity is lysine-227, which is known to form an imine with the substrate as part of the catalytic mechanism of the enzyme. 3. The results of the amidination experiments can be correlated in an interesting way with previous studies of thiol-group modification in the aldolases. Taken together, and arguing in part by analogy with the results of identical experiments with glyceraldehyde 3-phosphate dehydrogenases where the three-dimensional structure is known [Lambert & Perham (1977) Biochem. 4. 161. 49-62], they suggest that the region of primary structure from residues 107-227 may form the whole or part of a three-dimensional structural feature, perhaps a folding domain. A three-dimensional structure deduced from X-ray-crystallographic analysis will be needed to interpret these findings more closely. 4. The amino groups of lysine residues are commonly thought to reside at the ‘surface’ of protein structures. The patterns of specific lysine residues in glyceraldehyde 3-phosphate dehydrogenases and in aldolases that have been found to react poorly with methyl acetimidate in the native enzymes can be attributed to intramolecular ionic interactions deep in hydrophobic pockets and at the protein ‘surface’. Such ionic interactions may contribute significantly to the stability of a given protein.

Electron Microscopy of Cytoplasmic Contractile Proteins

1978 ◽  
Vol 36 (3) ◽  
pp. 606-614 ◽  
Author(s):  
T.D. Pollard ◽  
P. Maupin
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Uranyl Acetate ◽  
Contractile Proteins ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Cytoplasmic Matrix ◽  
Computer Image Processing ◽  
Nonmuscle Cells

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.

Sign in / Sign up

Export Citation Format

Share Document