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 the Z disk of sectioned bee flight muscle.

1989 ◽  
Vol 108 (5) ◽  
pp. 1761-1774 ◽  
Author(s):  
N Q Cheng ◽  
J F Deatherage
Keyword(s):  
Central Region ◽  
Actin Filaments ◽  
Flight Muscle ◽  
Three Dimensional ◽  
Opposite Polarity ◽  
Dimensional Structure ◽  
Three Dimensional Reconstruction ◽  
Thin Sections ◽  
Dimensional Reconstruction ◽  
Cross Links

The three-dimensional structure of the central region of the Z disk of honeybee flight muscle has been determined to a resolution of 70 A by three-dimensional reconstruction from electron micrographs of tilted thin sections. The reconstructions show a complex assembly in which actin filaments terminate and are cross-linked together; a number of structural domains of this network are resolved in quantitative three-dimensional detail. The central region of the Z disk contains two sets of overlapping actin filaments of opposite polarity, which originate in the sarcomeres adjacent to the Z disk, and connections between these filaments. The filaments are deflected by the attachment of cross-links; spacing between filaments change by greater than 100 A during their passage through the Z disk. Each actin filament is linked by connecting structures to four filaments of opposite polarity and two filaments are of the same polarity. Four types of connecting density domain are observed in association with pairs of filaments of opposite polarity: C1, C2, C3, and C5. Two of these, C3 and C5, are associated with the ends of actin filaments. Another connection, C4, is associated with three filaments of the same polarity; C4 is threefold symmetric.

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 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 Crystal structure of tris(2,2′-bipyridine)cobalt(II) bis(1,1,3,3-tetracyano-2-ethoxypropenide)

2019 ◽  
Vol 75 (2) ◽  
pp. 142-145
Author(s):  
Jamila Benabdallah ◽  
Zouaoui Setifi ◽  
Fatima Setifi ◽  
Habib Boughzala ◽  
Abderrahim Titi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Distorted Octahedron ◽  
Dimensional Structure ◽  
Cobalt Ion ◽  
Space Group ◽  
Three Dimensional Structure ◽  
Rotation Axes

In the title compound, [Co(C10H8N2)3](C9H5N4O)2, the tris(2,2′-bipyridine)cobalt(II) dication lies across a twofold rotation axes in the space group C2/c. The N atoms of the three bipyridine ligands form a distorted octahedron around the cobalt ion. All the N atoms of the polynitrile 1,1,3,3-tetracyano-2-ethoxypropenide anions participate in C—H...N hydrogen bonds ensuring crystal cohesion and forming a three-dimensional structure. The structure is further stabilized by C—H...π(cation) and anion...π(cation) interactions.

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.

scholarly journals The three-dimensional structure of the nemaline rod Z-band.

1990 ◽  
Vol 111 (6) ◽  
pp. 2961-2978 ◽  
Author(s):  
E P Morris ◽  
G Nneji ◽  
J M Squire
Keyword(s):  
Actin Filaments ◽  
Three Dimensional ◽  
Nemaline Myopathy ◽  
Opposite Polarity ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Filament Axis ◽  
Correct Alignment ◽  
Cardiac Muscles ◽  
Cross Links

In nemaline myopathy and some cardiac muscles, the Z-band becomes greatly enlarged and contains multiple layers of a zigzag structure similar to that seen in normal muscle. Because of the additional periodicity in the direction of the filament axis, these structures are particularly favorable for three-dimensional analysis since it becomes possible to average the data in all three dimensions and thus improve the reliability of the reconstruction. Individual views of the structure corresponding to tilted longitudinal and transverse sections were combined by matching the phases of common reflections. Examination of the tilted views strongly suggested that to the available resolution, the structure possesses fourfold screw symmetry along the actin filament axes. This symmetry could be used both in establishing the correct alignment for the combination of individual tilted views and to generate additional views not readily accessible in a single tilt series. The reconstruction shows actin filaments from one sarcomere surrounded by an array of four actin filaments with opposite polarity from the adjacent sacormere. The actin filaments show a right-handed twist and are connected by a structure that links adjacent filaments with the same polarity at the same axial level, then runs parallel to the filaments, and finally forms a link between two actin filaments whose polarity is opposite to that of the first pair. The connecting structure is probably composed of alpha-actinin which is located in Z-bands and cross-links actin filaments. The connecting structure may consist of two alpha-actinin molecules linking actin filaments of opposite polarity.

Structure of The Z Disk of Sectioned Bee Flight Muscle

1990 ◽  
Vol 48 (1) ◽  
pp. 512-513
Author(s):  
J.F. Deatherage ◽  
N. Cheng
Keyword(s):  
Complex Network ◽  
Actin Filament ◽  
Electron Micrographs ◽  
Central Region ◽  
Actin Filaments ◽  
Flight Muscle ◽  
Opposite Polarity ◽  
Structural Domains ◽  
Thin Sections ◽  
Averaging Technique

Information from oblique thin sections and from 3-D reconstructions of tilted transverse thin sections has been combined to determine the 3-D structure of the honeybee flight muscle Z disk at 7øÅ 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 .The 3-D structure of the central region of the Z disk of honeybee flight muscle has been determined by crystallographic 3-D reconstruction from electron micrographs of tilted thin sections. The reconstructions show a complex network in which actin filaments terminate and are crosslinked together (Figure 1); a number of structural domains are resolved in the network.The central region of the Z disk contains two sets of overlapping actin filaments of opposite polarity, which originate in the sarcomeres adjacent to the Z disk, and connections between these filaments. The filaments are deflected by the attachment of crosslinks; spacings between filaments change by over 1øøÅ during their passage through the Z disk. Each actin filament is linked by connecting structures to four filaments of opposite polarity and two filaments of the same polarity.

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