scholarly journals Three-dimensional structure of the Z band in a normal mammalian skeletal muscle.

1996 ◽  
Vol 133 (3) ◽  
pp. 571-583 ◽  
Author(s):  
J P Schroeter ◽  
J P Bretaudiere ◽  
R L Sass ◽  
M A Goldstein
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Three Dimensional ◽  
Square Lattice ◽  
Actin Binding ◽  
Dimensional Structure ◽  
Mammalian Skeletal Muscle ◽  
Axial Filament ◽  
Three Dimensional Structure ◽  
Dimensional Reconstruction

The three-dimensional structure of the vertebrate skeletal muscle Z band reflects its function as the muscle component essential for tension transmission between successive sarcomeres. We have investigated this structure as well as that of the nearby I band in a normal, unstimulated mammalian skeletal muscle by tomographic three-dimensional reconstruction from electron micrograph tilt series of sectioned tissue. The three-dimensional Z band structure consists of interdigitating axial filaments from opposite sarcomeres connected every 18 +/- 12 nm (mean +/- SD) to one to four cross-connecting Z-filaments are observed to meet the axial filaments in a fourfold symmetric arrangement. The substantial variation in the spacing between cross-connecting Z-filament to axial filament connection points suggests that the structure of the Z band is not determined solely by the arrangement of alpha-actinin to actin-binding sites along the axial filament. The cross-connecting filaments bind to or form a "relaxed interconnecting body" halfway between the axial filaments. This filamentous body is parallel to the Z band axial filaments and is observed to play an essential role in generating the small square lattice pattern seen in electron micrographs of unstimulated muscle cross sections. This structure is absent in cross section of the Z band from muscles fixed in rigor or in tetanus, suggesting that the Z band lattice must undergo dynamic rearrangement concomitant with crossbridge binding in the A band.

Three-dimensional reconstruction of a mammalian Z-band from skeletal muscle

1992 ◽  
Vol 50 (1) ◽  
pp. 542-543
Author(s):  
J. P. Schroeter ◽  
M. A. Goldstein ◽  
J. P. Bretaudiere ◽  
R. L. Sass
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Three Dimensional ◽  
Square Lattice ◽  
Back Projection ◽  
Axial Filament ◽  
Dimensional Reconstruction ◽  
Rat Soleus Muscle ◽  
Tilt Series ◽  
Three Dimensional Models

We have completed 3-d reconstructions of several regions of the Z-band in relaxed rat soleus muscle using the method of weighted back projection on a tilt series from two different longitudinal sections. Various displays of the reconstructions were interpreted after corrections for section shrinkage and comparisons to three dimensional models. Examination of cross-sections of the reconstructed Z-bands reveal that the lattice is in the small square form. We have previously shown that this form of the Z-band lattice is predominate in relaxed skeletal muscle. The reconstructions reveal that cross-connecting Z-filaments are arranged in opposing pairs along the axial filament. Successive pairs of filaments are rotated by ninety degrees about the axial filament, thus generating the four-fold appearance seen in the projected small square lattice.

A comparison of the Three-Dimensional structures of Z bands in unstimulated and rigor skeletal muscle

1995 ◽  
Vol 53 ◽  
pp. 1080-1081
Author(s):  
J.P. Schroeter ◽  
R.J. Edwards ◽  
M.A. Goldstein
Keyword(s):  
Skeletal Muscle ◽  
Electron Micrographs ◽  
Cross Sections ◽  
Structural Transition ◽  
Three Dimensional ◽  
Square Lattice ◽  
Thin Sections ◽  
Tomographic Method ◽  
Dimensional Reconstruction ◽  
Rat Soleus Muscle

Previous studies (reviewed in ref. 1) lead to the expectation that Z bands from unstimulated skeletal muscle exhibit the unactivated small square form of the Z band lattice. Rigor Z bands, on the other hand are expected to exhibit the basket-weave form of the Z band lattice associated with activation in skeletal muscle. This Z band structural transition has been investigated by three-dimensional reconstruction of Z bands and nearby I bands in unstimulated and rigor rat soleus muscle. The reconstructions were calculated using the tomographic method of weighted back-projection on a series of electron micrographs of longitudinal thin sections of muscle.Examination of Z band cross-sections of the reconstructions reveals that the unstimulated muscle does indeed exhibit the expected small square lattice form. Furthermore, Z band cross sections of the rigor reconstructions reveal the expected basket-weave lattice form. The lattice dimensions were 20 +- 1 nra for the small square lattice and 27 +- 4 nm for the basket-weave lattice, consistent with the results from electron micrographs of cross-sections.

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.

Three-Dimensional Structure of Cloned T3 Connector Protein at 1.6nm Resolution

1990 ◽  
Vol 48 (1) ◽  
pp. 282-283
Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa
Keyword(s):  
Dna Sequences ◽  
Expression Vector ◽  
Three Dimensional ◽  
Deae Cellulose ◽  
Dna Packaging ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Freezing And Thawing ◽  
Three Dimensional Structure ◽  
Dimensional Reconstruction

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.

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 the complex between calmodulin mutant lacking the c-terminal five residues and the calmodulin-binding peptide derived from skeletal muscle myosin light-chain kinase

2017 ◽  
Vol 39 (3) ◽  
pp. 309-319
Author(s):  
Vu Van Dung ◽  
Yoshitaka Umetsu ◽  
Shinya Ohki
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Skeletal Muscle Myosin ◽  
Three Dimensional Structure ◽  
Calmodulin Binding ◽  
Muscle Myosin

In our previous study, functional ability and conformational stability had been examined for C-terminal deletion mutants of a 148-residue Ca2+-binding protein, chicken calmodulin (CaM). In that study, we had reported that a mutant named CCMΔ5, missing five residues at the C-terminus, activates CaM-target as much as full-length CaM does. This finding is intriguing because CCMΔ5 lacks the key residues, Met144 and Met145, for the target activation. To uncover why CCMΔ5 displays proper function, here we report the three-dimensional structure of CCMΔ5 bound to the peptide derived from skeletal muscle myosin light-chain kinase (skMLCK). The structure determination was achieved using multidimensional nuclear magnetic resonance (NMR) spectroscopy. The complex structure of CCM∆5-skMLCK was compared to that of wild CaM-skMLCK. The results showed that the orientation of helix-1 and helix-5 in CCM∆5 differs from those in wild CaM. Moreover, distinctive hydrophobic interaction manner was found in the binding between CCM∆5 and peptide; Phe141, Ala128, Met109, Leu105 and Phe92 of CCM∆5 contribute to the interaction with Trp4 of the skMLCK peptide.   Abbreviations: CaM, calmodulin; CCMΔX, a deletion mutant of CaM that lacks X C-terminal residues; NMR, Nuclear magnetic resonance; PDB, Protein date bank; skMLCK, skeletal muscle myosin light-chain kinase; TOF-MS, Time-of-flight mass spectrometry; RMSD, root mean square deviation; SDS-PAGE, Sodium dodecyl sulfate polyacrylamide gel electrophoresis Citation: Vu Van Dung, Umetsu Y., Ohki S., 2017. Three-dimensional structure of the complex between calmodulin mutant lacking the c-terminal five residues and the calmodulin-binding peptide derived from skeletal muscle myosin light-chain kinase. Tap chi Sinh hoc, 39(3): 309-319. DOI: 10.15625/0866-7160/v39n3.10111. *Corresponding author: [email protected] Received 19 June 2017, accepted 20 August 2017 

scholarly journals Combining FIB and Automated Microcleaving Provides Fast, Accurate Cross Sections

1999 ◽  
Vol 7 (7) ◽  
pp. 34-35
Author(s):  
Janet Teshima
Keyword(s):  
Sample Preparation ◽  
Cross Sections ◽  
Three Dimensional ◽  
New Combination ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Sem And Tem ◽  
The Creation ◽  
Subsurface Defects

A large part of the preparation of semiconductor samples for SEM and TEM observations involves the creation of cross sections to expose subsurface defects and three-dimensional structure. A powerful new combination of FIB (FEI Company, Hillsboro, Oregon, http://www.feic.com ) with automated microcleaving technology (SELA, Santa Clara, California, http://www. sela.com ) now offers a comprehensive solution for fast, easy and accurate sample preparation.

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