Interaction of C-protein with pH 8.0 synthetic thick filaments prepared from the myosin of vertebrate skeletal muscle

1988 ◽  
Vol 9 (2) ◽  
pp. 174-183 ◽  
Author(s):  
Julien S. Davis
Keyword(s):  
Skeletal Muscle ◽  
C Protein ◽  
Thick Filaments ◽  
Vertebrate Skeletal Muscle

scholarly journals Localization of C-protein isoforms in chicken skeletal muscle: ultrastructural detection using monoclonal antibodies.

1984 ◽  
Vol 98 (4) ◽  
pp. 1514-1522 ◽  
Author(s):  
J E Dennis ◽  
T Shimizu ◽  
F C Reinach ◽  
D A Fischman
Keyword(s):  
Skeletal Muscle ◽  
Monoclonal Antibodies ◽  
Fiber Type ◽  
Ultrastructural Localization ◽  
Absolute Number ◽  
Protein Isoforms ◽  
C Protein ◽  
Thick Filaments ◽  
C Proteins ◽  
Chicken Skeletal Muscle

Monoclonal antibodies (McAbs) specific for the fast (MF-1) and slow (ALD-66) isoforms of C-protein from chicken skeletal muscle have been produced and characterized. Using these antibodies it was possible to demonstrate that skeletal muscles of varying fiber type express different isoforms of this protein and that in the posterior latissimus dorsi muscle both isoforms are co-expressed in the same myofiber (17, 18). Since we had shown that both isoforms were present in all sarcomeres, it was feasible to test whether the two isoforms co-distributed in the same 43-nm repeat within the A-band, thereby establishing a minimum number of C-proteins per repeat in the thick filaments. Here we describe the ultrastructural localization of C-protein in myofibers from three muscle types of the chicken using these same McAbs. We observed that although C-protein was present in a 43-nm repeat along the filaments in all three muscles, there were marked differences in the absolute number and position occupied by the different isoforms. Since McAbs MF-1 and ALD-66 decorated the same 43-nm repeats in the A-bands of the posterior latissimus dorsal muscle, we suggest that at least two C-proteins can co-localize at binding sites 43 nm apart along thick filaments of this muscle.

scholarly journals Fluorescence microscope study of the binding of added C protein to skeletal muscle myofibrils.

1981 ◽  
Vol 90 (1) ◽  
pp. 25-31 ◽  
Author(s):  
C Moos
Keyword(s):  
Skeletal Muscle ◽  
Fluorescence Microscopy ◽  
Calcium Ion ◽  
Ion Concentration ◽  
Free Calcium ◽  
Myofibrillar Atpase ◽  
C Protein ◽  
Thick Filaments ◽  
Calcium Ion Concentration

The binding of extra C protein to rabbit skeletal muscle myofibrils has been investigated by fluorescence microscopy with fluorescein-labeled C protein or unmodified C protein plus fluorescein-labeled anti-C protein. Added C protein binds strongly to the I bands, which is consistent with its binding to F actin in solution (Moos, C., C. M. Mason, J. M. Besterman, I. M. Feng, and J. H. Dubin. 1978. J. Mol. Biol. 124:571-586). Of particular interest, the binding to the I band is calcium regulated: it requires a free calcium ion concentration comparable to that which activates the myofibrillar ATPase. This increases the likelihood that C protein-actin interaction might be physiologically significant. When I band binding is suppressed, binding in the A band becomes evident. It appears to occur particularly near the M line, and possibly at the edges of the A band as well, suggesting that those parts of the thick filaments that lack C protein in vivo may nevertheless be capable of binding added C protein.

scholarly journals Myosin molecule packing within the vertebrate skeletal muscle thick filaments. A complete bipolar model.

2002 ◽  
Vol 49 (4) ◽  
pp. 829-840 ◽  
Author(s):  
Ludmila Skubiszak ◽  
Leszek Kowalczyk
Keyword(s):  
Skeletal Muscle ◽  
Computer Modelling ◽  
Thick Filament ◽  
Myosin Molecule ◽  
Bipolar Structure ◽  
Cross Bridge ◽  
Filament Axis ◽  
Thick Filaments ◽  
C Terminus ◽  
Vertebrate Skeletal Muscle

Computer modelling related to the real dimensions of both the whole filament and the myosin molecule subfragments has revealed two alternative modes for myosin molecule packing which lead to the head disposition similar to that observed by EM on the surface of the cross-bridge zone of the relaxed vertebrate skeletal muscle thick filaments. One of the modes has been known for three decades and is usually incorporated into the so-called three-stranded model. The new mode differs from the former one in two aspects: (1) myosin heads are grouped into asymmetrical cross-bridge crowns instead of symmetrical ones; (2) not the whole myosin tail, but only a 43-nm C-terminus of each of them is straightened and near-parallel to the filament axis, the rest of the tail is twisted. Concurrent exploration of these alternative modes has revealed their influence on the filament features. The parameter values for the filament models as well as for the building units depicting the myosin molecule subfragments are verified by experimental data found in the literature. On the basis of the new mode for myosin molecule packing a complete bipolar structure of the thick filament is created.

scholarly journals Frog skeletal muscle thick filaments are three-stranded.

1983 ◽  
Vol 96 (6) ◽  
pp. 1797-1802 ◽  
Author(s):  
R W Kensler ◽  
M Stewart
Keyword(s):  
Skeletal Muscle ◽  
Optical Diffraction ◽  
Layer Line ◽  
X Ray Diffraction ◽  
Computer Image Analysis ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Meridional Reflection ◽  
Vertebrate Skeletal Muscle

A procedure has been developed for isolating and negatively staining vertebrate skeletal muscle thick filaments that preserves the arrangement of the myosin crossbridges. Electron micrographs of these filaments showed a clear periodicity associated with crossbridges with an axial repeat of 42.9 nm. Optical diffraction patterns of these images showed clear layer lines and were qualitatively similar to published x-ray diffraction patterns, except that the 1/14.3-nm meridional reflection was somewhat weaker. Computer image analysis of negatively stained images of these filaments has enabled the number of strands to be established unequivocally. Both reconstructed images from layer line data and analysis of the phases of the inner maxima of the first layer line are consistent only with a three-stranded structure and cannot be reconciled with either two- or four-stranded models.

scholarly journals The vertebrate skeletal muscle thick filaments are not three-stranded. Reinterpretation of some experimental data.

2002 ◽  
Vol 49 (4) ◽  
pp. 841-853 ◽  
Author(s):  
Ludmila Skubiszak ◽  
Leszek Kowalczyk
Keyword(s):  
Skeletal Muscle ◽  
Mass Distribution ◽  
Thick Filament ◽  
X Ray Diffraction ◽  
Bipolar Structure ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Cross Bridges ◽  
Vertebrate Skeletal Muscle

Computer simulation of mass distribution within the model and Fourier transforms of images depicting mass distribution are explored for verification of two alternative modes of the myosin molecule arrangement within the vertebrate skeletal muscle thick filaments. The model well depicting the complete bipolar structure of the thick filament and revealing a true threefold-rotational symmetry is a tube covered by two helices with a pitch of 2 x 43 nm due to arrangement of the myosin tails along a helical path and grouping of all myosin heads in the crowns rotated by 240 degrees and each containing three cross-bridges separated by 0 degrees, 120 degrees, and 180 degrees. The cross-bridge crown parameters are verified by EM images as well as by optical and low-angle X-ray diffraction patterns found in the literature. The myosin tail arrangement, at which the C-terminus of about 43-nm length is near-parallel to the filament axis and the rest of the tail is quite strongly twisted around, is verified by the high-angle X-ray diffraction patterns. A consequence of the new packing is a new way of movement of the myosin cross-bridges, namely, not by bending in the hinge domains, but by unwrapping from the thick filament surface towards the thin filaments along a helical path.

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