scholarly journals Visualization of cardiac ventricular myosin heavy chain homodimers and heterodimers by monoclonal antibody epitope mapping.

1987 ◽  
Vol 105 (6) ◽  
pp. 3031-3037 ◽  
Author(s):  
C A Dechesne ◽  
P Bouvagnet ◽  
D Walzthöny ◽  
J J Léger
Keyword(s):  
Heavy Chain ◽  
Binding Sites ◽  
Epitope Mapping ◽  
Myosin Molecule ◽  
Myosin Heavy Chains ◽  
Cardiac Myosin ◽  
Heavy Chains ◽  
Ventricular Myosin ◽  
Alpha Beta ◽  
Myosin Rod

Two mAbs, one specific for cardiac alpha-myosin heavy chains (MHC) and the other specific for cardiac beta-MHC, were used to investigate the heavy-chain dimeric organization of rat cardiac ventricular myosin. Epitopes of the two mAbs were mapped on the myosin molecule by electron microscopy of rotary shadowed mAb-myosin complexes. mAbs were clearly identifiable by the different locations of their binding sites on the myosin rod. Thus, myosin molecules could be directly discriminated according to their alpha-or beta-MHC content. alpha alpha-MHC and beta beta-MHC homodimers were visualized in complexes consisting of two molecules of the same mAb bound to one myosin molecule. By simultaneously using the alpha-MHC-specific mAb and the beta-MHC-specific mAb, alpha beta-MHC heterodimers were visualized in complexes formed by one molecule of each of the two mAbs bound to one myosin molecule. Proportions of alpha alpha-and beta beta-MHC homodimers and alpha beta-MHC heterodimers were estimated from quantifications of mAb-myosin complexes and compared with the proportions given by electrophoreses under nondenaturing conditions. This visualization of cardiac myosin molecules clearly demonstrates the arrangement of alpha- and beta-MHC in alpha alpha-MHC homodimers, beta beta-MHC homodimers, and alpha beta-MHC heterodimers, as initially proposed by Hoh, J. F. Y., G. P. S. Yeoh, M. A. W. Thomas, and L. Higginbottom (1979).

scholarly journals Affinity labelling of the binding site of rabbit antibody. Evidence for the involvement of the hypervariable regions of the heavy chain

1974 ◽  
Vol 139 (1) ◽  
pp. 135-149 ◽  
Author(s):  
Christopher E. Fisher ◽  
Elizabeth M. Press
Keyword(s):  
Binding Site ◽  
Heavy Chain ◽  
Binding Sites ◽  
Light Chains ◽  
Rabbit Antibody ◽  
Heavy Chains ◽  
Group 4 ◽  
Hypervariable Regions ◽  
Affinity Labelling ◽  
Antibody Complex

The binding sites of rabbit antibodies with affinity for the haptenic group 4-azido-2-nitrophenyl-lysine have been specifically labelled by photolysis of the hapten–antibody complex. The extent of covalent labelling was 0.5–0.9mol of hapten bound/mol of antibody and, by using an immunoadsorbent, antibody with 1.3mol of hapten/mol was obtained. The antibody was specifically labelled in the binding site and the ratio of labelling of heavy and light chains was in the range 3.3–5.0. The labelled heavy chains were cleaved by CNBr treatment and after reduction and alkylation of the intrachain bonds, were digested with trypsin. Evidence is presented that two regions of the heavy chain, positions 29–34 and 95–114, together contain about 80% of the label on the heavy chain; these two regions respectively include two of the hypervariable regions of rabbit heavy chain.

Cardiac myosin heavy chains in mice treated with NG-nitro-l-arginine methyl ester and thyroxine

2013 ◽  
Vol 23 (5) ◽  
pp. 1639-1644 ◽  
Author(s):  
Mukhallad A. M. Mohammad ◽  
Muhanad S. Abdelwahab ◽  
Mohamad M. J. Mohamad ◽  
Othman El shboul ◽  
Waleed R. Ezzat
Keyword(s):  
Methyl Ester ◽  
Myosin Heavy Chains ◽  
Cardiac Myosin ◽  
Heavy Chains

scholarly journals Myocyte-specific enhancer factor 2 and thyroid hormone receptor associate and synergistically activate the alpha-cardiac myosin heavy-chain gene.

1997 ◽  
Vol 17 (5) ◽  
pp. 2745-2755 ◽  
Author(s):  
Y Lee ◽  
B Nadal-Ginard ◽  
V Mahdavi ◽  
S Izumo
Keyword(s):  
Thyroid Hormone ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Binding Sites ◽  
Hormone Receptor ◽  
Thyroid Hormone Receptor ◽  
Physical Interaction ◽  
Cardiac Myosin ◽  
Nonmuscle Cells ◽  
Enhancer Factor

The muscle-specific regulatory region of the alpha-cardiac myosin heavy-chain (MHC) gene contains the thyroid hormone response element (TRE) and two A/T-rich DNA sequences, designated A/T1 and A/T2, the putative myocyte-specific enhancer factor 2 (MEF2) binding sites. We investigated the roles of the TRE and MEF2 binding sites and the potential interaction between thyroid hormone receptor (TR) and MEF2 proteins regulating the alpha-MHC promoter. Deletion mutation analysis indicated that both the A/T2 motif and TRE were required for muscle-specific expression of the alpha-MHC gene. The alpha-MHC enhancer containing both the A/T2 motif and TRE was synergistically activated by coexpression of MEF2 and TR in nonmuscle cells, whereas neither factor by itself activated the alpha-MHC reporters. The reporter construct containing the A/T2 sequence and the TRE linked to a heterologous promoter also showed synergistic activation by coexpression of MEF2 and TR in nonmuscle cells. Moreover, protein binding assays demonstrated that MEF2 and TR specifically bound to one another in vitro and in vivo. The MADS domain of MEF2 and the DNA-binding domain of TR were necessary and sufficient to mediate their physical interaction. Our results suggest that the members of the MADS family (MEF2) and steroid receptor superfamily (TR) interact with one another to synergistically activate the alpha-cardiac MHC gene expression.

scholarly journals Monoclonal antibodies against seven sites on the head and tail of Dictyostelium myosin.

1985 ◽  
Vol 100 (4) ◽  
pp. 1016-1023 ◽  
Author(s):  
G Peltz ◽  
J A Spudich ◽  
P Parham
Keyword(s):  
Monoclonal Antibodies ◽  
Atpase Activity ◽  
Heavy Chain ◽  
Light Chain ◽  
Binding Sites ◽  
Myosin Molecule ◽  
Dictyostelium Myosin ◽  
Antigenic Sites ◽  
Myosin Filaments ◽  
A Site

Ten monoclonal antibodies (My1-10) against Dictyostelium discoideum myosin were prepared and characterized. Nine bound to the 210-kD heavy chain and one (My8) bound to the 18-kD light chain. They defined six topographically distinct antigenic sites of the heavy chain. Five binding sites (the My1, My5, My10 site, and the My2, My3, My4, and My9 sites) are located on the rod portion of the myosin molecule. The position of the sixth site (the My6 and My7 site) is less certain, but it appears to be near the junction of the globular heads and the rod. Three of the antibodies (My2, My3, and My6) bound to myosin filaments in solution and could be sedimented in stoichiometric amounts with the filamentous myosin. In contrast, My4, which recognized a site on the rod, inhibited the polymerization of monomeric myosin into filaments. A single antibody (My6) affected the actin-activated ATPase of myosin. The nature of the effect depended on the valency of the antibody and the myosin. Bivalent IgG and F(ab')2 fragments of My6 inhibited the actin-activated ATPase of filamentous myosin by 50% whereas univalent Fab' fragments increased the activity by 50%. The actin-activated ATPase activity of the soluble chymotryptic fragment of myosin was increased 80-90% by both F(ab')2 and Fab' of My6.

Sign in / Sign up

Export Citation Format

Share Document