| First Author | Colson BA | Year | 2007 |
| Journal | J Mol Biol | Volume | 367 |
| Issue | 1 | Pages | 36-41 |
| PubMed ID | 17254601 | Mgi Jnum | J:121672 |
| Mgi Id | MGI:3710921 | Doi | 10.1016/j.jmb.2006.12.063 |
| Citation | Colson BA, et al. (2007) Radial displacement of myosin cross-bridges in mouse myocardium due to ablation of myosin binding protein-C. J Mol Biol 367(1):36-41 |
| abstractText | Myosin binding protein-C (cMyBP-C) is a thick filament accessory protein, which in cardiac muscle functions to regulate the kinetics of cross-bridge interaction with actin; however, the underlying mechanism is not yet understood. To explore the structural basis for cMyBP-C function, we used synchrotron low-angle X-ray diffraction to measure interfilament lattice spacing and the equatorial intensity ratio, I(11)/I(10), in skinned myocardial preparations isolated from wild-type (WT) and cMyBP-C null (cMyBP-C(-/-)). In relaxed myocardium, ablation of cMyBP-C appeared to result in radial displacement of cross-bridges away from the thick filaments, as there was a significant increase ( approximately 30%) in the I(11)/I(10) ratio for cMyBP-C(-/-) (0.37+/-0.03) myocardium as compared to WT (0.28+/-0.01). While lattice spacing tended to be greater in cMyBP-C(-/-) myocardium (44.18+/-0.68 nm) when compared to WT (42.95+/-0.43 nm), the difference was not statistically significant. Furthermore, liquid-like disorder in the myofilament lattice was significantly greater ( approximately 40% greater) in cMyBP-C(-/-) myocardium as compared to WT. These results are consistent with our working hypothesis that cMyBP-C normally acts to tether myosin cross-bridges nearer to the thick filament backbone, thereby reducing the likelihood of cross-bridge binding to actin and limiting cooperative activation of the thin filament. |
