Myosin Binding Protein-C Decorates F-actin: A Small-Angle Neutron Scattering study.

A. Whitten1, C. Jeffries3, S. Harris2 and J. Trewhella3

As many as 1 in 500 young people are affected by a condition known as familial hypertrophic cardiomyopathy that causes a gradual thickening of heart muscle and can lead to heart failure. Mutations in MyBP-C are associated with this condition. The neutron scattering data show how MyBP-C attaches to actin thin filaments, with its extended structure positioned to modulate protein interactions between the thick and thin filaments, at the same time providing a physical link between them. These results are important to an understanding of healthy heart function and of how mutations in MyBP-C may cause disease.

Prof. Trewhella and her team used the CHRNS small-angle scattering instrument to show how myosin binding protein-C (MyBP-C) helps to regulate heart muscle contraction. Actin and myosin are the major constituents of the thin and thick filaments that slide past each other to shorten and lengthen heart muscle and accomplish its pumping action.

Several myosin binding protein C molecules (blue) decorating a single actin filament (pink). The assembly is only 20 nm across.

Neutron scattering data from the myosin binding protein-C/actin assembly, collected on NG3.

DMR-0454672FF0457488 (Australia)DE-FG02-05ER64026HL080367 (NIH)1ANSTO, 2UC Davis,3University of Sydney

A.E. Whitten, C.M. Jeffries, S.P. Harris, and J. Trewhella, PNAS 105,18360 (2008).