Crystal structure of the C1 domain of cardiac isoform of myosin binding protein-C at 1.3A
[MYPC3_HUMAN] Defects in MYBPC3 are the cause of familial hypertrophic cardiomyopathy type 4 (CMH4) [MIM:115197]. Familial hypertrophic cardiomyopathy is a hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death.                   
[MYPC3_HUMAN] Thick filament-associated protein located in the crossbridge region of vertebrate striated muscle a bands. In vitro it binds MHC, F-actin and native thin filaments, and modifies the activity of actin-activated myosin ATPase. It may modulate muscle contraction or may play a more structural role.
Publication Abstract from PubMed
Myosin-binding protein C (MyBP-C) is a myofibril-associated protein found in cardiac and skeletal muscle. The cardiac isoform (cMyBP-C) is subject to reversible phosphorylation and the surface-charge state of the protein is of keen interest with regard to understanding the inter-protein interactions that are implicated in its function. Diffraction data from the C1 domain of cMyBP-C were extended to 1.30 A resolution, where the <I/sigma(I)> of the diffraction data crosses 2.0, using intense synchrotron radiation. The protonation-state determinations were not above 2sigma (the best was 1.81sigma) and therefore an extrapolation is given, based on 100% data completeness and the average DPI, that a 3sigma determination could be possible if X-ray data could be measured to 1.02 A resolution. This might be possible via improved crystallization or multiple sample evaluation, e.g. using robotics or a yet more intense/collimated X-ray beam or combinations thereof. An alternative would be neutron protein crystallography at 2 A resolution, where it is estimated that for the unit-cell volume of the cMyBP-C C1 domain crystal a crystal volume of 0.10 mm3 would be needed with fully deuterated protein on LADI III. These efforts would optimally be combined in a joint X-ray and neutron model refinement.
An investigation into the protonation states of the C1 domain of cardiac myosin-binding protein C.,Fisher SJ, Helliwell JR, Khurshid S, Govada L, Redwood C, Squire JM, Chayen NE Acta Crystallogr D Biol Crystallogr. 2008 Jun;64(Pt 6):658-64. Epub 2008, May 14. PMID:18560154
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.