An investigation into the protonation states of the C1 domain of cardiac myosin-binding protein C.
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.
Fisher
S J
SJ
School of Chemistry, Brunswick Street, The University of Manchester, Manchester M13 9PL, England.
Helliwell
J R
JR
Khurshid
S
S
Govada
L
L
Redwood
C
C
Squire
J M
JM
Chayen
N E
NE
D001224:Aspartic Acid / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray / Q000379:methods / Q000706:statistics & numerical data; D018698:Glutamic Acid / Q000737:chemistry; D006801:Humans; D008958:Models, Molecular; D033363:Neutron Diffraction; D017434:Protein Structure, Tertiary; D011522:Protons; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D055672:Static Electricity; D017356:Synchrotrons; D000099163:Myosin Binding Protein C
D001224:Aspartic Acid; D002352:Carrier Proteins; D018698:Glutamic Acid; D011522:Protons; D011994:Recombinant Proteins; D000099163:Myosin Binding Protein C