Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Troponin Structural Dynamics in the Native Cardiac Thin Filament Revealed by Cryo Electron Microscopy.
Journal, issue, pages	J Mol Biol, Vol. 436, Issue 6, Page 168498, Year 2024
Publish date	Feb 20, 2024
Authors	Cristina M Risi / Betty Belknap / Jennifer Atherton / Isabella Leite Coscarella / Howard D White / P Bryant Chase / Jose R Pinto / Vitold E Galkin /
PubMed Abstract	Cardiac muscle contraction occurs due to repetitive interactions between myosin thick and actin thin filaments (TF) regulated by Ca levels, active cross-bridges, and cardiac myosin-binding protein C ...Cardiac muscle contraction occurs due to repetitive interactions between myosin thick and actin thin filaments (TF) regulated by Ca levels, active cross-bridges, and cardiac myosin-binding protein C (cMyBP-C). The cardiac TF (cTF) has two nonequivalent strands, each comprised of actin, tropomyosin (Tm), and troponin (Tn). Tn shifts Tm away from myosin-binding sites on actin at elevated Ca levels to allow formation of force-producing actomyosin cross-bridges. The Tn complex is comprised of three distinct polypeptides - Ca-binding TnC, inhibitory TnI, and Tm-binding TnT. The molecular mechanism of their collective action is unresolved due to lack of comprehensive structural information on Tn region of cTF. C1 domain of cMyBP-C activates cTF in the absence of Ca to the same extent as rigor myosin. Here we used cryo-EM of native cTFs to show that cTF Tn core adopts multiple structural conformations at high and low Ca levels and that the two strands are structurally distinct. At high Ca levels, cTF is not entirely activated by Ca but exists in either partially or fully activated state. Complete dissociation of TnI C-terminus is required for full activation. In presence of cMyBP-C C1 domain, Tn core adopts a fully activated conformation, even in absence of Ca. Our data provide a structural description for the requirement of myosin to fully activate cTFs and explain increased affinity of TnC to Ca in presence of active cross-bridges. We suggest that allosteric coupling between Tn subunits and Tm is required to control actomyosin interactions.
External links	J Mol Biol / PubMed:38387550 / PubMed Central
Methods	EM (single particle)
Resolution	5.1 - 7.1 Å
Structure data	42681 8uww EMDB-42681, PDB-8uww: The structure of the native cardiac thin filament troponin core in Ca2+-free state from the upper strand Method: EM (single particle) / Resolution: 5.1 Å 42682 8uwx EMDB-42682, PDB-8uwx: The structure of the native cardiac thin filament troponin core in Ca2+-free tilted state from the upper strand Method: EM (single particle) / Resolution: 6.0 Å 42683 8uwy EMDB-42683, PDB-8uwy: The structure of the native cardiac thin filament troponin core in Ca2+-free rotated state from the upper strand Method: EM (single particle) / Resolution: 5.5 Å 42800 8uyd EMDB-42800, PDB-8uyd: The structure of the native cardiac thin filament troponin core in Ca2+-free state from the lower strand Method: EM (single particle) / Resolution: 5.3 Å 42833 8uz5 EMDB-42833, PDB-8uz5: The structure of the native cardiac thin filament troponin core in Ca2+-free rotated state from the lower strand Method: EM (single particle) / Resolution: 5.9 Å 42835 8uz6 EMDB-42835, PDB-8uz6: The structure of the native cardiac thin filament troponin core in Ca2+-free tilted state from the lower strand Method: EM (single particle) / Resolution: 7.1 Å 42846 8uzx EMDB-42846, PDB-8uzx: The structure of the native cardiac thin filament troponin core in Ca2+-bound fully activated state from the upper strand Method: EM (single particle) / Resolution: 5.4 Å 42847 8uzy EMDB-42847, PDB-8uzy: The structure of the native cardiac thin filament troponin core in Ca2+-bound partially activated state from the upper strand Method: EM (single particle) / Resolution: 5.3 Å 42849 8v01 EMDB-42849, PDB-8v01: The structure of the native cardiac thin filament troponin core in Ca2+-bound fully activated state 1 from the lower strand Method: EM (single particle) / Resolution: 5.5 Å 42856 8v0i EMDB-42856, PDB-8v0i: The structure of the native cardiac thin filament troponin core in Ca2+-bound fully activated state 2 from the lower strand Method: EM (single particle) / Resolution: 5.8 Å 42858 8v0k EMDB-42858, PDB-8v0k: The structure of the native cardiac thin filament troponin core in Ca2+-bound partially activated state from the lower strand Method: EM (single particle) / Resolution: 5.2 Å 42874 8v0y EMDB-42874, PDB-8v0y: The structure of the native cardiac thin filament troponin core in Ca2+-free state from the upper strand activated by the C1-domain of cardiac myosin binding protein C Method: EM (single particle) / Resolution: 7.0 Å
Chemicals	ChemComp-ADP: ADENOSINE-5'-DIPHOSPHATE / ADP, energy-carrying moleculeYM ChemComp-MG: Unknown entry ChemComp-CA*: Unknown entry
Source	sus scrofa (pig)
Keywords	MOTOR PROTEIN / thin filament / troponin / tropomyosin / cryo-EM / muscle structure / myosin binding protein C