What does this research mean for the field?

Calcium activation causes residues within the cardiac troponin I inhibitory region to switch from a beta-turn/coil to an extended quasi-alpha-helical conformation with intra-distance increases of >8 Å, while the regulatory region remains alpha-helical. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

Determine the calcium-induced conformational changes within the inhibitory and regulatory regions of cardiac troponin I during cardiac muscle activation.

February 28, 2003Journal of Biological ChemistryOpen Access

Ca2+-induced Conformational Transition in the Inhibitory and Regulatory Regions of Cardiac Troponin I

Q: What is the clinical evidence from this study?

Study design: Other. Intervention: Ca2+ activation vs. Mg2+-saturated (deactivated) state. Primary outcome: Intra-cTnI distances.

View Full Paper

Ask AI

Bookmark

Key result

Ca2+ activation extends the cTnI inhibitory region, increasing intra-cTnI distances by >8 Å.

Population

Reconstituted binary (cTnC-cTnI) and ternary (cTnC-cTnI-cTnT) troponin complexes

Comparison

Ca2+ activation (Ca2+-saturated state) vs Deactivated (Mg2+-saturated) state

Design

Preclinical

Authors

WDWen‐Ji DongBioengineering (Switzerland)JRJohn M. RobinsonAtrium Health Wake Forest Baptist SSScott M. StaggFlorida State University

Discussion

Member takes

Implication

Should not yet influence clinical practice; extends molecular models of Ca2+-induced troponin I dynamics in animal systems.

Key Points

Determine the calcium-induced conformational changes within the inhibitory and regulatory regions of cardiac troponin I during cardiac muscle activation.
Reconstituted binary (cTnC-cTnI) and ternary (cTnC-cTnI-cTnT) cardiac troponin complexes under deactivated (Mg2+-saturated) and activated (Ca2+-saturated) states.
Measured three distinct intra-cTnI distances across the inhibitory (cTnI-I) and regulatory (cTnI-R) domains using Förster resonance energy transfer (FRET).
Distance A spanning the regulatory region (cTnI-R) remained unchanged upon Ca2+ binding, indicating that cTnI-R maintains an alpha-helical conformation in both states.
Distances B and C, which span across the inhibitory region (cTnI-I) and parts of cTnI-R, exhibited Ca2+-induced distance increases greater than 8 Å.
Structural modeling revealed that Ca2+ activation causes cTnI-I to transition from a beta-turn/coil into an extended quasi-alpha-helical conformation as actin interactions detach.

Structured PICO

Population

Reconstituted binary (cTnC-cTnI) and ternary (cTnC-cTnI-cTnT) troponin complexes

Intervention

Ca2+ activation (Ca2+-saturated state)

Comparator

Deactivated (Mg2+-saturated) state

Outcome

Intra-cTnI distances measured using Förster resonance energy transfersurrogate

Ca2+ activation causes residues within the inhibitory region of cardiac troponin I to switch to an extended quasi-alpha-helical conformation, providing a structural model for cardiac muscle activation.

Cite This Study

Dong et al. (2003) studied this question. Ca2+ activation vs. Mg2+-saturated (deactivated) state was evaluated on Intra-cTnI distances. Ca2+ activation causes residues within the cardiac troponin I inhibitory region to switch to an extended quasi-alpha-helical conformation, increasing specific intra-cTnI distances by >8 Å.

synapsesocial.com/papers/6aa6a18e3f249affa9f4cb6c https://doi.org/10.1074/jbc.m212886200

View Full Paper

Ask AI

Bookmark

Ca2+-induced Conformational Transition in the Inhibitory and Regulatory Regions of Cardiac Troponin I

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Ca2+-induced Conformational Transition in the Inhibitory and Regulatory Regions of Cardiac Troponin I

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider