Comparison of protein structures in solution using local conformations derived from NMR data: application to...

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Protein structure-function relationships are crucial for understanding biological processes.
• Comparing protein structures in solution is essential for studying dynamic changes and functional implications.
• Cytochrome c's redox states are critical for its role in electron transfer.

Purpose of the Study:

• To investigate the structural differences between the ferro- and ferricytochrome c redox states in solution.
• To apply a novel nuclear magnetic resonance (NMR)-based probabilistic strategy for conformational analysis.
• To correlate observed structural changes with functional aspects of cytochrome c's electron transfer.

Main Methods:

• Utilized a nuclear magnetic resonance (NMR)-based probabilistic strategy.
• Calculated main chain conformations based on published sequential d connectivity data.
• Analyzed conformational differences between horse ferro- and ferricytochrome c in solution.

Main Results:

• Statistically significant conformational differences were identified between the two redox states of horse cytochrome c in solution.
• Major conformational changes occurred in residues near the heme group.
• Solution structures exhibited greater oxidation state-dependent differences than crystal structures.

Conclusions:

• Oxidation state-dependent conformational changes in cytochrome c are significant in solution and may modulate interactions with redox partners.
• Crystal structures may not fully represent in vivo conditions due to environmental sensitivities like ionic strength.
• NMR-derived conformational data provide valuable insights into protein structure-function relationships in solution.