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10:03
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Co-rebinding in myoglobin as seen by time-resolved X-ray absorption spectroscopy
1INFM, Operative Group in Grenoble CRG-IN13, ILL, 6 Avenue J. Horowitz, BP 156, 38042 Grenoble, France. natali@ill.fr
European Biophysics Journal : EBJ
|May 25, 2001
Summary
Horse heart carbonmonoxy myoglobin (MbCO) dynamics were studied using time-resolved X-ray absorption spectroscopy. CO molecule approach precedes Fe displacement and porphyrin plane undoming, completing MbCO configuration within 1 minute at 90 K.
Area of Science:
- Biophysics
- Structural Biology
- Spectroscopy
Background:
- Carbonmonoxy myoglobin (MbCO) is crucial for understanding ligand binding dynamics.
- Conformational changes in myoglobin influence its function.
- The CO-rebinding process involves intricate molecular rearrangements.
Purpose of the Study:
- To investigate the dynamics of conformational coordinates during CO rebinding in horse heart MbCO.
- To elucidate the sequence of events following CO dissociation and rebinding.
- To characterize the active site configuration changes at low temperatures.
Main Methods:
- Time-resolved X-ray absorption spectroscopy was employed.
- Experiments were conducted at 90 K.
- Data analysis focused on the second time scale.
Main Results:
- The approach of CO to the Fe atom was observed as a precursor event.
- Fe displacement and subsequent undoming of the protein porphyrin plane were identified.
- The Fe-C-O bonding angle geometry rearrangement was documented.
Conclusions:
- The study reveals a step-wise mechanism for CO rebinding in MbCO.
- The complete MbCO active site configuration is achieved within 1 minute.
- Low-temperature spectroscopy provides insights into myoglobin's dynamic processes.
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