The contribution of heme propionate groups to the conformational dynamics associated with CO photodissociation from horse heart myoglobin.
Abstract: Photoacoustic calorimetry and transient absorption spectroscopy were used to study conformational dynamics associated with CO photodissociation from horse heart myoglobin (Mb) reconstituted with either Fe protoporphyrin IX dimethylester (FePPDME), Fe octaethylporphyrin (FeOEP), or with native Fe protoporphyrin IX (FePPIX). The volume and enthalpy changes associated with the Fe-CO bond dissociation and formation of a transient deoxyMb intermediate for the reconstituted Mbs were found to be similar to those determined for native Mb (DeltaV1 = -2.5+/-0.6 ml mol(-1) and DeltaH1 = 8.1+/-3.0 kcal mol(-1)). The replacement of FePPIX by FeOEP significantly alters the conformational dynamics associated with CO release from protein. Ligand escape from FeOEP reconstituted Mb was determined to be roughly a factor of two faster (tau=330 ns) relative to native protein (tau=700 ns) and accompanying reaction volume and enthalpy changes were also found to be smaller (DeltaV2 = 5.4+/-2.5 ml mol(-1) and DeltaH2 = 0.7+/-2.2 kcal mol(-1)) than those for native Mb (DeltaV2 = 14.3+/-0.8 ml mol(-1) and DeltaH2 = 7.8+/-3.5 kcal mol(-1)). On the other hand, volume and enthalpy changes for CO release from FePPIX or FePPDME reconstituted Mb were nearly identical to those of the native protein. These results suggest that the hydrogen bonding network between heme propionate groups and nearby amino acid residues likely play an important role in regulating ligand diffusion through protein matrix. Disruption of this network leads to a partially open conformation of protein with less restricted ligand access to the heme binding pocket.
Publication Date: 2007-04-02 PubMed ID: 17499362DOI: 10.1016/j.jinorgbio.2007.03.009Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
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The research is centred on the role of heme propionate groups in the conformational dynamics associated with CO photodissociation from horse heart myoglobin. It was observed that the change of propionate groups significantly alters the dynamics, with disruption leading to a partially open protein conformation and less restricted ligand access.
Research Methodology
- The study used photoacoustic calorimetry and transient absorption spectroscopy to investigate the conformational dynamics correlated with CO photodissociation from horse heart myoglobin (Mb).
- This protein was reconstituted with either Fe protoporphyrin IX dimethylester (FePPDME), Fe octaethylporphyrin (FeOEP), or with native Fe protoporphyrin IX (FePPIX).
Key Findings
- The researchers found that the volume and enthalpy changes related to Fe-CO bond dissociation and the creation of a temporary deoxyMb intermediate were similar in comparison with those determined for native Mb.
- The substitution of FePPIX by FeOEP significantly impacts associated conformational dynamics. Ligand escape from FeOEP reconstituted Mb was determined to be approximately two times faster relative to the native protein.
- Accompanying reaction volume and enthalpy changes were smaller than those of native Mb.
- In contrast, the volume and enthalpy changes for CO release from FePPIX or FePPDME reconstituted Mb were almost identical to that of the native protein.
Research Implications
- The results imply that the hydrogen bonding network between heme propionate groups and nearby amino acid residues potentially play a significant role in controlling ligand diffusion through the protein matrix.
- Disruption of this network causes a partially open conformation of the protein with less restricted ligand access to the heme binding pocket.
- This research has implications for understanding protein conformation, which is essential for drug design and the development of therapeutic interventions.
Cite This Article
APA
Belogortseva N, Rubio M, Terrell W, Miksovská J.
(2007).
The contribution of heme propionate groups to the conformational dynamics associated with CO photodissociation from horse heart myoglobin.
J Inorg Biochem, 101(7), 977-986.
https://doi.org/10.1016/j.jinorgbio.2007.03.009 Publication
Researcher Affiliations
- Chemistry Department, Marshall University, One John Marshall Drive, Huntington, WV 25755, USA.
MeSH Terms
- Animals
- Calorimetry
- Carbon Monoxide / chemistry
- Heme / chemistry
- Horses
- Models, Molecular
- Molecular Structure
- Myoglobin / chemistry
- Photochemistry
- Propionates / chemistry
- Protein Binding
- Protein Conformation
Citations
This article has been cited 4 times.- Butcher D, Moussaoui M, Baciou L, Miksovska J. Impact of azole drugs on energetics, kinetics, and ligand migration pathways of CO photo-dissociation in bacterial flavohemoglobins.. RSC Adv 2020 May 5;10(30):17930-17941.
- Gonzalez WG, Miksovska J. Submillisecond conformational changes in proteins resolved by photothermal beam deflection.. J Vis Exp 2014 Feb 18;(84):e50969.
- Huang X, Wang C, Celeste LR, Lovelace LL, Sun S, Dawson JH, Lebioda L. Complex of myoglobin with phenol bound in a proximal cavity.. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012 Dec 1;68(Pt 12):1465-71.
- Marcelli A, Abbruzzetti S, Bustamante JP, Feis A, Bonamore A, Boffi A, Gellini C, Salvi PR, Estrin DA, Bruno S, Viappiani C, Foggi P. Following ligand migration pathways from picoseconds to milliseconds in type II truncated hemoglobin from Thermobifida fusca.. PLoS One 2012;7(7):e39884.
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