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Communication Dans Un Congrès Année : 2003

Measurement of the isothermal compressibility of hydrated myoglobin by small-angle neutron scattering

Résumé

Small-angle neutron scattering experiments were carried out at room temperature on pD 6.6 solutions of horse heart azidometmyoglobin (MbN$_3$) at pressures up to 300 MPa. The measurements were performed using various concentrations of MbN$_3$ in order to determine the second virial coefficient of the protein solution and the actual radius of gyration of the protein. The results [1] shows that the interactions between the macromolecules are always strongly repulsive, even if their magnitude decreases with increasing pressure, whereas the radius of gyration of the protein remains constant. This indicates that the compactness of MbN$_3$ is not altered by pressures up to 300 MPa. However it is possible that a molten globule forms at the highest investigated pressures. Taking advantage of the pressure-induced contrast variation of the protein these experiments allow the partial specific volume of MbN$_3$ to be determined as a function of pressure. Its value decreases by about 5.4\% between atmospheric pressure and 300 MPa. In this range the isothermal compressibility of hydrated MbN$_3$ is found to be $(1.6 \pm 0.1) 10^{-4}$ MPa$^{-1}$ [1]. This result will be compared with those obtained by means of other techniques. [1] C. Loupiac, M. Bonetti, S. Pin and P. Calmettes, Eur. Jour. Biochem. 269 (2002) 4731-4737
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Dates et versions

hal-00165268 , version 1 (25-07-2007)

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  • HAL Id : hal-00165268 , version 1

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Camille Loupiac, M. Bonetti, S. Pin, P. Calmettes. Measurement of the isothermal compressibility of hydrated myoglobin by small-angle neutron scattering. 3rd European Conference on Neutron Scattering, 2003, Montpellier, France. ⟨hal-00165268⟩
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