We performed a room temperature molecular dynamics (MD) simulation on a system containing 1 carboxy-myoglobin (MbCO) molecule in a sucrose–water matrix of identical composition (89% [sucrose/(sucrose water)] w/w) as for a previous trehalose–water–MbCO simulation (Cottone et al., Biophys J 2001;80:931–938). Results show that, as for trehalose, the amplitude of protein atomic meansquare fluctuations, on the nanosecond timescale, is reduced with respect to aqueous solutions also in sucrose. A detailed comparison as a function of residue number evidences mobility differences along the protein backbone, which can be related to a different efficacy in bioprotection. Different heme pocket structures are observed in the 2 systems. The joint distribution of the magnitude of the electric field at the CO oxygen atom and of the angle between the field and the CO unit vector shows a secondary maximum in sucrose, absent in trehalose. This can explain the CO stretching band profile (A substates distribution) differences evidenced by infrared spectroscopy in sucrose- and trehalose-coated MbCO(Giuffrida et al., J Phys ChemB2004;108:15415– 15421), and in particular the appearance of a further substate in sucrose. Analysis of hydrogen bonds at the protein–solvent interface shows that the fraction of water molecules shared between the protein and the sugar is lower in sucrose than in trehalose, in spite of a larger number of water molecules bound to the protein in the former system, thus indicating a lower protein–matrix coupling, as recently observed by Fourier transform infrared (FTIR) experiments (Giuffrida et al., J Phys Chem B 2004;108:15415–15421).
COTTONE, G., GIUFFRIDA, S., CICCOTTI, G., CORDONE, L. (2005). Molecular Dynamics simulation of sucrose coated and trehalose coated carboxy-myoglobin. PROTEINS, 59, 291-302 [10.1002/prot.20414].
Molecular Dynamics simulation of sucrose coated and trehalose coated carboxy-myoglobin
COTTONE, Grazia;GIUFFRIDA, Sergio;CORDONE, Lorenzo
2005-01-01
Abstract
We performed a room temperature molecular dynamics (MD) simulation on a system containing 1 carboxy-myoglobin (MbCO) molecule in a sucrose–water matrix of identical composition (89% [sucrose/(sucrose water)] w/w) as for a previous trehalose–water–MbCO simulation (Cottone et al., Biophys J 2001;80:931–938). Results show that, as for trehalose, the amplitude of protein atomic meansquare fluctuations, on the nanosecond timescale, is reduced with respect to aqueous solutions also in sucrose. A detailed comparison as a function of residue number evidences mobility differences along the protein backbone, which can be related to a different efficacy in bioprotection. Different heme pocket structures are observed in the 2 systems. The joint distribution of the magnitude of the electric field at the CO oxygen atom and of the angle between the field and the CO unit vector shows a secondary maximum in sucrose, absent in trehalose. This can explain the CO stretching band profile (A substates distribution) differences evidenced by infrared spectroscopy in sucrose- and trehalose-coated MbCO(Giuffrida et al., J Phys ChemB2004;108:15415– 15421), and in particular the appearance of a further substate in sucrose. Analysis of hydrogen bonds at the protein–solvent interface shows that the fraction of water molecules shared between the protein and the sugar is lower in sucrose than in trehalose, in spite of a larger number of water molecules bound to the protein in the former system, thus indicating a lower protein–matrix coupling, as recently observed by Fourier transform infrared (FTIR) experiments (Giuffrida et al., J Phys Chem B 2004;108:15415–15421).File | Dimensione | Formato | |
---|---|---|---|
Proteins2005.pdf
Solo gestori archvio
Dimensione
656 kB
Formato
Adobe PDF
|
656 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.