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Isothermal microcalorimetry to investigate non specific interactions in biophysical chemistry.

Ball V, Maechling C - Int J Mol Sci (2009)

Bottom Line: We will emphasize that in most cases these "non specific" interactions, as their definition will indicate, are favoured or even driven by an increase in the entropy of the system.The origin of this entropy increase will be discussed for some particular systems.We will also show that in many cases entropy-enthalpy compensation phenomena occur.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale, Strasbourg, France. vincent.ball@medecine.u-strasbg.fr <vincent.ball@medecine.u-strasbg.fr>

ABSTRACT
Isothermal titration microcalorimetry (ITC) is mostly used to investigate the thermodynamics of "specific" host-guest interactions in biology as well as in supramolecular chemistry. The aim of this review is to demonstrate that ITC can also provide useful information about non-specific interactions, like electrostatic or hydrophobic interactions. More attention will be given in the use of ITC to investigate polyelectrolyte-polyelectrolyte (in particular DNA-polycation), polyelectrolyte-protein as well as protein-lipid interactions. We will emphasize that in most cases these "non specific" interactions, as their definition will indicate, are favoured or even driven by an increase in the entropy of the system. The origin of this entropy increase will be discussed for some particular systems. We will also show that in many cases entropy-enthalpy compensation phenomena occur.

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Related in: MedlinePlus

Enthalpy-entropy compensation plot for the ITC data of Bloomfiled et al. [121] describing the two interaction regimes between  and DNA. Enthalpy and entropy changes associated with: () -pUC118 binding and: (•) condensation of pUC118. The full and dashed lines correspond to the linear regression and the limit of the 95 % confidence interval respectively.
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f7-ijms-10-03283: Enthalpy-entropy compensation plot for the ITC data of Bloomfiled et al. [121] describing the two interaction regimes between and DNA. Enthalpy and entropy changes associated with: () -pUC118 binding and: (•) condensation of pUC118. The full and dashed lines correspond to the linear regression and the limit of the 95 % confidence interval respectively.

Mentions: The dilution heat of polystyrene sulfonate [119] as well as of other polyelectrolytes [118,123] is endothermic as expected from the counterion condensation theory [10]. The interaction between multivalent ions like cobalt hexaamine and circular pUC118 DNA displays a biphasic behavior, both events being endothermic. The first one is associated with the binding of to isolated phosphate groups whereas the second one is associated with the cation binding induced condensation of DNA. The transition from the first to the second binding regime is shifted to higher ratios when the NaCl concentration is increased. This reflects again a competition between Na+ and for the phosphate groups of DNA [121]. Most interestingly, the trivalent spermidine cations are less efficient than to induce condensation of DNA, which is expected on the basis of the higher charge density of . Of additional interest is the fact that the first binding event displays an enthalpy-entropy compensation phenomenon whereas this seems to be hardly the case for the second one (Figure 7). The same kind of biphasic titration has been found during the investigation of the interactions between cetyltrimethylammonium bromide and DNA [122].


Isothermal microcalorimetry to investigate non specific interactions in biophysical chemistry.

Ball V, Maechling C - Int J Mol Sci (2009)

Enthalpy-entropy compensation plot for the ITC data of Bloomfiled et al. [121] describing the two interaction regimes between  and DNA. Enthalpy and entropy changes associated with: () -pUC118 binding and: (•) condensation of pUC118. The full and dashed lines correspond to the linear regression and the limit of the 95 % confidence interval respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2812836&req=5

f7-ijms-10-03283: Enthalpy-entropy compensation plot for the ITC data of Bloomfiled et al. [121] describing the two interaction regimes between and DNA. Enthalpy and entropy changes associated with: () -pUC118 binding and: (•) condensation of pUC118. The full and dashed lines correspond to the linear regression and the limit of the 95 % confidence interval respectively.
Mentions: The dilution heat of polystyrene sulfonate [119] as well as of other polyelectrolytes [118,123] is endothermic as expected from the counterion condensation theory [10]. The interaction between multivalent ions like cobalt hexaamine and circular pUC118 DNA displays a biphasic behavior, both events being endothermic. The first one is associated with the binding of to isolated phosphate groups whereas the second one is associated with the cation binding induced condensation of DNA. The transition from the first to the second binding regime is shifted to higher ratios when the NaCl concentration is increased. This reflects again a competition between Na+ and for the phosphate groups of DNA [121]. Most interestingly, the trivalent spermidine cations are less efficient than to induce condensation of DNA, which is expected on the basis of the higher charge density of . Of additional interest is the fact that the first binding event displays an enthalpy-entropy compensation phenomenon whereas this seems to be hardly the case for the second one (Figure 7). The same kind of biphasic titration has been found during the investigation of the interactions between cetyltrimethylammonium bromide and DNA [122].

Bottom Line: We will emphasize that in most cases these "non specific" interactions, as their definition will indicate, are favoured or even driven by an increase in the entropy of the system.The origin of this entropy increase will be discussed for some particular systems.We will also show that in many cases entropy-enthalpy compensation phenomena occur.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale, Strasbourg, France. vincent.ball@medecine.u-strasbg.fr <vincent.ball@medecine.u-strasbg.fr>

ABSTRACT
Isothermal titration microcalorimetry (ITC) is mostly used to investigate the thermodynamics of "specific" host-guest interactions in biology as well as in supramolecular chemistry. The aim of this review is to demonstrate that ITC can also provide useful information about non-specific interactions, like electrostatic or hydrophobic interactions. More attention will be given in the use of ITC to investigate polyelectrolyte-polyelectrolyte (in particular DNA-polycation), polyelectrolyte-protein as well as protein-lipid interactions. We will emphasize that in most cases these "non specific" interactions, as their definition will indicate, are favoured or even driven by an increase in the entropy of the system. The origin of this entropy increase will be discussed for some particular systems. We will also show that in many cases entropy-enthalpy compensation phenomena occur.

Show MeSH
Related in: MedlinePlus