Question

Describe an experiment to test the assumption that the heat capacity for the binding of the OnPattro siRNA to its mRNA target is independent of temperature.

Describe an experiment to test the assumption that the heat capacity for the binding of the OnPattro siRNA to its mRNA target is independent of temperature. Include in your description what physical properties will be measured, what physical properties will be varied, and any necessary controls or reference points.

Answer 1

Heat capacity means the heat required to raise the temperature of substance by one degree.

Onpattro is a FDA approved drug. Which contains patisiran, a double stranded small interfering ribonucleic acid, formulated as a lipid complex for delivery to hepatocytes. It specifically binds to genetically conserved sequence in the 3' untranslated region (3' UTR) of mRNA.

There is one research which suggested that at lower temperature the siRNA mediated defence pathway drastically reduced at lower temperature meaning as the temperature increases the siRNA gradually increases.

In this experiment we have to consider the melting temperature and heat capacity change delta Cp as per the change in temperature.

Isothermal Titration Calorimetry (ITC) is one of the best method to study the thermodynamics of RNA-RNA binding. For ITC we require pure, high concentration grade samples without any impurity.

There are two cell in ITC, one is reference cell and the other is sample cell.

To start the experiment we will have to use onpattro drug as a reference and onpattro+its mRNA target in the sample cell. In both cell the concentration of onpattro shoud be same and volume of sampe should be equal. After keeping the sample in ITC, we have to study the entropy, enthalpy and delta cp value.

Here the drug is formulated as lipid complex. So as the temperature increases the heat will be absorbed by lipids present in it. As we know that lipid act as thermal insulators.