Question

19) (a) Imagine that SPR is used to study the binding of a coronavirus spike protein to several different immobilized receptors. Which SPR experiments will generally take the longer time to perform, those where the Kd value is small, or those where the Kd value is large? (1 pts) A) Experiments where Kd is small will take the longest time to perform. B) Experiments where Kd is large will take the longest time to perform. State the letter corresponding to the best chose here: (b) Explain your answer to part (a). (3 pts) 20) In an SPR experiment, what specific observation indicates that a plasmon has been created within the gold surface? (3 pts) A) the ligand is released from its binding partner. B) there is an increase in fluorescence from the ligand. C) there is an increase in fluorescence from the protein bound to the gold surface. D) there is an increase in intensity of reflected light reaching the detector. E) there is a decrease in intensity of reflected light reaching the detector. Write the letter corresponding to one best choice here: 21) Some SPR instruments can be used to determine AH for ligand binding, and some can't be used to determine AH. What is the key feature that an SPR instrument needs to have if it is to be used to determine AH for a binding interaction? (3 pts) 22) Estimate the percentage of ATP molecules within a typical human that contain at least one 13C atom. (3 pts)

Answer 1

Question 19:-

Kd is equilibrium constant and it is inversely proportional to the binding affinity of a ligand. So molecules with low Kd will bind very quickly while with high Kd will bind slowly.

So the right option is option (B). Experiment where Kd is large will take the longest time to take.

(b) part :-

As I stated above, low Kd means high binding affinity and high Kd means low binding affinity. So molecules with high Kd will take longer time to bind properly.

Question 20 :-

The two factors which are important in SPR is light enhancement and the angle change. The light is enhanced due to resonance by the excited metallic nanoparticles' oscillation.

Thus the right option is Option (D) There is an increase in intensity in the reflected light reaching the detector.