How do I interpret this 1D NMR spectrum?

[ambermoeba]

Hi there, I was wondering whether anybody would be able to help me with a question on NMR.

 

"The Lac repressor is a 150,000 MW tetrameric protein consisting of a core and a DNA-binding headpiece. Comment on the information that can be gained from the 1H NMR spectra below."

 

The isolated headpiece I suppose becomes unfolded in the absence of the core, giving greater flexibility and thus the broader peaks. However, I am stumped by the isolated core! At first glance, I would suggest that the core is small with few nuclei and thus a low intensity. However, looking up the structure I can see that the core is actually larger, so I'm not sure how to interpret it! Could anybody point me in the right direction? There is nothing in the question to suggest that any ligand is present.

[Essay]

Hi,

Although barely familiar with the NMR concept and its application, I can't offer any reliable or experienced-based answers to your questions. However, since nobody until somebody else....

 

Just by looking at the peaks, and how they are "subtracted" to produce some interesting differences, makes me think you are missing something when you "suppose" the headpiece becomes unfolded. That is not why corresponding peaks are different, I'm guessing. I think the "broader peaks" are simply a result of the addition/subtraction of the middle (flatish) graph, with the other.

 

Are you seeing the lower (isolated headpiece) as having the broader peaks (compared with the top graph [intact gene?])? It should work such that c + b = a, right?

 

~SA