i like this post (click again to cancel)
1
i dont like this post (click again to cancel) remove favorite mark from this question (click again to restore mark)

I have an aromatic spectrum of Tyr residues in p53 DNA binding domain. No peaks are seen for Tyr-205 at high temp, but as temp decreases 4 peaks are shown. Tyr-163 and Tyr-236 show two peak each at high temps. How come there aren't 4 peaks? The dynamic processes are said to occur on different time scales. What is the interpretation of this information? How is the core domain of p53 influenced by this? Thanks for your help!

asked Apr 10 '11 at 10:32

Am%C3%A9lie%20Wallenhammar's gravatar image

Amélie Wallenhammar
11


One Answer:
i like this answer (click again to cancel)
1
i dont like this answer (click again to cancel)

Is this a 1H spectrum? This could be a classic case of aromatic ring flips and slow vs. fast exchange. In the general case at low temp the different evironments of the C2H and C4H (delta H), and the C3H and C5H (epsilon H) protons are in formally different environments and give non-degenerate chemical shifts (so four peaks in all). As the temperature is raised the increased rate of the 180-degree ring flips (along the C1-C4 axis) lead to averaging of the chemical environments and line broadening and eventual collapse (in the fast exchange limit) to a single exchange-averaged chemical shift for each pair (so two peaks in total). In most proteins one observes fast exchange for most Tyr residues. Only a few Tyr (or Phe) residues ever exhibit true slow exchange and then only at relativly low temperatures. This was famously all worked out for the case of BPTI by Wuthrich and Wagner many years ago.

link

answered Apr 12 '11 at 04:30

Paul%20Driscoll's gravatar image

Paul Driscoll
81

Your answer
Please start posting your answer anonymously - your answer will be saved within the current session and published after you log in or create a new account. Please try to give a good answer, for discussions, please use comments and please do remember to vote (login to vote)
toggle preview

powered by CNPROG