Structural Biology Flashcards
What source is used to investigate your smaple in NMR
RF (radio frequency)
The ….. of RF absorbed induces a …..
frequency; resonance
nuclei can absorb RF under three conditions, what are they
- type of nucleus
- Type of environment
- spacial location in field if fields are not even
what is the name of the signal displayed by voltage caused by absorbed energy?
free induction decay (FID)
The larger the magnet, the larger the ….., the large the signal to …..
change in E, noise
What is free induction decay?
a time domain signal
What do you use to de-convolute free induction decay?
fourier transform
What is NMR structure determination?
protein expressed in native H1 then in N15 and C13 combo. spectra collected on each, the difference in spectra allows one to define distances between the various NMR active nuclei.
What does NMR structure determination tell you?
to determine various protein atoms and their structure
What is NMR Peptide Bonding?/What does it do?
determining the structure of a small peptide bound to a larger protein when the on-off rate is within the frequency range of the NMR experiment.
‘Memory’ of the nuclei of the peptide during the relaxation time time due to the fact that proteins are large and give ‘broad’ NMR peaks compared to peptides.
What is NMR D2O Exchange?/What does it do?
D2O exchange exchanges H1 for D2O in proteins - yielding changes in protein signal
Do a spectra to find out which protons have been exchanged.
This gives you a snapshot as to what was exposed and when it was exposed - dynamic protein folding.
What are the NMR Pros and Cons?
Pros:
1. doesn’t require crystals
2. You can look at some dynamic processes
Cons:
1. requires high []’s of sample (soluble and stable)
2. limited to 0-40kDa molecules
3. Need high efficiency expression system for labeling
4. No true ‘resolution’
