Chemistry Reference
In-Depth Information
Modified diffusion experiments can provide a variety of chemical, physical, and
structural information. Since PFG-NMR has become a well-established technique
for measuring diffusion coefficients and changes in diffusion coefficients for free
versus
bound ligands it is an easy way to probe ligand-protein interactions at the
molecular level [45]. However, very weakly bound molecules to the receptor are
difficult to be detected since the fraction of bound ligand in the NMR screening
experiment will be very small. This removes considerably the expected difference
in the diffusion coefficients [3, 35].
CONCLUSION
We have provided the reader with a broader and general understanding of the
main NMR experimental approaches applied to identify and characterize protein-
ligand binding affinity. NMR techniques for screening have been reviewed in
order to present specific aspects regardint their usage in the context of drug
discovery and design process [3, 4, 7, 10, 15, 19].
Table 1:
Summary of NMR spectroscopy techniques for the identification and characterization of
binding of ligands to protein
SAR by
NMR
NOE
pumping
STD
NMR
NMR
relaxation
Diffusion
NMR
WaterLOGSY
Protein (>30kDa)
limited
yes
Yes
yes
yes
no
Protein (<10kDa)
yes
no
No
no
yes
yes
Isotope-labeled
protein required
yes
no
No
no
no
no
Binding epitope
on protein
yes
no
No
no
no
no
Binding epitope
on ligand
no
yes
Yes
yes
no
no
Amount of protein
[nmol] at 500
MHz
25
~25
0.1
~25
~1
~100
Identification of
ligand
no
yes
Yes
yes
yes
yes
It is important to highlight that both ligand- and receptor-based approaches
present advantages and disadvantages. When receptor-based methods are possible,
