Hello there,
Assuming there is limited amount of sample (proteins and small molecules) with limited solubilities, how can you increase signal-to-noise ratio? The purpose is to solve protein 3D structure and/or examine protein-small molecule interactions.
I understand with microcoil probe, one can get a lot signal-to-noise gain per unit mass (which seems to be achieved by simply concentrating the sample?). But if my small molecule is only soluble up to 100 uM concentration, then what? Would the signal-to-noise be even worse when using microcoil than conventional ones per unit concentration?
Hi Clemens,
Thank you for the reply.
So with the same number of spins within the "coil range", the microcoil probe gives better S/N almost inversely proportional to diameter? And this actually is a decrease in terms of S/N per unit concentration? e.g. from 5 mm to 1 mm, assuming identical sample height in the NMR tube, the same mass would give a 25 times increase in concentration, but the S/N only increases 5 times or so.
In practice, I am mass limited for the protein (which of course requires a certain range of solvent composition and salt concentration to be stable), and solubility limited for the small organic molecule. Would a 5mm Shigemi tube be a better compromise?
Dear Yun,
just a minor comment from my side...if a protein requires high salt (ionic strength) we always use 3 mm tubes in our 5 mm probehead...we had cases where the S/N in the 3mm tube was actually the same as in the 5 mm tube (with identical concentration of the protein!)...otherwise I fully agree with Clemens, our 1.7 mm Cryo is the Champion...
Hope it helps....
Alfred
..just use you normal 5mm probehead....the only thing you need is a 3mm spinner....
Regards
Alfred
- Badges
- Science topic
- Similar topics
- Chemistry
- Theoretical Chemistry
- Computational Chemistry
- Molecular Dynamics