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Hello, what NMR experiments can detect hydrogen bonds directly?

Is there anything that can work with non-labeled samples at the natural abundance of isotopes?

We have a cyclic peptide that might form a beta-sheet made of two anti-parallel strands.

The problem is that it is made of two pieces of the same sequence closed into a cycle and in such arrangement NOE's from the "middle" part (if it is indeed forming two anti-parallel beta-strands) will be hard to distinguish as being intra- or inter-strand. That's why I think direct observation of hydrogen bonds would be very helpful.

Thanks!

asked Mar 08 '10 at 11:31

Evgeny%20Fadeev's gravatar image

Evgeny Fadeev
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updated Mar 08 '10 at 11:36


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Hydrogen bonded amide NH have a slower rate of H/D exchange with solvent compared to non hydrogen bonded amide NH.

The magnitude of the temperature dependence of the chemical shift is smaller for hydrogen bonded amide NH than for those that are not hydrogen bonded.

Direct detection of Hydrogen bonds: The H(N)CO-TROSY experiment has been used to detect scalar coupling across hydrogen bonds. However, it requires isotope labeling.

Speculation: An, E.COSY type experiment correlating proton (HN-selective) with carbon (Carbonyl-selective) with a long tau delay (optimized to minimize the signal from the sequential two bond and intra residue three bond HN and C' coupling) on unlabeled peptide MAY be able to detect scalar coupling across hydrogen bonds.

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answered Mar 14 '10 at 09:43

sekhar%20Talluri's gravatar image

sekhar Talluri
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There are two other ways that come to mind for establishing hydrogen bondedness and h-bond strength, though they don't identify H-bonded partners.

First is measuring H/D fractionation factors. Without going into great detail, one integrates the putatively H-bonded hydrogen in a series of H2O/D2O mixtures. If the hydrogen is only h-bonded with solvent, it will integrate to 0.5 in a 50/50 H2O/D2O mixture.

If the H-bond is strong, the hydrogen will be selectively enriched because of differential zero point energies. I haven't kept up on this literature, but you can check out the following references on the subject. It was a hot subject in Madison for awhile.

  1. Lin, J.; Frey, P. A. Journal of the American Chemical Society 2000, 122, 11258-11259.
  2. Lin, J.; Westler, W. M.; Cleland, W. W.; Markley, J. L.; Frey, P. A. Proceedings of the National Academy of Sciences of the United States of America 1998, 95, 14664-8.
  3. LiWang, A. C.; Bax, A. Journal of the American Chemical Society 1996, 118, 12864-12865.
  4. Loh, S. N.; Markley, J. L. Biochemistry 1994, 33, 1029-1036.

Second, there's this old reference that you may find particularly useful:

  1. Gunnarsson, G.; Wennerstrom, H.; Egan, W.; Forsen, S. Chemical Physics Letters 1976, 38, 96-9.

The main message is that if you compare 1H and 2H spectra of hydrogen-bonded systems, the chemical shifts of the signals will differ in proportion to their h-bond strength. In principle, if you took 1D 1H and 2H spectra of your peptide in 50/50 H/D2O, you'd observe slight differences between the frequencies of the same residue's amide "H" depending on whether it was 1H or 2H. Never tried it myself, but thought it might be useful.

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answered Mar 16 '10 at 14:41

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jkurutz
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updated Mar 18 '10 at 09:05

Evgeny%20Fadeev's gravatar image

Evgeny Fadeev
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The following more recent references may also be of interest with regard to direct detection of H-bonded 15N and 13C scalar coupling:

  1. Cordier, F., L. Nisius, A. J. Dingley, and S. Grzesiek. 2008. Direct detection of N-H ... O=C hydrogen bonds in biomolecules by NMR spectroscopy. Nature Protocols 3:235-241.
  2. Dingley, A. J., L. Nisius, F. Cordier, and S. Grzesiek. 2008. Direct detection of N-H ... N hydrogen bonds in biomolecules by NMR spectroscopy. Nature Protocols 3:242-248.
  3. Grzesiek, S., F. Cordier, V. Jaravine, and M. Barfield. 2004. Insights into biomolecular hydrogen bonds from hydrogen bond scalar couplings. Progress in Nuclear Magnetic Resonance Spectroscopy 45:275-300.
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answered Mar 18 '10 at 08:02

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jkurutz
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updated Mar 29 '10 at 15:43

Evgeny%20Fadeev's gravatar image

Evgeny Fadeev
5571

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