[NMR paper] Evidence for a strong hydrogen bond in the catalytic dyad of transition-state analogu

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Evidence for a strong hydrogen bond in the catalytic dyad of transition-state analogue inhibitor complexes of chymotrypsin from proton-triton NMR isotope shifts.

Related Articles Evidence for a strong hydrogen bond in the catalytic dyad of transition-state analogue inhibitor complexes of chymotrypsin from proton-triton NMR isotope shifts.

J Am Chem Soc. 2002 Apr 24;124(16):4196-7

Authors: Westler WM, Frey PA, Lin J, Wemmer DE, Morimoto H, Williams PG, Markley JL

We present here the first accurate measurements of 1H (H) versus 3H (T) isotope shift (DeltadeltaT-H = deltaT - deltaH) in a protein. This approach was used to investigate the strength of the hydrogen bond between His57 and Asp102 in the catalytic dyad of chymotrypsin in three transition-state analogue inhibited complexes: N-acetyl-l-phenylalanyl trifluoromethyl ketone (N-AcF-CF3), N-acetyl-l-valyl-l-phenylalanyl trifluoromethyl ketone (N-AcVF-CF3), and N-acetyl-l-leucyl-l--phenylalanyl trifluoromethyl ketone (N-AcLF-CF3). The measured DeltadeltaT-H values for His57 Hdelta1 in these complexes were between -0.63 and -0.68 ppm. These values are consistent with a strong hydrogen bond in each of these complexes, but not with a very strong hydrogen bond, which would be expected to have a DeltadeltaT-H. value near or greater than zero.

PMID: 11960433 [PubMed - indexed for MEDLINE]



Source: PubMed