Evidence for a strong hydrogen bond in the catalytic dyad of transition-state analogue inhibitor complexes of chymotrypsin from proton-triton NMR isotope shifts
| Autor: | David E. Wemmer, Jing Lin, Phillip G. Williams, William M. Westler, John L. Markley, Hiromi Morimoto, Perry A. Frey |
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| Rok vydání: | 2002 |
| Předmět: |
Chymotrypsin
Serine Proteinase Inhibitors Isotope biology Proton Hydrogen Hydrogen bond Chemistry chemistry.chemical_element Hydrogen Bonding General Chemistry Photochemistry Tritium Biochemistry Catalysis Crystallography Colloid and Surface Chemistry Transition state analog Trifluoromethyl ketone biology.protein Protons Nuclear Magnetic Resonance Biomolecular |
| Zdroj: | Journal of the American Chemical Society. 124(16) |
| ISSN: | 0002-7863 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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