Sharif, S. ; Fogle, E. ; Toney, M. D. ; Denisov, G. S. ; Shenderovich, I. G. ; Buntkowsky, G. ; Tolstoy, P. M. ; Huot, M. C. ; Limbach, H. H. (2007):
NMR localization of protons in critical enzyme hydrogen bonds.
In: Journal of the American Chemical Society, 129 (31), pp. 9558-+. [Article]
Abstract
Using N-15 NMR spectroscopy and hydrogen bond correlations, we have localized a mechanistically critical proton in aspartate aminotransferase in microcrystals and aqueous solution. It is in a H-bond between a carboxylate O of Asp222 and the pyridine nitrogen of pyridoxal-5'-phosphate. At neutral pH in water, aspartate and pyridine are unprotonated, but they share a proton in the enzyme. It is shown that such a binuclear base is typical for acid-base interactions in aprotic polar solvents. Active site H-bonds to Asp222 assist protonation of the pyridine nitrogen in the enzyme, which is considered a prerequisite for catalytic activity. We also show that acid-base behavior in enzymes should be modeled using aprotic polar solvents rather than aqueous solutions.
| Item Type: | Article |
|---|---|
| Erschienen: | 2007 |
| Creators: | Sharif, S. ; Fogle, E. ; Toney, M. D. ; Denisov, G. S. ; Shenderovich, I. G. ; Buntkowsky, G. ; Tolstoy, P. M. ; Huot, M. C. ; Limbach, H. H. |
| Title: | NMR localization of protons in critical enzyme hydrogen bonds |
| Language: | English |
| Abstract: | Using N-15 NMR spectroscopy and hydrogen bond correlations, we have localized a mechanistically critical proton in aspartate aminotransferase in microcrystals and aqueous solution. It is in a H-bond between a carboxylate O of Asp222 and the pyridine nitrogen of pyridoxal-5'-phosphate. At neutral pH in water, aspartate and pyridine are unprotonated, but they share a proton in the enzyme. It is shown that such a binuclear base is typical for acid-base interactions in aprotic polar solvents. Active site H-bonds to Asp222 assist protonation of the pyridine nitrogen in the enzyme, which is considered a prerequisite for catalytic activity. We also show that acid-base behavior in enzymes should be modeled using aprotic polar solvents rather than aqueous solutions. |
| Journal or Publication Title: | Journal of the American Chemical Society |
| Volume of the journal: | 129 |
| Issue Number: | 31 |
| Uncontrolled Keywords: | coli aspartate-aminotransferase escherichia-coli carboxylic-acids 10-18-ppm range h-1 resonances concanavalin-a model systems active-site solid-state pyridoxal |
| Divisions: | 07 Department of Chemistry 07 Department of Chemistry > Physical Chemistry |
| Date Deposited: | 27 Oct 2014 20:49 |
| URL / URN: | http://apps.webofknowledge.com/full_record.do?product=WOS&se... |
| Additional Information: | 196LW Times Cited:35 Cited References Count:31 |
| PPN: | |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Send an inquiry |
Options (only for editors)
 |
Show editorial Details |
Drucken
Impressum