Intramolecular Catalysis of Amide Isomerization: Kinetic Consequences of the 5-NH- -Na Hydrogen Bond in Prolyl Peptides
نویسنده
چکیده
The presence of an intramolecular hydrogen bond has been proposed to play a key role in the catalysis of amide isomerization by peptidylprolyl isomerases (PPIases), which are highly conserved and ubiquitous rotamase enzymes that catalyze the cis-trans isomerization of proline residues in peptides and proteins. We present herein kinetic and spectroscopic evidence that indicates the existence of an intramolecular hydrogen bond between the prolyl amide nitrogen and the adjacent amidic NH within a five-membered ring (the 5-NH-Na hydrogen bond) that is capable of catalyzing proline isomerization by up to 260-fold in model prolyl peptides. Our results provide the first systematic study of intramolecular general-acid-catalyzed amide
منابع مشابه
Intramolecular acid-catalyzed amide isomerization in aqueous solution.
[reaction: see text] We report for the first time that stoichiometric and even catalytic quantities of weak acids in aqueous solution can very efficiently catalyze amide isomerization in a carefully designed system in which a proton donor is situated so that intramolecular hydrogen bonding to the amide nitrogen is highly favored. Our results provide the first experimental verification that hydr...
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