Results 271 to 280 of about 84,757 (292)

Evidence of a Low-Barrier Hydrogen Bond in the Tryptophan Synthase Catalytic Mechanism

Biochemistry, 1996
In the absence of other substrates, L-Ser reacts rapidly with the tryptophan synthase alpha 2 beta 2 bienzyme from Salmonella typhimurium at pH 7.8 and 25 degrees C to give an equilibrating mixture of species dominated by comparable amounts of the L-Ser external aldimine Schiff base, E(Aex1), and the alpha-aminoacrylate Schiff base, E(A-A).
O, Hur, C, Leja, M F, Dunn
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Low-Barrier Hydrogen Bond between Phosphate and the Amide Group in Phosphopeptide

Journal of the American Chemical Society, 2005
As the conversion between the monoionic (1) and diionic (2) form of the phosphate occurs, the phosphorylated peptides or proteins can not only cause the formation of a hydrogen bond between the phosphate group and the amide group but also change the strength of the hydrogen bond to form low-barrier hydrogen bonds (LBHBs). This reversible protonation of
Jin-Tang, Du, Yan-Mei, Li, Wei, Wei, Guo-Shi, Wu, Yu-Fen, Zhao, Kenji, Kanazawa, Tadashi, Nemoto, Hiroshi, Nakanishi   +7 more
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Low barrier hydrogen bonds in sterically modified Schiff bases

Journal of the Chemical Society, Perkin Transactions 2, 2002
Five derivatives of an ortho-hydroxy Schiff base (2-(N-alkyl-α-iminoethyl)phenols) with very short intramolecular hydrogen bonds (dO(H)⋯N ≤ 2.500 A) were synthesised. The crystal structures were determined. The steric repulsion of the substituted methyl group results in an unusual strengthening of the hydrogen bonds, decreasing the barrier for the ...
Aleksander Filarowski, Aleksander Koll, Tadeusz Glowiak   +2 more
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Low barrier hydrogen bonds within salicylate mono-anions

Tetrahedron, 2001
Abstract Progressive incorporation of electron-withdrawing substituents into the aromatic ring of salicylic acid selectively acidifies the ArOH group, until the intrinsic pKa values of the ArOH and ArCO2H groups become matched, as in the case of 3-chloro-5-nitrosalicylic acid.
William L. Mock, Layne A. Morsch
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ChemInform Abstract: Low‐Barrier Hydrogen Bonds and Enzymic Catalysis.

ChemInform, 1994
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
W. W. CLELAND, M. M. KREEVOY
openaire   +1 more source

Are There Really Low-Barrier Hydrogen Bonds in Proteins? The Case of Photoactive Yellow Protein

Journal of the American Chemical Society, 2014
For a long time, low-barrier hydrogen bonds (LBHBs) have been proposed to exist in many enzymes and to play an important role in their catalytic function, but the proof of their existence has been elusive. The transient formation of an LBHB in a protein system has been detected for the first time using neutron diffraction techniques on a photoactive ...
Marc, Nadal-Ferret, Ricard, Gelabert, Miquel, Moreno, José M, Lluch   +3 more
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Low-Barrier Hydrogen Bond in the Catalytic Triad of Serine Enzymes

1998
Acetylcholinesterase (AChE) and chymotrypsin are serine enzymes whose catalytic mechanism involves a nucleophilic attack (serine) and a general acid-base moiety (histidine). The incipient imidiazolium which is formed as a result of the nucleophilic attack by serine is stabilized by the negatively charged carboxylate (Glu or Asp).
Rohit Medhekar, Nathan Baker, Kenneth Sando, William Kearney, Daniel Quinn   +4 more
openaire   +1 more source

Spectral Signatures of Proton-Transfer Dynamics at the Cusp of Low-Barrier Hydrogen Bonding

The Journal of Physical Chemistry Letters, 2018
Despite their importance in diverse chemical and biochemical processes, low-barrier hydrogen bonds remain elusive targets to classify and interpret spectroscopically. Here the correlated nature of hydrogen bonding and proton transfer in the low-barrier regime has been probed for the ground and excited electronic states of 6-hydroxy-2-formylfulvene by ...
Zachary N. Vealey, Lidor Foguel, Patrick H. Vaccaro   +2 more
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The low-barrier hydrogen bond in enzymic catalysis

2010
Publisher Summary This chapter describes the various aspects of the low-barrier hydrogen bond in enzymic catalysis. Hydrogen bonds come in a continuum of bond lengths and strengths. The first examples of enzymatic reactions where low-barrier hydrogen bonds played a role involved enolization of the substrate to change the p K of a key group in the ...
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Transient low-barrier hydrogen bond in the photoactive state of green fluorescent protein

Physical Chemistry Chemical Physics, 2015
A transient low-barrier hydrogen bond has been found directly after photoexcitation using quantum dynamics to study the excited-state process in GFP.
Marc Nadal-Ferret, Ricard Gelabert, Miquel Moreno, José M. Lluch   +3 more
openaire   +2 more sources