Proton transfer hydrogen bonding

Eckert, M., and Zundel, G., Proton polarizability, dipole moment, and proton transitions of an AH"B ee>A H B proton-transfer hydrogen bond as a function of an external electrical field An ab initio SCF treatment, J. Phys. Chem. 91,5170-5177 (1987). 

P. Rastogi, W. Kristof, and G. Zundel, Easily Polarisable Proton Transfer Hydrogen Bonds Between the Side Chains of Histidine and the Carboxylic Acid Groups of Glutamic and Aspartic Acid Residues in Proteins, Int. J. Biol Macromol 3, 154-158 (1981). 

Keywords On-the-lly dynamics simulation Excited-state proton transfer Excited-state tautomerization Water-assisted proton transfer Hydrogen bond rearrangement 7-Azaindole ADC(2)... 

M. W. Deprotonation of arylnitromethanes. Higher intrinsic rate constants with thiolate ions than with oxyanions or amines as the proton acceptors. Hydrogen bonding in the transition state and desolvation of the base as competing factors in proton transfer at carbon. 

Although the secrets of maximal rates of proton conduction are well illustrated in gA, multifunctional proteins that couple H+ conduction to other events do not exhibit well-formed, proton-conducting hydrogen bond networks. Indeed, in the bacterial reaction center the putative active path is poorly connected by hydrogen bonds detectable in the best current X-ray structures (2.2 A resolution Stowell et al., 1997). Paddock et al. (1999) have shown that chemical blockage or a simple mutational lesion of this active path diminishes proton transfer rates by at least 1000-fold. Thus, the several well-connected (but not quite continuous) files of water that are seen in the X-ray structures, reaching toward the Qg site from the cytoplasmic side, do not conduct protons at significant rates. 

Scheiner, S., and Wang, L., Effect of bond multiplicity upon hydrogen bonding and proton transfers. Double bonded atoms, J. Am. Chem. Soc. 114, 3650-3655 (1992). 

The availability of the coherent proton tunneling and cooperative proton tunneling and transfer of four protons in hydrogen bonds of benzoic acids crystals (including dye doped) have been revealed by Trommsdorff and collaborators [12,13] by reading the electron spectra of the crystals. 

In contrast to the case of tryptophan the photoreactions with tyrosine and histidine probably involve hydrogen atom transfer as the primary step. There are several indications for this. First, 0-methylated tyrosine (p-methoxy phenylalanine) did not show any photo-CIDNP effect and its reactivity as a photo-reductant towards flavins is strongly reduced (19). Similarly, 1-N-methyl histidine is not polarized at high pH (> 7.5), when no abstractable hydrogen is present. Secondly, in the protein ribonuclease A, which has a well known 3-dimensional structure, the residues Tyr 92 and His 105 have exposed rings, but their OH and NH protons are hydrogen bonded to backbone carbonyl groups. 

The presence of water in PVPA seems to contribute to the conductivity of PVPA, at a temperature below the boiling point of water, by proton transport in additional proton solvents. Hence, the proton movement in PVPA can be explained by rapid transfer of protons via hydrogen bond-forming and bondbreaking (hopping mechanism) and by self-diffusion (vehicle mechanism). Different conductivity values could be obtained due to a different water content. Also, recent studies have revealed that the behavior of PVPA as a polyelectrolyte is very similar to poly(actylic acid) in aqueous salt solution under identical conditions. ... 

---