Transmembrane pH gradients have previously been shown to induce an asymmetric transmembrane distribution of simple lipids that exhibit weak acid or basic characteristics (Hope, M.J. and Cullis, P.R. (1987) J. Biol. Chem. 262, 4360-4366). In the present study we have examined the influence of proton gradients on the inter-vesicular exchange of stearylamine and oleic acid. We show that vesicles c...

Rnf is a membrane protein complex that has been shown to be important in energy conservation. Here, Desulfovibrio alaskensis G20 and Rnf mutants of G20 were grown with different electron donor and acceptor combinations to determine the importance of Rnf in energy conservation and the type of ion gradient generated. The addition of the protonophore TCS strongly inhibited lactate-sulfate dependen...

Systematic ab initio calculations are combined with a deconvolution of electrostatic contributions to analyze the interplay between potential hydrogen bond acceptors and organic rings with C(sp(2))-H groups (benzene, pyridine and cyclopentadiene). A distinct anisotropic interaction between the ring systems and the electron lone pairs of cyanide, water and other acceptor species is revealed that...

Methyl formate (MF) is an important interstellar medium molecule and it has been the subject of several theoretical experimental studies in literature. The study complexation this with water never undertaken from a vibrational point view as well homodimer (MF)2. We highlight for first time presence three isomers (MF)2, MF-H2O MF-(H2O)2 complexes solid neon. For complex, we observe without ambig...

We recently published procedures describing the isolation of absolute infrared spectra for the intermediates of the bacteriorhodopsin (BR) photocycle and from these, obtaining transitional difference spectra between consecutive intermediates. In that work, we concentrated mainly on proton-binding centers and the route of proton transport across the membrane. In the current study, we used isolat...

The photophysics of the chromophore of the green fluorescent protein in Aequorea victoria (avGFP) are dominated by an excited state proton transfer reaction. In contrast the photophysics of the same chromophore in solution are dominated by radiationless decay, and photoacid behaviour is not observed. Here we show that modification of the pKa of the chromophore by fluorination leads to an excite...

Proton controlled intramolecular PET from an aniline moiety to a squaraine chromophore, attached to podand chains is reported, which to our knowledge is the first example where a squaraine dye is involved as an electron acceptor in an intramolecular PET process, and has implication in the design of PET based sensors.

ion moval of an atom (neutral or charged) from a molecular entity. For example: A chemical reaction or transformation, the main feature of which is the bimolecular reCH3COCH3 + (i-C3H7)2N(CH&OCH;?>+ (i-C3H7)2NH (proton abstraction from acetone) CH4 + C1' H3C' + HCl (hydrogen abstraction from methane) acceptor number (AN)

A subtractive implementation of the QM/QM hybrid method for the description of photochemical reactions occurring in molecular crystals is presented and tested by applying it in a simulation study of the ultrafast intramolecular excited-state proton transfer reaction in the crystal form of 7-(2-pyridyl)-indole, an organic compound featuring an intramolecular hydrogen bond within a six-membered r...