نتایج جستجو برای: protonation

تعداد نتایج: 3764  

Journal: :Analytical chemistry 2011
Lorna Ashton Christian Johannessen Royston Goodacre

The effect of protonation on amino acid monomers and protein phosphorylation was studied by means of a combination of Raman scattering and Raman optical activity (ROA). In the past, identifying spectral variations in phosphorylated proteins arising from either the phosphate stretch or amide vibrational modes has proven to be challenging mainly due to the loss of amide and P═O band intensity in ...

2012
J. MUEHLINGHAUS G. ZUNDEL

IR spectroscopic investigations were conducted with poly-L-histidine (PLH) films, hydrous imidazole and pyrazole solutions and anhydrous ./V-methylimidazole with respect to protonation. Continuous absorption arises with increasing protonation and is maximally intensive with PLH, imidazole and 7V-methylimidazole when 50% protonated. The absorption indicates the formation of N H ® # , , N bonds. ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Mohana Mahalingam Karina Martínez-Mayorga Michael F Brown Reiner Vogel

Activation of the G protein-coupled receptor (GPCR) rhodopsin is initiated by light-induced isomerization of the retinal ligand, which triggers 2 protonation switches in the conformational transition to the active receptor state Meta II. The first switch involves disruption of an interhelical salt bridge by internal proton transfer from the retinal protonated Schiff base (PSB) to its counterion...

Journal: :The journal of physical chemistry. B 2007
Elske J M Leenders Leonardo Guidoni Ursula Röthlisberger Jocelyne Vreede Peter G Bolhuis Evert Jan Meijer

The photoactive yellow protein (PYP) acts as a light sensor to its bacterial host: it responds to light by changing shape. After excitation by blue light, PYP undergoes several transformations, to partially unfold into its signaling state. One of the crucial steps in this photocycle is the protonation of p-coumaric acid after excitation and isomerization of this chromophore. Experimentalists st...

2015
Adelle Adriana Vandersteen Barbara Sherwood Lollar

The acid-catalyzed decarboxylation reactions of indoleand pyrrole-carboxylic acids require the addition of one equivalent of water to the carboxyl group and a proton to the heterocyclic ring carbon at the position α to the carboxyl. Where α-protonation is thermodynamically favoured over β-protonation, the magnitude of the observed 12C/13C kinetic isotope effect (CKIE) is greater than where the ...

Journal: :Biochemistry 2012
J I Mujika B Escribano E Akhmatskaya J M Ugalde X Lopez

Serum transferrin (sTf) carries iron in blood serum and delivers it into cells by receptor-mediated endocytosis. The protein can also bind other metals, including aluminum. The crystal structures of the metal-free and metal-loaded protein indicate that the metal release process involves an opening of the protein. In this process, Lys206 and Lys296 lying in the proximity of each other form the d...

Journal: :The Analyst 2013
Patricia Wright Alexander Alex Sophie Harvey Teresa Parsons Frank Pullen

Fragmentation of molecules under collision-induced dissociation (CID) conditions is not well-understood. This may make interpretation of MSMS spectra difficult and limit the effectiveness of software tools intended to aid mass spectral interpretation. Density Functional Theory (DFT) has been successfully applied to explain the thermodynamics of fragmentation in the gas phase by the modelling th...

Journal: :Biophysical chemistry 2008
Alina Asandei Loredana Mereuta Tudor Luchian

In this research we employed single-molecule electric recording techniques to investigate effects of the transmembrane and dipole potential on the reversible protonation of acidic residues from the constriction zone of the OmpF porin. Our results support the paradigm according to which the protonation state of aspartate 113 and glutamate 117 residues from the constriction region of OmpF is infl...

2013
Meekyum Olivia Kim Sara E. Nichols Yi Wang James Andrew McCammon

While it is well established that protonation and tautomeric states of ligands can significantly affect the results of virtual screening, such effects of ionizable residues of protein receptors are less well understood. In this study, we focus on histidine protonation and rotameric states and their impact on virtual screening of Mycobacterium tuberculosis enzyme RmlC. Depending on the net charg...

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