Enhanced Molecular CO 2 Electroreduction Enabled by a Flexible Hydrophilic Channel for Relay Proton Shuttling

ChemSusChem ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3412-3417 ◽  
Author(s):  
Caroline K. Williams ◽  
Amir Lashgari ◽  
Jingchao Chai ◽  
Jianbing “Jimmy” Jiang
Keyword(s):  
Proton Shuttling

Ultrafast Proton Shuttling in Psammocora Cyan Fluorescent Protein

2013 ◽  
Vol 117 (38) ◽  
pp. 11134-11143 ◽  
Author(s):  
John T. M. Kennis ◽  
Ivo H. M. van Stokkum ◽  
Dayna S. Peterson ◽  
Anjali Pandit ◽  
Rebekka M. Wachter
Keyword(s):  
Fluorescent Protein ◽  
Cyan Fluorescent Protein ◽  
Proton Shuttling

Ni-Catalyzed asymmetric reduction of α-keto-β-lactams via DKR enabled by proton shuttling

2020 ◽  
Vol 56 (99) ◽  
pp. 15557-15560
Author(s):  
Fangyuan Wang ◽  
Xuefeng Tan ◽  
Ting Wu ◽  
Long-Sheng Zheng ◽  
Gen-Qiang Chen ◽  
...  
Keyword(s):  
Asymmetric Reduction ◽  
Asymmetric Hydrogenation ◽  
Pivotal Role ◽  
Wide Range ◽  
Proton Shuttling

A wide range of α-keto-β-lactams were reduced efficiently and enantioselectively by Ni-catalyzed asymmetric hydrogenation. Phenylphosphinic acid was found to play a pivotal role in the DKR of α-keto-β-lactams by promoting the enolization process.

Interference by Herbicides with the Transmembrane Potential of Thylakoids

1987 ◽  
Vol 42 (6) ◽  
pp. 718-726 ◽  
Author(s):  
Donald E. Moreland ◽  
William P. Novitzky
Keyword(s):  
Electron Transport ◽  
Thylakoid Membrane ◽  
Transmembrane Potential ◽  
Proton Motive Force ◽  
Cyclic Electron Transport ◽  
Low Concentrations ◽  
High Concentrations ◽  
Proton Shuttling ◽  
Electrical Components ◽  
Spinach Thylakoids

Interferences expressed by herbicides classified as inhibitory uncouplers were measured on the induction and maintenance of ΔpH and ΔΨ, the chemical and electrical components, respectively. of the proton motive force (pmf) generated by light-induced cyclic electron transport in spinach thylakoids. Maintenance of the pmf is required for the synthesis of ATP. The inhibitory uncouplers arc known to inhibit photophosphorylation, but the mechanisms involved remain to be identified. The dinoseb types (dinitrophenols. benzimidazoles. benzonitriles. bromophenoxim. perfluidone. thiadiazoles) of inhibitory uncouplers, most of which contain dissociable protons, were found to discharge ΔpΗ at low concentrations and to collapse ΔΨ at high concentrations. Collapse of ΔpΗ can be attributed to the protonophoric (proton shuttling) action of the herbicides. However, collapse of ΔΨ can be caused by alterations induced to the integrity and loss of semipermeability of the thylakoid membrane. As a result the membrane bccomes permeable to protons and other cations, and the electrical charges across the membrane are neutralized. The non-ionic dicryl types of inhibitory uncouplers (acylanilides. dinitroanilines. diphenylethcrs. bis-carbamates) collapsed ΔΨ at concentrations that were somewhat lower than those required for the collapse of ΔpΗ. These herbicides appear only to alter the integrity and permeability of the thylakoid membrane. Inhibition of photophosphorylation by the inhibitory uncouplcrs correlated with their ability to dissipate the pmf.

Intermolecular proton shuttling in excited state proton transfer reactions: insights from theory

2014 ◽  
Vol 16 (18) ◽  
pp. 8661-8666 ◽  
Author(s):  
Marika Savarese ◽  
Paolo A. Netti ◽  
Nadia Rega ◽  
Carlo Adamo ◽  
Ilaria Ciofini
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Transfer Reactions ◽  
Td Dft ◽  
Excited State Proton Transfer ◽  
Proton Transfer Reactions ◽  
Proton Shuttling

The mechanism of intermolecular proton shuttling involved in a prototypical excited state proton transfer reaction is disclosed using DFT and TD-DFT.

Pentaerythritol-Based Molecular Sorbent for CO2 Capturing: A Highly Efficient Wet Scrubbing Agent Showing Proton Shuttling Phenomenon

2017 ◽  
Vol 31 (8) ◽  
pp. 8407-8414 ◽  
Author(s):  
Abdussalam K. Qaroush ◽  
Khaleel I. Assaf ◽  
Ala’a Al-Khateeb ◽  
Fatima Alsoubani ◽  
Enas Nabih ◽  
...  
Keyword(s):  
Highly Efficient ◽  
Wet Scrubbing ◽  
Co2 Capturing ◽  
Proton Shuttling

scholarly journals A case study of proton shuttling in palladium catalysis

2016 ◽  
Vol 7 (3) ◽  
pp. 2179-2187 ◽  
Author(s):  
Julien Monot ◽  
Paul Brunel ◽  
Christos E. Kefalidis ◽  
Noel Ángel Espinosa-Jalapa ◽  
Laurent Maron ◽  
...  
Keyword(s):  
Palladium Catalysis ◽  
Catalytic Performance ◽  
Pincer Complexes ◽  
Mechanistic Studies ◽  
Proton Shuttling

Thanks to mechanistic studies, the catalytic performance of SCS indenediide Pd pincer complexes has been spectacularly enhanced using catechol additives as proton shuttles.

scholarly journals Phosphoramidate-Assisted Alkyne Activation: Probing the Mechanism of Proton Shuttling in a N,O-Chelated Cp*Ir(III) Complex

2018 ◽  
Vol 37 (24) ◽  
pp. 4630-4638 ◽  
Author(s):  
Nina M. Leeb ◽  
Marcus W. Drover ◽  
Jennifer A. Love ◽  
Laurel L. Schafer ◽  
John M. Slattery
Keyword(s):  
Proton Shuttling

scholarly journals Insights into Activity Enhancement of H64A Carbonic Anhydrase by Imidazoles

2014 ◽  
Vol 70 (a1) ◽  
pp. C803-C803
Author(s):  
Mayank Aggarwal ◽  
Chingkuang Tu ◽  
David Silverman ◽  
Robert McKenna
Keyword(s):  
Binding Sites ◽  
Ph Regulation ◽  
Side Chain ◽  
Carbonic Anhydrases ◽  
Physiological Processes ◽  
Multiple Binding Sites ◽  
Zinc Metalloenzymes ◽  
Number Of Binding Sites ◽  
Activity Enhancement ◽  
Proton Shuttling

Human carbonic anhydrases (CAs) are zinc metalloenzymes that catalyze the hydration and dehydration of CO2 and HCO3-, respectively. The reaction follows a ping-pong mechanism, where the rate limiting step is the transfer of a proton from the zinc-bound solvent out of the active site, via His64 which is widely believed to be the proton shuttling residue. Being involved in a number of physiological processes such as respiration, pH regulation, ureagenesis etc., CAs are therapeutic targets for inhibition to treat various diseases. However, the physiologically dominant isoform is CA II, which is catalytically highly efficient and is easily crystallizable. Thus, most of our knowledge in the design of CA inhibitors with pharmacological applications is based on detailed CA II crystallographic studies. The catalytic activity of a variant of CA II in which His64 is replaced with Ala (H64A CA II) can be enhanced by exogenous proton donors/acceptors, usually derivatives of imidazoles and pyridines. This article examines the mechanism through which this activity enhancement might occur. X-ray crystal structures of H64A CA II in complex with four imidazole derivatives have been determined and reveal multiple binding sites. We have identified two molecules of imidazoles that bind in region that is otherwise occupied by the "in" and "out" dual conformation of the side chain of His64 in wild-type CA II. The data presented here not only corroborates the importance of imidazole side chain of His64 in proton transfer during CA catalysis, but also provides a complete structural understanding of the mechanism by which imidazoles enhance (and inhibit when used in higher concentrations) the activity of H64A CA II. In addition to inhibition of CA by these imidazoles, the presence of a large number of binding sites also gives insights and preliminary data required to fragment addition approach of drug design against CA.

P179. The role of the active site water molecule in proton shuttling revealed by structures of nNOS with l-arginine and NO bound

Nitric Oxide ◽  
2006 ◽  
Vol 14 (4) ◽  
pp. 75
Author(s):  
Huiying Li ◽  
Jotaro Igarashi ◽  
Joumana Jamal ◽  
Weiping Yang ◽  
Thomas L. Poulos
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Site Water ◽  
Proton Shuttling
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