1
|
Costa AM, Cascales V, Castro-Alvarez A, Vilarrasa J. Computational Study of the Stability of Pyrrolidine-Derived Iminium Ions: Exchange Equilibria between Iminium Ions and Carbonyl Compounds. ACS OMEGA 2022; 7:18247-18258. [PMID: 35694469 PMCID: PMC9178767 DOI: 10.1021/acsomega.1c07020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
The tendency of carbonyl compounds to form iminium ions by reaction with pyrrolidine or chiral pyrrolidine derivatives (in other words, the relative stability to hydrolysis of these iminium ions) has been computationally examined, mainly using the M06-2X/6-311+G(d,p) method. We have thus obtained the equilibrium positions for R-CH=O + CH2=CH-CH=N+R2* → R-CH=N+R2* + CH2=CH-CH=O reactions and for related exchanges. In these exchanges, there is a transfer of a secondary amine between two carbonyl compounds. Their relative energies may be used to predict which iminium species can be predominantly formed when two or more carbonyl groups are present in a reaction medium. In the catalytic Michael additions of nucleophiles to iminium ions arising from conjugated enals, dienals, and trienals, if the formation of the new Nu-C bond is favorable, the chances of amino-catalyzed reactions to efficiently proceed, with high conversions, depend on the calculated energy values for these exchange equilibria, where the iminium tetrafluoroborates of the adducts (final iminium intermediates) must be more prone to hydrolysis than the initial iminium tetrafluoroborates. The density functional theory (DFT) calculations indicate that the MacMillan catalysts and related oxazolidinones are especially suitable in this regard.
Collapse
|
2
|
Dekhtyar M, Rettig W, Rothe A, Kurdyukov V, Tolmachev A. Variation of Donor and Acceptor Strength in Analogues of Brooker’s Merocyanine and Generalization to Various Classes of Charge Transfer Compounds. J Phys Chem A 2019; 123:2694-2708. [DOI: 10.1021/acs.jpca.8b10660] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Dekhtyar
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| | - W. Rettig
- Institute of Chemistry, Humboldt University of Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - A. Rothe
- Institute of Chemistry, Humboldt University of Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - V. Kurdyukov
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| | - A. Tolmachev
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| |
Collapse
|
3
|
Vierock J, Grimm C, Nitzan N, Hegemann P. Molecular determinants of proton selectivity and gating in the red-light activated channelrhodopsin Chrimson. Sci Rep 2017; 7:9928. [PMID: 28855540 PMCID: PMC5577340 DOI: 10.1038/s41598-017-09600-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/21/2017] [Indexed: 12/15/2022] Open
Abstract
Channelrhodopsins are light-gated ion channels of green algae used for the precise temporal and spatial control of transmembrane ion fluxes. The channelrhodopsin Chrimson from Chlamydomonas noctigama allows unprecedented deep tissue penetration due to peak absorption at 590 nm. We demonstrate by electrophysiological recordings and imaging techniques that Chrimson is highly proton selective causing intracellular acidification in HEK cells that is responsible for slow photocurrent decline during prolonged illumination. We localized molecular determinants of both high proton selectivity and red light activation to the extracellular pore. Whereas exchange of Glu143 only drops proton conductance and generates an operational Na-channel with 590 nm activation, exchange of Glu139 in addition increased the open state lifetime and shifted the absorption hypsochromic by 70 nm. In conjunction with Glu300 in the center and Glu124 and Glu125 at the intracellular end of the pore, Glu139 contributes to a delocalized activation gate and stabilizes by long-range interaction counterion configuration involving protonation of Glu165 that we identified as a key determinant of the large opsin shift in Chrimson.
Collapse
Affiliation(s)
- Johannes Vierock
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany.
| | - Christiane Grimm
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Noam Nitzan
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany.,Neuroscience Research Center, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| |
Collapse
|
4
|
Tang X, Yu F, Guo W, Wang T, Zhang Q, Zhu Q, Zhang X, Pei M. A facile procedure to fabricate nano calcium carbonate–polymer-based superhydrophobic surfaces. NEW J CHEM 2014. [DOI: 10.1039/c3nj01592k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A facile procedure to fabricate superhydrophobic surfaces based on nano calcium carbonate–polymer composites has been described.
Collapse
Affiliation(s)
- Xinde Tang
- School of Material Science and Engineering
- Shandong Jiaotong University
- Jinan 250023, China
| | - Faqi Yu
- School of Chemistry and Chemical Engineering
- University of Jinan
- Jinan 250022, China
| | - Wenjuan Guo
- School of Chemistry and Chemical Engineering
- University of Jinan
- Jinan 250022, China
| | - Tieshi Wang
- School of Chemistry and Chemical Engineering
- University of Jinan
- Jinan 250022, China
| | - Qun Zhang
- School of Chemistry and Chemical Engineering
- University of Jinan
- Jinan 250022, China
| | - Qiangqiang Zhu
- School of Material Science and Engineering
- Shandong Jiaotong University
- Jinan 250023, China
| | - Xiao Zhang
- School of Material Science and Engineering
- Shandong Jiaotong University
- Jinan 250023, China
| | - Meishan Pei
- School of Chemistry and Chemical Engineering
- University of Jinan
- Jinan 250022, China
| |
Collapse
|
5
|
Lasogga L, Bricks J, Merk V, Kneipp J, Rettig W. Electric field effects on donor–acceptor dyes: A model compound study using UV/vis absorption and Raman spectroscopy. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
6
|
Letrun R, Koch M, Dekhtyar ML, Kurdyukov VV, Tolmachev AI, Rettig W, Vauthey E. Ultrafast Excited-State Dynamics of Donor–Acceptor Biaryls: Comparison between Pyridinium and Pyrylium Phenolates. J Phys Chem A 2013; 117:13112-26. [DOI: 10.1021/jp409646g] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Romain Letrun
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Marius Koch
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Marina L. Dekhtyar
- Institute
of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| | - Vladimir V. Kurdyukov
- Institute
of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| | - Alexei I. Tolmachev
- Institute
of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, Kiev, 02094, Ukraine
| | - Wolfgang Rettig
- Institut
für Chemie der Humboldt-Universität Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany
| | - Eric Vauthey
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| |
Collapse
|
7
|
Sneskov K, Olsen JMH, Schwabe T, Hättig C, Christiansen O, Kongsted J. Computational screening of one- and two-photon spectrally tuned channelrhodopsin mutants. Phys Chem Chem Phys 2013; 15:7567-76. [DOI: 10.1039/c3cp44350g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
8
|
Crystal structure of the channelrhodopsin light-gated cation channel. Nature 2012; 482:369-74. [PMID: 22266941 PMCID: PMC4160518 DOI: 10.1038/nature10870] [Citation(s) in RCA: 389] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 01/03/2012] [Indexed: 01/23/2023]
Abstract
Channelrhodopsins (ChRs) are light-gated cation channels derived from algae that have shown experimental utility in optogenetics; for example, neurons expressing ChRs can be optically controlled with high temporal precision within systems as complex as freely moving mammals. Although ChRs have been broadly applied to neuroscience research, little is known about the molecular mechanisms by which these unusual and powerful proteins operate. Here we present the crystal structure of a ChR (a C1C2 chimaera between ChR1 and ChR2 from Chlamydomonas reinhardtii) at 2.3 Å resolution. The structure reveals the essential molecular architecture of ChRs, including the retinal-binding pocket and cation conduction pathway. This integration of structural and electrophysiological analyses provides insight into the molecular basis for the remarkable function of ChRs, and paves the way for the precise and principled design of ChR variants with novel properties.
Collapse
|