Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions

2015 ◽  
Vol 13 (41) ◽  
pp. 10279-10284 ◽  
Author(s):  
Jin Cui ◽  
Satoshi Kawatake ◽  
Yuichi Umegawa ◽  
Sébastien Lethu ◽  
Masaki Yamagami ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Proton Pump ◽  
Stereoselective Synthesis ◽  
Purple Membrane ◽  
Major Constituent ◽  
Head Group ◽  
Lipid Interactions ◽  
Pump Activity

Phosphatidylglycerophosphate methyl ester (PGP-Me), a major constituent of the archaeal purple membrane, is essential for the proper proton-pump activity of bacteriorhodopsin (bR).

scholarly journals Tip-Enhanced Infrared Difference-Nanospectroscopy of the Proton Pump Activity of Bacteriorhodopsin in Single Purple Membrane Patches

Nano Letters ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 3104-3114 ◽  
Author(s):  
Valeria Giliberti ◽  
Raffaella Polito ◽  
Eglof Ritter ◽  
Matthias Broser ◽  
Peter Hegemann ◽  
...  
Keyword(s):  
Proton Pump ◽  
Purple Membrane ◽  
Pump Activity

scholarly journals Correction: Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions

2015 ◽  
Vol 13 (42) ◽  
pp. 10578-10578
Author(s):  
Jin Cui ◽  
Satoshi Kawatake ◽  
Yuichi Umegawa ◽  
Sébastien Lethu ◽  
Masaki Yamagami ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Head Group ◽  
Lipid Interactions

Correction for ‘Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions’ by Jin Cui, et al., Org. Biomol. Chem., 2015, DOI: 10.1039/c5ob01252j.

scholarly journals Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates

2021 ◽  
Vol 8 ◽  
Author(s):  
Sabine Panzer ◽  
Chong Zhang ◽  
Tilen Konte ◽  
Celine Bräuer ◽  
Anne Diemar ◽  
...  
Keyword(s):  
Proton Pump ◽  
Membrane Trafficking ◽  
Mammalian Cells ◽  
Aureobasidium Pullulans ◽  
Green Light ◽  
Maximal Activity ◽  
Site Directed Mutagenesis ◽  
Proton Pumps ◽  
C Terminus ◽  
Pump Activity

Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications.

scholarly journals Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

2018 ◽  
Vol 18 (5) ◽  
pp. 3249-3268 ◽  
Author(s):  
Federica Sebastiani ◽  
Richard A. Campbell ◽  
Kunal Rastogi ◽  
Christian Pfrang
Keyword(s):  
Oleic Acid ◽  
Double Bond ◽  
Methyl Ester ◽  
Reaction Kinetics ◽  
Chain Length ◽  
Rate Coefficients ◽  
Head Group ◽  
Water Interface ◽  
Organic Monolayers ◽  
Air Water Interface

Abstract. Reactions of the key atmospheric nighttime oxidant NO3 with organic monolayers at the air–water interface are used as proxies for the ageing of organic-coated aqueous aerosols. The surfactant molecules chosen for this study are oleic acid (OA), palmitoleic acid (POA), methyl oleate (MO) and stearic acid (SA) to investigate the effects of chain length, head group and degree of unsaturation on the reaction kinetics and products formed. Fully and partially deuterated surfactants were studied using neutron reflectometry (NR) to determine the reaction kinetics of organic monolayers with NO3 at the air–water interface for the first time. Kinetic modelling allowed us to determine the rate coefficients for the oxidation of OA, POA and MO monolayers to be (2.8±0.7) × 10−8, (2.4±0.5) × 10−8and (3.3±0.6) × 10−8 cm2 molecule−1 s−1 for fitted initial desorption lifetimes of NO3 at the closely packed organic monolayers, τd, NO3, 1, of 8.1±4.0, 16±4.0 and 8.1±3.0 ns, respectively. The approximately doubled desorption lifetime found in the best fit for POA compared to OA and MO is consistent with a more accessible double bond associated with the shorter alkyl chain of POA facilitating initial NO3 attack at the double bond in a closely packed monolayer. The corresponding uptake coefficients for OA, POA and MO were found to be (2.1±0.5) × 10−3, (1.7±0.3) × 10−3 and (2.1±0.4) × 10−3, respectively. For the much slower NO3-initiated oxidation of the saturated surfactant SA we estimated a loss rate of approximately (5±1) × 10−12 cm2 molecule−1 s−1, which we consider to be an upper limit for the reactive loss, and estimated an uptake coefficient of ca. (5±1) × 10−7. Our investigations demonstrate that NO3 will contribute substantially to the processing of unsaturated surfactants at the air–water interface during nighttime given its reactivity is ca. 2 orders of magnitude higher than that of O3. Furthermore, the relative contributions of NO3 and O3 to the oxidative losses vary massively between species that are closely related in structure: NO3 reacts ca. 400 times faster than O3 with the common model surfactant oleic acid, but only ca. 60 times faster with its methyl ester MO. It is therefore necessary to perform a case-by-case assessment of the relative contributions of the different degradation routes for any specific surfactant. The overall impact of NO3 on the fate of saturated surfactants is slightly less clear given the lack of prior kinetic data for comparison, but NO3 is likely to contribute significantly to the loss of saturated species and dominate their loss during nighttime. The retention of the organic character at the air–water interface differs fundamentally between the different surfactant species: the fatty acids studied (OA and POA) form products with a yield of  ∼ 20 % that are stable at the interface while NO3-initiated oxidation of the methyl ester MO rapidly and effectively removes the organic character ( ≤ 3 % surface-active products). The film-forming potential of reaction products in real aerosol is thus likely to depend on the relative proportions of saturated and unsaturated surfactants as well as the head group properties. Atmospheric lifetimes of unsaturated species are much longer than those determined with respect to their reactions at the air–water interface, so they must be protected from oxidative attack, for example, by incorporation into a complex aerosol matrix or in mixed surface films with yet unexplored kinetic behaviour.

scholarly journals 3P168 Quantitative assay of ATP-driven proton-pump activity of F_oF_1(11. Molecular motor,Poster)

2013 ◽  
Vol 53 (supplement1-2) ◽  
pp. S239
Author(s):  
Ken Tasaki ◽  
Yuzo Kasuya ◽  
Naoki Soga ◽  
Toshiharu Suzuki ◽  
Masasuke Yoshida ◽  
...  
Keyword(s):  
Proton Pump ◽  
Molecular Motor ◽  
Quantitative Assay ◽  
Pump Activity

Transport of ammonium and methylamine in Elodea densa leaves in conditions of low or high proton pump activity

1995 ◽  
Vol 129 (4) ◽  
pp. 1083-1084
Author(s):  
A. Venegoni ◽  
S. Gazzarrini ◽  
C. Margarini ◽  
M.T. Marré
Keyword(s):  
Proton Pump ◽  
Elodea Densa ◽  
High Proton ◽  
Pump Activity

A facile stereoselective synthesis of leukotriene A4(LTA4) methyl ester

1986 ◽  
Vol 27 (38) ◽  
pp. 4583-4584 ◽  
Author(s):  
Yanfang Wang ◽  
Jincui Li ◽  
Yulin Wu ◽  
Yaozeng Huang ◽  
Lilan Shi ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Stereoselective Synthesis ◽  
Leukotriene A4

Stable Expression of Gastric Proton Pump Activity at the Cell Surface

2002 ◽  
Vol 131 (6) ◽  
pp. 923-932 ◽  
Author(s):  
T. Kimura ◽  
A. Yoshida ◽  
Y. Tabuchi ◽  
A. Ikari ◽  
N. Takeguchi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Proton Pump ◽  
Stable Expression ◽  
Pump Activity ◽  
Gastric Proton Pump

Stereoselective synthesis of 13-dehydroxy-(14S)-hydroxyamphotericin B methyl ester

1995 ◽  
Vol 36 (10) ◽  
pp. 1735-1738 ◽  
Author(s):  
William S. MacLachlan ◽  
Simon A. Readshaw
Keyword(s):  
Methyl Ester ◽  
Stereoselective Synthesis
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