Microenvironment alterations enhance photocurrents from photosystem I confined in supported lipid bilayers

2018 ◽  
Vol 6 (26) ◽  
pp. 12281-12290 ◽  
Author(s):  
Hanieh Niroomand ◽  
Ravi Pamu ◽  
Dibyendu Mukherjee ◽  
Bamin Khomami
Keyword(s):  
Lipid Bilayers ◽  
Photosystem I ◽  
Charge Separation ◽  
Critical Role ◽  
Supported Lipid Bilayers ◽  
Induced Charge

This work elucidates the role of natural membrane confinements of photosystem I complexes (PSI) in light-induced charge separation by comparing the photocurrents of isolated PSI with PSI encapsulated within solid-supported lipid bilayers on electrodes. Our results indicate the critical role of the microenvironment alterations in achieving enhanced photocurrent and stability.

scholarly journals Adsorption of α-Synuclein to Supported Lipid Bilayers: Positioning and Role of Electrostatics

2013 ◽  
Vol 4 (10) ◽  
pp. 1339-1351 ◽  
Author(s):  
Erik Hellstrand ◽  
Marie Grey ◽  
Marie-Louise Ainalem ◽  
John Ankner ◽  
V. Trevor Forsyth ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Supported Lipid Bilayers

scholarly journals Cryo-EM structures of the DCPIB-inhibited volume-regulated anion channel LRRC8A in lipid nanodiscs

2018 ◽  
Author(s):  
David M. Kern ◽  
SeCheol Oh ◽  
Richard K. Hite ◽  
Stephen G. Brohawn
Keyword(s):  
Lipid Bilayers ◽  
Critical Role ◽  
Anion Channel ◽  
Lipid Binding ◽  
Channel Structure ◽  
Anion Channels ◽  
Cryo Electron Microscopy ◽  
Lipid Nanodiscs ◽  
Insight Into

AbstractHypoosmotic conditions activate volume-regulated anion channels in vertebrate cells. These channels are formed by leucine-rich repeat-containing protein 8 (LRRC8) family members and contain LRRC8A in homo- or hetero-hexameric assemblies. Here we present single-particle cryo-electron microscopy structures of LRRC8A in complex with the inhibitor DCPIB reconstituted in lipid nanodiscs. DCPIB plugs the channel like a cork in a bottle - binding in the extracellular selectivity filter and sterically occluding ion conduction. Constricted and expanded structures reveal coupled dilation of cytoplasmic LRRs and the channel pore, suggesting a mechanism for channel gating by internal stimuli. Conformational and symmetry differences between LRRC8A structures determined in detergent micelles and lipid bilayers related to reorganization of intersubunit lipid binding sites demonstrate a critical role for the membrane in determining channel structure. These results provide insight into LRRC8 gating and inhibition and the role of lipids in the structure of an ionic-strength sensing ion channel.

scholarly journals The role of surface charge in the interaction of nanoparticles with model pulmonary surfactants

Soft Matter ◽  
2018 ◽  
Vol 14 (28) ◽  
pp. 5764-5774 ◽  
Author(s):  
F. Mousseau ◽  
J.-F. Berret
Keyword(s):  
Surface Charge ◽  
Lipid Bilayers ◽  
Pulmonary Surfactant ◽  
Lipid Vesicles ◽  
Electrostatic Charge ◽  
Supported Lipid Bilayers ◽  
Pulmonary Surfactants ◽  
Inhaled Nanoparticles

Inhaled nanoparticles reaching the respiratory zone in the lungs enter first in contact with the pulmonary surfactant. It is shown here that nanoparticles and lipid vesicles formulated from different surfactant mimetics interact predominantlyviaelectrostatic charge mediated attraction and do not form supported lipid bilayers spontaneously.

Light-Induced Charge Separation between Plastocyanin and the Iron–Sulfur Clusters FAand FBin the Complex of Plastocyanin and Photosystem I

1996 ◽  
Vol 330 (2) ◽  
pp. 414-418 ◽  
Author(s):  
Michael Hippler ◽  
Astrid Riedel ◽  
Uwe Schröer ◽  
Wolfgang Nitschke ◽  
Wolfgang Haehnel
Keyword(s):  
Photosystem I ◽  
Charge Separation ◽  
Iron Sulfur Clusters ◽  
Iron Sulfur ◽  
Induced Charge

Sensitization of Light-Induced Charge Separation in Photosystem I by Synthetic Fluorescent Dyes

2008 ◽  
pp. 1273-1275
Author(s):  
Akimasa Nakamura ◽  
Shinji Mizoguchi ◽  
Yoshitaka Miyajima ◽  
Yuki Kato ◽  
Tadashi Watanabe
Keyword(s):  
Photosystem I ◽  
Charge Separation ◽  
Fluorescent Dyes ◽  
Induced Charge

scholarly journals Perturbation of Hydrogen Bonding Networks over Supported Lipid Bilayers by Poly (Allylamine Hydrochloride)

2019 ◽  
Author(s):  
Naomi Dalchand ◽  
Merve Dogangun ◽  
Paul E. Ohno ◽  
Emily Ma ◽  
Alex Martinson ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Electrostatic Interactions ◽  
Supported Lipid Bilayers ◽  
Water Molecules ◽  
Interfacial Water ◽  
Sum Frequency ◽  
Biochemical Processes ◽  
Zwitterionic Lipids ◽  
Allylamine Hydrochloride

<div><div><div><p>Water is vital to many biochemical processes and is necessary for driving many fundamental interactions of cell membranes with their external environments, yet it is difficult to probe the membrane/water interface directly and without the use of external labels. Here, we employ vibrational sum frequency generation (SFG) spectroscopy to understand the role of interfacial water molecules above bilayers formed from zwitterionic (phosphatidylcholine, PC) and anionic (phosphatidylglycerol, PG, and phosphatidylserine, PS) lipids as they are exposed to the common polycation poly (allylamine hydrochloride) (PAH) in 100 mM NaCl. We show that as the concentration of PAH is increased, the interfacial water molecules are irreversibly displaced and find that it requires 10 times more PAH to displace interfacial water molecules from membranes formed from purely zwitterionic lipids when compared to membranes that contain the anionic PG and PS lipids. This outcome is likely due to difference in (1) the energy with which water molecules are bound to the lipid headgroups, (2) the number of water molecules bound to the headgroups, which is related to the headgroup area, and (3) the electrostatic interactions between the PAH molecules and the negatively charged lipids that are favored when compared to the zwitterionic lipid headgroups. The findings presented here contribute to establishing causal relationships in nanotoxicology and to understanding, controlling, and predicting the initial steps that lead to the lysis of cells exposed to membrane disrupting polycations, or to transfection.</p></div></div></div>

scholarly journals A critical role of VMP1 in lipoprotein secretion

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Hideaki Morishita ◽  
Yan G Zhao ◽  
Norito Tamura ◽  
Taki Nishimura ◽  
Yuki Kanda ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Neutral Lipids ◽  
Protein Complexes ◽  
Transmembrane Protein ◽  
Critical Role ◽  
Visceral Endoderm ◽  
Peripheral Tissues ◽  
Lipoprotein Secretion ◽  
Er Membrane

Lipoproteins are lipid-protein complexes that are primarily generated and secreted from the intestine, liver, and visceral endoderm and delivered to peripheral tissues. Lipoproteins, which are assembled in the endoplasmic reticulum (ER) membrane, are released into the ER lumen for secretion, but its mechanism remains largely unknown. Here, we show that the release of lipoproteins from the ER membrane requires VMP1, an ER transmembrane protein essential for autophagy and certain types of secretion. Loss of vmp1, but not other autophagy-related genes, in zebrafish causes lipoprotein accumulation in the intestine and liver. Vmp1 deficiency in mice also leads to lipid accumulation in the visceral endoderm and intestine. In VMP1-depleted cells, neutral lipids accumulate within lipid bilayers of the ER membrane, thus affecting lipoprotein secretion. These results suggest that VMP1 is important for the release of lipoproteins from the ER membrane to the ER lumen in addition to its previously known functions.

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