scholarly journals Lipid Influence on the Structure of the Light Harvesting B 800—850 Proteins

1987 ◽  
Vol 42 (1-2) ◽  
pp. 109-117
Author(s):  
Joachim Peschke ◽  
Helmuth Möhwald
Keyword(s):  
Phase State ◽  
Transient Absorption ◽  
Photosynthetic Bacterium ◽  
Head Group ◽  
Lipid Phase ◽  
Elastic Model ◽  
Structural Protein ◽  
Protein Change ◽  
Lipid Environment ◽  
Lipid Head Group

Abstract Interaction of the antenna protein B 800-850 with the lipid environment and with the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides is studied by fluorescence spectroscopy, transient absorption techniques, light scattering and electron microscopy. Using vesicles of synthetic phospholipids it is shown that solidification of the m em brane causes a structural protein change evident from a reduction in fluorescence quantum yield. The change occurs at a tem perature up to 5 °C below that corresponding to the gel/fluid transition tem perature and indicates local melting. The structural change is not specific for the lipid head group nor chain length (investigated for lengths of 12 to 16 CH2 groups) and can be understood applying a simple elastic model. It can also be included isothermally by changing the ionic milied and thus varying the lipid phase state. Energy transfer LHCP→RC is proven to be highly efficient in model m em branes and is not affected by the existence of a phase transition. This indicates two LHCP fractions one tightly - and one non-bound to the RC.

scholarly journals Correction: Effect of lipid head group interactions on membrane properties and membrane-induced cationic β-hairpin folding

2016 ◽  
Vol 18 (38) ◽  
pp. 26998-26998
Author(s):  
Sai J. Ganesan ◽  
Hongcheng Xu ◽  
Silvina Matysiak
Keyword(s):  
Chem Phys ◽  
Membrane Properties ◽  
Head Group ◽  
Group Interactions ◽  
Correction Effect ◽  
Lipid Head Group ◽  
Phys Chem Chem Phys

Correction for ‘Effect of lipid head group interactions on membrane properties and membrane-induced cationic β-hairpin folding’ by Sai J. Ganesan et al., Phys. Chem. Chem. Phys., 2016, 18, 17836–17850.

Raman study of lipid phase state in freezing mammalian embryos and oocytes

Cryobiology ◽  
2018 ◽  
Vol 85 ◽  
pp. 165
Author(s):  
Konstantin A. Okotrub ◽  
Valentina I. Mokrousova ◽  
Sergei Ya. Amstislavsky ◽  
Nikolay V. Surovtsev
Keyword(s):  
Phase State ◽  
Lipid Phase ◽  
Mammalian Embryos ◽  
Raman Study

scholarly journals How Transmembrane Model Peptides Affect Lipid Head Group Orientation: An Application of 14N NMR

2011 ◽  
Vol 100 (3) ◽  
pp. 638a-639a ◽  
Author(s):  
Jacques P.F. Doux ◽  
Benjamin A. Hall ◽  
J. Antoinette Killian
Keyword(s):  
Head Group ◽  
Group Orientation ◽  
Lipid Head Group ◽  
14N Nmr ◽  
Model Peptides

scholarly journals Phenobarbital selectively modulates the glucagon-stimulated activity of adenylate cyclase by depressing the lipid phase separation occurring in the outer half of the bilayer of liver plasma membranes

1981 ◽  
Vol 197 (3) ◽  
pp. 675-681 ◽  
Author(s):  
M D Houslay ◽  
I Dipple ◽  
L M Gordon
Keyword(s):  
Adenylate Cyclase ◽  
Spin Probe ◽  
Plasma Membranes ◽  
Chemical Constituents ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Arrhenius Plots ◽  
Lipid Environment ◽  
Lipid Phase Separation ◽  
Outer Half

The glucagon-stimulated (coupled) activity of rat liver plasma-membrane adenylate cyclase could be selectively modulated by the anionic drug phenobarbital, whereas the fluoride-stimulated (uncoupled) activity remained unaffected. It is suggested that the cationic drug phenobarbital preferentially interacts with the external half of the bilayer, as the negatively charged phospholipids are found at the cytosol-facing side. This results in a selective fluidization of the external half of the bilayer, leading to a depression in the high-temperature onset of the lipid phase transition (from 28 degree to 16 degree C) occurring there. This was detected both by e.s.r. analysis, using a fatty acid spin probe, and also by Arrhenius plots of glucagon-stimulated activity, where the enzyme forms a transmembrane complex with the receptor and is sensitive to the lipid environment of both halves of the bilayer. However, in the absence of hormone, adenylate cyclase only senses the lipid environment of the inner (cytosol) half of the bilayer. Thus its fluoride stimulated activity and Arrhenius plots of this activity remained unaffected by the presence of phenobarbital (less than 12 mM) in the assay. These results support the view that independent modulation of the fluidity or chemical constituents of each half of the bilayer can selectively affect the receptor-coupled and uncoupled activities of adenylate cyclase.

scholarly journals Stability and flexibility of marginally hydrophobic–segment stalling at the endoplasmic reticulum translocon

2016 ◽  
Vol 27 (6) ◽  
pp. 930-940 ◽  
Author(s):  
Yuichiro Kida ◽  
Yudai Ishihara ◽  
Hidenobu Fujita ◽  
Yukiko Onishi ◽  
Masao Sakaguchi
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Lipid Phase ◽  
Endoplasmic Reticulum Membrane ◽  
Dependent Manner ◽  
Transmembrane Segment ◽  
Conducting Channel ◽  
Transmembrane Segments ◽  
Lipid Environment ◽  
Sec61 Channel

Many membrane proteins are integrated into the endoplasmic reticulum membrane through the protein-conducting channel, the translocon. Transmembrane segments with insufficient hydrophobicity for membrane integration are frequently found in multispanning membrane proteins, and such marginally hydrophobic (mH) segments should be accommodated, at least transiently, at the membrane. Here we investigated how mH-segments stall at the membrane and their stability. Our findings show that mH-segments can be retained at the membrane without moving into the lipid phase and that such segments flank Sec61α, the core channel of the translocon, in the translational intermediate state. The mH-segments are gradually transferred from the Sec61 channel to the lipid environment in a hydrophobicity-dependent manner, and this lateral movement may be affected by the ribosome. In addition, stalling mH-segments allow for insertion of the following transmembrane segment, forming an Ncytosol/Clumen orientation, suggesting that mH-segments can move laterally to accommodate the next transmembrane segment. These findings suggest that mH-segments may be accommodated at the ER membrane with lateral fluctuation between the Sec61 channel and the lipid phase.

scholarly journals Internalization of Phospholipids from the Plasma Membrane of Human Osteoblasts Depends on the Lipid Head Group

1999 ◽  
Vol 14 (5) ◽  
pp. 690-699 ◽  
Author(s):  
Jeanette Libera ◽  
Thomas Pomorski ◽  
Oliviera Josimović-Alasević ◽  
Karl-Gerd Fritsch ◽  
Andreas Herrmann
Keyword(s):  
Plasma Membrane ◽  
Head Group ◽  
Human Osteoblasts ◽  
Lipid Head Group

scholarly journals Presence and persistence of a highly ordered lipid phase state in the avian stratum corneum

2018 ◽  
Vol 221 (11) ◽  
pp. jeb176438 ◽  
Author(s):  
Alex M. Champagne ◽  
Victoria A. Pigg ◽  
Heather C. Allen ◽  
Joseph B. Williams
Keyword(s):  
Stratum Corneum ◽  
Phase State ◽  
Lipid Phase

Temperature- and ionic strength-induced conformational changes in the lipid head group region of liposomes as suggested by zeta potential data

1991 ◽  
Vol 41 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Kimiko Makino ◽  
Takeshi Yamada ◽  
Mariko Kimura ◽  
Takashi Oka ◽  
Hiroyuki Ohshima ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Zeta Potential ◽  
Conformational Changes ◽  
Head Group ◽  
Lipid Head Group

scholarly journals An examination of how structural changes can affect the rate of electron transfer in a mutated bacterial photoreaction centre

2000 ◽  
Vol 351 (3) ◽  
pp. 567-578 ◽  
Author(s):  
Justin P. RIDGE ◽  
Paul K. FYFE ◽  
Katherine E. McAULEY ◽  
Marion E. VAN BREDERODE ◽  
Bruno ROBERT ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Structural Changes ◽  
Structural Model ◽  
Transient Absorption ◽  
Photosynthetic Bacterium ◽  
Primary Electron ◽  
Interface Region ◽  
Reaction Centre ◽  
Primary Donor ◽  
Out Of Plane

A series of reaction centres bearing mutations at the (Phe) M197 position were constructed in the photosynthetic bacterium Rhodobacter sphaeroides. This residue is adjacent to the pair of bacteriochlorophyll molecules (PL and PM) that is the primary donor of electrons (P) in photosynthetic light-energy transduction. All of the mutations affected the optical and electrochemical properties of the P bacteriochlorophylls. A mutant reaction centre with the change Phe M197 to Arg (FM197R) was crystallized, and a structural model constructed at 2.3 Å (1Å = 0.1nm) resolution. The mutation resulted in a change in the structure of the protein at the interface region between the P bacteriochlorophylls and the monomeric bacteriochlorophyll that is the first electron acceptor (BL). The new Arg residue at the M197 position undergoes a significant reorientation, creating a cavity at the interface region between P and BL. The acetyl carbonyl substituent group of the PM bacteriochlorophyll undergoes an out-of-plane rotation, which decreases the edge-to-edge distance between the macrocycles of PM and BL. In addition, two new buried water molecules partially filled the cavity that is created by the reorientation of the Arg residue. These waters are in a suitable position to connect the macrocycles of P and BL via three hydrogen bonds. Transient absorption measurements show that, despite an inferred decrease in the driving force for primary electron transfer in the FM197R reaction centre, there is little effect on the overall rate of the primary reaction in the bulk of the reaction-centre population. Examination of the X-ray crystal structure reveals a number of small changes in the structure of the reaction centre in the interface region between the P and BL bacteriochlorophylls that could account for this faster-than-predicted rate of primary electron transfer.

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