Kinetics of Dye Efflux and Lipid Flip-Flop Induced by δ-Lysin in Phosphatidylcholine Vesicles and the Mechanism of Graded Release by Amphipathic, α-Helical Peptides†

Biochemistry ◽  
2004 ◽  
Vol 43 (27) ◽  
pp. 8846-8857 ◽  
Author(s):  
Antje Pokorny ◽  
Paulo F. F. Almeida
Keyword(s):  
Helical Peptides ◽  
Flip Flop ◽  
Graded Release ◽  
Kinetics Of

Comparison between Ca2+-induced scrambling of various fluorescently labelled lipid analogues in red blood cells

2002 ◽  
Vol 362 (3) ◽  
pp. 741-747 ◽  
Author(s):  
David W. C. DEKKERS ◽  
Paul COMFURIUS ◽  
Edouard M. BEVERS ◽  
Robert F. A. ZWAAL
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Red Blood Cells ◽  
Phospholipase D ◽  
Blood Cells ◽  
Amino Group ◽  
Flip Flop ◽  
Putative Membrane Protein ◽  
Kinetics Of

Treatment of red blood cells with calcium and ionomycin causes activation of the lipid scramblase, a putative membrane protein catalysing flip-flop of (phospho)lipids. Various fluorescent 1-oleoyl-2-[6(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] caproyl (C6-NBD) analogues were tested for transbilayer movement across the plasma membrane of red blood cells. Among these phospholipid analogues were phosphatidylgalactose, phosphatidylmaltose and phosphatidylmaltotriose, which were obtained from C6-NBD-phosphatidylcholine by phospholipase D-catalysed transphosphatidylation. The inward movement after the onset of scrambling was monitored by extraction of the non-internalized probe with BSA. We demonstrate that both the amino group and the size of the headgroup determine the kinetics of lipid scrambling, and that lipids with a ceramide backbone migrate much more slowly than glycerophospholipids with the same headgroup.

Kinetics of amide proton exchange in helical peptides of varying chain lengths. Interpretation by the Lifson-Roig equation

Biochemistry ◽  
1992 ◽  
Vol 31 (5) ◽  
pp. 1263-1269 ◽  
Author(s):  
Carol A. Rohl ◽  
J. Martin Scholtz ◽  
Eunice J. York ◽  
John M. Stewart ◽  
Robert L. Baldwin
Keyword(s):  
Proton Exchange ◽  
Amide Proton ◽  
Helical Peptides ◽  
Amide Proton Exchange ◽  
Chain Lengths ◽  
Kinetics Of

scholarly journals Kinetics of Registration, Antiregistration, and Flip-Flop in Phase-Separating Bilayers

2016 ◽  
Vol 110 (3) ◽  
pp. 16a
Author(s):  
John J. Williamson ◽  
Peter Olmsted
Keyword(s):  
Flip Flop ◽  
Kinetics Of

scholarly journals Inhibition of biogenic membrane flippase activity in reconstituted ER proteoliposomes in the presence of low cholesterol levels

2012 ◽  
Vol 17 (1) ◽  
Author(s):  
Archita Rajasekharan ◽  
Sathyanarayana Gummadi
Keyword(s):  
Life Time ◽  
Bovine Liver ◽  
Flip Flop ◽  
Activity Inhibition ◽  
Cholesterol Levels ◽  
Loose Packing ◽  
Low Levels ◽  
Kinetics Of ◽  
Low Cholesterol ◽  
Spinach Leaves

AbstractBiogenic membranes or self-synthesizing membranes are the site of synthesis of new lipids such as the endoplasmic reticulum (ER) in eukaryotes. Newly synthesized phospholipids (PLs) at the cytosolic leaflet of ER need to be translocated to the lumen side for membrane biogenesis and this is facilitated by a special class of lipid translocators called biogenic membrane flippase. Even though ER is the major site of cholesterol synthesis, it contains very low amounts of cholesterol, since newly synthesized cholesterol in ER is rapidly transported to other organelles and is highly enriched in plasma membrane. Thus, only low levels of cholesterol are present at the biosynthetic compartment (ER), which results in loose packing of ER lipids. We hypothesize that the prevalence of cholesterol in biogenic membranes might affect the rapid flip-flop. To validate our hypothesis, detergent solubilized ER membranes from both bovine liver and spinach leaves were reconstituted into proteoliposomes with varying mol% of cholesterol. Our results show that (i) with increase in the cholesterol/PL ratio, the half-life time of PL translocation increased, suggesting that cholesterol affects the kinetics of flipping, (ii) flipping activity was completely inhibited in proteoliposomes reconstituted with 1 mol% cholesterol, and (iii) FRAP and DSC experiments revealed that 1 mol% cholesterol did not alter the bilayer properties significantly and that flippase activity inhibition is probably mediated by interaction of cholesterol with the protein.

scholarly journals Flip-flop kinetics of ropivacaine during continuous epidural infusion influences its accumulation rate

2010 ◽  
Vol 67 (4) ◽  
pp. 399-406 ◽  
Author(s):  
Maria Cusato ◽  
Massimo Allegri ◽  
Tekla Niebel ◽  
Pablo Ingelmo ◽  
Monica Broglia ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Epidural Infusion ◽  
Continuous Epidural Infusion ◽  
Flip Flop ◽  
Kinetics Of

scholarly journals Length Dependent Folding Kinetics of Alanine-Based Helical Peptides from Optimal Dimensionality Reduction

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 385
Author(s):  
Krzysztof Kuczera ◽  
Robert Szoszkiewicz ◽  
Jinyan He ◽  
Gouri S. Jas
Keyword(s):  
Dimensionality Reduction ◽  
Relaxation Times ◽  
Coarse Grained ◽  
Free Energies ◽  
Folding Kinetics ◽  
Helical Peptides ◽  
Peptide Conformations ◽  
Dynamical Parameters ◽  
Dynamics Simulations ◽  
Kinetics Of

We present a computer simulation study of helix folding in alanine homopeptides (ALA)n of length n = 5, 8, 15, and 21 residues. Based on multi-microsecond molecular dynamics simulations at room temperature, we found helix populations and relaxation times increasing from about 6% and ~2 ns for ALA5 to about 60% and ~500 ns for ALA21, and folding free energies decreasing linearly with the increasing number of residues. The helix folding was analyzed with the Optimal Dimensionality Reduction method, yielding coarse-grained kinetic models that provided a detailed representation of the folding process. The shorter peptides, ALA5 and ALA8, tended to convert directly from coil to helix, while ALA15 and ALA21 traveled through several intermediates. Coarse-grained aggregate states representing the helix, coil, and intermediates were heterogeneous, encompassing multiple peptide conformations. The folding involved multiple pathways and interesting intermediate states were present on the folding paths, with partially formed helices, turns, and compact coils. Statistically, helix initiation was favored at both termini, and the helix was most stable in the central region. Importantly, we found the presence of underlying universal local dynamics in helical peptides with correlated transitions for neighboring hydrogen bonds. Overall, the structural and dynamical parameters extracted from the trajectories are in good agreement with experimental observables, providing microscopic insights into the complex helix folding kinetics.

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