Orientation of melittin in phospholipid bilayers. A polarized attenuated total reflection infrared study

Frey, Sammy; Tamm, Lukas K.

doi:10.1016/s0006-3495(91)82126-9

Cited by 289 publications

(272 citation statements)

References 34 publications

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“…The R ATR for the symmetric methylene stretch was 1.4, which results in a value of 0.4 for S L . This S L value would be considered low for DMPC but is consistent with liquid-crystalline lipids having an average bilayer orientation perpendicular to the supporting crystal and is in good agreement with S L values reported previously for gel-phase lipids taken above the phase transition temperature (41) and previous studies of POPC (45).…”

Section: Ir Spectroscopy In Lipid Bilayerssupporting

confidence: 91%

Conformation of the synaptobrevin transmembrane domain

Bowen

Brunger

2006

Proc. Natl. Acad. Sci. U.S.A.

101

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The synaptic vesicle protein synaptobrevin (also called VAMP, vesicle-associated membrane protein) forms part of the SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex, which is essential for vesicle fusion. Additionally, the synaptobrevin transmembrane domain can promote lipid mixing independently of complex formation. Here, the conformation of the transmembrane domain was studied by using circular dichroism and attenuated total reflection Fourier-transform infrared spectroscopy. The synaptobrevin transmembrane domain has an ␣-helical structure that breaks in the juxtamembrane region, leaving the cytoplasmic domain unstructured. In phospholipid bilayers, infrared dichroism data indicate that the transmembrane domain adopts a 36°angle with respect to the membrane normal, similar to that reported for viral fusion peptides. A conserved aromatic͞basic motif in the juxtamembrane region may be causing this relatively high insertion angle.Fourier-transform infrared spectroscopy ͉ membrane fusion ͉ membrane protein ͉ neuotransmission I n neurons, synaptic vesicles dock at the plasma membrane and fuse upon an increase in local Ca 2ϩ concentration, releasing neurotransmitters into the synaptic cleft (1-3). Many of the proteins involved in this complex reaction have been identified (4-8). Members of the SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) family are involved in the final stages of neurotransmitter release. The binding of the synaptic vesicle protein synaptobrevin to the plasma membrane proteins syntaxin and SNAP-25 is essential for stimulated neurotransmitter release. Although the required factors and precise sequence of events that trigger Ca 2ϩ -dependent vesicle fusion is hotly debated, the SNAREs are well established as a fundamental yet incomplete part of the fusion machinery (6).The neuronal SNARE proteins are largely unstructured as monomers (9-12) and undergo a dramatic structural transition to form an ␣-helical heterotrimer (13, 14). The energy from this structural transition was proposed to drive membrane fusion (10, 13, 15), but recent studies have shown that SNARE complex formation can occur without inducing fusion (16,17) and that SNAREs disrupt membranes and promote lipid mixing independent of complex formation (16,(18)(19)(20). Thus, the relationship between structure induction, complex formation, and membrane fusion activity remains unclear.Synaptobrevin (also called VAMP, vesicle-associated membrane protein) contains a single SNARE motif involved in formation of the complex with syntaxin and SNAP-25 and a C-terminal transmembrane domain. The conserved juxtamembrane region (residues 77-90) binds phospholipids and calmodulin (21). Tryptophan residues in the juxtamembrane region cause portions of the SNARE motif to insert into the bilayer (22). These interactions have been suggested to regulate SNARE complex formation and play a role in vesicle fusion (23)(24)(25). However, the effect of the transmembrane domain on the structure of ...

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Section: Ir Spectroscopy In Lipid Bilayerssupporting

confidence: 91%

Conformation of the synaptobrevin transmembrane domain

Bowen

Brunger

2006

Proc. Natl. Acad. Sci. U.S.A.

101

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“…In control cells, the orientation of the absorption transition moment of the DiI is largely parallel to the membrane surface resulting in negative ͗P 2 ͘ values (Fig. 8B) (53,54). Having determined the average value in control cells, we next confirmed that dibucaine and valproate increased the fluidity of the cells.…”

Section: Transient Increase In Membrane Fluidity Does Not Alter Caveolaementioning

confidence: 58%

Phosphatidylserine dictates the assembly and dynamics of caveolae in the plasma membrane

Hirama

Das

Yang

et al. 2017

Journal of Biological Chemistry

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Edited by Dennis R. VoelkerCaveolae are bulb-shaped nanodomains of the plasma membrane that are enriched in cholesterol and sphingolipids. They have many physiological functions, including endocytic transport, mechanosensing, and regulation of membrane and lipid transport. Caveola formation relies on integral membrane proteins termed caveolins (Cavs) and the cavin family of peripheral proteins. Both protein families bind anionic phospholipids, but the precise roles of these lipids are unknown. Here, we studied the effects of phosphatidylserine (PtdSer), phosphatidylinositol 4-phosphate (PtdIns4P), and phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P 2 ) on caveolar formation and dynamics. Using live-cell, single-particle tracking of GFP-labeled Cav1 and ultrastructural analyses, we compared the effect of PtdSer disruption or phosphoinositide depletion with caveola disassembly caused by cavin1 loss. We found that PtdSer plays a crucial role in both caveola formation and stability. Sequestration or depletion of PtdSer decreased the number of detectable Cav1-GFP puncta and the number of caveolae visualized by electron microscopy. Under PtdSer-limiting conditions, the co-localization of Cav1 and cavin1 was diminished, and cavin1 degradation was increased. Using rapamycin-recruitable phosphatases, we also found that the acute depletion of PtdIns4P and PtdIns (4,5)P 2 has minimal impact on caveola assembly but results in decreased lateral confinement. Finally, we show in a model of phospholipid scrambling, a feature of apoptotic cells, that caveola stability is acutely affected by the scrambling. We conclude that the predominant plasmalemmal anionic lipid PtdSer is essential for proper Cav clustering, caveola formation, and caveola dynamics and that membrane scrambling can perturb caveolar stability.

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“…We note that a comparison between maculatin 1.1 and the peptide melittin, a channel forming peptide [14], reveals a remarkably similar sequence homology (see Table 2). Both peptides are rich in hydrophobic residues at their N-termini and both have a central proline residue which is seven residues apart from the lysine.…”

Section: Discussionmentioning

confidence: 82%

“…Melittin, in contrast, a 26-residue pore-forming peptide isolated from bee venom, was found to adopt a transmembrane orientation [14], i.e. perpendicular to the membrane plane, in phospholipid bilayers.…”

Section: Introductionmentioning

confidence: 92%

The orientation of the antibiotic peptide maculatin 1.1 in DMPG and DMPC lipid bilayers. Support for a pore‐forming mechanism

et al. 2002

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Maculatin 1.1 is an antimicrobial peptide isolated from the Australian tree frog Litoria genimaculata that adopts an amphipathic, K K-helical structure in solution. Its orientation and conformation when incorporated to pre-formed DMPG (1,2-dimyristoyl-sn-glycero-3-phosphoglycerol) and DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) vesicles was determined using polarised Fourier transform infrared^attenuated total reflection infrared and deuterium exchange experiments. For DMPG membranes, our results show insertion of V V70% of the maculatin 1.1 molecules, with an angle of insertion of approximately 35³ to the membrane normal and with a predominant K K-helical structure. These results suggest that maculatin 1.1 acts through a pore-forming mechanism to lyse bacterial membranes. A similar degree of insertion in DMPG (65%) and K K-helical structure was observed for a biologically inactive, less amphipathic maculatin 1.1 analogue, P15A, although the helix tilt was found to be greater (46³) than for maculatin 1.1. Similar experiments performed using DMPC liposomes showed poor insertion, less than 5%, for both maculatin 1.1 and its analogue. In addition, the shape of the amide I band in these samples is consistent with K K-helix, L L-structure and disordered structures being present in similar proportion. These results clearly show that maculatin 1.1 inserts preferentially in negatively charged membranes (DMPG) which mimic the negatively charged membrane of Gram-positive bacteria. We attribute the high percentage of insertion of the biologically inactive analogue in DMPG to the fact that its concentration on the membrane surface in our experiments is likely to be much higher than that found in physiological conditions. ß 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

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Orientation of melittin in phospholipid bilayers. A polarized attenuated total reflection infrared study

Cited by 289 publications

References 34 publications

Conformation of the synaptobrevin transmembrane domain

Conformation of the synaptobrevin transmembrane domain

Phosphatidylserine dictates the assembly and dynamics of caveolae in the plasma membrane

The orientation of the antibiotic peptide maculatin 1.1 in DMPG and DMPC lipid bilayers. Support for a pore‐forming mechanism

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