Probing Elastic and Viscous Properties of Phospholipid Bilayers Using Neutron Spin Echo Spectroscopy

Nagao, Michihiro; Kelley, Elizabeth G.; Ashkar, Rana; Bradbury, Robert; Butler, Paul

doi:10.1021/acs.jpclett.7b01830

Cited by 110 publications

(160 citation statements)

References 79 publications

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“…Therefore, we assumed the cholesterols were always associated with saturated lipids and the lipids were always more rigid than unsaturated lipids. These assumptions resulted in the saturated lipid membranes being more rigid and less elastic than that of unsaturated lipid membranes, which is consistent with experimental findings [23]. Furthermore, as mentioned below, the simulations under these assumptions demonstrated the following results, i) the diffusion of saturated lipids was slower than that of unsaturated lipids and ii) the saturated lipid domains that may correspond to the ordered lipid raft domains appeared through the phase separation between saturated and unsaturated lipids (see the “Parameters for simulations” section in the Results).…”

Section: Model and Methodssupporting

confidence: 89%

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Kaneshige

Hayashi

Morigaki

et al. 2019

Preprint

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24 The visual photopigment protein rhodopsin (Rh) is a typical G protein-coupled receptor 25 (GPCR) that initiates the phototransduction cascade in retinal disk membrane of 26 rod-photoreceptor cells. Rh molecule has a tendency to form dimer, and the dimer tends 27 to form rows, which is suggested to heighten phototransduction efficiency in 28 single-photon regime. In addition, the dimerization confers Rh an affinity for lipid raft, 29 i.e. raftophilicity. However, the mechanism by which Rh-dimer raftophilicity 30 contributes to the organization of the higher order structure remains unknown. In this 31 study, we performed coarse-grained molecular dynamics simulations of a disk 32 membrane model containing unsaturated lipids, saturated lipids with cholesterol, and 33 Rh-dimers. We described the Rh-dimers by two-dimensional particle populations where 34 the palmitoyl moieties of each Rh exhibits raftophilicity. We simulated the structuring 35 of Rh in a disk for two types of Rh-dimer, i.e., the most and second most stable Rh 36 dimers, which exposes the raftophilic regions at the dimerization-interface (H1/H8 37 dimer) and two edges away from the interface (H4/H5 dimer), respectively. Our 38 simulations revealed that only the H1/H8 dimer could form a row structure. A small 39 number of raftophilic lipids recruited to and intercalated in a narrow space between 40 H1/H8 dimers stabilize the side-by-side interaction between dimers in a row. Our results 41 implicate that the nano-sized lipid raft domains act as a "glue" to organize the long row 42 structures of Rh-dimers. 43 44 INTRODUCTION 45 The visual pigment rhodopsin (Rh) initiates the phototransduction cascade in vertebrate 46 disk membranes of rod photoreceptor cells. Rh is a prototypical seven-transmembrane 47 G protein-coupled receptor (GPCR) and is highly concentrated in the disk membrane, 48 occupying approximately 30% of the total disk membrane area [1,2]. 49Similar to many other GPCRs, Rh is doubly palmitoylated (C16:0) at the 50 C-terminus of the juxta-membrane eighth-helix (H8) [3]. The tandem palmitoyls are 51 known to be a robust raft-targeting signal for membrane proteins [4][5][6][7][8][9]. However, 52 despite having two palmitoyls, Rh prefers polyunsaturated phospholipids because of its 53 rough intramembrane surface, which is similar to other membrane proteins [10,11].54 Thus, rhodopsin is inherently a non-raftophilic (raftophobic) membrane protein.55 Nevertheless, dimerization, which is stabilized by the binding of the cognate G protein 56 transducin, confers a high lipid raft affinity (raftophilicity) for Rh , i.e., the di-palmitoyl 57 modification at the C-terminus of H8 is prerequisite for the dimerization-dependent 58 raftophilicity of Rh [12]. Single-and semi-multimolecular observations on rhodopsin 59 dynamics in retinal disk have revealed that the oligomerization-induced raftophilicity of 60 Rh promotes spontaneous formation of raftophilic Rh-clusters [13]. 61 The organization and dynamics of Rh in the disk membrane have long been 62 debate...

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Section: Model and Methodssupporting

confidence: 89%

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Kaneshige

Hayashi

Morigaki

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Therefore, we assumed the cholesterols were always associated with saturated lipids and the lipids were always more rigid than unsaturated lipids. These assumptions resulted in the saturated lipid membranes being more rigid and less elastic than that of unsaturated lipid membranes, which is consistent with experimental findings [33]. Furthermore, as mentioned below, the simulations under these assumptions demonstrated the following results, i) the diffusion of saturated lipids was slower than that of unsaturated lipids and ii) the saturated lipid domains that may correspond to the ordered lipid raft domains appeared through the phase separation between saturated and unsaturated lipids (see the "Parameters for simulations" section in the Results).…”

Section: Introductionsupporting

confidence: 90%

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Kaneshige¹,

Hayashi²,

Morigaki³

et al. 2020

PLoS ONE

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The visual photopigment protein rhodopsin (Rh) is a typical G protein-coupled receptor (GPCR) that initiates the phototransduction cascade in retinal disk membrane of rod-photoreceptor cells. Rh molecule has a tendency to form dimer, and the dimer tends to form rows, which is suggested to heighten phototransduction efficiency in single-photon regime. In addition, the dimerization confers Rh an affinity for lipid raft, i.e. raftophilicity. However, the mechanism by which Rh-dimer raftophilicity contributes to the organization of the higher order structure remains unknown. In this study, we performed coarse-grained molecular dynamics simulations of a disk membrane model containing unsaturated lipids, saturated lipids with cholesterol, and Rh-dimers. We described the Rh-dimers by two-dimensional particle populations where the palmitoyl moieties of each Rh exhibits raftophilicity. We simulated the structuring of Rh in a disk for two types of Rh-dimer, i.e., the most and second most stable Rh dimers, which exposes the raftophilic regions at the dimerization-interface (H1/H8 dimer) and two edges away from the interface (H4/H5 dimer), respectively. Our simulations revealed that only the H1/H8 dimer could form a row structure. A small number of raftophilic lipids recruited to and intercalated in a narrow space between H1/H8 dimers stabilize the side-by-side interaction between dimers in a row. Our results implicate that the nano-sized lipid raft domains act as a "glue" to organize the long row structures of Rhdimers.

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“…Bilayer thickness fluctuations where monitored more in detail by NSE utilizing contrast matched fatty acid tails by Nagao and coworkers. 6,37 The authors added an empirical Lorentzian function to equation 7, to account for the additional peak in the experimental data 6,37 Γ m g = Γ pq g +…”

Section: Contribution Of Thickness Fluctuations Nagao Modelmentioning

confidence: 99%

Modeling the dynamics of phospholipids in the fluid phase of liposomes

Gupta

Schneider

2020

Soft Matter

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We present the derivation of a new model to describe neutron spin echo spectroscopy and quasielastic neutron scattering data on liposomes. We compare the new model with existing approaches and benchmark it with experimental data. The analysis indicates the importance of including all major contributions into modeling of the intermediate scattering function. Simultaneous analysis of the experimental data on lipids with full contrast and tail contrast matched samples, reveals highly confined lipid tail motion. A comparison of their dynamics demonstrates the statistical independence of tail-motion and height-height correlation of the membrane. A more detailed analysis indicates that lipid tails are subject to relaxations in a potential with cylindrical symmetry, in addition to the undulation and diffusive motion of the liposome. Despite substantial differences in the chemistry of the fatty acid tails, the observation indicates a universal behavior. The analysis of partially deuterated systems confirms the strong contribution of the lipid tail to the intermediate scattering function. Within the time range from 5 to 100 ns, the intermediate scattering function can be described by the height-height correlation function. The existence of the fast-localized tail motion and the contribution of slow translational diffusion of liposomes determines the intermediate scattering function for t < 5 ns and t > 100 ns, respectively. Taking into account the limited

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Probing Elastic and Viscous Properties of Phospholipid Bilayers Using Neutron Spin Echo Spectroscopy

Cited by 110 publications

References 79 publications

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Affinity of rhodopsin to raft enables the aligned oligomer formation from dimers: Coarse-grained molecular dynamics simulation of disk membranes

Modeling the dynamics of phospholipids in the fluid phase of liposomes

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