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Tazawa K, Yamazaki M. Effect of monolayer spontaneous curvature on constant tension-induced pore formation in lipid bilayers. J Chem Phys 2023; 158:081101. [PMID: 36859073 DOI: 10.1063/5.0135561] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The methodology of constant tension-induced rupture of giant unilamellar vesicles (GUVs) has provided information on tension-induced pore formation. This method was used to investigate the effect of spontaneous curvature (H0) for a lipid monolayer on the rate constant (kr) for constant tension (σ)-induced rupture, which originates from pore formation in lipid bilayers. Lipids were incorporated with different H0 values into GUV membranes to change the overall H0 value for the GUV monolayer. The dioleoylphosphatidylglycerol (DOPG)/dioleoylphosphatidylethanolamine (DOPE) (4/6, molar ratio, here and elsewhere) monolayer has a negative H0, whereas the DOPG/dioleoylphosphatidylcholine (DOPC) (4/6) monolayer has an essentially zero H0. A higher tension was required to induce the rupture of DOPG/DOPE (4/6)-GUVs compared with DOPG/DOPC (4/6)-GUVs. The line tension (Γ) for a pre-pore in DOPG/DOPE (4/6)-GUVs, determined by the analysis of the tension dependence of kr, was 1.5 times larger than that in DOPG/DOPC (4/6)-GUVs. The kr values for GUVs comprising DOPG/DOPC/18:1 lysophosphatidylcholine (LPC) (40/55/10), which has a positive H0, were larger than those for DOPG/DOPC (4/6)-GUVs under the same tension. The Γ value for DOPG/DOPC/LPC (40/55/10)-GUVs was almost half that for DOPG/DOPC (4/6)-GUVs. These results indicate that Γ decreases with increasing H0, which results in an increase in kr. Based on these results, the effect of H0 on kr and Γ is discussed.
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Affiliation(s)
- Kanta Tazawa
- Physics Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Physics Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
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Sodium caseinate-coated and β-cyclodextrin/vitamin E inclusion complex-loaded nanoliposomes: A novel stabilized nanocarrier. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.112174] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Oka T. Small-Angle X-ray Crystallography on Single-Crystal Regions of Inverse Bicontinuous Cubic Phases: Lipid Bilayer Structures and Gaussian Curvature-Dependent Fluctuations. J Phys Chem B 2017; 121:11399-11409. [PMID: 29172522 DOI: 10.1021/acs.jpcb.7b08589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
I report for the first time an X-ray crystallographic study on single-crystal regions of cubic phases of a lyotropic liquid crystal. The single-crystal regions of three inverse bicontinuous cubic phases of a lipid, monoolein, diffracted X-ray only in small-angle regions, but amplitudes of structure factors were determined from the small-angle X-ray diffraction data with high accuracy. Structure factors from lipid bilayer models with constant thickness were optimized to amplitudes obtained from the X-ray data. By using amplitudes of the structure factors from X-ray data and phases from the models, electron density maps of three cubic phases were reconstructed. Lipid bilayer membranes, consisting of high density head regions and low density tail regions, were clearly distinguished in the electron density maps. Water regions had slightly lower density than that of the lipid head regions and were clearly visible for two of the cubic phases. Centers of bilayer membranes were located on the corresponding triply periodic minimal surfaces in the maps. Electron density data indicated Gaussian curvature-dependent fluctuations of bilayer membranes: the smaller the Gaussian curvature is, the larger the fluctuation becomes. The technique described in this report is expected to bring new knowledge in the structural research of lyotropic liquid crystals.
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Affiliation(s)
- Toshihiko Oka
- Department of Physics, Faculty of Science, and ‡Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University , Shizuoka 422-8529, Japan
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Oka T, Hasan M, Islam MZ, Moniruzzaman M, Yamazaki M. Low-pH-Induced Lamellar to Bicontinuous Primitive Cubic Phase Transition in Dioleoylphosphatidylserine/Monoolein Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:12487-12496. [PMID: 28967756 DOI: 10.1021/acs.langmuir.7b02512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electrostatic interactions (EIs) play important roles in the structure and stability of inverse bicontinuous cubic (QII) phases of lipid membranes. We examined the effect of pH on the phase of dioleoylphosphatidylserine (DOPS)/monoolein (MO) membranes at low ionic strengths using small-angle X-ray scattering (SAXS). We found that the phase transitions from lamellar liquid-crystalline (Lα) to primitive cubic (QIIP) phases in DOPS/MO (2/8 molar ratio) membranes occurred in buffers containing 50 mM NaCl at and below the final pH of 2.75 as the pH of the membrane suspension was decreased from a neutral value. The kinetic pathway of this transition was revealed using time-resolved SAXS with a stopped-flow apparatus. The first step is a rapid transition from the Lα phase to the hexagonal II (HII) phase, and the second step is a slow transition from the HII phase to the QIIP phase. We determined the rate constants of the first step, k1, and of the second step, k2, by analyzing the time course of SAXS intensities quantitatively. The k1 value increased with temperature. The analysis of this result provided the values of its apparent activation energy, which were constant over temperature but increased with pH. This can be explained by an EI effect on the free energy of the transition state. In contrast, the k2 value decreased with temperature, indicating that the true activation energy increased with temperature. These experimental results were analyzed using the theory of the activation energy of phase transitions of lipid membranes when the free energy of the transition state depends on temperature. On the basis of these results, we discussed the mechanism of this phase transition.
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Affiliation(s)
- Toshihiko Oka
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Moynul Hasan
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Md Zahidul Islam
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Md Moniruzzaman
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
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Sharmin S, Islam MZ, Karal MAS, Alam Shibly SU, Dohra H, Yamazaki M. Effects of Lipid Composition on the Entry of Cell-Penetrating Peptide Oligoarginine into Single Vesicles. Biochemistry 2016; 55:4154-65. [DOI: 10.1021/acs.biochem.6b00189] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sabrina Sharmin
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | - Md. Zahidul Islam
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | - Mohammad Abu Sayem Karal
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | - Sayed Ul Alam Shibly
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | - Hideo Dohra
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Integrated
Bioscience Section, Graduate School of Science and Technology, ‡Instrumental Research
Support Office, Research Institute of Green Science and Technology, §Nanomaterials Research
Division, Research Institute of Electronics, and ∥Department of Physics, Graduate
School of Science, Shizuoka University, Shizuoka 422-8529, Japan
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Oka T, Saiki T, Alam JM, Yamazaki M. Activation Energy of the Low-pH-Induced Lamellar to Bicontinuous Cubic Phase Transition in Dioleoylphosphatidylserine/Monoolein. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1327-1337. [PMID: 26766583 DOI: 10.1021/acs.langmuir.5b03785] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electrostatic interaction is an important factor for phase transitions between lamellar liquid-crystalline (Lα) and inverse bicontinuous cubic (QII) phases. We investigated the effect of temperature on the low-pH-induced Lα to double-diamond cubic (QII(D)) phase transition in dioleoylphosphatidylserine (DOPS)/monoolein (MO) using time-resolved small-angle X-ray scattering with a stopped-flow apparatus. Under all conditions of temperature and pH, the Lα phase was directly transformed into an intermediate inverse hexagonal (HII) phase, and subsequently the HII phase slowly converted to the QII(D) phase. We obtained the rate constants of the initial step (i.e., the Lα to HII phase transition) and of the second step (i.e., the HII to QII(D) phase transition) using the non-negative matrix factorization method. The rate constant of the initial step increased with temperature. By analyzing this result, we obtained the values of its apparent activation energy, Ea (Lα → HII), which did not change with temperature but increased with an increase in pH. In contrast, the rate constant of the second step decreased with temperature at pH 2.6, although it increased with temperature at pH 2.7 and 2.8. These results indicate that the value of Ea (HII → QII(D)) at pH 2.6 increased with temperature, but the values of Ea (HII → QII(D)) at pH 2.7 and 2.8 were constant with temperature. The values of Ea (HII → QII(D)) were smaller than those of Ea (Lα → HII) at the same pH. We analyzed these results using a modified quantitative theory on the activation energy of phase transitions of lipid membranes proposed initially by Squires et al. (Squires, A. M.; Conn, C. E.; Seddon, J. M.; Templer, R. H. Soft Matter 2009, 5, 4773). On the basis of these results, we discuss the mechanism of this phase transition.
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Affiliation(s)
- Toshihiko Oka
- Nanomaterials Research Division, Research Institute of Electronics, ‡Dept. Physics, Graduate School of Science, §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Takahiro Saiki
- Nanomaterials Research Division, Research Institute of Electronics, ‡Dept. Physics, Graduate School of Science, §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Jahangir Md Alam
- Nanomaterials Research Division, Research Institute of Electronics, ‡Dept. Physics, Graduate School of Science, §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
| | - Masahito Yamazaki
- Nanomaterials Research Division, Research Institute of Electronics, ‡Dept. Physics, Graduate School of Science, §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
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Oka T. Transformation between Inverse Bicontinuous Cubic Phases of a Lipid from Diamond to Gyroid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11353-11359. [PMID: 26425878 DOI: 10.1021/acs.langmuir.5b02180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The transformation between inverse bicontinuous cubic phases of a lipid from diamond (QII(D)) to gyroid (QII(G)) in the single crystal region of monoolein was studied. X-ray diffraction data indicate that the single orientation of the QII(D) phase was converted into an almost single orientation of the QII(G) phase. The [111] and [11̅0] directions of a single crystal of the QII(D) phase corresponded to the [202] and [04̅0] directions of the QII(G) phase, respectively. This orientation relationship indicated that one direction in the four-branched water channels of the QII(D) phase was preserved in the three-branched water channels of the QII(G) phase. Using this relationship, a transformation model was constructed in which one direction of the water channels was preserved while another direction appeared.
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Affiliation(s)
- Toshihiko Oka
- Department of Physics, Faculty of Science and Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University , Shizuoka 422-8529, Japan
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Oka T. Transformation between inverse bicontinuous cubic phases of a lipid from diamond to primitive. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3180-3185. [PMID: 25719417 DOI: 10.1021/la504295v] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
I studied the transformation between inverse bicontinuous cubic phases (QII) from diamond (QII(D)) to primitive (QII(P)) in a single-crystal region of monoolein. X-ray diffraction data reveal that the crystallographic orientation of QII(P) rotates 55° around the [01̅1] axis from QII(D). This indicates that one direction of the four-branched water channels in the QII(D) phase is preserved in the six-branched water channels of the QII(P) phase. I therefore built a transformation model that would keep the direction of the water channels fixed in both phases and cause the water channels along other direction in QII(D) to shrink and disappear.
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Affiliation(s)
- Toshihiko Oka
- Department of Physics, Graduate School of Science, and Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 422-8529, Japan
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Oka T, Tsuboi TA, Saiki T, Takahashi T, Alam JM, Yamazaki M. Initial step of pH-jump-induced lamellar to bicontinuous cubic phase transition in dioleoylphosphatidylserine/monoolein. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8131-8140. [PMID: 24949525 DOI: 10.1021/la5021719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Electrostatic interactions (EI) are an important factor for phase transitions between lamellar liquid-crystalline (L(α)) and inverse bicontinuous cubic (Q(II)) phases. We investigated the low pH-induced L(α) to double-diamond cubic (Q(II)(D)) phase transition in dioleoylphosphatidylserine (DOPS)/monoolein (MO) using time-resolved small-angle X-ray scattering. Using a stopped-flow apparatus, a suspension of liposomes (multilamellar vesicles (MLVs) or large unilamellar vesicles (LUVs)) of 20%-DOPS/80%-MO membrane at neutral pH was rapidly mixed with a low pH buffer, and then the structural change of the membranes in the resultant suspension was observed as a function of time (i.e., pH-jump experiment). At the initial step, the L(α) phase was directly transformed into the hexagonal II (H(II)) phase, and subsequently, the H(II) phase slowly converted into the Q(II)(D) phase. We obtained the rate constants of the initial step (i.e., the L(α) to H(II) phase transition) and of the second step (i.e., the H(II) to Q(II)(D) phase transition) using the non-negative matrix factorization method. The rate constant of the initial step was independent of the MLV concentration, indicating that single MLVs can convert into the HII phase without any interaction with other MLVs. On the other hand, the rate constant of the initial step increased with a decrease in pH, 0.041 s(-1) at pH 2.6 and 0.013 s(-1) at pH 2.8, and also exhibited a size dependence; for smaller vesicles such as LUVs and smaller MLVs with diameters of ~1 μm, the rate constant was smaller. They were reasonably explained by the classical nucleation theory. These results provide the first experimental evidence of the total kinetics of EI-induced L(α)/Q(II) phase transitions.
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Affiliation(s)
- Toshihiko Oka
- Nanomaterials Research Division, Research Institute of Electronics, ‡Department of Physics, Graduate School of Science, and §Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University , Shizuoka 422-8529, Japan
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Alam MM, Oka T, Ohta N, Yamazaki M. Kinetics of low pH-induced lamellar to bicontinuous cubic phase transition in dioleoylphosphatidylserine∕monoolein. J Chem Phys 2011; 134:145102. [PMID: 21495771 DOI: 10.1063/1.3575240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recently, it has been well recognized that the modulation of electrostatic interactions due to surface charges can induce transitions between lamellar liquid-crystalline (L(α)) and inverse bicontinuous double-diamond cubic (Q(II)(D)) phases in biological lipids. To reveal their kinetic pathway and mechanism, we investigated the low pH-induced L(α) to Q(II)(D) phase transitions in 20%-dioleoylphosphatidylserine (DOPS)/80%-monoolein (MO) using time-resolved small-angle x-ray scattering and a rapid mixing method. At a final pH of 2.6-2.9, the L(α) phase was transformed completely into the hexagonal II (H(II)) phase within 2-10 s after mixing a low pH buffer with a suspension of multilamellar vesicles of 20%-DOPS∕80%-MO (the initial step). Subsequently, the H(II) phase slowly converted into the Q(II)(D) phase and completely disappeared within 15-30 min (the second step). The rate constants of the second step were obtained using the singular value decomposition analysis. On the basis of these data, we discuss the underlying mechanism of the kinetic pathway of the low pH-induced L(α) to Q(II)(D) phase transitions.
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Affiliation(s)
- Mahay Md Alam
- Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan
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