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Yoon BK, Jackman JA, Kim MC, Sut TN, Cho NJ. Correlating Membrane Morphological Responses with Micellar Aggregation Behavior of Capric Acid and Monocaprin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2750-2759. [PMID: 28263610 DOI: 10.1021/acs.langmuir.6b03944] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The interaction of single-chain lipid amphiphiles with phospholipid membranes is relevant to many scientific fields, including molecular evolution, medicine, and biofuels. Two widely studied compounds within this class are the medium-chain saturated fatty acid, capric acid, and its monoglyceride derivative, monocaprin. To date, most studies about these compounds have involved in vitro evaluation of their biological activities, while mechanistic details of how capric acid and monocaprin interact with phospholipid bilayers remain elusive. Herein, we investigated the effect of these two compounds on the morphological and fluidic properties of prefabricated, supported lipid bilayers (SLBs). The critical micelle concentration (CMC) of each compound was determined by fluorescence spectroscopy measurements. At or above its CMC, capric acid induced the formation of elongated tubules protruding from the SLB, as determined by quartz crystal microbalance-dissipation and fluorescence microscopy experiments. By contrast, monocaprin induced the formation of elongated tubules or membrane buds below and above its CMC, respectively. Fluorescence recovery after photobleaching (FRAP) experiments indicated that capric acid increased bilayer fluidity only above its CMC, whereas monocaprin increased bilayer fluidity both above and below its CMC. We discuss these findings in the context of the two compounds' structural properties, including net charge, molecular length and hydrogen-bonding capacity. Collectively, the findings demonstrate that capric acid and monocaprin differentially affect the morphological and fluidic properties of SLBs, and that the aggregation state of the compounds plays a critical role in modulating their interactions with phospholipid membranes.
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Affiliation(s)
- Bo Kyeong Yoon
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, 637553, Singapore
| | - Joshua A Jackman
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, 637553, Singapore
| | - Min Chul Kim
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, 637553, Singapore
| | - Tun Naw Sut
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, 637553, Singapore
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798, Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, 637553, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University , 62 Nanyang Drive, 637459, Singapore
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Effect of methanol on the phase-transition properties of glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulations: In quest of the biphasic effect. J Mol Graph Model 2015; 55:85-104. [DOI: 10.1016/j.jmgm.2014.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/29/2014] [Accepted: 10/30/2014] [Indexed: 11/21/2022]
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Laner M, Horta BAC, Hünenberger PH. Long-timescale motions in glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulation. J Mol Graph Model 2014; 55:48-64. [PMID: 25437095 DOI: 10.1016/j.jmgm.2014.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
Abstract
The occurrence of long-timescale motions in glycerol-1-monopalmitate (GMP) lipid bilayers is investigated based on previously reported 600 ns molecular dynamics simulations of a 2×8×8 GMP bilayer patch in the temperature range 302-338 K, performed at three different hydration levels, or in the presence of the cosolutes methanol or trehalose at three different concentrations. The types of long-timescale motions considered are: (i) the possible phase transitions; (ii) the precession of the relative collective tilt-angle of the two leaflets in the gel phase; (iii) the trans-gauche isomerization of the dihedral angles within the lipid aliphatic tails; and (iv) the flipping of single lipids across the two leaflets. The results provide a picture of GMP bilayers involving a rich spectrum of events occurring on a wide range of timescales, from the 100-ps range isomerization of single dihedral angles, via the 100-ns range of tilt precession motions, to the multi-μs range of phase transitions and lipid-flipping events.
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Affiliation(s)
- Monika Laner
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
| | - Bruno A C Horta
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland; Dpto. de Engenharia Elétrica, PUC-Rio, Rio de Janeiro, Brazil; Dpto. de Ciências Biológicas, UEZO, Rio de Janeiro, Brazil.
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Effect of the cosolutes trehalose and methanol on the equilibrium and phase-transition properties of glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulations. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:517-44. [DOI: 10.1007/s00249-014-0982-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/16/2014] [Accepted: 07/24/2014] [Indexed: 10/24/2022]
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