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잔류 유기 용매가 모델 세포 지질막의 상전이, 상전이 엔탈피 및 상전이 온도에 미치는 영향

Effects of Residual Solvents in the Phase Transition, Transition Enthalpy, and Transition Temperature of Phospholipid Membranes

  • 안은설 (서울과학기술대학교, 에너지바이오대학, 정밀화학과) ;
  • 최재순 (서울과학기술대학교, 에너지바이오대학, 정밀화학과) ;
  • 이동국 (서울과학기술대학교, 에너지바이오대학, 정밀화학과)
  • An, Eun Seol (Department of Fine Chemistry, Seoul National University of Science and Technology) ;
  • Choi, Jae Sun (Department of Fine Chemistry, Seoul National University of Science and Technology) ;
  • Lee, Dong Kuk (Department of Fine Chemistry, Seoul National University of Science and Technology)
  • 투고 : 2014.05.12
  • 심사 : 2014.05.29
  • 발행 : 2014.06.30

초록

Phosphatidylcholine (PC) 인지질로 이루어진 모델 지질막은 세포막을 대신하여 지질막과 여러 분자간의 상호 작용을 연구하는 생물리 연구에 흔히 이용된다. 이들 모델 지질막을 제조하는 과정에서 지질 분자나 지질막과 작용하는 분자를 용해하는데 여러 가지 유기 용매가 이용된다. 용해 과정에 사용된 용매는 물론 제거되거나 소량 사용되기 때문에 실험 결과에 미치는 영향이 미미한 것으로 간주되어 보통 무시된다. 하지만 용매의 종류에 따라 소량의 용매가 용질 분자에 남아서 실험 결과에 영향을 미칠 수 있다. 본 연구에서는 시차열분석기와 인($^{31}P$) 고체 핵자기 공명 실험을 통하여 유기 용매가 지질막의 상변이와 지질막의 물리적 성질에 미치는 영향을 조사하였다. 클로로폼에 용해한 지질의 경우 비교적 쉽게 제거되었으며, 에탄올, trifluoroethanol(TFE) 또는 trifluoroacetic acid (TFA)에 용해한 분자들의 경우 용질에 잔류하여 지질과 용질의 상호작용시 지질의 물리적 성질에 영향을 미치는 것이 확인되었다. 따라서 지질막과 상호작용하는 분자들의 연구에서 용매의 선택이 중요하며 비록 미량이 사용되었을지라도 시료 제조와 실험 결과의 해석에 각별한 주의가 필요함을 보여 준다.

Lipid membranes composed of phosphatidylcholine (PC) are used in biophysical study to mimic cellular membranes and interactions between the membrane and chemicals, where organics solvents are used in dissolving lipids or chemicals. Later, solvents are removed from the solution under nitrogen gas at room temperature, followed by the further removal of the solvent at vacuum condition for several hours. In this process, some solvents are easily removed under described conditions above and others are required more severe conditions. In this study, $^{31}P$ solid-state nuclear magnetic resonance (SSNMR) techniques and differential scanning calorimetry (DSC) were used to see any changes in the line shapes of $^{31}P$ NMR spectra of multilamellar vesicles (MLVs) samples of POPC and in the phase change temperature of multilamellar vesicles (MLVs) of DPPC in DSC thermogram with or without any residual solvents. The thermodynamic parameters associated with the solvents did exhibit noticeable changes depending on solvent types. Thus, it is concluded that solvents should be carefully chosen and removed completely and experimental results should also be interpreted with caution particularly for the experiments investigating lipid phase changes and related topics.

키워드

참고문헌

  1. K. J. Tierney, D. E. Block, and M. L. Longo, Elasticity and phase behavior of DPPC membrane modulated by cholesterol, ergosterol, and ethanol, Biophysical. J., 89, 2481 (2005). https://doi.org/10.1529/biophysj.104.057943
  2. D. L. MacDonald and H. Goldfine, Effects of solvents and alcohols on the polar lipid composition of clostridium butyricum under conditions of controlled lipid chain composition, Appl. Environ. Microbiol., 57(12), 3517 (1991).
  3. P. L. Yeagle, The structure of biological membranes 2nd ed., 173, CRC Press, Boca Raton, Florida (2005).
  4. H. V. Ly and M. L. Longo, The influence of short-chain alcohols on interfacial tension, mechanical properties, area/molecule, and permeability of fluid lipid bilayers, Biophys. J., 87, 1013 (2004). https://doi.org/10.1529/biophysj.103.034280
  5. H. V. Ly, D. E. Block, and M. L. Longo, Interfacial tension effect of ethanol on lipid bilayer rigidity, stability, and area/molecule: a micropipet aspiration approach, Langmuir, 18, 8988 (2002). https://doi.org/10.1021/la026010q
  6. H. Gaussier, H. Morency, M. C. Lavoie, and M. Subirade, Replacement of trifluoroacetic acid with HCl in the hydrophobic purification steps of pediocin PA-1: a structural effect, Appl. Environ. Microbiol., 68(10), 4803 (2002). https://doi.org/10.1128/AEM.68.10.4803-4808.2002
  7. M. Goodman, F. Chen, and F. R. Prince, Conformational aspect of polypeptide structure. XLIV. Conformational transitions of poly (N-methyl-alanines) induced by trifluoroacetic acid, Biopolymers, 12(11), 2549 (1973). https://doi.org/10.1002/bip.1973.360121109
  8. F. D. Sonnichsen, J. E. Van Eyk, R. S. Hodges, and B. D. Sykes, Effect of trifluoroethanol on protein secondary structure: an NMR and CD study using a synthetic actin peptide, Biochemistry, 31(37), 8790 (1992). https://doi.org/10.1021/bi00152a015
  9. R. Xue, S. Wang, C. Wang, T. Zhu, F. Li, and H. Sun, HFIP-induced structures and assemblies of the peptides from the transmembrane domain 4 of membrane protein Nramp1, Biopolymer, 84(3), 329 (2006). https://doi.org/10.1002/bip.20478
  10. R. B. Nellas, Q. R. Johnson, and T. Shen, Solventinduced ${\alpha}$- to 3(10)-helix transition of an amphiphilic peptide, Biochemistry, 52(40), 7137 (2013). https://doi.org/10.1021/bi400537z
  11. R. B. Gennis, Biomembranes: Molecular structure and function, ed. Springer, Springer Verlag, New York (1989).
  12. H. L. Scott Jr. and T. J. Coe, A theoretical study of lipid-protein interactions in bilayers, Biophys. J., 42(3), 219 (1983). https://doi.org/10.1016/S0006-3495(83)84389-6
  13. A. G. Lee, Lipid-protein interactions in biological membranes: a structural perspective, Biochimica. et. Biophysica. Acta., 1612, 1 (2003). https://doi.org/10.1016/S0005-2736(03)00056-7
  14. A. G. Lee, Lipid-protein interactions, Biochem. Soc. Trans., 39(3), 761 (2011). https://doi.org/10.1042/BST0390761
  15. A. C. Newton, Interaction of Proteins With Lipid Headgroups: Lessons from Protein Kinase C, Annu. Rev. Biophys. Biomol. Struct., 22, 1 (1993). https://doi.org/10.1146/annurev.bb.22.060193.000245
  16. M. J. Sanderson, Peptide-lipid interactions: Insights and perspectives, Org. Biomol. Chem., 3, 201 (2005). https://doi.org/10.1039/b415499a
  17. R. S. Harrison, P. C. Sharpe, Y. Singh, and D. P. Fairlie, Amyloid peptides and proteins in review, Rev. Physiol. Biochem. Pharmacol., 159, 1 (2007).
  18. E. A. Smith and P. K. Dea, Applications of calorimetry in a wide context-differential scanning calorimetry, isothermal titration calorimetry and microcalorimetry : Chapter 18, ed. Amal Ali Elkordy, In Tech, Croatia (2013).
  19. S. Tristram-Nagle, T. Moore, H. I. Petrache, and J. F. Nagle, DMSO produces a new subgel phase in DPPC: DSC and X-ray diffraction study, Biochimica. et. Biophysica. Acta., 1369, 19 (1998). https://doi.org/10.1016/S0005-2736(97)00197-1
  20. S. Ali, S. Minchey, A. Janoff, and E. Mayhew, A differential scanning calorimetry study of phosphocholines mixed with paclitaxel and its bromoacylated taxanes, Biophys. J., 78(1), 246 (2000). https://doi.org/10.1016/S0006-3495(00)76588-X
  21. I. C. P. Smith and I. H. Ekiel, Phosphorus-31 NMR: Principles and applications, ed. D. Gorenstein, 447, Academic Press Inc., London, England (1984).
  22. J. Seelig, $^{31}P$ nuclear magnetic resonance and the head group structure of phospholipids in membranes, Biochim. Biophys. Acta., 515, 105 (1978). https://doi.org/10.1016/0304-4157(78)90001-1
  23. K. A. H. Wildman, D. K. Lee, and A. Ramamoorthy, Mechanism of lipid bilayer disruption by the human antimicrobial peptide, LL-37, Biochemistry, 42(21), 6545 (2003). https://doi.org/10.1021/bi0273563
  24. K. J. Hallock, D. K. Lee, and A. Ramamoorthy, MSI-78, an analogue of the magainin antimicrobial peptides, disrupts lipid bilayer structure via positive curvature strain, Biophys. J., 84(5), 3052 (2003). https://doi.org/10.1016/S0006-3495(03)70031-9
  25. P. L. Yeagle, Encyclopedia of nuclear magnetic resonance, eds. D. M. Grant and R.K. Harris, 3015, John Wiley, Toronto, Canada (1996).
  26. J. Safar, P. P. Roller, D. C. Gadusek, and C. J. Gibbs Jr., Thermal stability and conformational transitions of scrapie amyloid (prion) protein correlate with infectivity, Protein Science, 2, 2206 (1993). https://doi.org/10.1002/pro.5560021220
  27. T. Hayakawa, Y. Kondo, and H. Yamamoto, Secondary structure of poly-L-arginine and its derivatives, Bulletin of Chemical Society of Japan, 42, 1937 (1969). https://doi.org/10.1246/bcsj.42.1937
  28. S. P. Brazier, B. Ramesh, P. I. Haris, D. C. Lee, and S. K. S. Srai, Secondary structure analysis of the putative membrane-associated domains of the inward rectifier K+ channel ROMK1, Biochem. J., 335, 375 (1998). https://doi.org/10.1042/bj3350375