摘要(英) |
Biological membranes contain domains of distinct lipid and protein compositions. Accumulating evidence suggests that specialized domains, called lipid rafts, play important roles in many biological processes. Raft domains, rich in cholesterol and sphingolipids, are though to be in a more ordered liquid-crystalline phase than its surroundings. We investigate the membrane structure and phase behavior of model membrane composed of 1-palmitoyl-2-oleoyl-sn- glycero-3-phosphocholine (POPC) and cholesterol bilayers using deuterium nuclear magnetic resonance (2H NMR). The sn-1 chain of POPC was perdeuterated and spectra were taken as a function of cholesterol concentration and temperature. It is found that addition of cholesterol decreases the order of the so-phase POPC membranes, whereas increases the chain order of the liquid-phase POPC membranes. Analysis of the liquid crystalline spectra suggests that two types of liquid crystalline domains, having distinct average chain conformations, coexist over wide cholesterol concentration and temperature ranges above the so-to-ld transition temperature of POPC membranes. Furthermore, the temperature-composition phase diagram of POPC/chol exhibits a considerably broader two-liquid-phase region than DPPC/chol [1]. This suggests that the unsaturated chain of POPC hinders the interaction of POPC with cholesterol, such than liquid-liquid immiscibility in POPC/chol occurs over a larger composition range than in DPPC/chol membranes. |
參考文獻 |
[1] Molecular Biology of The Cell, Third Edition. Bruce Alberts, Dennis Bray, et al.
[2] Molecular Cell Biology, Fourth Edition. Harvey Lodish, Arnold Berk, et al.
[3] E. Gorter and F. Grendel (1925). J. Exp. Med. 41;439-443.
[4] K. Simons and E. Ikonen (1997). Nature. 387:569-572.
[5] Life – As A Matter of Fat. Ole G. Mouritsen.
[6] D. A. Brown and E. London (2000). J. Biol. Chem. 275: 17221-17224
[7] D. A. Brown and J. K. Rose (1992). Cell. 68: 533-544.
[8] M. S. Bretscher and S. Munro (1993). Science 261:1280-1281.
[9] P. J. Casey (1995). Science. 268:221-225.
[10] K. Simons and E. Ikonen (1997). Nature. 387:569-572.
[11] K. Simons and D. Toomre (2000). Nat. Rev. Mol. Cell Biol. 1: 31-41.
[12] K. Simons and E. Ikonen. (2000). Science. 1290:1721-1726.
[13] R. G. Anderson and K. Jacobson (2002). Science. 296:1821-1825.
[14] J. R. Silvius (2003). B.B.A. 1610:174-183.
[15] Robert B. Gennis. Biomembranes-molecular structure and function. 1989.
[16] M. R. Vist and J. H. Davis (1990). Biochemistry 29, 451-464.
[17] The structure of biological membranes, Second edition CRC Press LLC, Boca Raton, p.58. Philip L. Yeagle. 2004.
[18] T. Kochy and T. M. Bayerl (1993). P.R.E. 47:2109-2116.
[19] Paul Karakatsanis (1996). P.R.E. 54:1785-1790.
[20] Andrey Filippov et al (2004). B.J. 86:891-896.
[21] S. Raffy and J. Teissie (1999). B.J. 76: 2072-2080.
[22] Huang et al (1999). B.B.A. 1417:89-100.
[23] C. Pare and M. Lafleur (1998). B.J. 74:899-909.
[24] W. Guo et al (2002). B.J. 83:1465-1478.
[25] Y. W. Hsueh et al (2005). B.J. 88:1799.
[26] Y. K. Shin, and J. H. Freed (1989). B. J. 55:537-550.
[27] J. L. Thewalt et al (1992). Acta. Pharm. 42:9-23.
[28] E. Fukushima and Stephen B.W. Roeder. Experimental Pulse NMR: A Nuts and Bols Approach.
[29] J. H. Davis et al (1976). Chem. Phys. Lett. 42:390-394.
[30] Thewalt, J. L., and M. Bloom (1992). B. J. 63:1176-1181.
[31] Y.W. Hsueh, M. Zuckermann, J. Thewalt (2005). Concepts in Magnetic Resonance, 26A:35-46.
[32] Nezil, F.A., S. Bayerl, and M. Bloom (1992). B.J. 61:1413-1426.
[33] Lafleur, M., B. Fine, E. Sternin, P. R. Cullis, M. Bloom. B.J. 56:1037-1041.
[34] de Almeida, RFM, A. Fedorov, and M. Prieto (2003). B.J. 85:2406-2416.
[35] Filippov, A., G. Oradd, and G. Lindblom (2003). B.J. 84:3079-3086.
[36] S. L.Veatch and S. L. Keller (2005). P.R.L. 94:148101-148104.
[37] S. L. Veatch et al (2004). B.J. 86:2910-2922.
[38] M. R. Ali et al (2006). Biochem. 45:12629-12638.
[39] G. Lindblom et al (1981). Biochem. 17:2464-2468. |