Lipids in Membranes - Membrane Biophysics, Biological and Medical Physics, Biomedical Engineering - page 48

monolayer curvature, and lipid intrinsic curvature profiles. These changes certainly
affect membrane energetics [ 2 , 5 ], with considerable effects on lipid phase properties.
Based on the above research, it is clear that the presence of peptides in membranes
alters lipid phase properties, and it is also clear that the presence of multicompo-
nent peptides may help multiple lipid phases (e.g., inverse hexagonal, cubic, etc.) to
co-exist. This study again confirms the possibility of co-existence of various phases,
not only due to the membrane-forming primary biophysical parameters such as
osmotic pressure, hydration, etc., but also due to other natural or artificial external
agents, such as various peptides. Also, we have found that specific lipid phases may
be due to the effects of certain peptides. In biological membranes, the lipid phase dia-
grams are therefore more complicated than the ones presented earlier in this chapter
or proposed elsewhere so far. Considering the biophysical contributions from all
participating agents that are directly responsible for constructing membranes, and
agents that reside inside membranes, the construction of exact lipid phase diagrams
is yet to be achieved.
References
1. Ashrafuzzaman, Md.: Department of Biochemistry, University of Alberta, unpublished (2007)
2. Ashrafuzzaman, Md., Tuszynski, J.A.: Ion Pore Formation in Membranes due to Complex
Interactions Between Lipids and Antimicrobial Peptides or Biomolecules. In: Goddard, W.,
Brenner, D., Lyshevki, S., Iafrate, G. (eds.) Handbook on Nanoscience, Engineering and Nan-
otechnology. Taylor & Francis Group (in CRC press), Boca Raton (2011)
3. Ashrafuzzaman, Md., McElhaney, R.N., Andersen, O.S.: One antimicrobial peptide (grami-
cidin S) can affect the function of another (gramicidin A or alamethicin) via effects on the
phospholipid bilayer. Biophys. J. 94 , 21a (2008)
4. Ashrafuzzaman, Md., Koeppe, R.E., II, Andersen, O.S.: Lipid bilayer elasticity and intrinsic
curvature as regulators of channel function: a comparative single molecule study. New J. Phys.
(2011) (Accepted)
5. Ashrafuzzaman, Md., Tseng, C.-Y., Tuszynski, J.A.: Chemotherapy drugs form ion pores in
membranes due to phyical interactions with lipids (2011) (Submitted)
6. Gawrisch, K., Parsegian, V.A., Hajduk, D.A., Tate, M.W., Gruner, S.M., Fuller, N.L., Rand,
R.P.: Energetics of a hexagonal-lamellarhexagonal transition sequence in dioleoylphos-
phatidylethanolaminemembranes. Biochemistry 31 , 2856-2864 (1992)
7. Gruner, S.M.: Intrinsic curvature hypothesis for biomembrane lipid composition: a role for
nonbilayer lipids. Proc. Natl. Acad. Sci. USA 82 , 3665-3669 (1983)
8. Hinz, H.-J., Kuttenreich, H., Meyer, R., Renner, M., Frund, R., Koynova, R., Boyanov, A.I.,
Tenchov, B.G.: Stereochemistry and size of supar headgroups determine structure and phase
behavior of glycolipidmembranes: densitometric, calorimetric andX-ray studies. Biochemistry
30 , 5125-5138 (1991)
9. Israelachvili, J.N., Marcelja, S., Horn, R.G.: Physical principles of membrane organization.
Q. Rev. Biophys. 13 , 121-200 (1980)
10. Jain, M.: Introduction to Biological Membranes, 2nd ed. Wiley, New York (1988)
11. Keller, S.L., Gruner, S.M., Gawrisch, K.: Small concentrations of alamethicin induce a cubic
phase in bulk phosphatidylethanolamine mixtures. Biochim. Biophys. Acta 1127 , 241-246
(1996)
12. Killian, J.A., de Kruijff, B.: The influence of proteins and peptides on the phase properties of
lipids. Chem. Phys. Lipids 40 , 259-284 (1986)