title: A novel technique to study pore-forming peptides in a natural membrane.
abstract: The biophysical characteristics and the pore formation dynamics of synthetic or naturally occurring peptides forming membrane-spanning channels were investigated by using isolated photoreceptor rod outer segments (OS) recorded in whole-cell configuration. Once blocking the two OS endogenous conductances (the cGMP channels by light and the Na(+):Ca(2+),K(+) exchanger by removing one of the transported ion species from both sides of the membrane, i.e. K(+), Na(+) or Ca(2+)), the OS membrane resistance (R ( m )) was typically larger than 1 GOmega in the presence of 1 mM external Ca(2+). Therefore, any exogenous current could be studied down to the single channel level. The peptides were applied to (and removed from) the extracellular OS side in approximately 50 ms with a computer-controlled microperfusion system, in which every perfusion parameter, as the rate of solution flow, the temporal sequence of solution changes or the number of automatic, self-washing cycles were controlled by a user-friendly interface. This technique was then used to determine the biophysical properties and the pore formation dynamics of antibiotic peptaibols, as the native alamethicin mixture, the synthesized major component of the neutral fraction (F50/5) of alamethicin, and the synthetic trichogin GA IV.
authors: CNISM, Dipartimento di Biologia ed Evoluzione, Sezione di Fisiologia e Biofisica and Centro di Neuroscienze, Università di Ferrara, via Borsari 46, Ferrara, Italy.
authors: Natascia
authors: N
authors: Vedovato
authors: Giorgio
authors: G
authors: Rispoli
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000502:physiology; D007473:Ion Channels / Q000502:physiology*; D017136:Ion Transport / Q000502:physiology; D008027:Light; D010455:Peptides / Q000737:chemistry* / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D011893:Rana esculenta / Q000502:physiology*; D012374:Rod Cell Outer Segment / Q000502:physiology*; D012964:Sodium / Q000378:metabolism
chemical_list: D007473:Ion Channels; D010455:Peptides; D012964:Sodium; D006152:Cyclic GMP; D011188:Potassium; D002118:Calcium
references: Biopolymers. 2004;76(6):485-93
references: 15499566
references: Cell Biochem Biophys. 2002;36(1):89-101
references: 11939373
references: Biochemistry. 2000 Oct 3;39(39):11855-64
references: 11009597
references: FEBS Lett. 2003 Sep 18;552(1):28-34
references: 12972148
references: Biochim Biophys Acta. 2000 Mar 15;1464(1):69-82
references: 10704921
references: Curr Opin Struct Biol. 2006 Aug;16(4):473-9
references: 16828281
references: Biophys J. 2003 Sep;85(3):1647-55
references: 12944279
references: Biophys J. 1995 Jul;69(1):74-83
references: 7669912
references: Biochim Biophys Acta. 2002 Aug 31;1564(2):359-64
references: 12175918
references: Mini Rev Med Chem. 2002 Aug;2(4):331-42
references: 12370054
references: J Membr Biol. 1974;19(3):277-303
references: 4475108
references: Biophys J. 2005 May;88(5):3411-21
references: 15722429
references: Eur J Biochem. 2001 Mar;268(6):1659-69
references: 11248685
references: J Pept Sci. 2003 Nov-Dec;9(11-12):679-89
references: 14658789
references: Photochem Photobiol Sci. 2003 Dec;2(12):1292-8
references: 14717223
references: J Membr Biol. 1973 Dec 31;14(2):143-76
references: 4774545
references: J Physiol. 1993 Jun;465:513-37
references: 8229848
references: Adv Virus Res. 1995;45:61-112
references: 7793329
references: J Photochem Photobiol B. 1998 Jun 15;44(1):1-20
references: 9745724
references: Cell Mol Life Sci. 2001 Aug;58(9):1179-88
references: 11577977