Gramicidin channel kinetics under tension.
We have measured the effect of tension on dimerization kinetics of the channel-forming peptide gramicidin A. By aspirating large unilamellar vesicles into a micropipette electrode, we are able to simultaneously monitor membrane tension and electrical activity. We find that the dimer formation rate increases by a factor of 5 as tension ranges from 0 to 4 dyn/cm. The dimer lifetime also increases with tension. This behavior is well described by a phenomenological model of membrane elasticity in which tension modulates the mismatch in thickness between the gramicidin dimer and membrane.
Goulian
M
M
Center for Studies in Physics and Biology, Rockefeller University, New York, New York 10021, USA. goulian@menard.rockefeller.edu
Mesquita
O N
ON
Fygenson
D K
DK
Nielsen
C
C
Andersen
O S
OS
Libchaber
A
A
D019281:Dimerization; D004563:Electrochemistry; D006096:Gramicidin / Q000031:analogs & derivatives / Q000737:chemistry*; D007473:Ion Channels / Q000737:chemistry* / Q000502:physiology; D008051:Lipid Bilayers; D008954:Models, Biological; D008958:Models, Molecular; D018408:Patch-Clamp Techniques / Q000295:instrumentation; D010713:Phosphatidylcholines / Q000737:chemistry; D011336:Probability; D013314:Stress, Mechanical; D013816:Thermodynamics
D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D006096:Gramicidin; C017251:1,2-oleoylphosphatidylcholine