A single-channel sensor based on gramicidin controlled by molecular recognition at bilayer lipid membranes containing receptor.
A novel ion-channel sensor based on a membrane bound receptor and a single gramicidin channel is described, in which the binding of an analyte to the membrane bound receptor modulates the single-channel activity of gramicidin. The sensor is composed of a planar bilayer lipid membrane (BLM) containing biotin-labeled phosphatidylethanolamine as receptor for avidin and gramicidin as signal transducer. When the receptor catches an analyte (avidin or ferritin-labeled avidin (FA)) at the membrane surface, the bilayer structure is locally distorted and the gramicidin monomer/dimer kinetics is modulated in a manner that the fraction of channel opening with a short lifetime ( < or = 100 ms) to the total opening events increases. The fraction was found to increase with the concentration of avidin from 1.0 x 10(-9) to 1.0 x 10(-6) M and of FA from 1.0 x 10(-9) to 1.0 x 10(-8) M. With dinitrophenyl-labeled PE embedded as receptor in the BLM for monoclonal anti-dinitrophenyl antibody (anti-DNP), the fraction of channel openings ( < or = 100 ms) increased with the concentration of anti-DNP from 2.0 x 10(-9) to 2.0 x 10(-7) g/ml. Bovine serum albumin (BSA) and anti-BSA antibody caused no changes in the channel opening. The possible mechanism of analyte-induced modulation of single-channel activity of gramicidin is also discussed.
Hirano
Ayumi
A
Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
Wakabayashi
Masaki
M
Matsuno
Yuka
Y
Sugawara
Masao
M
D001360:Avidin / Q000032:analysis* / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D006096:Gramicidin / Q000737:chemistry*; D015640:Ion Channel Gating; D008051:Lipid Bilayers / Q000737:chemistry*; D008564:Membrane Potentials; D008567:Membranes, Artificial; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D008051:Lipid Bilayers; D008567:Membranes, Artificial; D001360:Avidin; D006096:Gramicidin