Gramicidin
Family:
Non-ribosomally Synthesized Channels
Description:
Gramicidin is a heterogeneous mixture of three antibiotic compounds, gramicidins A, B and C, making up 80%, 6%, and 14%, respectively, all of which are obtained from the soil bacterial species Bacillus brevis and called collectively gramicidin D.
Topology:
Gramicidin is a polypeptide. The chain assembles inside of the hydrophobic interior of the cellular lipid bilayer to form a β-helix. The helix itself is not long enough to span the membrane, but it dimerizes to form the elongated channel needed to span the whole membrane.
Function:
Gramicidin's bactericidal activity is a result of increasing the permeability of the bacterial cell membrane, allowing inorganic monovalent cations (e.g. Na+) to travel through unrestricted and thereby destroying the ion gradient between the cytoplasm and the extracellular environment.
Webinars
27.01.2016 | Webinar: Instant bilayers - just add protein
Orbit 16 and 
Orbit Mini
This webinar covers the use of the lipid bilayer platforms from Nanion: the Orbit16 and the Orbit mini for characterization of membrane proteins like ion channels, bacterial porins and biological nanopores. Both bilayer systems support high quality low noise recordings, but differ in throughput capabilities and experimental features. The Orbit16, introduced in 2012 is a device for efficient formation of 16 lipid bilayers simultaneously, allowing for parallel bilayer-reconstitution of ion channels and nanopores.
Data and Applications
Gramicidin - Rapid Internal Solution Exchange
Port-a-Patch and 
Vesicle Prep Pro data and applications:
Switching of internal solutions during gramicidin recordings from a lipid bilayer was obtained within seconds. A lipid bilayer was formed using giant unilamellar vesicles. Currents were recorded at a holding potential of +150 mV. The internal solution was switched from HCl to KCl, resulting in lower channel conductance.
Gramicidin - Ion Channel Forming Antibiotic
Orbit 16 and applications:
Data were kindly provided by Ionera.
Screenshots of a recording window of a typical Gramicidin ion channel forming activity assay on the Orbit 16.
Conditions: symmetrical 0,1 HCl, +150 mV.
Gramicidin - Bilayer Recordings
Patchliner data and applications:
With suction the GUVs are attracted to the aperture. As soon as one GUV hits the glass substrate, it bursts and forms a bilayer across the aperture. Shown are single channel recordings from gramicidin which was incorprated into the bilayer after its formation. Traces were recorded in 100 mM HCl at −100 mV.
Gramicidin - Single Channel Analysis
Port-a-Patch and Vesicle Prep Pro data and applications:
Recordings were kindly supplied by Tohoku University, Tohoku, Japan.
Plotting the current amplitude vs. the voltage reveals conductances of 94.88 pS and 28.28 pS, which correspond to two different gramicidin derivates present in the bilayer. Traces were recorded in 100 mM HCl at the indicated potentials. Clearly two gramicidin derivates (94.88 pS and 28.28 pS) can be distinguished.
Publications
2019 - Real-time monitoring β-lactam/β-lactamase inhibitor (BL/BLI) mixture towards the bacteria porin pathway at single molecule level
Orbit 16 publication in Analytical and Bioanalytical Chemistry (2019)
Authors:
Wang J., Fertig N., Ying Y.L.
2019 - Activity of the Gramicidin A Ion Channel in a Lipid Membrane with Switchable Physical Properties
Orbit 16 publication in Langmuir (2019)
Authors:
Reiter R., Zaitseva E., Baaken G., Halimeh I., Behrends J.C., Zumbuehl A
2018 - The Multifaceted Antibacterial Mechanisms of the Pioneering Peptide Antibiotics Tyrocidine and Gramicidin S
Orbit 16 publication in American Society for Microbiology (2018)
Authors:
Wenzel M., Rautenbach M., Vosloo J.A., Siersma T., Aisenbrey C.H.M., Zaitseva E., Laubscher W.E., van Rensburg W., Behrends J.C., Bechinger B., Hamoen L.W.
2016 - Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
SURFE²R N1 publication in Nature Communications (2016)
Authors:
Li K., Wilkinson C., Kellosalo J., Tsai J., Kajander T, Jeuken L.J.C., Sun Y., Goldman A.
2015 - Automated Formation of Lipid Membrane Microarrays for Ionic Single-Molecule Sensing with Protein Nanopores
Orbit 16 publication in Small (2015)
Authors:
Del Rio Martinez J.M., Zaitseva E., Petersen S., Baaken G., Behrends J.C.
2012 - Natural and artificial ion channels for biosensing platforms
Port-a-Patch, Patchliner, 
SyncroPatch 96 ((a predecessor model of SyncroPatch 384PE) and Vesicle Prep Pro publication in Analytical and Bioanalytical Chemistry (2012)
Authors:
Steller L., Kreir M., Salzer R.
2009 - Measuring Ion Channels on Solid Supported Membranes
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Biophysical Journal (2009)
Authors:
Schulz P., Dueck B., Mourot A., Hatahet L., Fendler K.
2008 - Planar patch clamp: Advances in electrophysiology
Port-a-Patch book chapter in "Potassium Channels" (2008)
Authors:
Brüggemann A., Farre C., Haarmann C., Haythornthwaite A., Kreir M., Stoelzle S., George M., Fertig N.
2003 - Simultaneous optical and electrical recording of single gramicidin channels
Port-a-Patch publication in Biophysical Journal (2003)
Authors:
Borisenko V., Lougheed L., Hesse J., Fuereder-Kitzmueller E., Fertig N., Behrends, J.C., Woolley G.A., Schuetz G.J.