Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 932–941 |
| Number of pages | 10 |
| Journal | BBA Biomembranes |
| Volume | 1848 |
| Issue number | 4 |
| Early online date | 29 Dec 2014 |
| DOIs | |
| Publication status | Published - Apr 2015 |
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Channel-forming activity of syringomycin E in two mercury-supported biomimetic membranes. / Becucci, Lucia; Tramonti, Vania; Fiore, Alberto; Fogliano, Vincenzo; Scanloni, Andrea; Guidelli, Rolando.
In: BBA Biomembranes, Vol. 1848, No. 4, 04.2015, p. 932–941.Research output: Contribution to journal › Article
TY - JOUR
T1 - Channel-forming activity of syringomycin E in two mercury-supported biomimetic membranes
AU - Becucci, Lucia
AU - Tramonti, Vania
AU - Fiore, Alberto
AU - Fogliano, Vincenzo
AU - Scanloni, Andrea
AU - Guidelli, Rolando
PY - 2015/4
Y1 - 2015/4
N2 - The lipodepsipeptide syringomycin E (SR-E) interacts with two mercury-supported biomimetic membranes, which consist of a self-assembled phospholipid monolayer (SAM) and of a tethered bilayer lipid membrane (tBLM) separated from the mercury surface by a hydrophilic tetraethyleneoxy (TEO) spacer that acts as an ionic reservoir. SR-E interacts more rapidly and effectively with a SAM of dioleoylphosphatidylserine (DOPS) than with one of dioleoylphosphatidylcholine (DOPC). The proximal lipid monolayer of the tBLM has no polar head region, being linked to the TEO spacer via an ether bond, while the distal monolayer consists of either a DOPC or a DOPS leaflet. The ion flow into or out of the spacer through the lipid bilayer moiety of the tBLM was monitored by potential step chronocoulometry and cyclic voltammetry. With the distal monolayer bathed by aqueous 0.1 M KCl and 0.8 μM SR-E, an ion flow in two stages was monitored with DOPC at pH 3 and 5.4 and with DOPS at pH 3, while a single stage was observed with DOPS at pH 5.4. This behavior was compared with that already described at conventional bilayer lipid membranes. The sigmoidal shape of the chronocoulometric charge transients points to an aggregation of SR-E monomers forming an ion channel via a mechanism of nucleation and growth. The ion flow is mainly determined by potassium ions, and is inhibited by calcium ions. The contribution to the transmembrane potential from the distal leaflet depends more on the nature of the lipid than that of the ion channel.
AB - The lipodepsipeptide syringomycin E (SR-E) interacts with two mercury-supported biomimetic membranes, which consist of a self-assembled phospholipid monolayer (SAM) and of a tethered bilayer lipid membrane (tBLM) separated from the mercury surface by a hydrophilic tetraethyleneoxy (TEO) spacer that acts as an ionic reservoir. SR-E interacts more rapidly and effectively with a SAM of dioleoylphosphatidylserine (DOPS) than with one of dioleoylphosphatidylcholine (DOPC). The proximal lipid monolayer of the tBLM has no polar head region, being linked to the TEO spacer via an ether bond, while the distal monolayer consists of either a DOPC or a DOPS leaflet. The ion flow into or out of the spacer through the lipid bilayer moiety of the tBLM was monitored by potential step chronocoulometry and cyclic voltammetry. With the distal monolayer bathed by aqueous 0.1 M KCl and 0.8 μM SR-E, an ion flow in two stages was monitored with DOPC at pH 3 and 5.4 and with DOPS at pH 3, while a single stage was observed with DOPS at pH 5.4. This behavior was compared with that already described at conventional bilayer lipid membranes. The sigmoidal shape of the chronocoulometric charge transients points to an aggregation of SR-E monomers forming an ion channel via a mechanism of nucleation and growth. The ion flow is mainly determined by potassium ions, and is inhibited by calcium ions. The contribution to the transmembrane potential from the distal leaflet depends more on the nature of the lipid than that of the ion channel.
U2 - 10.1016/j.bbamem.2014.12.007
DO - 10.1016/j.bbamem.2014.12.007
M3 - Article
VL - 1848
SP - 932
EP - 941
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 4
ER -