| 18688484 |
You L, Li R, Gokel GW: Anion transport properties of amine and amide-sidechained peptides are affected by charge and phospholipid composition. Org Biomol Chem. 2008 Aug 21;6(16):2914-23. Epub 2008 Jun 16.
Four synthetic anion transporters (SATs) having the general formula (n-C (18) H (37))(2) N-COCH (2) OCH (2) CO-(Gly)(3) Pro-Lys (epsilon-N-R)-(Gly)(2)-O -n-C (7) H (15) were prepared and studied. The group R was Cbz, H (TFA salt), t-Boc, and dansyl in peptides 1, 2, 3, and 4 respectively. The glutamine analog (GGGPQAG sequence) was also included. A dansyl-substituted fluorescent SAT was used to probe peptide insertion; the dansyl sidechain resides in an environment near the bilayer's midpolar regime. When the lysine sidechain was free or protected amine, little effect was noted on final Cl (-) transport rate in DOPC : DOPA (7 : 3) liposomes. This stands in contrast to the significant retardation of transport previously observed when a negative glutamate residue was present in the peptide sequence. It was also found that Cl (-) release from liposomes depended on the phospholipid composition of the vesicles. Chloride transport diminished significantly for the free lysine containing SAT, 2, when the lipid was altered from DOPC : DOPA to pure DOPC. Amide-sidechained SATs 1 and 5 showed a relatively small decrease in Cl (-) transport. The effect of lipid composition on Cl (-) transport was explained by differences in electrostatic interaction between amino acid sidechain and lipid headgroup, which was modeled by computation. |
1(0,0,0,1) |