6 Dendritic Dipeptides as Aquaporin Transmembrane
Protein Mimics
Aquaporin (AQP) is an hour-glass transmembrane channel that mediates the transport of water through biological membranes [112]. AQP transports water with
100% selectivity at a rate of 3 Â 10
9 molecules of water per second per channel.
No protons, protonated water, or other ionic species pass through AQP. A primitive
mimic of AQP was accomplished by attaching homochiral Tyr-Ala dipeptide
containing a diversity of protecting groups at the dendron apex [113].
Figure 11 outlines the structure of the homochiral enantiomers of the dendritic
dipeptide, the CD and UV spectra as a function of temperature recorded in cyclohexane (a solvent that mimics the hydrophobic wall of the biological membrane and
mediates self-assembly), and the structures of the supramolecular assemblies
Fig. 10 The irreversible intramolecular electrocyclization of cis-transoidal polyphenylacetylene
(a) taking place during the helix–coil transition of the polymer (b), its elimination by encapsulation of the polymer in a cylindrical supramolecular polymer and the transformation of the
helix–coil into a helix–helix transition (c)
188
V. Percec
Protein Mimics
Aquaporin (AQP) is an hour-glass transmembrane channel that mediates the transport of water through biological membranes [112]. AQP transports water with
100% selectivity at a rate of 3 Â 10
9 molecules of water per second per channel.
No protons, protonated water, or other ionic species pass through AQP. A primitive
mimic of AQP was accomplished by attaching homochiral Tyr-Ala dipeptide
containing a diversity of protecting groups at the dendron apex [113].
Figure 11 outlines the structure of the homochiral enantiomers of the dendritic
dipeptide, the CD and UV spectra as a function of temperature recorded in cyclohexane (a solvent that mimics the hydrophobic wall of the biological membrane and
mediates self-assembly), and the structures of the supramolecular assemblies
Fig. 10 The irreversible intramolecular electrocyclization of cis-transoidal polyphenylacetylene
(a) taking place during the helix–coil transition of the polymer (b), its elimination by encapsulation of the polymer in a cylindrical supramolecular polymer and the transformation of the
helix–coil into a helix–helix transition (c)
188
V. Percec