Ca2+ binding cyclic octapeptides having an alternating Sar and a hydrophobic amino acid in the sequence.
Cyclic octapeptides having alternating Sar and hydrophobic amino acid sequences, such as cyclo[Lys(Z)-Sar-Leu-Sar-Leu-Sar-Leu-Sar] (C8KL), cyclo[Glu(OMe)-Sar-Lys(Z)-Sar-Leu-Sar-Leu-Sar] (C8KE, and cyclo[Lys(Suc)-Sar-Leu-Sar-Leu-Sar-Leu-Sar] [C8K(Suc)L, Suc represents succinic acid], were synthesized. These cyclic octapeptides formed a complex selectively with Ca2+. Upon complexation, trans peptide bonds of Sar residues were isomerized to cis peptide bonds. C8KL and C8KE showed very similar characteristics of Ca2+ binding, extraction of Ca2+ from an aqueous solution to a chloroform solution, and Ca2+ transport through a liquid chloroform membrane. C8KL transported Ca2+ across the lipid bilayer membrane above the phase-transition temperature, while C8KE and C8K(Suc)L did not. Therefore, the transport of Ca2+ through the lipid bilayer membrane is very sensitive to the hydrophobicity of the carrier molecule.
Kimura
S
S
Ozeki
E
E
Imanishi
Y
Y
D000595:Amino Acid Sequence; D002118:Calcium; D008969:Molecular Sequence Data; D009842:Oligopeptides; D010456:Peptides, Cyclic; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
D009842:Oligopeptides; D010456:Peptides, Cyclic; D002118:Calcium