Ca2+ binding cyclic octapeptides having an alternating sar and a hydrophobic amino acid in the sequence
✍ Scribed by Shunsaku Kimura; Eiichi Ozeki; Yukio Imanishi
- Book ID
- 102763508
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1989
- Tongue
- English
- Weight
- 556 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
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] (CBKE), and cyclo[Lys(Suc)-Sar-~u-Sar-~u-Sar-Leu-Sar] [CBK(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 Ca" across the lipid bilayer membrane above the phase-transition temperature, while C8KE and C8K(Suc)L did not. Therefore, thc transport of Ca2' through the lipid bilayer membrane is very sensitive to the hydrophobicity of the carrier molecule.