Brack A, Caille A. Synthesis and beta-conformation of copolypeptides with alternating hydrophilic and hydrophobic residues.
INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1978;
11:128-39. [PMID:
640771 DOI:
10.1111/j.1399-3011.1978.tb02831.x]
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Abstract
Copolypeptides with alternating hydrophilic and hydrophobic residues were prepared, and their ability to form beta-structures in aqueous solutions was investigated by circular dichroism. Optically pure samples of poly (Lys-Leu-Lys-Leu) and poly (Leu-Glu-Leu-Glu), obtained via the 2-hydroxyphenyl esters, undergo a coil-to-beta transition in presence of salt. The beta-structures obtained under identical conditions with partially racemized samples of poly (Leu-Lys)Np and poly (Leu-Glu)Np, prepared by polycondensation of the corresponding dipeptide p-nitrophenyl esters, appear to be less regular. Non-alternating poly (Gly-Lys-Leu-Lys-Leu) does not form beta-structures in presence of NaCl as does alternating poly (Lys-Leu-Lys-Leu) indicating that the amino acid sequence can dramatically change the tendency to form beta-structures.
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