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Conformational structure of the tetrapeptide Boc–Aib–Leu–Leu–Aib–OMe–the central fragment of the nonapeptide antibiotic leucinostatin A
Author(s) -
Nandel Fateh S.,
Singh Balvinder,
Saran Anil
Publication year - 1992
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560420606
Subject(s) - tetrapeptide , chemistry , intramolecular force , hydrogen bond , side chain , stereochemistry , bilayer , helix (gastropod) , peptide , crystallography , membrane , molecule , organic chemistry , biochemistry , ecology , snail , biology , polymer
The conformational structure of the tetrapeptide Boc–Aib–Leu–Leu–Aib–OMe has been investigated by the PCILO method. The computational results show the formation of two closed β‐turns, both of which are of type III, and the peptide backbone folds into a right‐handed 3 10 ‐helical conformation stabilized by two intramolecular 4 → 1 hydrogen bonds. The helix thus formed generates a pore of ∼3 Å along helix axis with hydrophobic amino acid side chains located on the outside of the helix, and this tendency of leucine side chains may enable leucinostatin A to fit into the membrane bilayer. The pore thus formed is cation‐selective, and through this pore, the cation can pass only in a single file.