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Manipulation of peptide conformations by fine‐tuning of the environment and/or the primary sequence
Author(s) -
Li ShunCheng,
Kim Peter K.,
Deber Charles M.
Publication year - 1995
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360350612
Subject(s) - chemistry , peptide , sequence (biology) , peptide sequence , protein secondary structure , vesicle , folding (dsp implementation) , micelle , monomer , protein primary structure , phosphatidylcholine , phospholipid , stereochemistry , amino acid , crystallography , aqueous solution , biochemistry , organic chemistry , membrane , electrical engineering , gene , engineering , polymer
The widely observed phenomenon that peptides are capable of adopting multiple conformations in different environments suggests that secondary structure formation in a peptide segment is a process involving not only the peptide itself hut also the surrounding solvent media. The influence of the primary sequence and the molecular environment on peptide conformations are now investigated using synthetic peptides of amino acid sequence H 2 N‐(Ser‐Lys) 2 ‐Ala‐X‐Gly‐Ala‐X‐Gly‐Trp‐Ala‐X‐Gly‐(Lys‐Ser) 3 ‐OH, where X = Ile or Val. These two peptides, namely 3I (X = Ile) and 3V (X = Val), are found to lack defined secondary structure in aqueous buffer. However, discrete conformational states, e.g., α‐helices and β‐sheets, are readily generated and interconverted for both peptides when the buffer is modulated with the addition of methanol, sodium dodecyl sulfate (SDS) micelles, or phospholipid vesicles. The role of the primary sequence in affecting peptide conformations is manifested in that peptides 3I and 3V, which differ respectively in their content of β‐branched Ile or Val residues, differ in their secondary structures at monomeric concentrations in 2 mM SDS and in mixed lipid vesicles of phosphatidic acid and phosphatidylcholine. The overall results suggest that peptide segments can be conformationally flexible entities poised to react to minor modulations in cither the molecular environment or the primary sequence, a circumstance that may he relevant to protein functioning and folding. © 1995 John Wiley & Sons, Inc.