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Conformational transitions of leucine‐containing isomeric sequential basic polytripeptides
Author(s) -
Štokrová Štěpánka,
Bohdanecký Miloslav,
Bláha Karel,
Šponar Jaroslav
Publication year - 1989
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.360281007
Subject(s) - chemistry , aqueous solution , salt (chemistry) , leucine , sedimentation equilibrium , stereochemistry , helix (gastropod) , crystallography , amino acid , biochemistry , organic chemistry , ultracentrifuge , ecology , snail , biology
Conformational transitions of basic sequential polytripeptides (Lys‐Ala‐Leu) n , (Arg‐Ala‐Ala) n , (Arg‐Leu‐Ala) n , and (Arg‐Ala‐Leu) n , induced by elevated salt concentrations and/or temperatures in aqueous solutions, were investigated by CD, sedimentation equilibrium, and viscometry. The behavior of (Lys‐Ala‐Leu) n was compared with that of the sequential isomer (Lys‐Leu‐Ala) n , studied previously. It was found that both polypeptides are highly helical with a tendency to aggregate in high salt solutions. Although the hydrophobic interactions between Lys and Leu residues play an important role in both cases, the final effect on helix stabilization and aggregation is different. The Arg‐containing polypeptides were found to assume the α‐helical conformation. Compared to the Lys‐containing polypeptides (Lys‐Ala‐Leu) n and (Lys‐Leu‐Ala) n , a very low tendency to aggregate was observed.