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Electromigration behavior of poly‐( L ‐glutamate) conformers in concentrated polyacrylamide gels
Author(s) -
Dolník Vladislav,
Novotny Milos,
Chmelík Josef
Publication year - 1993
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.360330814
Subject(s) - chemistry , helix (gastropod) , electrophoresis , crystallography , electropherogram , electrolyte , stereochemistry , chromatography , ecology , electrode , snail , biology
During electrophoretic separation of anionic polyamino acids, resolution according to the number of peptide units can be achieved in capillaries filled with hydrophilic gels. While polyaspartate preparations yield single peaks for the individual oligomers at pH above 8.0, polyglutamates exhibit an anomalous behavior of peak splitting, which is attributed here to the separation of the oligopeptide conformers. An Asp‐Glu (1:1) copolymer yields single peaks under similar conditions. At pH near 4.5, where polyglutamate is expected to exist in its α‐helix form, peak splitting disappears. Upon heating to 95°C for at least 120 h (procedure described to transform the α‐helix into a β form), peak splitting disappeared, but could be reestablished after cooling for several days. When a highly charged cation spermine was added to the operational electrolyte, triple peaks appeared in the electropherogram due to the ion‐pair formation. The largest peak in every triplet has been tentatively assigned to the α‐helix form. The electrophoretic results described have been largely supported by CD spectra. © 1993 John Wiley & Sons, Inc.