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dc.contributor.authorKodona, E. K.en
dc.contributor.authorAlexopoulos, C.en
dc.contributor.authorPanou-Pomonis, E.en
dc.contributor.authorPomonis, P. J.en
dc.rightsDefault Licence-
dc.subjectordered micellar aggregatesen
dc.subjectpoly-l-glutamic aciden
dc.subjectpoly-d-glutamic aciden
dc.subjectthermal stabilityen
dc.subjectmesoporous silicaen
dc.subjectamphipathic peptidesen
dc.subjectracemic mixturesen
dc.titleChirality and helix stability of polyglutamic acid enantiomersen
heal.type.enJournal articleen
heal.type.elΆρθρο Περιοδικούel
heal.identifier.primaryDOI 10.1016/j.jcis.2007.10.063-
heal.identifier.secondary<Go to ISI>://000252750400011-
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείαςel
heal.abstractIn this work the chirality and the relative thermal stability of ordered micellar aggregates of poly-L- and poly-D-glutamic acids with the cationic surfactant C(14)TAB is examined. The complexed mesophases poly-L-Glu/C(14)TAB and poly-D-Glu/C-14 TAB were characterized by circular dichroism (CD) in the temperature range 10-70 degrees C for their chirality and thermal stability as well as by X-ray diffraction (XRD) for the micellar ordered structure. Low angle XRD analysis showed that both micellar aggregates poly-L-Glu/C(14)TAB and poly-D-Glu/C(14)TAB are hexagonally packed in a MCM-41 fashion with an intermicellar distance identical and equal to 3.55 +/- 0.10 nm. The CID spectra indicated that both complexes poly-L-Glu/C(14)TAB and poly-D-Glu/C(14)TAB possess a mainly alpha-helix structure and are exact mirror images to each other. The same mirror images and a mainly a-helix configuration were also observed by CID for the free poly-L- and poly-D-glutamic acids at room temperature. As the temperature increases from 10 up to 70 degrees C the ce-helix of the poly-L-glutamic acid is gradually transformed to a mixture containing increased amounts of the 3(10)-helix while the alpha-helix structure of the poly-D-glutamic acid is constantly degenerated. In contrast the alpha-helices of the corresponding complexes poly-L-Glu/C(14)TAB and poly-D-Glu/C(14)TAB are degenerated upon heating without appreciable increase of the 3(10)-helices as an intermediate configuration. This difference in helix conservation is attributed to increase protection of the L-enantiomers, compared to D-enantiomers, which might be related to the survival of L-aminoacids in the living world. (c) 2007 Elsevier Inc. All rights reserved.en
heal.journalNameJ Colloid Interface Scien
heal.journalTypepeer reviewed-
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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