Conformations of bombolitins I and III in aqueous solutions: circular dichroism, 1H NMR, and computer simulation studies

dc.contributor.authorBairaktari, E.en
dc.contributor.authorMierke, D. F.en
dc.contributor.authorMammi, S.en
dc.contributor.authorPeggion, E.en
dc.date.accessioned2015-11-24T19:27:47Z
dc.date.available2015-11-24T19:27:47Z
dc.identifier.issn0006-2960-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/22844
dc.rightsDefault Licence-
dc.subjectAmino Acid Sequenceen
dc.subjectCircular Dichroismen
dc.subjectMagnetic Resonance Spectroscopyen
dc.subjectMolecular Conformationen
dc.subjectMolecular Sequence Dataen
dc.subjectPeptides/*chemistryen
dc.subjectSolutionsen
dc.subjectWateren
dc.titleConformations of bombolitins I and III in aqueous solutions: circular dichroism, 1H NMR, and computer simulation studiesen
heal.abstractThe heptadecapeptides bombolitin I and bombolitin III are two of a series of peptides postulated to be biologically active within a membrane environment. In the preceding paper [Bairaktari, E., Mierke, D.F., Mammi, S., & Peggion, E. (1990) Biochemistry (preceding paper in this issue)] the conformational preferences of these peptides in the presence of SDS surfactant micelles, a mimetic for biological membranes, were examined. During these studies the conformations of these peptides were investigated in aqueous solutions by circular dichroism and nuclear magnetic resonance. A large difference was observed for the two peptides. Bombolitin I lacks any observable secondary structure in aqueous solution, independent of temperature, pH, and concentration. In striking contrast, bombolitin III adopts a well-defined alpha-helix at concentrations greater than 1.3 mM. This is indeed surprising given the great similarity of the two peptides. The alpha-helix of bombolitin III is pH dependent, with a great decrease in the observed secondary structure at pH values below 3.5. This observation could only be due to the protonation of the Asp residue at the fifth position. These findings suggest that the secondary structure arises from molecular aggregation of bombolitin III through the formation of a salt bridge involving the Asp side chain. The alpha-helix observed at "high" concentration (greater than 2.5 mM) has been characterized by CD and by the NOE's measured throughout a majority of the peptide. The experimentally determined structure has been energy refined with restrained molecular dynamics. The conformational results from this study are then compared with the conformations found in the presence of surfactant micelles.en
heal.accesscampus-
heal.fullTextAvailabilityTRUE-
heal.identifier.secondaryhttp://www.ncbi.nlm.nih.gov/pubmed/2271640-
heal.identifier.secondaryhttp://pubs.acs.org/doi/pdf/10.1021/bi00495a012-
heal.journalNameBiochemistryen
heal.journalTypepeer-reviewed-
heal.languageen-
heal.publicationDate1990-
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικήςel
heal.typejournalArticle-
heal.type.elΆρθρο Περιοδικούel
heal.type.enJournal articleen

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