title: Interaction of cyclic and linear Labaditin peptides with anionic and zwitterionic micelles.
abstract: Conformational changes of the cyclic (Lo) peptide Labaditin (VWTVWGTIAG) and its linear analogue (L1) promoted by presence of anionic sodium dodecyl sulfate (SDS) and zwitterionic L-α-Lysophosphatidylcholine (LPC) micelles were investigated. Results from λ(max) blue-shift of tryptophan fluorescence emission combined with Stern-Volmer constants values and molecular dynamics (MD) simulations indicated that L1 interacts with SDS micelles to a higher extent than does Lo. Further, the MD simulation demonstrated that both Lo and L1 interact similarly with LPC micelles, being preferentially located at the micelle/water interface. The peptide-micelle interaction elicits conformational changes in the peptides. Lo undergoes limited modifications and presents unordered structure in both LPC and SDS micelles. On the other hand, L1 displays a random-coil structure in aqueous medium, pH 7.0, and it acquires a β-structure upon interaction with SDS and LPC, albeit with structural differences in each medium.
authors.affiliation: Departamento de Química, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: S C
authors.initials: SC
authors.lastname: Barbosa
authors.affiliation: Departamento de Bioquímica e Biotecnologia, IQ-UNESP-Univ. Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: E M
authors.initials: EM
authors.lastname: Cilli
authors.affiliation: Departamento de Química, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: L G
authors.initials: LG
authors.lastname: Dias
authors.affiliation: Departamento de Química, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: C A
authors.initials: CA
authors.lastname: Fuzo
authors.affiliation: Departamento de Química, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Degrève
authors.affiliation: Centro de Estudos de Biomoléculas Aplicadas a Medicina (CEBio), Núcleo de Saúde (NUSAU), Universidade Federal de Rondônia (UNIR), Fundação Oswaldo Cruz - Fundação Oswaldo Cruz - Rondônia (FIOCRUZ), 76812-245 Porto Velho, RO, Brazil.
authors.forename: R G
authors.initials: RG
authors.lastname: Stabeli
authors.affiliation: Departamento de Física Aplicada, Instituto de Física, IF-USP, São Paulo, SP, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Itri
authors.affiliation: Departamento de Química, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil. Electronic address: pietro@ffclrp.usp.br.
authors.forename: P
authors.initials: P
authors.lastname: Ciancaglini
mesh_terms: D000838:Anions / Q000737:chemistry; D002942:Circular Dichroism; D008823:Micelles; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: D000838:Anions; D008823:Micelles; D010455:Peptides; D010456:Peptides, Cyclic
keywords: Circular dichroism; Cyclic peptide; Fluorescence; Labaditin; Molecular dynamic