Conformation of a synthetic antigenic peptide from HIV-1 p24 protein induced by ionic micelles.
We studied the interaction of the peptide AAMQMLKETINEEAAEWDRVHPVHAGPIA from the HIV-1 p24 protein in the presence of SDS (anionic) and CTABr (cationic) micelles at pH 7.0 by circular dichroism, fluorescence, and electron spin resonance (ESR). The micelles induced secondary structure as well as a blue shift in the tryptophan fluorescence emission, indicating an interaction between the peptide and the micelles. However, different contents of secondary structure elements were found when the peptide interacts with SDS or CTABr micelles. Steady-state anisotropy indicates a constraint on the rotational mobility of the tryptophan residue of the peptide upon interaction with micelles. ESR studies pointed to different locations for the peptide in either micelle. Our results suggested that at least part of the peptide might be located at the hydrophobic core of the CTABr micelles, probably at the C-terminal region, while it is more inserted into the SDS micelles.
Campana
Patricia T
PT
Departamento de Física e Informática, Instituto de Física de São Carlos, C.P. 369, CEP 13566-970, São Carlos, Brazil.
Beltramini
Leila M
LM
Costa-Filho
Antonio J
AJ
Tonarelli
Georgina
G
Lottersberger
Javier
J
Bianconi
M Lucia
ML
D000595:Amino Acid Sequence; D001665:Binding Sites; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D002942:Circular Dichroism; D004578:Electron Spin Resonance Spectroscopy; D005453:Fluorescence; D016655:HIV Core Protein p24 / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D008823:Micelles; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D014364:Tryptophan / Q000737:chemistry
D002593:Cetrimonium Compounds; D016655:HIV Core Protein p24; D007477:Ions; D008823:Micelles; D010455:Peptides; D012967:Sodium Dodecyl Sulfate; D014364:Tryptophan; D000077286:Cetrimonium