BINDING OF PEPTIDE-FRAGMENTS FROM A 7 HELIX MEMBRANE-RECEPTOR TO LIPID BILAYERS AND TO MICELLES

BINDING OF PEPTIDE-FRAGMENTS FROM A 7 HELIX MEMBRANE-RECEPTOR TO LIPID BILAYERS AND TO MICELLES

Author Pertinhezsini, T. A. Google Scholar
Nakaie, Clovis Ryuichi Autor UNIFESP Google Scholar
Carvalho, Regina Siqueira Haddad Autor UNIFESP Google Scholar
Paiva, Antonio Cechelli de Mattos Autor UNIFESP Google Scholar
Tabak, M. Google Scholar
Toma, F. Google Scholar
Schreier, Shirley Autor UNIFESP Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
CEA
Abstract Membrane proteins influence the organizational and motional properties of lipids,while the conformation and function of these proteins (receptors, channels, enzymes, pumps) are affected by the lipid environment. Model systems consisting of peptides and lipids can provide information at a molecular level about the interactions between proteins and lipids in biological membranes. We have synthesized peptides (residues 253-266 (EYWSTFGNLHHISL) from the seven-helix receptor expressed by the mas oncogene),having free or blocked N- and C-terminals. An analog was obtained by linking a spin-labeled amino acid to the N-terminal via a peptide bond. Several spectroscopic techniques were employed to study the interaction between the peptides and lipophilic systems (zwitterionic and negatively charged phospholipid bilayers,and negatively charged,positively charged, zwitterionic and nonionic micelles). Peptide conformational changes were monitored by circular dichroism (CD). The peptides acquired an increased secondary structure upon binding to the lipid systems. Additional evidence for peptide incorporation into micelles came from fluorescence measurements which indicated a blue shift of the tryptophan's emission wavelength,and from ESR spectra of the spin-labeled analog. While narrow lines were obtained in the aqueous phase, line broadening indicative of slower motion was observed in the presence of the lipophilic aggregates. The slow exchange between the two media allowed the evaluation of partition coefficients. The spectra in aqueous solution were also sensitive to conformational changes
Keywords PEPTIDE-BILAYER INTERACTION
MAS ONCOGENE PROTEIN
LIPID BILAYER
MICELLE
ELECTRON SPIN RESONANCE
FLUORESCENCE
CIRCULAR DICHROISM
Language English
Date 1994-02-01
Published in Brazilian Journal Of Medical And Biological Research. Sao Paulo: Assoc Bras Divulg Cientifica, v. 27, n. 2, p. 535-540, 1994.
ISSN 0100-879X (Sherpa/Romeo, impact factor)
Publisher Assoc Bras Divulg Cientifica
Extent 535-540
Access rights Closed access
Type Article
Web of Science ID WOS:A1994MX60900066
URI http://repositorio.unifesp.br/11600/43056

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