Interaction of adrenocorticotropin-(11-24)-tetradecapeptide with neutral lipid membranes revealed by infrared attenuated total reflection spectroscopy.
Biochemistry
; 23(8): 1808-10, 1984 Apr 10.
Article
em En
| MEDLINE
| ID: mdl-6326811
ABSTRACT
Infrared attenuated total reflection spectroscopy (IR-ATR) revealed that the hydrophilic adrenocorticotropin-(11-24)-tetradecapeptide ( ACTH11 -24, net charge 6+) assumed an irregular secondary structure when incorporated into the aqueous layers between equilibrated multibilayers of planar membranes prepared from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine ( POPC ). This structure was characterized by a perpendicular orientation of the peptide bonds on the bilayer surfaces, as observed earlier for the corresponding segment of adrenocorticotropin-(1-24)-tetracosapeptide (ACTH1-24, 6+). Once incorporated, ACTH11 -24 was not removed by washing, in agreement with its strong positive charge. In contrast to ACTH1-24, ACTH11 -24 was not measurably adsorbed to the neutral membranes from 0.1 mM aqueous solutions. The more hydrophobic adrenocorticotropin-(1-10)-decapeptide is also not adsorbed. We therefore concluded that adsorption of ACTH1-24 to neutral membranes was dependent on its amphiphilic primary (amphipathic primary) structure that resulted from the covalent combination of the hydrophobic ACTH1-10 segment with the hydrophilic ACTH11 -24 segment. This conclusion was consistent with the results obtained by vesicle-mediated hydrophobic photolabeling and equilibrium dialysis.
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Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Fosfatidilcolinas
/
Cosintropina
/
Hormônio Adrenocorticotrópico
/
Lipossomos
Idioma:
En
Ano de publicação:
1984
Tipo de documento:
Article