Short peptide constructs mimic agonist sites of AT sub(1)R and BK receptors

Extracellular peptide ligand binding sites, which bind the N-termini of angiotensin II (AngII) and bradykinin (BK) peptides, are located on the N-terminal and extracellular loop 3 regions of the AT sub(1)R and BKRB sub(1) or BKRB sub(2) G-protein-coupled receptors (GPCRs). Here we synthesized peptid...

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Bibliographic Details
Published inAmino acids Vol. 44; no. 3; pp. 835 - 846
Main Authors Lopes, Douglas D, Vieira, Renata FF, Malavolta, Luciana, Poletti, Erick F, Shimuta, Suma I, Paiva, Antonio CM, Schreier, Shirley, Oliveira, Laerte, Nakaie, Clovis R
Format Journal Article
LanguageEnglish
Published 01.03.2013
Subjects
Active control
Amino acids
Construction
Construction specifications
Fluorescence
Fragments
Peptides
Receptors
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Summary:Extracellular peptide ligand binding sites, which bind the N-termini of angiotensin II (AngII) and bradykinin (BK) peptides, are located on the N-terminal and extracellular loop 3 regions of the AT sub(1)R and BKRB sub(1) or BKRB sub(2) G-protein-coupled receptors (GPCRs). Here we synthesized peptides P15 and P13 corresponding to these receptor fragments and showed that only constructs in which these peptides were linked by S-S bond, and cyclized by closing the gap between them, could bind agonists. The formation of construct-agonist complexes was revealed by electron paramagnetic resonance spectra and fluorescence measurements of spin labeled biologically active analogs of AngII and BK (Toac super(1)-AngII and Toac super(0)-BK), where Toac is the amino acid-type paramagnetic and fluorescence quencher 2, 2, 6, 6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid. The inactive derivatives Toac super(3)-AngII and Toac super(3)-BK were used as controls. The interactions characterized by a significant immobilization of Toac and quenching of fluorescence in complexes between agonists and cyclic constructs were specific for each system of peptide-receptor construct assayed since no crossed reactions or reaction with inactive peptides could be detected. Similarities among AT, BKR, and chemokine receptors were identified, thus resulting in a configuration for AT sub(1)R and BKRB cyclic constructs based on the structure of the CXCR sub(4), an alpha -chemokine GPCR-type receptor.
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ISSN:0939-4451
1438-2199
DOI:10.1007/s00726-012-1405-9