Far-UV Circular Dichroism Reveals a Conformational Switch in a Peptide Fragment from the .beta.-Sheet of Hen Lysozyme

Biochemistry ◽  
1994 ◽  
Vol 33 (23) ◽  
pp. 7345-7353 ◽  
Author(s):  
Jenny Jie Yang ◽  
Maureen Pitkeathly ◽  
Sheena E. Radford
Keyword(s):  
Circular Dichroism ◽  
Beta Sheet ◽  
Peptide Fragment ◽  
Conformational Switch ◽  
Circular Dichroïsm

scholarly journals A circular-dichroism study of epidermolytic toxins A and B from Staphylococcus aureus

1982 ◽  
Vol 203 (3) ◽  
pp. 775-778 ◽  
Author(s):  
C J Bailey ◽  
S R Martin ◽  
P M Bayley
Keyword(s):  
Staphylococcus Aureus ◽  
Circular Dichroism ◽  
Alpha Helix ◽  
Side Chain ◽  
Initial Increase ◽  
Beta Sheet ◽  
Circular Dichroism Spectra ◽  
Aromatic Side Chain ◽  
Circular Dichroïsm

The far-u.v. circular-dichroism spectra of the two epidermolytic toxins was analysed into fractional contributions of 0.09 helix and 0.46 beta-sheet to each toxin structure. Trifluoroethanol perturbation caused an initial increase in dichroic absorption at 205 nm and then a change characterized as a beta-sheet-to-alpha-helix transition. The intense near-u.v. spectra suggested that the toxins have unusually rigid, though different, aromatic-side-chain arrangements.

scholarly journals Análisis conformacional de un fragmento peptídico del primer bucle extracelular del receptor tipo 1 de angiotensina humano

2018 ◽  
pp. 87-91
Keyword(s):  
Circular Dichroism ◽  
Sao Paulo ◽  
At1 Receptor ◽  
Activation Process ◽  
São Paulo ◽  
Peptide Fragment ◽  
Unilamellar Vesicles ◽  
Large Unilamellar Vesicles ◽  
Circular Dichroïsm

Análisis conformacional de un fragmento peptídico del primer bucle extracelular del receptor tipo 1 de angiotensina humano Conformational analysis of a peptide fragment from first extracelular loop of the receptor human type 1 of angiotensin Nélida Marín Huachaca1, Clóvis R. Nakaie2 y Shirley Schreier1 1 Departamento de Bioquímica de la Universidade de São Paulo, Av. Prof. Lineu Prestes 748, CEP: 05513-970 São Paulo, Brasil 2 Departamento de Biofísica de la Universidade Federal de São Paulo, Rua 3 de Maio 100, CEP: 04044-020, São Paulo, Brasil. Recibido el 15 de noviembre del 2017, aceptado el 20 de diciembre del 2017 DOI: https://doi.org/10.33017/RevECIPeru2017.0009/ Resumen El receptor tipo 1 de angiotensina (AT1) es mediador importante de las funciones vasoconstrictoras de la angiotensina II. Durante el proceso de activación del receptor, éste sufre alteración estructural que conlleva al proceso de transducción de señal. En el presente estudio se investigaron las propiedades conformacionales del fragmento peptídico Ac-YRWPFGNYL-CONH2 (fEC1) correspondiente al primer bucle extracelular del receptor AT1 humano tanto en medio acuoso como en la presencia de sistemas que mimetizan la membrana biológica. De esta manera, se utilizaron micelas y vesículas unilamelares grandes (LUV) -tanto de naturaleza aniónica como zwitteriónica- como sistemas biomiméticos. Las micelas fueron preparadas a partir de los lisofosfolípidos: 1-palmitoil-2-hidroxi-fosfatidilcolina (LPC) y 1-palmitoil-2-hidroxi-fosfatidilglicerol (LPG), mientras que, las LUV fueron preparadas a partir de 1-palmitoil-1-oleoil-fosfatidilcolina (POPC) y 1-palmitoil-2-oleoil-fosfatidilglicerol (POPG). El péptido fue sintetizado por el método de síntesis en fase sólida y los análisis conformacionales fueron realizados mediante dicroísmo circular. Los experimentos fueron realizados en pH 7.0. En este pH la carga teórica de fEC1 es +1. El espectro de dicroísmo circular de fEC1 en solución presentó una banda positiva en aproximadamente 226 nm, mientras que, en la presencia de micelas zwitteriónicas y aniónicas y, en la presencia de LUV aniónicas fueron observadas alteraciones espectrales, esto es, la adquisición de estructura secundaria del péptido como consecuencia de la interacción péptido-sistema biomimético. Descriptores: Receptor AT1 humano, dicroísmo circular, micelas, vesículas unilamelares grandes Abstract The type 1 receptor for angiotensin (AT1) is an important mediator of the vasoconstrictor functions of angiotensin II. During the activation process of the receiver, it undergoes structural alteration that leads to the process of signal transduction. In the present study, the conformational properties of the peptide fragment Ac-YRWPFGNYL-CONH2 (fEC1) corresponding to the first extracellular loop of the human AT1 receptor both in aqueous medium and in the presence of systems that mimics the biological membrane were investigated. In this way, micelles and large unilamellar vesicles (LUV) -both anionic and zwitterionic in nature- were used as biomimetic systems. The micelles were prepared from the lysophospholipids: 1-palmitoyl-2-hydroxy-phosphatidylcholine (LPC) and 1-palmitoyl-2-hydroxy-phosphatidylglycerol (LPG), whereas, the LUV were prepared from 1-palmitoyl- 1-oleoyl-phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG). The peptide was synthesized by the solid phase synthesis method and the conformational analyzes were performed by circular dichroism. The experiments were performed at pH 7.0. At this pH the theoretical charge of fEC1 is +1. The circular dichroism spectrum of fEC1 in solution showed a positive band at approximately 226 nm, whereas in the presence of zwitterionic and anionic micelles and, in the presence of anionic LUV, spectral alterations were observed, that is, the acquisition of secondary structure of the peptide as a consequence of the peptide-biomimetic system interaction. Keywords: Human AT1 receptor, circular dichroism, micelles, large unilamellar vesicles

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

Circular dichroism spectra of adsorbed dye-aggregates

1968 ◽  
Vol 65 ◽  
pp. 146-151 ◽  
Author(s):  
G. Scheibe ◽  
O. Wörz ◽  
F. Haimerl ◽  
W. Seiffert ◽  
J. Winkler
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Circular Dichroïsm
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