CD and Fourier transform ir spectroscopic studies of peptides. II. Detection of β‐turns in linear peptides

Hollósi, Miklós; Majer, Zsuzsanna; Rónai, A. Z.; Magyar, Anna; Medzihradszky, K.; Holly, S.; Perczel, András; Fasman, Gerald D.

doi:10.1002/bip.360340204

Cited by 92 publications

(89 citation statements)

References 29 publications

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“…The FTIR spectrum of peptide 1 is given in Figure 4A and its second derivative spectrum in Figure 4B; the band at 1,638 cm" is consistent with a C = 0 involved in a 1 t 4 hydrogen bond in a p-turn (Holl6si et al, 1994) type 11 p-turn from the CD spectra. Glutamine side-chain amides (Fig.…”

Section: Turn Prediction In the Peptidesmentioning

confidence: 69%

“…3A), indicating their structural similarity. The amide I band of peptides 4-6 (Table 3) shifts from 1,646 cm" (peptide 4) to 1,644 cm-l (peptide 5) and 1,642 cm" (peptide 6), compatible with increasing hydrogen bonding character as in a 1 t 4 hydrogen bond in a p-turn (Holl6si et al, 1994). Second derivative spectra of peptides 4 and 6 (Fig.…”

Section: Conformation Of Cyclo-pgqgqqgyyptspqq (Peptide 3)mentioning

confidence: 78%

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Structure characterization of the central repetitive domain of high molecular weight gluten proteins. I. Model studies using cyclic and linear peptides

et al. 1997

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The high molecular weight (HMW) proteins from wheat contain a repetitive domain that forms 60‐80% of their sequence. The consensus peptides PGQGQQ and GYYPTSPQQ form more than 90% of the domain; both are predicted to adopt /3‐turn structure. This paper describes the structural characterization of these consensus peptides and forms the basis for the structural characterization of the repetitive HMW domain, described in the companion paper. The cyclic peptides cyclo‐[PGQGQQPGQGQQ] (peptide 1), cyclo‐[GYYPTSPQQGA] (peptide 2), and cyclo‐[PGQGQQGYYPTSPQQ] (peptide 3) were prepared using a novel synthesis route. In addition, the linear peptides (PGQGQQ) (n = 1, 3, 5) were prepared. CD, FTIR, and NMR data demonstrated a type II /3‐turn structure at QPGQ in the cyclic peptide 1 that was also observed in the linear peptides (PGQGQQ). A type I /3‐turn was observed at YPTS and SPQQ in peptides 2 and 3, with additional /3‐turns of either type I or II at GAGY (peptide 2) and QQGY (peptide 3). The proline in YPTS showed considerable cis/trans isomerization, with up to 50% of the population in the cis‐conformation; the other prolines were more than 90% in the trans conformation. The conversion from trans to cis destroys the type I /3‐turn at YPTS, but leads to an increase in turn character at SPQQ and GAGY (peptide 2) or QQGY (peptide 3).

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Section: Turn Prediction In the Peptidesmentioning

confidence: 69%

Section: Conformation Of Cyclo-pgqgqqgyyptspqq (Peptide 3)mentioning

confidence: 78%

Structure characterization of the central repetitive domain of high molecular weight gluten proteins. I. Model studies using cyclic and linear peptides

et al. 1997

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“…1). FTIR spectra of SP-B1-9 in methanol showed major components at 1,662, 1,656, 1,641, and 1,633 cm", suggesting populations of &turn and helical conformers (Hollosi et al, 1994). Fourier self deconvolution and curve fitting indicated that &turn structures were the principal conformation for SP-B1-9 in methanol, although significant contributions were also found for &sheet and helical conformations ( Table 2).…”

Section: Conformation and Helical Axis Orientation Of Sp-b1_25 In Strmentioning

confidence: 96%

Conformation and molecular topography of the N‐terminal segment of surfactant protein B in structure‐promoting environments

et al. 1996

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Although the effects of surfactant protein B (SP-B) on lipid surface activity in vitro and in vivo are well known, the relationship between molecular structure and function is still not fully understood. To further characterize protein structure-activity correlations, we have used physical techniques to study conformation, orientation, and molecular topography of N-terminal SP-B peptides in lipids and structure-promoting environments. Fourier transform infrared (FTIR) and CD measurements of SP-B1_25 (residues 1-25) in methanol, SDS micelles, egg yolk lecithin (EYL) liposomes, and surfactant lipids indicate the peptide has a dominant helical content, with minor turn and disordered components. Polarized FTIR studies of SP-B,-25 indicate the long molecular axis lies at an oblique angle to the surface of lipid films. Truncated peptides were similarly examined to assign more accurately the discrete conformations within the SP-B,_,, sequence. Residues Cys-8-Gly-25 are largely a-helix in methanol, whereas the N-terminal segment Phe-1-Cys-8 had turn and helical propensities. Addition of SP-Bl-25 spin-labeled at the N-terminal Phe (i.e., SP-BT_25) to SDS, EYL, or surfactant lipids yielded electron spin resonance spectra that reflect peptide bound to lipids, but retaining considerable mobility. The absence of characteristic radical broadening indicates that SP-B1-25 is minimally aggregated when it interacts with these lipids. Further, the high polarity of SP-BI-25 argues that the reporter on Phe-1 resides in the headgroup of the lipid dispersions. The blue-shift in the endogenous fluorescence of Trp-9 near the N-terminus of SP-B1-25 suggests that this residue also lies near the lipid headgroup. A summary model based on the above physical experiments is presented for SP-BI-2S interacting with lipids.

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“…Usou-se função lorentziana, considerando-se que as absorções do infravermelho são desse tipo, com pouca contribuição de gaussiana 19,22,23 . A função lorentziana está descrita pela equação (1).…”

Section: Materiais E Métodosunclassified

Estudo de métodos de aumento de resolução de espectros de FTIR para análise de estruturas secundárias de proteínas

Forato¹,

Filho²,

Colnago³

1998

Quím. Nova

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FTIR. The FTIR spectroscopy has been used to quantify the secondary structures of proteins, using amide I band (1600 -1700 cm -1 ). The resolution enhancement methods have been used to resolve the individual components of this band that correlate to the secondary structure. In this paper we discuss the methods of derivative, Fourier deconvolution and fitting with simulated spectra. The results shows that they have serious problems and can be used only as a qualitative or semiquatitative method.Keywords: methods of resolution enhancement; FTIR; protein. ARTIGO I. INTRODUÇÃOAs técnicas utilizadas para a determinação das estruturas tridimensionais de proteínas em alta resolução são a cristalografia de raios X e a Ressonância Magnética Nuclear (RMN) 1 . A técnica de raios X exige monocristais de alta qualidade, o que não é trivial de obter, principalmente no caso de proteínas de membranas [1][2][3][4][5] . Já a RMN se restringe a proteínas de baixo peso molecular 3 . Dessa forma, técnicas como dicroísmo circular (CD) e as espectroscopias Raman e Infravermelho com transformada de Fourier (FTIR) têm sido utilizadas para quantificar os tipos de estruturas secundárias de proteínas (ESP) presentes nas amostras sem, contudo, determinar as suas localizações [3][4][5] . As principais vantagens dessas técnicas são a rapidez na realização das medidas, o fato de não haver restrições quanto ao peso molecular da proteína em estudo e a não necessidade de cristais.Dentre essas técnicas o FTIR vêm apresentando grandes avanços 2,3,4 pois além de ser uma técnica rápida, permite que a amostra seja analisada em vários ambientes como solução aquosa 3,4,5 , sólido amorfo 6 ou cristalino 3 , filmes 3,6,7,8 , membranas 3,4,5,9 , pastilhas de KBr 10 , além dos espectrômetros de FTIR serem mais facilmente encontrados do que os de Raman e Dicroísmo Circular.A maioria das informações de FTIR sobre as estruturas secundárias das proteínas (α-hélice, folhas β, voltas β e irregulares) é obtida da análise da banda de amida I, que ocorre na região de 1700-1600 cm -1 . Esta banda é devida principalmente ao estiramento da ligação C=O da ligação peptídica e é sensí-vel às diferentes conformações das ESP.A atribuição dos picos da banda de amida I às diferentes estruturas secundárias é encontrada na literatura 11 . Para α-hélices em solução aquosa a absorção ocorre em 1656 cm -1 ; para as folhas β em 1624, 1627, 1632, 1638 e 1642 cm -1 , voltas β em 1666, 1672, 1680, 1688 cm -1 e as irregulares em 1650 cm -1 . Como todos esses sinais podem estar presen-E-mail:lucimara@cnpdia.embrapa.br; E-mail:rubens@cnpdia.embrapa.br; E-mail:colnago@cnpdia.embrapa.br tes numa única proteína, a banda de amida I é uma banda altamente complexa, onde esses componentes não são observados individualmente 5 . Assim o processo de quantificação das ESP a partir de espectros de FTIR envolve o uso de métodos matemáticos como os de aumento de resolução e reconhecimento de padrões [3][4][5]6,8 . Desses métodos os de aumento de resolução são os mais usados 4 e serão analisados neste ...

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CD and Fourier transform ir spectroscopic studies of peptides. II. Detection of β‐turns in linear peptides

Cited by 92 publications

References 29 publications

Structure characterization of the central repetitive domain of high molecular weight gluten proteins. I. Model studies using cyclic and linear peptides

Structure characterization of the central repetitive domain of high molecular weight gluten proteins. I. Model studies using cyclic and linear peptides

Conformation and molecular topography of the N‐terminal segment of surfactant protein B in structure‐promoting environments

Estudo de métodos de aumento de resolução de espectros de FTIR para análise de estruturas secundárias de proteínas

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