Circular Dichroism Studies of Secondary Structure of Peptides

Juban, Martha M.; Javadpour, Maryam M.; Barkley, Mary D.

doi:10.1385/0-89603-408-9:73

Cited by 31 publications

(32 citation statements)

References 3 publications

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“…The CD spectra at different temperatures cross-over at a single wavelength (isodichroic point). The isodichroic point is typically taken as evidence of the existence of only two molecular species (35). Therefore, these results strongly suggest that only the ssRNA and one type of G-quadruplex coexist in equilibrium.…”

Section: Resultsmentioning

confidence: 99%

The high kinetic stability of a G-quadruplex limits hnRNP F qRRM3 binding to G-tract RNA

Samatanga

Dominguez

Jelesarov

et al. 2012

Nucleic Acids Research

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The RNA binding protein heterogeneous nuclear ribonucleoprotein (hnRNP) F is involved in telomeres maintenance and pre-mRNA processing, such as alternative splicing and polyadenylation. It specifically recognizes RNA containing three consecutive guanines (G-tracts) that have the potential to assemble into G-quadruplexes. We have proposed recently that hnRNP F could regulate alternative splicing by remodeling RNA structures, such as G-quadruplexes. However, the exact mechanism of hnRNP F binding to such RNA sequences remains unknown. Here, we have studied the binding of the third RNA binding domain of hnRNP F [quasi-RNA recognition motif 3 (qRRM3)] to G-tract RNA using isothermal titration calorimetry, circular dichroism and nuclear magnetic resonance spectroscopy. Our results show that qRRM3 binds specifically exclusively to single-stranded G-tracts (ssRNA), in contrast to previous reports stating that the G-quadruplex was recognized as well. Furthermore, we demonstrate that the pre-existent ssRNA/G-quadruplex equilibrium slows down the formation of the protein–ssRNA complex. Based on in vitro transcription assays, we show that the rate of the protein–RNA complex formation is faster than that of the G-quadruplex. We propose a model according to which hnRNP F could bind RNA co-transcriptionally and prevents G-quadruplex formation.

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Section: Resultsmentioning

confidence: 99%

The high kinetic stability of a G-quadruplex limits hnRNP F qRRM3 binding to G-tract RNA

Samatanga

Dominguez

Jelesarov

et al. 2012

Nucleic Acids Research

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“…The data obtained by means of CD spectroscopy of EPS–AMP systems are reported in Fig. 4, where the molar ellipticity was transformed into per cent of α‐helix conformation in AMP by using the formula reported in (Juban et al ., 1997). Although the addition of C9343 caused some precipitation in AMP solutions, its CD data were also included in the discussion as some structural information could still be obtained.…”

Section: Resultsmentioning

confidence: 99%

Inhibition of cathelicidin activity by bacterial exopolysaccharides

Foschiatti

Cescutti

Tossi

et al. 2009

Molecular Microbiology

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SummaryThe interaction of bacterial exopolysaccharides, produced by opportunistic lung pathogens, with antimicrobial peptides of the innate primate immune system was investigated. The exopolysaccharides were produced by Pseudomonas aeruginosa, Inquilinus limosus and clinical isolates of the Burkholderia cepacia complex, bacteria that are all involved in lung infections of cystic fibrosis patients. The effects of the biological activities of three orthologous cathelicidins from Homo sapiens sapiens, Pongo pygmaeus (orangutan) and Presbitys obscurus (dusky leaf monkey) were examined. Inhibition of the antimicrobial activity of peptides was assessed using minimum inhibitory concentration assays on a reference Escherichia coli strain in the presence and absence of exopolysaccharides, whereas complex formation between peptides and exopolysaccharides was investigated by means of circular dichroism, fluorescence spectroscopy and atomic force microscopy. Biological assays revealed that the higher the negative charge of exopolysaccharides the stronger was their inhibiting effect. Spectroscopic studies indicated the formation of molecular complexes of varying stability between peptides and exopolysaccharides, explaining the inhibition. Atomic force microscopy provided a direct visualization of the molecular complexes. A model is proposed where peptides with an a-helical conformation interact with exopolysaccharides through electrostatic and other non-covalent interactions.

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“…After increasing the TFE concentration, the band at 198 -200 nm disappeared, and two ellipticity bands appeared at 205-208 and 218 -222 nm. These bands are relative to a -* transition and an n-* transition, respectively, which are indicative of an ␣-helical structure (44). This indicated that the random coil structure of both peptides could be changed to a regular helical structure in the presence of TFE.…”

Section: Peptide Synthesis and Characterization-mentioning

confidence: 91%

C-terminal Amidation of an Osteocalcin-derived Peptide Promotes Hydroxyapatite Crystallization

Hosseini

Naderi-Manesh

Mountassif

et al. 2013

Journal of Biological Chemistry

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Background: A natural motif sequence was used as substrate to template hydroxyapatite (HA) formation. Results: HA crystal formation is attributed to C-terminal amidation of a natural peptide derived from osteocalcin. Conclusion: The chemical structure of the peptide controls HA crystal formation and growth. Significance: HA-binding peptides are relevant for biomimetic bone synthesis, hard tissue regeneration, and improvement of osseointegration of biomedical implants.

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Circular Dichroism Studies of Secondary Structure of Peptides

Cited by 31 publications

References 3 publications

The high kinetic stability of a G-quadruplex limits hnRNP F qRRM3 binding to G-tract RNA

The high kinetic stability of a G-quadruplex limits hnRNP F qRRM3 binding to G-tract RNA

Inhibition of cathelicidin activity by bacterial exopolysaccharides

C-terminal Amidation of an Osteocalcin-derived Peptide Promotes Hydroxyapatite Crystallization

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