Fourier Transform Infrared Spectroscopy of Peptides

Bakshi, Kunal; Liyanage, Mangala Roshan; Volkin, David B.; Middaugh, C. Russell

doi:10.1007/978-1-62703-673-3_18

Cited by 25 publications

(21 citation statements)

References 8 publications

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“…The normalized amid I vibration band that is presented in Figure 10 shows the differences in the spectra of studied multilayers films, in particular, at the shoulders of the spectra between 1610–1640 cm −1 (Figure 10a). In this region, the β-sheet conformation usually appears, indicating the existence of intermolecular aggregates [62].…”

Section: Resultsmentioning

confidence: 99%

“…Table 5 and Figures S5 and S6 present the decomposition of amid I vibration bands spectra. The increase of the band with the wavelength around 1615 cm −1 was observed that could be attributed to the structural changes that are associated with the formation of aggregates as the result of interactions with underlying polypeptide layer for both caseins at the multilayer film [62]. That increase was more pronounced for the multilayers of caseins with poly-L-arginine.…”

Section: Resultsmentioning

confidence: 99%

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Interactions of Casein and Polypeptides in Multilayer Films Studied by FTIR and Molecular Dynamics

2019

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Multilayer films containing α- and β-casein and polypeptides, poly-L-lysine (PLL), and poly-L-arginine (PLArg) were formed by the layer-by-layer technique and Fourier Transform InfraRed spectroscopy with Attenuated Total Reflection (FTIR-ATR) and FTIR/Grazing Angle analyzed their infrared spectra. We investigated the changes of conformations of casein and polypeptides in the complexes formed during the build-up of the films. To elucidate the differences in the mechanism of complex formation leading to various growths of (PLL/casein)n and (PLArg/casein)n films, we performed the molecular dynamics simulations of the systems consisting of short PLL and PLArg chains and the representative peptide chains—casein fragments, which consists of several aminoacid sequences. The results of the simulation indicated the preferential formation of hydrogen bonds of poly-L-arginine with phosphoserine and glutamic acid residues of caseins. FTIR spectra confirmed those, which revealed greater conformational changes during the formation of casein complex with poly-L-arginine than with poly-L-lysine resulting from stronger interactions, which was also reflected in the bigger growth of (PLArg/casein)n films with the number of deposited layers.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Interactions of Casein and Polypeptides in Multilayer Films Studied by FTIR and Molecular Dynamics

2019

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“…The 1700–1500 cm –1 region corresponds to the amide I and amide II modes and reflects the peptides’ secondary and dynamic structure whereas the signal in the 3450–3150 cm –1 region results from the amide A and H 2 O stretching modes. 45−47 Spectra shown in gray and black solid lines in Figure 5a and b were collected on a sample that was dried by desiccation and exposed to the atmosphere for 10 and 20 min, respectively. The peptides absorb atmospheric humidity, which results in an increase in the H 2 O stretching band around 3270 cm –1 .…”

Section: Resultsmentioning

confidence: 99%

Pyroglutamylated Amyloid-β Peptide Reverses Cross β-Sheets by a Prion-Like Mechanism

et al. 2014

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The amyloid hypothesis causatively relates the fibrillar deposits of amyloid β peptide (Aβ) to Alzheimer’s disease (AD). More recent data, however, identify the soluble oligomers as the major cytotoxic entities. Pyroglutamylated Aβ (pE-Aβ) is present in AD brains and exerts augmented neurotoxicity, which is believed to result from its higher β-sheet propensity and faster fibrillization. While this concept is based on a set of experimental results, others have reported similar β-sheet contents in unmodified and pyroglutamylated Aβ, and slower aggregation of pE-Aβ as compared to unmodified Aβ, leaving the issue unresolved. Here, we assess the structural differences between Aβ and pE-Aβ peptides that may underlie their distinct cytotoxicities. Transmission electron microscopy identifies a larger number of prefibrillar aggregates of pE-Aβ at early stages of aggregation and suggests that pE-Aβ affects the fibrillogenesis even at low molar fractions. Circular dichroism and FTIR data indicate that while the unmodified Aβ readily forms β-sheet fibrils in aqueous media, pE-Aβ displays increased α-helical and decreased β-sheet propensity. Moreover, isotope-edited FTIR spectroscopy shows that pE-Aβ reverses β-sheet formation and hence fibrillogenesis of the unmodified Aβ peptide via a prion-like mechanism. These data provide a novel structural mechanism for pE-Aβ hypertoxicity; pE-Aβ undergoes faster formation of prefibrillar aggregates due to its increased hydrophobicity, thus shifting the initial stages of fibrillogenesis toward smaller, hypertoxic oligomers of partial α-helical structure.

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“…These results demonstrated that MFP was successfully added to the particle surface. The ATR-FTIR spectra of MFP@AgNPs conjugates exhibited variations in the Ag-O/Ag-Ag ($565 cm À1 and 730 cm À1 ) 41,42 and stretching variations of C]O (1650 cm À1 ) and bending variations of N-H (1540 cm À1 and 1515 cm À1 ) 43 (Fig. 1C).…”

Section: Preparation and Characterization Of Mfp@agnps Conjugatesmentioning

confidence: 98%

Antimicrobial peptide-modified silver nanoparticles for enhancing the antibacterial efficacy

Sun

et al. 2020

RSC Adv.

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Fourier Transform Infrared Spectroscopy of Peptides

Cited by 25 publications

References 8 publications

Interactions of Casein and Polypeptides in Multilayer Films Studied by FTIR and Molecular Dynamics

Interactions of Casein and Polypeptides in Multilayer Films Studied by FTIR and Molecular Dynamics

Pyroglutamylated Amyloid-β Peptide Reverses Cross β-Sheets by a Prion-Like Mechanism

Antimicrobial peptide-modified silver nanoparticles for enhancing the antibacterial efficacy

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