Vibrational circular dichroism of polypeptides. III. Film studies of several α‐helical and β‐sheet polypeptides

Sen, Ashish; Keiderling, Timothy A.

doi:10.1002/bip.360230809

Cited by 53 publications

(42 citation statements)

References 30 publications

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“…Thus, both a-helix and b-sheet structures were present in B 16 D 45 B 16 , while PBGL chains of the other copolymers mainly assumed a-helix conformation. [38][39][40][41][42] The results were consistent with previous research results. 17,37 As reported in the literature, both a-helixes and b-sheets secondary structures are present in the polypeptide segments with shorter chain lengths (n < 18), whereas the b-sheets secondary structure becomes less stable in the longer polypeptides (n > 18) and the polypeptide segment almost exclusively adopts an a-helical secondary structures.…”

Section: Synthesis and Characterization Of Pblg-b-pdms-b-pblg Tribcpssupporting

confidence: 83%

“…3a, the signal at 1735 cm À1 was related to the C]O stretching of the benzyl ester protecting group of the PBLG block. [38][39][40][41][42] In the high resolution FTIR spectra (Fig. 3b) Scheme 1 (indicated with the arrow) was quite obvious, compared to other copolymers.…”

Section: Synthesis and Characterization Of Pblg-b-pdms-b-pblg Tribcpsmentioning

confidence: 99%

“…The PBLG were known to form three different secondary structures: a-helixes, b-sheets and random coil conformation. 38 The locations of the amide-I and amide-II bands in the FTIR spectra can be used to determine the conformation of the polypeptide. As shown in Fig.…”

Section: Synthesis and Characterization Of Pblg-b-pdms-b-pblg Tribcpsmentioning

confidence: 99%

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A novel self-assembled hybrid organogel of polypeptide-based block copolymers with inclusion of polypeptide-functionalized graphene

Lei

Shi

et al. 2017

RSC Adv.

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Self-assembled hybrid organogels of polypeptides containing block copolymers with the inclusion of polypeptide-functionalized graphene were designed and elaborately prepared, and showed interesting microstructures as well as enhanced mechanical performances. Firstly, a series of peptide-based triblock copolymers (triBCPs),, with different lengths of PBLG helices, were synthesized and characterized. As the length of the PBLG helices increased, the critical gelation concentration of the BDB triBCPs decreased while the gel-sol transition temperature increased. Moreover, the PBLG covalently modified graphene oxide (GO) sheets were successfully incorporated into the BDB organogels in toluene and hybrid organogels were prepared. In the presence of GO sheets, the minimum gelation concentration of the hybrid organogel was slightly lowered, and the hybrid organogels preserved thermoreversibility. In the hybrid gels, the triBCPs still self-assembled into nanoribbon structures and the functionalized GO sheets were well dispersed in the gel medium, which was obviously observed by transmission electron microscopy. In addition, the inclusion of the functionalized graphene greatly enhanced the mechanical performance of the hybrid gels, which was demonstrated by the significant increase of the moduli and the fracture stress of the hybrid gels compared with the corresponding native gels in the rheology experiments.

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Section: Synthesis and Characterization Of Pblg-b-pdms-b-pblg Tribcpssupporting

confidence: 83%

Section: Synthesis and Characterization Of Pblg-b-pdms-b-pblg Tribcpsmentioning

confidence: 99%

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A novel self-assembled hybrid organogel of polypeptide-based block copolymers with inclusion of polypeptide-functionalized graphene

Lei

Shi

et al. 2017

RSC Adv.

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“…This could explain why the VCD spectrum of the amide I 0 band, which probes the local environment, shows a PPII like signal. As shown by Keiderling and coworkers, 31 the observed enhancement is typical for peptide films. The effect could result from the anisotropy of the formed film and/or from interpeptide vibrational coupling between the amide I modes of adjacent PLP molecules.…”

Section: Comparison With Literaturementioning

confidence: 57%

Kinetics of the self‐aggregation and film formation of poly‐L‐proline at high temperatures explored by circular dichroism spectroscopy

et al. 2010

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Poly-L-proline has been used as a model system for various purposes over a period of more than 60 years. Its relevance among the protein/peptide community stems from its use as a reference system for determining the conformational distributions of unfolded peptides and proteins, its use as a molecular ruler, and from the pivotal role of proline residues in conformational transitions and protein-protein interactions. While several studies indicate that polyproline can aggregate and precipitate in aqueous solution, a systematic study of the aggregation process is still outstanding. We found, by means of UV-circular dichroism and IR measurements, that polyproline is predominantly monomeric at room temperature at millimolar concentrations. Upon heating, the polypeptide stays in its monomeric state until the temperature reaches a threshold of ca. 60 degrees C. At higher temperatures, the peptide aggregates as a film on the inside surface of the employed cuvette. The process proceeds on a time scale of 10(3) s and can best be described by a bi-exponential relaxation function. The respective CD and IR spectra are qualitatively different from the canonical spectra of polyproline in aqueous solution, and are indicative of a highly packed state.

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“…22 We find that films of these polypeptides give somewhat lower-frequency amide-I bands. 17 Our results indicated that solution and film data are significantly different such that frequency shifts alone are not sufficient to determine conformation. Since only the amide N-H was deuterated, the lack of such a n effect on the PBLA spectrum may indicate that the new, resonant mode for the deuterated amide is sensitive to the conformational constraints of this left-handed L-configuration form.…”

Section: CLmentioning

confidence: 75%

Vibrational circular dichroism of polypeptides. II. Solution amide II and deuteration results

Sen

Keiderling

1984

Biopolymers

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SynopsisVibrational CD (VCD) of amide I and I1 vibrations of several a-helical polypeptides have been measured in solution. For the amide I1 as well as the amide I [previously published: Lal, B.B. & Nafie, L.A. (1982) Biopolymers 21, 21611 we find the VCD to be characteristic of the polypeptide secondary structure. Amide I1 bands of right-handed u helices were all found to have negative VCD and to have their maximum rotational strength for the parallel (low-energy) component. However, left-handed a helices formed from L-amino acids gave positive amide I1 bands at higher frequencies than found for the right-handed helices, indicating that the VCD was sensitive to the stereochemical difference. The amide-I VCD spectra of some deuterated right-handed a-helical polypeptides have a new negative feature to low frequency that does not reflect theoretical predictions but also appears to be stereochemically sensitive. Amide-I1 and amide-A VCD of a few deuterated polypeptides imply retention of the secondary-structure-dependent characteristics seen in the hydrogenated VCD.

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Vibrational circular dichroism of polypeptides. III. Film studies of several α‐helical and β‐sheet polypeptides

Cited by 53 publications

References 30 publications

A novel self-assembled hybrid organogel of polypeptide-based block copolymers with inclusion of polypeptide-functionalized graphene

A novel self-assembled hybrid organogel of polypeptide-based block copolymers with inclusion of polypeptide-functionalized graphene

Kinetics of the self‐aggregation and film formation of poly‐L‐proline at high temperatures explored by circular dichroism spectroscopy

Vibrational circular dichroism of polypeptides. II. Solution amide II and deuteration results

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