Fourier transform IR attenuated total reflectance study on the secondary structure of poly(γ ‐methyl <scp>L</scp>‐glutamate) surfaces treated with formic acid

Kugo, Kohei; Okuno, Masaki; Kitayama, Koji; Kitaura, Tatsuro; Nishino, Jun; Ikuta, Nobuo; Nishio, Etsuo; Iwatsuki, Makoto

doi:10.1002/bip.360320302

Cited by 14 publications

(15 citation statements)

References 13 publications

(1 reference statement)

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“…The Amide II band around 1544 cm −1 is assigned to α-helix structures of proteins [12]. The shift to lower frequency values, as in our case, indicate a change in protein secondary structure and conformation, probably by an increase in content of random coil structures [30]. Apart Table 3 Changes in some of the bandwidth values and area ratios of the infrared bands for control and diabetic EDL muscles…”

Section: Resultssupporting

confidence: 50%

The effect of diabetes mellitus on rat skeletal extensor digitorum longus muscle tissue: An FTIR study

Bozkurt

Bilgin

Severcan

2007

Journal of Spectroscopy

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Diabetes mellitus (DM) is a chronic disorder of carbohydrate, fat and protein metabolism, which is characterized by a defective insulin secretory response. Skeletal muscle takes role in determination of carbohydrate and lipid metabolism, therefore; it is one of the target tissues of diabetes. Herein this study, application of Fourier Transform Infrared (FTIR) spectroscopy in diabetic skeletal Extensor Digitorum Longus (EDL) muscle tissues will be presented which highlight the promise of this technique in medical research. Type I DM was induced in rats by injection of streptozotocin (STZ) which is one of the most popular experimental models. In diabetes, a significant increase was observed in lipid order together with an increase in hydration of phospholipid molecules in membrane structure. There was a decrease in lipid and nucleic acid content in diabetic EDL muscles. A dramatic increase in the bandwidth of amide II band (1540 cm−1) and shifting of the position of this band to lower frequency values in diabetes was observed indicating structural changes occurring in proteins of diabetic EDL muscles.

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Section: Resultssupporting

confidence: 50%

The effect of diabetes mellitus on rat skeletal extensor digitorum longus muscle tissue: An FTIR study

Bozkurt

Bilgin

Severcan

2007

Journal of Spectroscopy

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“…To study the effects of formic acid in the vapor phase (denoted by " υ ") on both spin-coated films and grafted brushes, we placed 48nm-thick PMLG spin-coated films and 40-nm-thick PMLG grafted brushes in a sealed petri dish, as shown in previous work. 32 The films were taken out of the petri dish after each reaction condition and then quickly dried overnight in vacuo at room temperature before we examined their conformational changes by ex situ atomic force microscopy (AFM) as well as FTIR and CD spectroscopy.…”

Section: Sample Preparationmentioning

confidence: 99%

“…However, the β-sheet conformation predominates when a pyridinerich solvent, such as trifluoroacetic acid (TFA) or formic acid, is used. 24,[28][29][30][31][32] Besides, the non-peptide oligomer blending was employed to investigate the secondary conformations of PBLG and PMLG. It was found that α-helical conformation is greatly influenced by the side chain rigidity of poypeptides as well as the intermolecular hydrogen bonding induced by the blending oligomer.…”

Section: Introductionmentioning

confidence: 99%

“…32,42 The helix orientation of end-grafted PMLG brushes on the aluminum substrate was recorded by external reflection FTIR (ER-FTIR, Nicolet Magna-IR 860 spectrometer with a clean sample as the reference, 32 scans; resolution, (JASCO J-60 spectropolarimeter) was used to examine the conformations of surface-grafted polypeptides on quartz substrates. The spectra were recorded at a bandwidth of 1 nm and a scanning rate of 20 nm/min.…”

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confidence: 99%

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Chemoresponsive surface-tethered polypeptide brushes based on switchable secondary conformations

et al. 2015

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Surface-tethered chemoresponsive polypetides prepared by surface-initiated vapor deposition polymerization were used to investigate conversion efficiency between α-helical and β-sheet conformations. β-sheet α-helixSurface-tethered chemoresponsive polypetides prepared by surfaceinitiated vapor deposition polymerization (SI-VDP) were used to investigate the conversion efficiency between α-helical and β-sheet conformations of poly(γ-methyl-L-glutamate) (PMLG) homopolypeptide and PMLG-b-poly(βbenzyl-L-glutamate) (PBLG) copolypeptide brushes. The end-grafted PMLG brush predominantly adopted a β-sheet conformation after exposure to formic acid vapor, and it was converted back to a predominantly α-helical conformation after treatment with a mixture of dichloroacetic acid (DCA) and chloroform (CHCl3). This conformational inter-conversion process was reversible and repeatable for a number of cycles. Factors that affected the conversion efficiency between α-helix and β-sheet were studied, including PMLG chain mobility, concentration of DCA, and temperature of formic acid vapor. For end-grafted PMLG brushes with one end chain restriction, 60 % conversion efficiency from α to β was achieved with 40 o C formic acid vapor treatment for 2 days, while for the PMLG in end-grafted PMLG-b-PBLG brushes, 40 % conversion was achieved after 9 days, which was slower than end-grafted PMLG brushes due to the additional chain restriction from the PBLG block. In comparison, in spin-coated PMLG films in which the PMLG chains had no end chain restrictions, 80 % conversion was achieved within 2 days in the same condition. The effects of solvent on the morphologies of surface-grafted PMLG brushes were also observed. The changes of the properties of these films, including surface wettability, thickness, and surface morphologies, were characterized by contact angle measurement, ellipsometry, and atomic force microscopy, respectively.

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“…Multidimensional nuclear magnetic resonance (NMR) spectroscopy has been used to obtain estimates of Γ and the train, loop‐tail distribution on the surface, through interpretation of changes in the relaxation spectra as a result of motional constraints imposed on the chain segments and depletion layer thicknesses, when appropriate 33–35. Attenuated total reflectance (ATR) IR spectroscopy has been used successfully to determine Γ, the proportion of polymer trains on the surface or interface, and the nature of the segment–surface interaction, the kinetics of slow exchange of one polymer for another, insight into preferential adsorption as a function of delta( N ), the difference in chain length, delta (χ ps ), the difference in the segment–surface interaction energy, Δ, the interaction energy between an end group and the surface, and global conformational changes with specific reference to adsorbed proteins 36–54. Ellipsometry has shed light on the effective thickness of the equilibrated layer and on the kinetics of slow‐exchange processes,55–58 as has the newer family of ATM techniques, some of which can be applied in situ 59, 60.…”

Section: Introductionmentioning

confidence: 99%

Trends in the adsorption of mono-end-capped polystyrenes onto polar substrates: Theoretical predictions and experimental observations

Zhang

Zajac

Chakrabarti

et al. 2000

J. Appl. Polym. Sci.

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ABSTRACT:Predictions of the influence of the solvent quality (), the segment-substrate interaction parameter (ps), the chain length (N), and the end cap-substrate interaction parameter (⌬) on the equilibrium-adsorbed amount from a dilute solution of end-functionalized homopolymers (⌫) onto a solid substrate, when both the end cap and polymer segments compete for sites on the surface, were made through application of the self-consistent-field (SCF) theory. These predictions were tested and evaluated through measurement of the equilibrium-adsorbed amount, from a dilute solution of single-end-functionalized custom synthesized relatively monodisperse polystyrenes, possessing an end group (X) chosen to interact with a mildly acidic inorganic substrate (Aerosil 130) and a mildly basic inorganic substrate (aluminum oxide C) through dipole-dipole interactions, hydrogen-bonding interactions, and specific acid-base interactions, as a function of , ps, ⌬, and N. A protocol was developed for the numerical estimation of ⌬ through the establishment of dimensionless ratios of the type ⌫ X /⌫ H , by experiment and through SCF calculation, as a function of ⌬, for polymer/solvent/ substrate systems characterized by specific combinations of , ps, and N.

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Fourier transform IR attenuated total reflectance study on the secondary structure of poly(γ ‐methyl L‐glutamate) surfaces treated with formic acid

Cited by 14 publications

References 13 publications

The effect of diabetes mellitus on rat skeletal extensor digitorum longus muscle tissue: An FTIR study

The effect of diabetes mellitus on rat skeletal extensor digitorum longus muscle tissue: An FTIR study

Chemoresponsive surface-tethered polypeptide brushes based on switchable secondary conformations

Trends in the adsorption of mono-end-capped polystyrenes onto polar substrates: Theoretical predictions and experimental observations

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