Conformation change of α-synuclein(61－95) at the air-water interface and quantitative measurement of the tilt angle of the axis of its α-helix by multiple angle incidence resolution spectroscopy

Wang, Chengshan; Sharma, Shiv K.; Olaluwoye, Oladimeji S; Alrashdi, Saad Ayidh; Hasegawa, Takeshi; Leblanc, Roger M.

doi:10.1016/j.colsurfb.2019.110401

Cited by 8 publications

(17 citation statements)

References 48 publications

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“…α-Syn and α-syn(61–95) showed similar behavior at the air–water interface as the following [ 18 , 19 ]. First, both α-syn and α-syn(61–95) formed a stable Langmuir monolayer at the air–water interface.…”

Section: Introductionmentioning

confidence: 64%

“…(1) shown in Materials and methods section in the Supplemental Information. To exhibit the above-mentioned character, IR-ERS and pMAIRS were compared by examining the orientation of α-syn and α-syn(61–95) because of their extensive interaction with membranes as discussed below [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the above-mentioned surface FT-IR techniques can be combined with Langmuir monolayer technique to address both the conformation and orientation of peptides/proteins at the interface [ 14 , 18 ]. Thus, the conformation and the orientation of α-syn and α-syn(61–95) in the monolayer at the interface have been examined and compared as the following [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…First, both α-syn and α-syn(61–95) formed a stable Langmuir monolayer at the air–water interface. Second, both of them were unstructured in aqueous solution and transformed to α-helical conformation at the interface [ 18 , 19 ]. This conformation change and the consequent high stability of the monolayer at the interface may be responsible for the accumulation of α-syn and α-syn(61–95) at the interface [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…Second, both of them were unstructured in aqueous solution and transformed to α-helical conformation at the interface [ 18 , 19 ]. This conformation change and the consequent high stability of the monolayer at the interface may be responsible for the accumulation of α-syn and α-syn(61–95) at the interface [ 18 , 19 ]. Finally, IR-ERS and pMAIRS were compared during the examination of the orientation of the axis of α-helical α-syn.…”

Section: Introductionmentioning

confidence: 99%

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Determine both the conformation and orientation of a specific residue in α-synuclein(61–95) even in monolayer by 13C isotopic label and p-polarized multiple-angle incidence resolution spectrometry (pMAIRS)

et al. 2022

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Protein’s magic function stems from its structure and various analytical techniques have been developed for it. Among proteins, membrane proteins are encoded 20–30% of genomes, whereas cause challenges for many analytical techniques. For example, lots of membrane proteins cannot form single crystal structure required by X-ray crystallography. As for NMR, the measurements were hindered by the low tumbling rates of membrane (i.e., phospholipid bilayers) where membrane proteins exist. In addition, membrane proteins usually lay parallel to the surface of phospholipid bilayers or form transmembrane structure. No matter parallel or perpendicular to phospholipid bilayers surface, membrane proteins form monolayer structure which is also difficult for X-ray and NMR to provide high-resolution results. Because NMR and X-ray crystallography are the two major analytical techniques to address protein’s structure, membrane proteins only contribute 2.4% to the solved protein databank. Surface FT-IR techniques can evaluate the conformation and orientation of membrane proteins by amide I band. Specifically for α-helical peptides/proteins, the orientation of the axis is critical to decide whether proteins form transmembrane structure. Notice that the traditional FT-IR can only provide “low-resolution” results. Here, 13C isotope was introduced into the nonamyloid component (NAC), which spans residues 61–95 of α-synuclein (α-syn). Then, p-polarized multiple-angle incidence resolution spectrometry (pMAIRS) was used to determine the orientation of a specific residue of α-helical NAC in monolayer. In general, pMAIRS is a novel technique to work complementary with X-ray and NMR to address membrane peptides/proteins structure with high resolution even in monolayer. Graphical abstract

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Section: Introductionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Determine both the conformation and orientation of a specific residue in α-synuclein(61–95) even in monolayer by 13C isotopic label and p-polarized multiple-angle incidence resolution spectrometry (pMAIRS)

et al. 2022

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Interfaces Determine the Fate of Seeded α‐Synuclein Aggregation

Campioni

Bagnani

Pinotsi

et al. 2020

Adv Materials Inter

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Amyloid fibrils formed by the α‐Synuclein (α‐Syn) protein are the pathological hallmark of multiple human disorders, generally termed α‐synucleinopathies. The aggregation process of α‐Syn into amyloids appears to be highly dependent on the presence of: i) hydrophobic–hydrophilic interfaces, and ii) pre‐formed seed fibrils. By combining Thioflavin T binding measurements with different microscopy techniques (direct stochastic optical reconstruction microscopy, atomic force microscopy, correlative super‐resolution light microscopy, and scanning electron microscopy), the effect of the air–water interface (AWI) is tested on seeded α‐Syn aggregation. The correlation of the results provided by each method reveals striking differences in the mechanism of formation, yield, length, thickness, and morphology of fibrils obtained from samples having equal initial amounts of seeds and monomers, but incubated in the presence or absence of an AWI. Overall, the results indicate that the AWI determines how amyloids grow and proliferate, the final balance between monomer and aggregates, and the morphological properties of the aggregates themselves. These observations may set the basis for amplifying and tuning the properties of specific fibril polymorphs of interest, in structural biology and cytotoxicity studies, as well as in those materials science applications featuring amyloids.

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Simultaneous Analysis of Molecular Orientation and Quantity Change of Constituents in a Thin Film Using pMAIRS

et al. 2020

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Spectral analysis using chemometrics is extensively used for quantitative chemical analysis in a mixture, but it works powerfully only when the peak intensity is solely proportional to the quantity of chemical components. In this sense, thin films on a solid substrate are not suitable for chemometric analysis, because the molecular orientation also influences the peak intensity via the surface selection rules. In the present study, this long-term analytical issue has readily been overcome by using p-polarized multiple-angle incidence resolution spectrometry (pMAIRS), which has a characteristic that the in-plane (IP) and out-of-plane (OP) vibrational spectra of a thin-film sample are obtained simultaneously in a common ordinate scale. Thanks to this unique power of pMAIRS, the average of the IP and OP spectra annihilates optical anisotropy, yielding an orientation-free spectrum, which enables us to perform the simultaneous quantitative analysis of both quantity change and molecular orientation of the constituents in a thin film. Now, we are ready to examine chemical reactions quantitatively in a thin film.

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Conformation change of α-synuclein(61－95) at the air-water interface and quantitative measurement of the tilt angle of the axis of its α-helix by multiple angle incidence resolution spectroscopy

Cited by 8 publications

References 48 publications

Determine both the conformation and orientation of a specific residue in α-synuclein(61–95) even in monolayer by 13C isotopic label and p-polarized multiple-angle incidence resolution spectrometry (pMAIRS)

Determine both the conformation and orientation of a specific residue in α-synuclein(61–95) even in monolayer by 13C isotopic label and p-polarized multiple-angle incidence resolution spectrometry (pMAIRS)

Interfaces Determine the Fate of Seeded α‐Synuclein Aggregation

Simultaneous Analysis of Molecular Orientation and Quantity Change of Constituents in a Thin Film Using pMAIRS

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