Infrared Microspectroscopy study of insulin crystals at high pressure

Piccirilli, Federica; Mangialardo, Sara; Lupi, S.; Postorino, P.; Perucchi, A.

doi:10.1088/1742-6596/359/1/012014

Cited by 7 publications

(5 citation statements)

References 7 publications

(6 reference statements)

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“…The formation of three-dimensional crystals we observed at about 4 kbar supports this idea. 35 Fibrils in advanced stages of maturation (formed after 1 day and 4 days under fibrillation favouring conditions) show a reduced high pressure susceptibility, resulting in the weakening of lateral packing and in the enhancement of fibrils' flexibility. While the reaction proceeds, even if no further changes can be detected from the infrared spectrum of amyloids, fibrils' high pressure response remarks the achievement of a more stable state, resulting in the hardening of the core of the structure possibly due to collapse of void volumes.…”

Section: Discussionmentioning

confidence: 99%

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Sequential dissociation of insulin amyloids probed by high pressure Fourier transform infrared spectroscopy

Piccirilli

Mangialardo²,

Postorino

et al. 2012

Soft Matter

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High pressure (HP) Fourier transform infrared (FTIR) spectroscopy has been here employed to investigate the thermodynamic stability of bovine pancreatic insulin (BPI) amyloids. Once the aggregation reaction has started, the backbone arrangement of the proteins forming the amyloid is known to reach a stationary phase in a few hours; after this time the infrared absorption of fibrils becomes stable. It is here shown how further stabilization of the structure during the stationary phase can be probed via FTIR spectroscopy, through the observation of the high pressure behaviour of fibrils formed at different maturation stages. We report on the high pressure fragmentation of insulin amyloids, probed on fibrils formed in the early stages of the stationary phase. Moreover, we noticed a sequentiality high pressure dissociation that seems to respect a pre-existing hierarchy of structures: the stabilization of a protofibrillar state is observed at pressures in the order of a few kbar and our results suggest the possible occurrence of a partial refolding, induced by pressures up to 11.4 kbar. Our findings remark the importance of high pressure in stabilizing intermediate structures and in evaluating the driving forces of fibrillation, demonstrating how the control of electrostatic interactions and hydrophobic effects can be used to characterize the factors that modulate amyloids stability

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Section: Discussionmentioning

confidence: 99%

“…During the compression cycle, at about 4 kbar, we also observed the crystallization of the protein. 35 We considered this phenomenon as a further hint of the fragmentation of fibers.…”

Section: Ambient Pressure Ftir Measurements: Evaluation Of Time Scale...mentioning

confidence: 99%

Sequential dissociation of insulin amyloids probed by high pressure Fourier transform infrared spectroscopy

Piccirilli

Mangialardo²,

Postorino

et al. 2012

Soft Matter

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“…Recently, there are a few reports for studying the spherulite deformation using the infrared microspectroscopic imaging measurement. [19][20][21] The inuence of different tensile conditions on the transformation from a crystal to b crystal of PVDF lms under the uniaxial tension process was studied in this paper. In particular, our studies focused on the in situ change of the spherulites of acrystal during the tensile process by using of optical tensile stress microscopy tester (OTSMT).…”

Section: Introductionmentioning

confidence: 99%

Studies on the transformation process of PVDF from α to β phase by stretching

Li¹,

Zhang²,

Rong³

et al. 2014

RSC Adv.

304

177

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Poly(vinylidene fluoride) (PVDF) has excellent pyro-and piezoelectric properties which are related to the bcrystal of PVDF. Most of the b-crystal of PVDF can be transformed from the a-crystal by mechanical stretching. The effects of stretching conditions on the transformation from a to b phase of PVDF were studied in this paper. In addition, changes of crystalline structure of PVDF during the stretching process were observed in situ under an optical tensile stress microscopy tester, and the samples after being stretched were investigated using a 3D digital microscope and an infrared microscope. The results show that stretching temperature (T s ) and drawing ratio (l) are critical to the transformation from a-crystal to b-crystal of PVDF. The T s around 100 C and l above 3 is recommended. The in situ observation indicates that the deformation of crystalline structure began from the middle of a-spherulite and extended to another spherulite, and caused the large-scale transformation. Scanning results of infrared microspectroscopic and 3D digital microscopy revealed that a phase of PVDF would change into b phase with the deformation of the spherulite, and the distribution of the different crystalline phase in PVDF after being stretched was also given. It is believed that this work is instructive and meaningful to studies on phase transformation and production of the piezoelectric film of PVDF.

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“…In the case of WT and A30P fibrils, we do not observe any β-sheet component other than a residual fibrillar one absorbing at about 1619 cm −1 . Conversely, the A53T sample shows a band at 1628 cm −1 attributed to peptide chains with weakly coupled β-sheets [29]. The presence of this absorption moiety could possibly reflect the presence of intermediate, possibly oligomeric β-sheet rich species.…”

Section: Kinetics Analysis Of Ftir and Saxs Datamentioning

confidence: 96%

“…The use of several pressure approaches in the last years has allowed biochemists and biophysicists to analyse the role of hydration and interactions in the formation of aggregates. For example, high-pressure effects on the structure, oligomerization state, interactions and dynamics of model proteins have been recently reported [26,22,24,27,28,29,30], with emphasis on hydration changes. On this basis, since high pressure induces the decrease of the total volume of the system, the destabilisation processes 2 of aSN fibrils toward states with a minor contribution of void volumes can be investigated in a controlled way by pressure.…”

Section: Introductionmentioning

confidence: 99%

Pressure effects on α-synuclein amyloid fibrils: An experimental investigation on their dissociation and reversible nature

Piccirilli

Plotegher

Spinozzi

et al. 2017

Archives of Biochemistry and Biophysics

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Abstractα-synuclein amyloid fibrils are found in surviving neurons of Parkinson's disease affected patients, but the role they play in the disease development is still under debate. A growing number of evidences point to soluble oligomers as the major cytotoxic species, while insoluble fibrillar aggregates could even play a protection role. In this work, we investigate α-synuclein fibrils dissociation induced at high pressure by means of Small Angle X-ray Scattering and Fourier Transform Infrared Spectroscopy. Fibrils were produced from wild type α-synuclein and two mutants associated with Parkinson's disease, A30P and A53T. Our results enlighten the different reversible nature of α-synuclein fibrils fragmentation at high pressure and suggest water excluded volumes presence in the fibrils core. Wild type and A30P species stabilized at high pressure are highly amyloidogenic and quickly re-associate into fibrils upon decompression, while A53T species shows a partial reversibility of the process likely due to the presence of an intermediate oligomeric state stabilized at high pressure. The amyloid fibrils dissociation process is here suggested to be associated to a negative activation volume, supporting the notion that α-synuclein fibrils are in a high-volume and high-compressibility state and hinting at the presence of a hydration-mediated activated state from which dissociation occurs.

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Infrared Microspectroscopy study of insulin crystals at high pressure

Cited by 7 publications

References 7 publications

Sequential dissociation of insulin amyloids probed by high pressure Fourier transform infrared spectroscopy

Sequential dissociation of insulin amyloids probed by high pressure Fourier transform infrared spectroscopy

Studies on the transformation process of PVDF from α to β phase by stretching

Pressure effects on α-synuclein amyloid fibrils: An experimental investigation on their dissociation and reversible nature

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