The transition from the native to the acid-state characterized by multi-spectroscopy approach: Study for the holo-form of bovine α-lactalbumin

Litwińczuk, Adriana; Ryu, Soo Ryeon; Nafie, Laurence A.; Lee, Jong Wha; Kim, Hugh I.; Jung, Young Mee; Czarnik-Matusewicz, Bogusława

doi:10.1016/j.bbapap.2013.12.018

Cited by 25 publications

(16 citation statements)

References 64 publications

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“…[24][25][26] 2D correlation spectroscopy combined with PCA enables improved characterization of the structural changes in biomolecules at a detailed molecular level. [17,23] The all-atom molecular dynamics (AAMD) simulation method is a powerful tool that enables the examination of complex systems and processes at the atomic level. Due to significant advances in computing power, AAMD simulations have been widely used to investigate the structural and dynamic properties of condensed-phase systems.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, 2D IR correlation spectroscopy has been extensively used in fundamental protein research because it allows the evolution of protein structures to be explored. [17][18][19][20][21][22][23] In this study, to elucidate the molecular structures and thermal behavior of insulin nanoparticles of two different shapes, the temperature-dependent IR spectra of the particles were analyzed using 2D correlation spectroscopy. A principal component analysis (PCA) was also performed to monitor the evolution of the spectral changes of the two shapes of insulin with increasing temperature.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Structural Differences between Spherical and Rod‐Shaped Human Insulin Nanoparticles Produced by Supercritical Fluids Precipitation

et al. 2014

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In this study, the thermal denaturation mechanism and secondary structures of two types of human insulin nanoparticles produced by a process of solution-enhanced dispersion by supercritical fluids using dimethyl sulfoxide (DMSO) and ethanol (EtOH) solutions of insulin are investigated using spectroscopic approaches and molecular dynamics calculations. First, the temperature-dependent IR spectra of spherical and rod-shaped insulin nanoparticles prepared from DMSO and EtOH solution, respectively, are analyzed using principal component analysis (PCA) and 2D correlation spectroscopy to obtain a deeper understanding of the molecular structures and thermal behavior of the two insulin particle shapes. All-atom molecular dynamics (AAMD) calculations are performed to investigate the influence of the solvent molecules on the production of the insulin nanoparticles and to elucidate the geometric differences between the two types of nanoparticles. The results of the PCA, the 2D correlation spectroscopic analysis, and the AAMD calculations clearly reveal that the thermal denaturation mechanisms and the degrees of hydrogen bonding in the spherical and rod-shaped insulin nanoparticles are different. The polarity of the solvent might not alter the structure or function of the insulin produced, but the solvent polarity does influence the synthesis of different shapes of insulin nanoparticles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Understanding the Structural Differences between Spherical and Rod‐Shaped Human Insulin Nanoparticles Produced by Supercritical Fluids Precipitation

et al. 2014

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“…12 These reports suggest that the structural aspects of proteins in solution can be maintained after transfer into the gas phase. Utilizing the soft feature of ESI, numerous studies have successfully investigated protein conformations [13][14][15][16][17][18] and noncovalent protein assemblies. 19,20 The transfer of solution-phase structural information into the gas phase is an important prerequisite for the application of ESI-MS to characterize protein structures.…”

Section: Introductionmentioning

confidence: 99%

Solvent-induced structural transitions of lysozyme in an electrospray ionization source

Lee

Kim

2015

Analyst

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The structural characterization of proteins using electrospray ionization mass spectrometry (ESI-MS) has become an important method for understanding protein structural dynamics. The correlation between the structures of proteins in solution and gas phase needs to be understood for the application of ESI-MS to protein structural studies. Hen egg white lysozyme (Lyz) is a small protein with a stable compact structure in solution. Although it was known that denatured Lyz in solution undergoes compaction during transfer into the gas phase via ESI, detailed characterization of the process was not available. In the present study, we show that the organic cosolvent, which denatures Lyz in solution, induces the collapse of the extended Lyz structure into compact structures during ESI. This process is further facilitated by the presence of acids, whose conjugate bases can interact with Lyz to reduce its charge state and the electrostatic repulsion between its charged residues (Analyst, 2015, 140, 661-669). Exposure of ESI droplets to acid and solvent vapors confirms that the overall process most probably occurs in the charged droplets from ESI. This study provides a detailed understanding of the possible influence of the solvent environment on protein structure during transfer into the gas phase.

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“…[1][2][3] ALA has several partially folded intermediate states. In particular, the intermediate states of ALA that forms in the presence of oleic acid displays cytotoxic activity in cancer cells.…”

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confidence: 99%

“…The Tyr residue (Tyr36) is close to the Ca 2+ binding site. 1 Therefore, a change in the Tyr residues may affect the release of Ca 2+ in the A-state. Rearrangement of the β-turns also occurs in the A-state.…”

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Two‐Dimensional Correlation Analysis of pH‐induced Raman Spectral Changes of α‐Lactalbumin

Park

Kim

Vikram

et al. 2016

Bulletin Korean Chem Soc

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Bovine α-lactalbumin (ALA) assumes an intermediate state (or molten globule state) under various conditions, such as high pressure, low pH, heating, high concentration, and chemical denaturants.1-3 ALA has several partially folded intermediate states. In particular, the intermediate states of ALA that forms in the presence of oleic acid displays cytotoxic activity in cancer cells. 4 Elucidating the structural changes in ALA induced by various factors is of great importance. We previously investigated 1 pHinduced structural changes in the holo-form of bovine ALA during its transition from the native (N) state to the intermediate state by near-and far-UV circular dichroism, electrospray ionization ion mobility mass spectrometry, vibrational circular dichroism, and FTIR spectroscopy in both attenuated total reflection and transmission modes. We used principal component analysis (PCA) and twodimensional (2D) correlation spectroscopy to perform more in-depth analyses of pH-induced spectral changes at the molecular level. At low pH values, the acid (A) state of ALA is the classical molten globule (intermediate) state. The results of the spectroscopic analysis confirmed that the pH-induced transition of ALA from native to the A-state molten globule occurs through a variable twostate cooperative mechanism. The protonation of the side chain carboxyl groups on aspartate (Asp) and glutamate (Glu) residues and the release of calcium ion (Ca 2+ ) to induce structural changes at both the secondary and tertiary levels were also demonstrated.In this study, spectral changes in aromatic amino acid residues, such as tyrosine (Tyr) and tryptophan (Trp), in bovine holo-ALA were investigated at varying pH values by Raman spectroscopy. PCA and 2D correlation spectroscopy were applied to the pH-induced Raman spectra of bovine holo-ALA to obtain a deeper understanding of the conformational changes in the polypeptide backbone.Raman spectra that are rich in signatures coming from side chain vibrations and from vibrations of the polypeptide backbone facilitate the investigation of tertiary structure changes that triggers further unfolding process leading to the denatured state. 5,6 Figure 1 presents the Raman spectra of bovine holo-ALA obtained at pH values of from 7 to 1. Nearly all bands for the amide I, amide II, amide III, amide IV, and amide V regions with the 600-1750 cm −1 range were sensitive to pH changes. Information on the side chain bands of ALA below 1400 cm −1 was clearly observed. Changes in the relative intensities of the Tyr doublet bands at 830 and 850 cm −1 (R = I 850 /I 830 ) and the Trp doublet bands at 1356 and 1338 cm −1 (I 1356 /I 1338 ) were very clear. Tyr doublet bands are sensitive to hydrogen bonding by the phenolic hydroxyl group or to its ionization state, but are much less sensitive to changes in the environment around the benzene ring or in the conformation of the backbone.7-9 The R value decreased below pH 3.5, which is similar to the observation by Van Dael et al. 8 that the acid conformer at pH 2 has a ...

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The transition from the native to the acid-state characterized by multi-spectroscopy approach: Study for the holo-form of bovine α-lactalbumin

Cited by 25 publications

References 64 publications

Understanding the Structural Differences between Spherical and Rod‐Shaped Human Insulin Nanoparticles Produced by Supercritical Fluids Precipitation

Understanding the Structural Differences between Spherical and Rod‐Shaped Human Insulin Nanoparticles Produced by Supercritical Fluids Precipitation

Solvent-induced structural transitions of lysozyme in an electrospray ionization source

Two‐Dimensional Correlation Analysis of pH‐induced Raman Spectral Changes of α‐Lactalbumin

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