Protein denaturation by combined effect of shear and air-liquid interface

Maa, Yuh‐Fun; Hsu, Chia‐Wei

doi:10.1002/(sici)1097-0290(19970620)54:6<503::aid-bit1>3.0.co;2-n

Cited by 321 publications

(223 citation statements)

References 10 publications

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“…In both experiments, the air-liquid interface was present, yet this interfacial area alone was insufficient to drive aggregation upon milder agitation. We do not dispute the importance of the air-liquid interface in protein instability 32,33 but argue that the main factor determining protein aggregation in our experiments was the concentration of non-native species in solution. The observed disparity between the mild and rigorous agitation experiments can be explained by reversible changes in protein structure.…”

Section: Agitation-induced Mab Aggregationmentioning

confidence: 56%

The use of native cation‐exchange chromatography to study aggregation and phase separation of monoclonal antibodies

et al. 2010

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This study introduces a novel analytical approach for studying aggregation and phase separation of monoclonal antibodies (mAbs). The approach is based on using analytical scale cation-exchange chromatography (CEX) for measuring the loss of soluble monomer in the case of individual and mixed protein solutions. Native CEX outperforms traditional size-exclusion chromatography in separating complex protein mixtures, offering an easy way to assess mAb aggregation propensity. Different IgG1 and IgG2 molecules were tested individually and in mixtures consisting of up to four protein molecules. Antibody aggregation was induced by four different stress factors: high temperature, low pH, addition of fatty acids, and rigorous agitation. The extent of aggregation was determined from the amount of monomeric protein remaining in solution after stress. Consequently, it was possible to address the role of specific mAb regions in antibody aggregation by co-incubating Fab and Fc fragments with their respective full-length molecules. Our results revealed that the relative contribution of Fab and Fc regions in mAb aggregation is strongly dependent on pH and the stress factor applied. In addition, the CEX-based approach was used to study reversible protein precipitation due to phase separation, which demonstrated its use for a broader range of protein-protein association phenomena. In all cases, the role of Fab and Fc was clearly dissected, providing important information for engineering more stable mAb-based therapeutics.

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Section: Agitation-induced Mab Aggregationmentioning

confidence: 56%

The use of native cation‐exchange chromatography to study aggregation and phase separation of monoclonal antibodies

et al. 2010

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“…38 Further studies on both samples showed that rhGH denatured upon exposure to high shear in the presence of an air-liquid interface whereas rhDNase remained relatively stable. 64 The stability of rhDNase was attributed to its comparatively high surface tension and low foaming tendency in solution.…”

Section: Effects Of Shear Flow On Protein Structure and Functionmentioning

confidence: 99%

“…Several studies show that the initial destabilization of the protein structure occurs at the solvent-air or solvent-solid interface, where surface tension forces unfold the native protein. 36,37,64,79 The air-water interfacial force is estimated to be 140 pN, 80 taking the air-water interface to be 2 nm in depth with a 0.07 N/m surface tension. 81 This value is comparable to the 150 pN observed to unfold globular proteins in atomic force microscopy studies.…”

Section: Protein Aggregationmentioning

confidence: 99%

“…121,132,133 However, it has been established that the shear-stability of a protein molecule depends on: (i) its primary structure and molecular weight (ii) the magnitude of shear strain and the duration of its application, and (iii) the viscosity of its surrounding medium. 31,64,65 Therefore, these factors must be taken in consideration for a complete understanding of the shear-stability of protein systems. Advancing knowledge in this field will be crucial for the design of processes, especially in the bioprocessing industry, to ensure protein stability, maintain functionality, and promote process yield.…”

Section: Implications In Physiology and Bioprocessingmentioning

confidence: 99%

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The effects of shear flow on protein structure and function

Bekard

Asimakis

Bertolini³

et al. 2011

Biopolymers

180

140

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Toxoplasma gondii usually causes an asymptomatic and then latent infection in human adults; however, a potentially fatal disseminated form can occur in immunocompromised patients. Given that the diagnosis of acute Toxoplasma infection, as opposed to latent disease, relies on finding direct evidence of T. gondii infection in tissue, pathologic examination is critical. There have only been a few reports describing the cytomorphology of Toxoplasma in exfoliative cytology, and no reports of the findings in Thin Prep. In this report, we describe a fatal case of toxoplasmosis in a cardiac transplant patient that was diagnosed by respiratory cytopathology. Although the extracellular organisms were well visualized on the Wright‐Giemsa stained cytospin, they were only faintly seen on the Pap‐stained cytospin trapped within mucin and were not easily appreciated on the ThinPrep slides nor the H&E stained cell block sections. An immunohistochemical stain for Toxoplasma performed on the cell block was strongly positive, and an autopsy performed on the patient confirmed disseminated infection. Our case illustrates that the diagnosis of Toxoplasma in exfoliative cytology specimens can be challenging since organisms are not well visualized on ThinPrep or Pap‐stained material; therefore, Wright‐Giemsa stained material can be particularly helpful. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.

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“…It has been reported for example that shear flows increase protein adsorption [86], which is obviously of interest in the context of the human circulatory system where shear rates can vary from 1 sec -1 to 10 5 sec -1 [90]. However, while protein aggregation has been studied at high shear flow rates (10 6 sec -1 ) [91,92] adsorption to surfaces is yet to be probed under these conditions. Further, it is generally believed that in multi-component systems, smaller proteins adsorb fastest, which are then displaced by larger ones [83,85].…”

Section: Introductionmentioning

confidence: 99%

Electrospray–differential mobility analysis of bionanoparticles

Guha

Tarlov

et al. 2012

Trends in Biotechnology

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The growth of the multibillion dollar bionanoparticle industry has spurred the development of new physical characterization methods. One such method, electrospraydifferential mobility analysis (ES-DMA) constitutes an electrospray for aerosolization of bionanoparticles (such as viruses, gold-nanoparticles, proteins, nanoparticle-protein complexes) and an ion mobility method that operates at atmospheric conditions, and separates bionanoparticles spatially. This dissertation identifies some relevant "problem" areas for ES-DMA by reviewing selected applications.Some such problems are: proteins while passing through ES capillaries are found to interact with it and thus produce time dependent size distributions. Further, it is thought that adsorbed proteins may subsequently desorb and influence size distributions with the ES-DMA which may concomitantly affect quantification of aggregates. These artifacts are studied systematically and it is demonstrated that ES-DMA can quantify adsorption-desorption of complex protein mixtures at high shear rates. Further, it is shown that desorbing proteins do not have a significant effect on size distributions. Another artifact of the ES takes place during the aersolization process. Two units (called monomers) of a bionanoparticle may get encapsulated in the same ES droplet and upon drying of the droplet create artificial dimers thus affecting quantification with ES-DMA. Assuming Poisson distribution, this thesis provides a systematic approach that can be undertaken to eliminate this artifact. A third artifact arises from the low sensitivity of the DMA to size increase. When a ligand (for e.g. protein) adsorbs to a bionanoparticle it creates an increase in the size of the later, which can be used to quantify the amount of ligand adsorbed per bionanoparticle. As ligands can change conformations upon adsorption, using ES-DMA for such applications may be flawed. This issue has been identified and a solution has been provided by integrating a mass analyzer after the ES-DMA.After correcting for these artifacts, this dissertation delves into characterization of different types of bionanoparticles and demonstrates that ES-DMA has several advantages over other traditional techniques such as transmission electron microscopy, size exclusion chromatography, analytical ultracentrifugation, dynamic light scattering and plaque assay and thus has immense potential to become a process analytical technique in biomanufacturing environments. ELECTROSPRAY-DIFFERENTIAL MOBILITY ANALYSIS OF BIONANOPARTICLES

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Protein denaturation by combined effect of shear and air-liquid interface

Cited by 321 publications

References 10 publications

The use of native cation‐exchange chromatography to study aggregation and phase separation of monoclonal antibodies

The use of native cation‐exchange chromatography to study aggregation and phase separation of monoclonal antibodies

The effects of shear flow on protein structure and function

Electrospray–differential mobility analysis of bionanoparticles

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