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Steinbach J, Fait F, Mayer HA, Kandelbauer A. Sol-Gel-Controlled Size and Morphology of Mesoporous Silica Microspheres Using Hard Templates. ACS OMEGA 2023; 8:30273-30284. [PMID: 37636943 PMCID: PMC10448668 DOI: 10.1021/acsomega.3c03098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/28/2023] [Indexed: 08/29/2023]
Abstract
Mesoporous silica microspheres (MPSMs) represent a promising material as a stationary phase for HPLC separations. The use of hard templates provides a preparation strategy for producing such monodisperse silica microspheres. Here, 15 MPSMs were systematically synthesized by varying the sol-gel reaction parameters of water-to-precursor ratio and ammonia concentration in the presence of a porous p(GMA-co-EDMA) polymeric hard template. Changing the sol-gel process factors resulted in a wide range of MPSMs with varying particle sizes from smaller than one to several micrometers. The application of response surface methodology allowed to derive quantitative predictive models based on the process factor effects on particle size, pore size, pore volume, and specific surface area of the MPSMs. A narrow size distribution of the silica particles was maintained over the entire experimental space. Two larger-scale batches of MPSMs were prepared, and the particles were functionalized with trimethoxy(octadecyl) silane for the application as stationary phase in reversed-phases liquid chromatography. The separation of proteins and amino acids was successfully accomplished, and the effect of the pore properties of the silica particles on separation was demonstrated.
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Affiliation(s)
- Julia
C. Steinbach
- Process Analysis
& Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstraße 150, Reutlingen 72762, Germany
- Institute of Inorganic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Fabio Fait
- Process Analysis
& Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstraße 150, Reutlingen 72762, Germany
- Institute of Inorganic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Hermann A. Mayer
- Institute of Inorganic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Andreas Kandelbauer
- Process Analysis
& Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstraße 150, Reutlingen 72762, Germany
- Institute of Wood Technology and Renewable
Materials, Department of Material Sciences and Process Engineering
(MAP), University of Natural Resources and
Life Sciences, Gregor-Mendel-Straße
33, Vienna 1180, Austria
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Farsang E, Lukács D, József S, Horváth K. Effect of time-invariant pressure gradients on peak formation and efficiency in ultrahigh-pressure liquid chromatography. J Chromatogr A 2023; 1704:464135. [PMID: 37302250 DOI: 10.1016/j.chroma.2023.464135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/02/2023] [Accepted: 06/04/2023] [Indexed: 06/13/2023]
Abstract
In chromatography, pressure can affect the retention factors of compounds significantly. In liquid chromatography, this effect is primarily related to the change in the molecular volume of solute during adsorption that is remarkably high for large biomolecules such as peptides and proteins. As a result, the migration velocities of chromatographic bands vary spatially through the column affecting the degree of band broadening. In this work, based on theoretical considerations, chromatographic efficiencies are studied under pressure-induced gradient conditions. The retention factor and migration velocity of different components are examined, and it is shown that components with the same retention time can have different migration patterns. The width of the initial band after injection is affected by the pressure gradient, providing significantly thinner initial bands for compounds with higher pressure sensitivity. In addition to classical band broadening phenomena, the influence of pressure gradients on band broadening is remarkable. The positive velocity gradient leads to extra band broadening. Our results clearly demonstrate that the zones are significantly wider at the end of the column if the change of molar volume of solute during adsorption is large. If the pressure drop is increasing, this effect becomes more significant. In the same time, the high release velocity of the bands somewhat counteracts the extra band broadening effect, however, it can not offset it perfectly. As a result, the separation efficiency of large biomolecules is decreased significantly due to the chromatographic pressure gradient. Under UHPLC conditions, the extent of apparent efficiency loss can reach up to 50% compared to the intrinsic efficiency of the column.
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Affiliation(s)
- Evelin Farsang
- Research Group of Analytical Chemistry, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - Diána Lukács
- Research Group of Analytical Chemistry, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - Simon József
- Research Group of Analytical Chemistry, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary; MS Metabolomics Research Laboratory, Centre for Structural Science, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Krisztián Horváth
- Research Group of Analytical Chemistry, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary.
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Agrawal N, Parisini E. Early Stages of Misfolding of PAP248-286 at two different pH values: An Insight from Molecular Dynamics Simulations. Comput Struct Biotechnol J 2022; 20:4892-4901. [PMID: 36147683 PMCID: PMC9474323 DOI: 10.1016/j.csbj.2022.08.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 01/01/2023] Open
Abstract
PAP248-286 peptides, which are highly abundant in human semen, aggregate and form amyloid fibrils that enhance HIV infection. Previous experimental studies have shown that the infection-promoting activity of PAP248-286 begins to increase well before amyloid formation takes place and that pH plays a key role in the enhancement of PAP248-286-related infection. Hence, understanding the early stages of misfolding of the PAP2482-86 peptide is crucial. To this end, we have performed 60 independent MD simulations for a total of 24 µs at two different pH values (4.2 and 7.2). Our data shows that early stages of misfolding of the PAP248-286 peptide is a multistage process and that the first step of the process is a transition from an “I-shaped” structure to a “U-shaped” structure. We further observed that the structure of PAP248-286 at the two different pH values shows significantly different features. At pH 4.2, the peptide has less intra-molecular H-bonds and a reduced α-helical content than at pH 7.2. Moreover, differences in intra-peptide residues contacts are also observed at the two pH values. Finally, free energy landscape analysis shows that there are more local minima in the energy surface of the peptide at pH 7.2 than at pH 4.2. Overall, the present study elucidates the early stages of misfolding of the PAP248-286 peptide at the atomic level, thus possibly opening new avenues in structure-based drug discovery against HIV infection.
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Affiliation(s)
- Nikhil Agrawal
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV, Riga 1006, Latvia
- College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
- Corresponding authors at: Latvian Institute of Organic Synthesis, Aizkraukles 21, LV, Riga 1006, Latvia.
| | - Emilio Parisini
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV, Riga 1006, Latvia
- Department of Chemistry “G. Ciamician”, University of Bologna, Bologna, Italy
- Corresponding authors at: Latvian Institute of Organic Synthesis, Aizkraukles 21, LV, Riga 1006, Latvia.
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Ahmad IAH, Losacco GL, Regalado EL. Nonlinear Predictive Modelling Enables In Silico Optimization of Chromatographic Methods for Complex Stationary Phase‑Analyte Interactions. LCGC EUROPE 2022. [DOI: 10.56530/lcgc.eu.uf5786p6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The development of robust analytical assays for separation and analysis of complex multicomponent mixtures can often be challenging, reflecting the increased complexity of new medicine and vaccine processes. In silico liquid chromatography (LC) method development strategies for small molecules have reached a mature stage across the pharmaceutical industry. However, a straightforward approach for large molecules remains elusive because of conformational changes that can often influence chromatographic retention. Nonetheless, an excellent correlation between experimental and predicted retention time is possible by deploying the correct regression retention models in terms of ln k vs. %B and ln k vs. 1/T (ΔtR < 0.1%). Excellent outcomes generated through in silico chromatographic method development of large molecules using different chaotropic and denaturing mobile phases are illustrated. Linear and nonlinear (polynomial regression) retention models using readily available software were deployed as a function of several chromatographic parameters (gradient slope and column temperature) for a variety of proteins (12–670 kDa) and peptides.
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Wahl O, Jorajuria S. Development and validation of a new UHPLC method for related proteins in insulin and insulin analogues as an alternative to the European Pharmacopoeia RP-HPLC method. J Pharm Biomed Anal 2019; 166:71-82. [DOI: 10.1016/j.jpba.2018.12.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 01/26/2023]
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Yu T, Lin M, Wan J, Cao X. Molecular interaction mechanisms in reverse micellar extraction of microbial transglutaminase. J Chromatogr A 2017; 1511:25-36. [PMID: 28697931 DOI: 10.1016/j.chroma.2017.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/23/2017] [Accepted: 07/03/2017] [Indexed: 11/17/2022]
Abstract
Reverse micellar extraction is an efficient and economical alternative for protein purification. In this study, microbial transglutaminase (MTGase) from crude materials was purified using reverse micellar extraction, and the molecular interaction mechanism in reverse micellar extraction of MTGase was explored. By using a molecular simulation study, the interaction mechanism of forward extraction was investigated. The molecular simulation results reveal the interaction of MTGase-water-surfactant is the major driving force for the forward extraction. Further, the effect of ionic strength on molecular interactions in backward extraction was investigated using 1H low-field nuclear magnetic resonance (LF-NMR) and circular dichroism (CD) spectra. In backward extraction, the interactions between water and the other two molecules (MTGase and surfactant molecules) are enhanced while the interactions between target molecules (MTGase) and the other two molecules (water and surfactant molecules) are weakened as the ionic strength increases. Moreover, the effect of size exclusion on backward extraction was also investigated. The results demonstrate size exclusion has limit effect at high ionic strength, and the weakened interaction of MTGase-water-surfactant is the main reason causing the release of the target molecules in backward extraction. This work might provide valuable reference to the MTGase purification and downstream processing.
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Affiliation(s)
- Tingting Yu
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Mingxiang Lin
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Junfen Wan
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Xuejun Cao
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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Mann BF, Makarov AA, Wang H, Welch CJ. Effects of pressure and frictional heating on protein separation using monolithic columns in reversed-phase chromatography. J Chromatogr A 2017; 1489:58-64. [DOI: 10.1016/j.chroma.2017.01.071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/21/2016] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
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Steady-migration retention characteristics of peptides under gradient elution: application towards a dynamic separation method for minor-adjustments of the retention of peptides in RPLC. Sci China Chem 2016. [DOI: 10.1007/s11426-016-0318-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Makarov AA, Helmy R. Combining size-exclusion chromatography with differential hydrogen–deuterium exchange to study protein conformational changes. J Chromatogr A 2016; 1431:224-230. [DOI: 10.1016/j.chroma.2015.12.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 12/25/2015] [Indexed: 01/12/2023]
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Makarov AA, Schafer WA, Helmy R. Use of pressure in reversed-phase liquid chromatography to study protein conformational changes by differential deuterium exchange. Anal Chem 2015; 87:2396-402. [PMID: 25620238 DOI: 10.1021/ac5043494] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The market of protein therapeutics is exploding, and characterization methods for proteins are being further developed to understand and explore conformational structures with regards to function and activity. There are several spectroscopic techniques that allow for analyzing protein secondary structure in solution. However, a majority of these techniques need to use purified protein, concentrated enough in the solution to produce a relevant spectrum. In this study, we describe a novel approach which uses ultrahigh pressure liquid chromatography (UHPLC) coupled with mass-spectrometry (MS) to explore compressibility of the secondary structure of proteins under increasing pressure detected by hydrogen-deuterium exchange (HDX). Several model proteins were used for these studies. The studies were conducted with UHPLC in isocratic mode at constant flow rate and temperature. The pressure was modified by a backpressure regulator up to about 1200 bar. It was found that the increase of retention factors upon pressure increase, at constant flow rate and temperature, was based on reduction of the proteins' molecular molar volume. The change in the proteins' molecular molar volume was caused by changes in protein folding, as was revealed by differential deuterium exchange. The degree of protein folding under certain UHPLC conditions can be controlled by pressure, at constant temperature and flow rate. By modifying pressure during UHPLC separation, it was possible to achieve changes in protein folding, which were manifested as changes in the number of labile protons exchanged to deuterons, or vice versa. Moreover, it was demonstrated with bovine insulin that a small difference in the number of protons exchanged to deuterons (based on protein folding under pressure) could be observed between batches obtained from different sources. The use of HDX during UHPLC separation allowed one to examine protein folding by pressure at constant flow rate and temperature in a mixture of sample solution with minimal amounts of sample used for analysis.
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Affiliation(s)
- Alexey A Makarov
- Department of Process and Analytical Chemistry, Merck Research Laboratories , 126 East Lincoln Ave., Rahway, New Jersey 07065, United States
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McCalley DV. The impact of pressure and frictional heating on retention, selectivity and efficiency in ultra-high-pressure liquid chromatography. Trends Analyt Chem 2014. [DOI: 10.1016/j.trac.2014.06.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Effect of pressure on the chromatographic separation of enantiomers under reversed-phase conditions. J Chromatogr A 2014; 1352:87-92. [DOI: 10.1016/j.chroma.2014.05.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/09/2014] [Accepted: 05/18/2014] [Indexed: 11/23/2022]
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