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Atta H, Mahmoud KR, Salim ESI, Elmohsnawy E, El-Shaer A. Correlation between positron annihilation lifetime and photoluminescence measurements for calcined Hydroxyapatite. Sci Rep 2024; 14:10370. [PMID: 38710708 DOI: 10.1038/s41598-024-59855-1] [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: 11/27/2023] [Accepted: 04/16/2024] [Indexed: 05/08/2024] Open
Abstract
Hydroxyapatite (HAp) Ca10(PO4)6(OH)2 is a compound that has stable chemical properties, composition, and an affinity for human bone. As a result, it can be used in odontology, cancer treatment, and orthopedic grafts to repair damaged bone. To produce calcined HAp at 600 °C with different pH values, a wet chemical precipitation method was employed. All synthesized HAp samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL), Zeta potential, and positron annihilation lifetime spectroscopy (PALS). The XRD results revealed that all calcined HAp samples were formed in a hexagonal structure with a preferred (002) orientation at different pH values. The crystal size of the samples was determined using the Scherrer equation, which ranged from 16 to 25 nm. The SEM and TEM results showed that the morphology of the samples varied from nanorods to nanospheres and rice-like structures depending on the pH value of the sample. The PL measurements indicated that the blue and green emission peaks of HAp were due to defects (bulk, surface, and interface) in the samples, which created additional energy levels within the band gap. According to Zeta potential measurements, the charge carrier changed from a positive to negative value, ranging from 3.94 mV to - 2.95 mV. PALS was used to understand the relationship between the defects and the photoluminescence (PL) properties of HAp. Our results suggest that HAp nanoparticles have excellent potential for developing non-toxic biomedical and optical devices for phototherapy.
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Affiliation(s)
- Hoda Atta
- Physics Department, Faculty of Science, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.
| | - Kamal R Mahmoud
- Physics Department, Faculty of Science, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.
| | - El Sayed I Salim
- Research Lab. of Molecular Carcinogenesis, Zoology Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Eithar Elmohsnawy
- Department of Botany, Faculty of Science, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt
| | - Abdelhamid El-Shaer
- Physics Department, Faculty of Science, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.
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Gupta D, Kumari R, Kumar M, Singh M, Rawat S, Ethayathulla AS, Kaur P. Influence of different pH milieu on the structure and function of human Aurora kinase B protein (AURK-B): Amalgamation of both spectroscopic and computational approach. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 312:124047. [PMID: 38394881 DOI: 10.1016/j.saa.2024.124047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 02/08/2024] [Accepted: 02/10/2024] [Indexed: 02/25/2024]
Abstract
Aurora kinase B (AURK-B) is a serine/threonine kinase protein that plays an essential role in chromosomal separation during the cell cycle event. AURK-B is highly expressed in various types of cancer such as human seminoma, thyroid carcinoma, non-small cell lung carcinoma (NSCLC), oral carcinoma, and gastric cancer. Hence, it is a potential therapeutic target in the treatment of various cancers. The structure of AURK-B in complex with one of its substrate inner centromeric protein (INCENP) is present, but the structural and functional characterization of native AURK-B at different pH environment is still unexplored.This study determines the effect of different pH milieu on the structure and function of AURK-B protein wherein the influence of pH on the protein conformation was probed using Circular dichroism (CD) and fluorescence spectroscopy. The structural studies were further combined with functional activity assay to observe the change in kinase activity at various pH milieu (2.0-11.0). CD and fluorescence spectroscopy experiments dictate that at high acidic conditions (pH 2.0 - 5.0), the secondary and tertiary structures of AURK-B become distorted, leading to diminished activity. The protein, however, was observed to stabilize towards pH 7.0 - 8.0 with minimal structure alteration over the basic pH range (pH 9.0 -11.0). The measured spectroscopic structural features were found to be in-line with obtained experimental kinase activity assays. Further, in-vitro experiments indicate that the enzyme is maximally active at pH 8.0. More ordered conformation and compact structure was observed at this pH (pH 8.0) as compared to other pH values through molecular dynamics simulation studies (MDS). As AURK-B localizes itself in the intracellular compartment, this study may provide a clue about the role of different pH environments in enhancing cancer growth, proliferation, and invasion.
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Affiliation(s)
- Deepali Gupta
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Renu Kumari
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Mukesh Kumar
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Mandeep Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Shivani Rawat
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - A S Ethayathulla
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Punit Kaur
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India.
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Božič A, Podgornik R. Changes in total charge on spike protein of SARS-CoV-2 in emerging lineages. BIOINFORMATICS ADVANCES 2024; 4:vbae053. [PMID: 38645718 PMCID: PMC11031363 DOI: 10.1093/bioadv/vbae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/13/2024] [Accepted: 04/04/2024] [Indexed: 04/23/2024]
Abstract
Motivation Charged amino acid residues on the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been shown to influence its binding to different cell surface receptors, its non-specific electrostatic interactions with the environment, and its structural stability and conformation. It is therefore important to obtain a good understanding of amino acid mutations that affect the total charge on the spike protein which have arisen across different SARS-CoV-2 lineages during the course of the virus' evolution. Results We analyse the change in the number of ionizable amino acids and the corresponding total charge on the spike proteins of almost 2200 SARS-CoV-2 lineages that have emerged over the span of the pandemic. Our results show that the previously observed trend toward an increase in the positive charge on the spike protein of SARS-CoV-2 variants of concern has essentially stopped with the emergence of the early omicron variants. Furthermore, recently emerged lineages show a greater diversity in terms of their composition of ionizable amino acids. We also demonstrate that the patterns of change in the number of ionizable amino acids on the spike protein are characteristic of related lineages within the broader clade division of the SARS-CoV-2 phylogenetic tree. Due to the ubiquity of electrostatic interactions in the biological environment, our findings are relevant for a broad range of studies dealing with the structural stability of SARS-CoV-2 and its interactions with the environment. Availability and implementation The data underlying the article are available in the Supplementary material.
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Affiliation(s)
- Anže Božič
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana 1000, Slovenia
| | - Rudolf Podgornik
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
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Popova TO, Zhulina EB, Borisov OV. Interaction of Polyanionic and Polycationic Brushes with Globular Proteins and Protein-like Nanocolloids. Biomimetics (Basel) 2023; 8:597. [PMID: 38132536 PMCID: PMC10741738 DOI: 10.3390/biomimetics8080597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/25/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
A large number of experimental studies have demonstrated that globular proteins can be absorbed from the solution by both polycationic and polyanionic brushes when the net charge of protein globules is of the same or of the opposite sign with respect to that of brush-forming polyelectrolyte chains. Here, we overview the results of experimental studies on interactions between globular proteins and polycationic or polyanionic brushes, and present a self-consistent field theoretical model that allows us to account for the asymmetry of interactions of protein-like nanocolloid particles comprising weak (pH-sensitive) cationic and anionic groups with a positively or negatively charged polyelectrolyte brush. The position-dependent insertion free energy and the net charge of the particle are calculated. The theoretical model predicts that if the numbers of cationic and anionic ionizable groups of the protein are approximately equal, then the interaction patterns for both cationic and anionic brushes at equal offset on the "wrong side" from the isoelectric point (IEP), i.e., when the particle and the brush charge are of the same sign, are similar. An essential asymmetry in interactions of particles with polycationic and polyanionic brushes is predicted when fractions of cationic and anionic groups differ significantly. That is, at a pH above IEP, the anionic brush better absorbs negatively charged particles with a larger fraction of ionizable cationic groups and vice versa.
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Affiliation(s)
- Tatiana O. Popova
- Chemical Engineering Center, National Research University ITMO, 199004 St. Petersburg, Russia;
- Institute of Macromolecular Compoundsof the Russian Academy of Sciences, 199004 St. Petersburg, Russia;
| | - Ekaterina B. Zhulina
- Institute of Macromolecular Compoundsof the Russian Academy of Sciences, 199004 St. Petersburg, Russia;
| | - Oleg V. Borisov
- Chemical Engineering Center, National Research University ITMO, 199004 St. Petersburg, Russia;
- Institute of Macromolecular Compoundsof the Russian Academy of Sciences, 199004 St. Petersburg, Russia;
- CNRS, Université de Pau et des Pays de l’Adour UMR 5254, Institut des Sciences Analytiques et de Physico-Chimie Pour l’Environnement et les Matériaux, 64053 Pau, France
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Contardo I, Guzmán F, Enrione J. Conformational and Structural Changes in Chickpea Proteins Caused by Simulated Salivary Alterations in the Elderly. Foods 2023; 12:3668. [PMID: 37835321 PMCID: PMC10572786 DOI: 10.3390/foods12193668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
The impact of salivary alterations on chickpea protein structure in the elderly has not been well documented. This study aimed to understand the role of simulated salivary alterations in the conformational properties and secondary structure of the chickpea protein isolate (CPI). Whey protein isolate (WPI) was used as the reference. Protein dispersions (10%) were subjected to in vitro oral processing under simulated salivary conditions in both the elderly and adult subjects. Proteins and their oral counterparts were characterized in terms of their composition, charge, size, solubility, water absorption, molecular weight (MW), and secondary structure (Circular Dichroism and Raman spectroscopy). Under condition of simulated oral digestion in the elderly population, the ordered secondary protein structure was significantly affected, decreasing α-helix by ~36% and ~29% in CPI and WPI compared to the control (adult) population, respectively. An increase in the unordered random coil state was observed. These results could be attributed to an increase in electrolytes in the salivary composition. The structure of CPI is more stable than that of WPI because of its higher MW, more rigid structure, less charged surface, and different amino acid compositions. This study is meaningful in understanding how alterations in the elderly oral system affect protein conformation and is expected to improve the understanding of plant-based protein digestibility.
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Affiliation(s)
- Ingrid Contardo
- Biopolymer Research and Engineering Laboratory (BiopREL), School of Nutrition and Dietetics, Faculty of Medicine, Universidad de los Andes, Chile, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago 7620086, Chile;
- Centro de Investigación e Innovación Biomédica (CIIB), Universidad de los Andes, Chile, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago 7620086, Chile
| | - Fanny Guzmán
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile;
| | - Javier Enrione
- Biopolymer Research and Engineering Laboratory (BiopREL), School of Nutrition and Dietetics, Faculty of Medicine, Universidad de los Andes, Chile, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago 7620086, Chile;
- Centro de Investigación e Innovación Biomédica (CIIB), Universidad de los Andes, Chile, Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago 7620086, Chile
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Konevtsova OV, Golushko IY, Podgornik R, Rochal SB. Integration of Cypoviruses into polyhedrin matrix. NANOSCALE ADVANCES 2023; 5:4140-4148. [PMID: 37560430 PMCID: PMC10408579 DOI: 10.1039/d3na00393k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/14/2023] [Indexed: 08/11/2023]
Abstract
Unlike in other viruses, in Cypoviruses the genome is doubly protected since their icosahedral capsids are embedded into a perfect polyhedrin crystal. Current experimental methods cannot resolve the resulting interface structure and we propose a symmetry-based approach to predict it. We reveal a remarkable match between the surfaces of Cypovirus and the outer polyhedrin matrix. The match arises due to the preservation of the common tetragonal symmetry, allowing perfect contacts of polyhedrin trimers with VP1 and VP5 capsid proteins. We highlight a crucial role of the VP5 proteins in embedding the Cypovirus into the polyhedrin matrix and discuss the relationship between the nucleoside triphosphatase activity of the proteins and their role in the superstructure formation. Additionally, we propose an electrostatic mechanism that drives the viral superstructure disassembly occurring in the alkaline environment of the insect intestines. Our study may underpin novel strategies for engineering proteinaceous nanocontainers in diverse biotechnological and chemical applications.
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Affiliation(s)
| | - Ivan Yu Golushko
- Physics Faculty, Southern Federal University Rostov-on-Don Russia
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences Beijing 100049 China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100190 China
- Wenzhou Institute of the University of Chinese Academy of Sciences Wenzhou Zhejiang 325000 China
| | - Sergei B Rochal
- Physics Faculty, Southern Federal University Rostov-on-Don Russia
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Nath H, Sarmah RJ, Kundu S. Langmuir monolayer of lysozyme at variable subphase pH conditions: a comprehensive study on structure, morphology and hysteresis behaviour. RSC Adv 2023; 13:22789-22799. [PMID: 37520086 PMCID: PMC10373444 DOI: 10.1039/d3ra03710j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 07/15/2023] [Indexed: 08/01/2023] Open
Abstract
Formation of a pure Langmuir monolayer of lysozyme at the air-water interface and its investigation by means of a surface pressure (π)-mean molecular area (A) isotherm has been accomplished under different subphase pH conditions. A normalized area-time curve confirms the stable nature of the lysozyme monolayer whose compressibility variation with an increased surface pressure at specific subphase pH has also been studied from π-A isotherms. The monolayers exhibit irreversible hysteresis behaviour irrespective of subphase pH conditions, as evidenced from successive compression-expansion π-A isotherm cycles. Comparison of surface thermodynamics under hysteresis with subphase pH variation confirms that the monolayer at subphase pH ≈ 4.0 involves a greater amount of energy to attain and retain the ordered and compact monolayer than the other two pH conditions (pH ≈ 7.0 and 9.5). In situ visualization of lysozyme monolayers by Brewster angle microscopy suggests the homogeneous and stripe-like pattern formation at lower and higher surface pressure respectively. Further investigations of lysozyme films at solid surfaces have been carried out with atomic force microscopy and X-ray reflectivity (XRR) analysis. Structural reversibility of lysozyme molecules under compression-expansion-compression of the monolayer is revealed from the comparison of height profiles of AFM images and electron density profiles as extracted from XRR analysis of the films deposited during both first and second compressions of the monolayer. The mechanism of the structural rearrangement of lysozyme molecules with surface pressure variation at different subphase pH is explored, correlating macroscopic and microscopic information.
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Affiliation(s)
- Himadri Nath
- Soft Nano Laboratory (SNL), Physical Sciences Division, Institute of Advanced Study in Science and Technology (IASST) Vigyan Path, Paschim Boragaon, Garchuk Guwahati Assam 781035 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
| | - Raktim J Sarmah
- Soft Nano Laboratory (SNL), Physical Sciences Division, Institute of Advanced Study in Science and Technology (IASST) Vigyan Path, Paschim Boragaon, Garchuk Guwahati Assam 781035 India
| | - Sarathi Kundu
- Soft Nano Laboratory (SNL), Physical Sciences Division, Institute of Advanced Study in Science and Technology (IASST) Vigyan Path, Paschim Boragaon, Garchuk Guwahati Assam 781035 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
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8
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Božič A, Podgornik R. Evolutionary changes in the number of dissociable amino acids on spike proteins and nucleoproteins of SARS-CoV-2 variants. Virus Evol 2023; 9:vead040. [PMID: 37583936 PMCID: PMC10424713 DOI: 10.1093/ve/vead040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/12/2023] [Accepted: 06/27/2023] [Indexed: 08/17/2023] Open
Abstract
The spike protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for target recognition, cellular entry, and endosomal escape of the virus. At the same time, it is the part of the virus that exhibits the greatest sequence variation across the many variants which have emerged during its evolution. Recent studies have indicated that with progressive lineage emergence, the positive charge on the spike protein has been increasing, with certain positively charged amino acids (AAs) improving the binding of the spike protein to cell receptors. We have performed a detailed analysis of dissociable AAs of more than 1400 different SARS-CoV-2 lineages, which confirms these observations while suggesting that this progression has reached a plateau with Omicron and its subvariants and that the positive charge is not increasing further. Analysis of the nucleocapsid protein shows no similar increase in positive charge with novel variants, which further indicates that positive charge of the spike protein is being evolutionarily selected for. Furthermore, comparison with the spike proteins of known coronaviruses shows that already the wild-type SARS-CoV-2 spike protein carries an unusually large amount of positively charged AAs when compared to most other betacoronaviruses. Our study sheds light on the evolutionary changes in the number of dissociable AAs on the spike protein of SARS-CoV-2, complementing existing studies and providing a stepping stone towards a better understanding of the relationship between the spike protein charge and viral infectivity and transmissibility.
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Affiliation(s)
- Anže Božič
- Department of Theoretical Physics, Jožef Stefan Institute, Jamova 39, Ljubljana SI-1000, Slovenia
| | - Rudolf Podgornik
- School of Physical Sciences, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, No. 3 Nanyitiao, Zhongguancun, Haidian District, Beijing 100049, China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, No. 8 3rd South Street, Zhongguancun, Haidian District, Beijing 100190, China
- Wenzhou Institute of the University of Chinese Academy of Sciences, No.1 Jinlian Road, Wenzhou, Zhejiang 325001, China
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, Ljubljana SI-1000, Slovenia
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9
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Blanco PM, Narambuena CF, Madurga S, Mas F, Garcés JL. Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes. Polymers (Basel) 2023; 15:2680. [PMID: 37376324 DOI: 10.3390/polym15122680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023] Open
Abstract
This article reviews the state of the art of the studies on charge regulation (CR) effects in flexible weak polyelectrolytes (FWPE). The characteristic of FWPE is the strong coupling of ionization and conformational degrees of freedom. After introducing the necessary fundamental concepts, some unconventional aspects of the the physical chemistry of FWPE are discussed. These aspects are: (i) the extension of statistical mechanics techniques to include ionization equilibria and, in particular, the use of the recently proposed Site Binding-Rotational Isomeric State (SBRIS) model, which allows the calculation of ionization and conformational properties on the same foot; (ii) the recent progresses in the inclusion of proton equilibria in computer simulations; (iii) the possibility of mechanically induced CR in the stretching of FWPE; (iv) the non-trivial adsorption of FWPE on ionized surfaces with the same charge sign as the PE (the so-called "wrong side" of the isoelectric point); (v) the influence of macromolecular crowding on CR.
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Affiliation(s)
- Pablo M Blanco
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Claudio F Narambuena
- Grupo de Bionanotecnologia y Sistemas Complejos, Infap-CONICET & Facultad Regional San Rafael, Universidad Tecnológica Nacional, San Rafael 5600, Argentina
| | - Sergio Madurga
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Francesc Mas
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Josep L Garcés
- Chemistry Department, Technical School of Agricultural Engineering & AGROTECNIO, Lleida University (UdL), 25003 Lleida, Catalonia, Spain
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Meunier-Carmenate Y, Valdés-García G, Maya-Martinez R, French-Pacheco L, Fernández-Silva A, González-Onofre Y, Millan-Pacheco C, Pastor N, Amero C. Unfolding and Aggregation Pathways of Variable Domains from Immunoglobulin Light Chains. Biochemistry 2023; 62:1000-1011. [PMID: 36802343 DOI: 10.1021/acs.biochem.2c00704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Light chain amyloidosis is the most common form of systemic amyloidosis. This disease is caused by the formation and deposition of amyloid fibers made from immunoglobulin light chains. Environmental conditions such as pH and temperature can affect protein structure and induce the development of these fibers. Several studies have shed light on the native state, stability, dynamics, and final amyloid state of these proteins; however, the initiation process and the fibril formation pathway remain poorly understood structurally and kinetically. To study this, we analyzed the unfolding and aggregation process of the 6aJL2 protein under acidic conditions, with temperature changes, and upon mutation, using biophysical and computational techniques. Our results suggest that the differences in amyloidogenicity displayed by 6aJL2 under these conditions are caused by traversing different aggregation pathways, including unfolded intermediates and the formation of oligomers.
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Affiliation(s)
- Yadira Meunier-Carmenate
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Gilberto Valdés-García
- Centro de Investigacion en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Roberto Maya-Martinez
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Leidys French-Pacheco
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Arline Fernández-Silva
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Yoselin González-Onofre
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Cesar Millan-Pacheco
- Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Nina Pastor
- Centro de Investigacion en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
| | - Carlos Amero
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Morelos, Mexico
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Funk RHW, Scholkmann F. The significance of bioelectricity on all levels of organization of an organism. Part 1: From the subcellular level to cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:185-201. [PMID: 36481271 DOI: 10.1016/j.pbiomolbio.2022.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/24/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022]
Abstract
Bioelectricity plays an essential role in the structural and functional organization of biological organisms. In this first article of our three-part series, we summarize the importance of bioelectricity for the basic structural level of biological organization, i.e. from the subcellular level (charges, ion channels, molecules and cell organelles) to cells.
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Affiliation(s)
- Richard H W Funk
- Institute of Anatomy, Center for Theoretical Medicine, TU-Dresden, 01307, Dresden, Germany; Dresden International University, 01067, Dresden, Germany.
| | - Felix Scholkmann
- Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland.
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12
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Schwahn AB, Baek J, Lin S, Pohl CA, Cook K. A Universal Eluent System for Method Scouting and Separation of Biotherapeutic Proteins by Ion-Exchange, Size-Exclusion, and Hydrophobic Interaction Chromatography. Anal Chem 2022; 94:16369-16375. [DOI: 10.1021/acs.analchem.2c03531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - Julia Baek
- Thermo Fisher Scientific, Sunnyvale, California94085, United States
| | - Shanhua Lin
- Thermo Fisher Scientific, Sunnyvale, California94085, United States
| | | | - Ken Cook
- Thermo Fisher Scientific, Hemel Hempstead, HertfordshireHP2 7GE, U.K
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13
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Rochal SB, Konevtsova OV, Roshal DS, Božič A, Golushko IY, Podgornik R. Packing and trimer-to-dimer protein reconstruction in icosahedral viral shells with a single type of symmetrical structural unit. NANOSCALE ADVANCES 2022; 4:4677-4688. [PMID: 36341291 PMCID: PMC9595183 DOI: 10.1039/d2na00461e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Understanding the principles of protein packing and the mechanisms driving morphological transformations in virus shells (capsids) during their maturation can be pivotal for the development of new antiviral strategies. Here, we study how these principles and mechanisms manifest themselves in icosahedral viral capsids assembled from identical symmetric structural units (capsomeres). To rationalize such shells, we model capsomers as symmetrical groups of identical particles interacting with a short-range potential typical of the classic Tammes problem. The capsomere particles are assumed to retain their relative positions on the vertices of planar polygons placed on the spherical shell and to interact only with the particles from other capsomeres. Minimization of the interaction energy enforces equal distances between the nearest particles belonging to neighboring capsomeres and minimizes the number of different local environments. Thus, our model implements the Caspar and Klug quasi-equivalence principle and leads to packings strikingly similar to real capsids. We then study a reconstruction of protein trimers into dimers in a Flavivirus shell during its maturation, connecting the relevant structural changes with the modifications of the electrostatic charges of proteins, wrought by the oxidative switch in the bathing solution that is essential for the process. We highlight the key role of pr peptides in the shell reconstruction and show that the highly ordered arrangement of these subunits in the dimeric state is energetically favored at a low pH level. We also discuss the electrostatic mechanisms controlling the release of pr peptides in the last irreversible step of the maturation process.
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Affiliation(s)
- Sergei B Rochal
- Physics Faculty, Southern Federal University Rostov-on-Don Russia
| | | | - Daria S Roshal
- Physics Faculty, Southern Federal University Rostov-on-Don Russia
| | - Anže Božič
- Department of Theoretical Physics, Jožef Stefan Institute SI-1000 Ljubljana Slovenia
| | - Ivan Yu Golushko
- Physics Faculty, Southern Federal University Rostov-on-Don Russia
| | - Rudolf Podgornik
- Department of Theoretical Physics, Jožef Stefan Institute SI-1000 Ljubljana Slovenia
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana SI-1000 Ljubljana Slovenia
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences Beijing 100049 China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100190 China
- Wenzhou Institute of the University of Chinese Academy of Sciences Wenzhou Zhejiang 325000 China
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14
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Fu Q, Xie D, Ge J, Zhang W, Shan H. Negatively Charged Composite Nanofibrous Hydrogel Membranes for High-Performance Protein Adsorption. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12193500. [PMID: 36234628 PMCID: PMC9565482 DOI: 10.3390/nano12193500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/26/2022] [Accepted: 10/01/2022] [Indexed: 06/02/2023]
Abstract
Nanofibrous materials are considered as promising candidates for fabricating high-efficiency chromatography media, which are urgently needed in protein pharmaceuticals purification and biological research, yet still face several bottlenecks. Herein, novel negatively charged composite nanofibrous hydrogel membranes (NHMs) are obtained by a facile combination of electrospinning and surface coating modification. The resulting NHMs exhibit controllable morphologies and chemical structures. Benefitting from the combined effect of the stable framework of silicon dioxide (SiO2) nanofiber and the function layer of negatively charged hydrogel, as well as good pore connectivity among nanofibers, NHMs exhibit a high protein adsorption capacity of around 1000 mg g-1, and are superior to the commercial cellulose fibrous adsorbent (Sartobind®) and the reported nanofibrous membranous adsorbents. Moreover, due to their relatively stable physicochemical and mechanical properties, NHMs possess comprehensive adsorption performance, favorable resistance to acid and solvents, good selectivity, and excellent regenerability. The designed NHMs composite adsorbents are expected to supply a new protein chromatography platform for effective protein purification in biopharmaceuticals and biochemical reagents.
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Affiliation(s)
- Qiuxia Fu
- School of Textile and Clothing, Nantong University, Nantong 226019, China
- National and Local Joint Engineering Research Center of Technical Fiber Composites for Safety and Health, Nantong University, Nantong 226019, China
| | - Dandan Xie
- School of Textile and Clothing, Nantong University, Nantong 226019, China
| | - Jianlong Ge
- School of Textile and Clothing, Nantong University, Nantong 226019, China
| | - Wei Zhang
- School of Textile and Clothing, Nantong University, Nantong 226019, China
- National and Local Joint Engineering Research Center of Technical Fiber Composites for Safety and Health, Nantong University, Nantong 226019, China
| | - Haoru Shan
- School of Textile and Clothing, Nantong University, Nantong 226019, China
- National and Local Joint Engineering Research Center of Technical Fiber Composites for Safety and Health, Nantong University, Nantong 226019, China
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15
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Blanco PM, Achetoni MM, Garcés JL, Madurga S, Mas F, Baieli MF, Narambuena CF. Adsorption of flexible proteins in the 'wrong side' of the isoelectric point: Casein macropeptide as a model system. Colloids Surf B Biointerfaces 2022; 217:112617. [PMID: 35738075 DOI: 10.1016/j.colsurfb.2022.112617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/10/2022] [Accepted: 06/06/2022] [Indexed: 01/05/2023]
Abstract
We analyze the conditions of the adsorption of a flexible peptide onto a charged substrate in the 'wrong side' of the isoelectric point (WSIP), i.e. when surface and peptide charges have the same sign. As a model system, we focus on the casein macropeptide (CMP), both in the aglycosylated (aCMP) and fully glycosydated (gCMP) forms. We model the substrate as a uniformly charged plane while CMP is treated as a bead-and-spring model including electrostatic interactions, excluded volume effects and acid/base equilibria. Adsorption coverage, aminoacid charges and concentration profiles are computed by means of Monte Carlo simulations at fixed pH and salt concentration. We conclude that for different reasons the CMP can be adsorbed to both positively and negatively charged surfaces in the WSIP. For negatively charged surfaces, WSIP adsorption is due to the patchy distribution of charges: the peptide is attached to the surface by the positively charged end of the chain, while the repulsion of the surface for the negatively charged tail is screened by the small ions of the added salt. This effect increases with salt concentration. Conversely, a positively charged substrate induces strong charge regulation of the peptide: the acidic groups are deprotonated, and the peptide becomes negatively charged. This effect is stronger at low salt concentrations and it is more intense for gCMP than for aCMP, due to the presence of the additional sialic groups in gCMP.
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Affiliation(s)
- Pablo M Blanco
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 00 Prague 2, Czech Republic; Department of Material Science and Physical Chemistry & Institute of Theoretical and Computational Chemistry (IQTC), University of Barcelona, C/ Martí i Franquès, 1, 08028 Barcelona, Catalonia, Spain
| | - Micaela M Achetoni
- Universidad Tecnología Nacional & Grupo Bionanotecnología y Sistemas Complejos. (UTN-CONICET), Facultad Regional San Rafael, Av. General Urquiza 314C.P.:5600, San Rafael, Mendoza, Argentina
| | - Josep L Garcés
- Department of Chemistry, University of Lleida, Av. Alcalde Rovira Roure 191, E-25198 Lleida, Catalonia, Spain
| | - Sergio Madurga
- Department of Material Science and Physical Chemistry & Institute of Theoretical and Computational Chemistry (IQTC), University of Barcelona, C/ Martí i Franquès, 1, 08028 Barcelona, Catalonia, Spain
| | - Francesc Mas
- Department of Material Science and Physical Chemistry & Institute of Theoretical and Computational Chemistry (IQTC), University of Barcelona, C/ Martí i Franquès, 1, 08028 Barcelona, Catalonia, Spain
| | - María F Baieli
- Universidad de Buenos Aires & Instituto de Nanobiotecnología (UBA-CONICET), Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
| | - Claudio F Narambuena
- Universidad Tecnología Nacional & Grupo Bionanotecnología y Sistemas Complejos. (UTN-CONICET), Facultad Regional San Rafael, Av. General Urquiza 314C.P.:5600, San Rafael, Mendoza, Argentina.
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16
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Karmakar S, Sankhla A, Katiyar V. Reversible and biocompatible AuNP-decorated [Zn2+]:[Insulin] condensed assembly for potential therapeutic applications. Eur J Pharm Sci 2022; 173:106168. [DOI: 10.1016/j.ejps.2022.106168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/02/2022] [Accepted: 03/15/2022] [Indexed: 11/03/2022]
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17
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Bandara YMNDY, Farajpour N, Freedman KJ. Nanopore Current Enhancements Lack Protein Charge Dependence and Elucidate Maximum Unfolding at Protein's Isoelectric Point. J Am Chem Soc 2022; 144:3063-3073. [PMID: 35143193 DOI: 10.1021/jacs.1c11540] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein sequencing, as well as protein fingerprinting, has gained tremendous attention in the electrical sensing realm of solid-state nanopores and is challenging due to fast translocations and the use of high molar electrolytes. Despite providing an appreciable signal-to-noise ratio, high electrolyte concentrations can have adverse effects on the native protein structure. Herein, we present a thorough investigation of low electrolyte sensing conditions across a broad pH and voltage range generating conductive pulses (CPs) irrespective of protein net charge. We used Cas9 as the model protein and demonstrated that unfolding is noncooperative, represented by the gradual elongation or stretching of the protein, and sensitive to both the applied voltage and pH (i.e., charge state). The magnitude of unfolding and the isoelectric point (pI) of Cas9 was found to be correlated and a critical factor in our experiments. Electroosmotic flow (EOF) was always aligned with the transit direction, whereas electrophoretic force (EPF) was either reinforcing (pH < pI) or opposing (pH > pI) the protein's movement, which led to slower translocations at higher pH values. Further exploration of higher pH values led to slowing down of protein with > 30% of the population being slower than 0.5 ms. Our results would be critical for protein sensing at very low electrolytes and to retard their translocation speed without resorting to high-bandwidth equipment.
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Affiliation(s)
- Y M Nuwan D Y Bandara
- Department of Bioengineering, University of California, Riverside, 900 University Ave., Riverside, California 92521, United States
| | - Nasim Farajpour
- Department of Bioengineering, University of California, Riverside, 900 University Ave., Riverside, California 92521, United States
| | - Kevin J Freedman
- Department of Bioengineering, University of California, Riverside, 900 University Ave., Riverside, California 92521, United States
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18
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Lunkad R, Barroso da Silva FL, Košovan P. Both Charge-Regulation and Charge-Patch Distribution Can Drive Adsorption on the Wrong Side of the Isoelectric Point. J Am Chem Soc 2022; 144:1813-1825. [DOI: 10.1021/jacs.1c11676] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Raju Lunkad
- Department of Physical and Macromolecular Chemistry, Charles University, Hlavova 8, 128 43 Prague, Czech Republic
| | - Fernando L. Barroso da Silva
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Biomolecular Sciences, School of Pharmaceutical Sciences at Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo 14040-900, Brazil
| | - Peter Košovan
- Department of Physical and Macromolecular Chemistry, Charles University, Hlavova 8, 128 43 Prague, Czech Republic
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19
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Božič A, Podgornik R. Site Correlations, Capacitance, and Polarizability From Protein Protonation Fluctuations. J Phys Chem B 2021; 125:12902-12908. [PMID: 34784480 DOI: 10.1021/acs.jpcb.1c08200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We generalize the Kirkwood-Shumaker theory of protonation fluctuation for an anisotropic distribution of dissociable charges on a globular protein. The fluctuations of the total charge and the total dipole moment, in contrast to their average values, depend on the same proton occupancy correlator, thus exhibiting a similar dependence also on the solution pH. This has important consequences for the Kirkwood-Shumaker interaction and its dependence on the bathing solution conditions.
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Affiliation(s)
- Anže Božič
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
| | - Rudolf Podgornik
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China.,Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana SI-1000, Slovenia
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20
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Dung DN, Phan AD, Nguyen TT, Lam VD. Effects of surface charge and environmental factors on the electrostatic interaction of fiber with virus-like particle: A case of coronavirus. AIP ADVANCES 2021; 11:105008. [PMID: 34646585 PMCID: PMC8501974 DOI: 10.1063/5.0065147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/25/2021] [Indexed: 05/09/2023]
Abstract
We propose a theoretical model to elucidate intermolecular electrostatic interactions between a virus and a substrate. Our model treats the virus as a homogeneous particle having surface charge and the polymer fiber of the respirator as a charged plane. Electric potentials surrounding the virus and fiber are influenced by the surface charge distribution of the virus. We use Poisson-Boltzmann equations to calculate electric potentials. Then, Derjaguin's approximation and a linear superposition of the potential function are extended to determine the electrostatic force. In this work, we apply this model for coronavirus or SARS-CoV-2 case and numerical results quantitatively agree with prior simulation. We find that the influence of fiber's potential on the surface charge of the virus is important and is considered in interaction calculations to obtain better accuracy. The electrostatic interaction significantly decays with increasing separation distance, and this curve becomes steeper when adding more salt. Although the interaction force increases with heating, one can observe the repulsive-attractive transition when the environment is acidic.
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Affiliation(s)
- D. N. Dung
- Faculty of Materials Science and Engineering, Phenikaa University, Yen Nghia, Ha Dong, Ha Noi 12116, Vietnam
| | - Anh D. Phan
- Author to whom correspondence should be addressed:
| | - Toan T. Nguyen
- Key Laboratory for Multiscale Simulation of Complex Systems, and Department of Theoretical Physics, Faculty of Physics, VNU University of Science, Vietnam National University—Hanoi, 334 Nguyen Trai Street, Thanh Xuan District, Hanoi 10000, Vietnam
| | - Vu D. Lam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Vietnam
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21
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Mishra S, Chaturvedi N. Simulation and machine learning modelling based comparative study of InAlGaN and AlGaN high electron mobility transistors for the detection of HER-2. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:3659-3666. [PMID: 34323894 DOI: 10.1039/d1ay00707f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The detection of the cancer biomarker human epidermal growth factor receptor 2 (HER-2) has always been challenging at the early stages of cancer due to its very small presence. A systematic study of biosensors to achieve optimum sensitivity is of paramount significance. Thus, in this paper, we report a simulation study and machine learning (ML) based model for the comparative analysis of indium aluminum gallium nitride (InAlGaN) and aluminum gallium nitride (AlGaN) based high electron mobility transistors (HEMTs) for the detection of HER-2. The sensing performance of the InAlGaN based HEMT exhibits 1.8 times higher sensitivity as compared to that of the AlGaN based HEMT. The presented work also provides insights into the importance of the pH of the medium of HER-2. The results produced by the developed ML-based model are in good agreement with the simulation results. The model is not only capable of predicting within the trained range but also it can predict reasonably well even beyond the range of the training data. The introduction of a ML-based model significantly reduces the computational cost, time to perform similar type of simulations and, unlike the physics-based modelling, it also eliminates the need for empirical fitting of the model parameters.
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Affiliation(s)
- Shivanshu Mishra
- CSIR-Central Electronics Engineering Research Institute, Pilani, Rajasthan, India.
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22
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Marson GV, Pereira DTV, da Costa Machado MT, Di Luccio M, Martínez J, Belleville MP, Hubinger MD. Ultrafiltration performance of spent brewer's yeast protein hydrolysate: Impact of pH and membrane material on fouling. J FOOD ENG 2021. [DOI: 10.1016/j.jfoodeng.2021.110569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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23
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Javidpour L, BoŽič A, Naji A, Podgornik R. Electrostatic interactions between the SARS-CoV-2 virus and a charged electret fibre. SOFT MATTER 2021; 17:4296-4303. [PMID: 33908595 DOI: 10.1039/d1sm00232e] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
While almost any kind of face mask offers some protection against particles and pathogens of different sizes, the most efficient ones make use of a layered structure where one or more layers are electrically charged. These electret layers are essential for the efficient filtration of difficult-to-capture small particles, yet the exact nature of electrostatic capture with respect to the charge on both the particles and the electret fibres as well as the effect of the immediate environment remain unclear. Here, we explore in detail the electrostatic interactions between the surface of a single charged electret fibre and a model of the SARS-CoV-2 virus. Using Poisson-Boltzmann electrostatics coupled to a detailed spike protein charge regulation model, we show how pH and salt concentration drastically change both the scale and the sign of the interaction. Furthermore, the configuration of the few spike proteins closest to the electret fibre turns out to be as important for the strength of the interaction as their total number on the virus envelope, a direct consequence of spike protein charge regulation. The results of our work elucidate the details of virus electrostatics and contribute to the general understanding of efficient virus filtration mechanisms.
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Affiliation(s)
- Leili Javidpour
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - AnŽe BoŽič
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Ali Naji
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran and School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. and Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
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24
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Casasanta MA, Jonaid GM, Kaylor L, Luqiu WY, Solares MJ, Schroen ML, Dearnaley WJ, Wilson J, Dukes MJ, Kelly DF. Microchip-based structure determination of low-molecular weight proteins using cryo-electron microscopy. NANOSCALE 2021; 13:7285-7293. [PMID: 33889923 PMCID: PMC8135184 DOI: 10.1039/d1nr00388g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interest in cryo-Electron Microscopy (EM) imaging has skyrocketed in recent years due to its pristine views of macromolecules and materials. As advances in instrumentation and computing algorithms spurred this progress, there is renewed focus to address specimen-related challenges. Here we contribute a microchip-based toolkit to perform complementary structural and biochemical analysis on low-molecular weight proteins. As a model system, we used the SARS-CoV-2 nucleocapsid (N) protein (48 kDa) due to its stability and important role in therapeutic development. Cryo-EM structures of the N protein monomer revealed a flexible N-terminal "top hat" motif and a helical-rich C-terminal domain. To complement our structural findings, we engineered microchip-based immunoprecipitation assays that led to the discovery of the first antibody binding site on the N protein. The data also facilitated molecular modeling of a variety of pandemic and common cold-related coronavirus proteins. Such insights may guide future pandemic-preparedness protocols through immuno-engineering strategies to mitigate viral outbreaks.
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Affiliation(s)
- Michael A Casasanta
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA.
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25
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Bakhshandeh A, Frydel D, Levin Y. Charge regulation of colloidal particles in aqueous solutions. Phys Chem Chem Phys 2020; 22:24712-24728. [PMID: 33104140 DOI: 10.1039/d0cp03633a] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We study the charge regulation of colloidal particles inside aqueous electrolyte solutions. To stabilize a colloidal suspension against precipitation, colloidal particles are synthesized with either acidic or basic groups on their surface. On contact with water, these surface groups undergo proton transfer reactions, resulting in colloidal surface charge. The charge is determined by the condition of local chemical equilibrium between hydronium ions inside the solution and at the colloidal surface. We use a model of Baxter sticky spheres to explicitly calculate the equilibrium dissociation constants and to construct a theory which is able to quantitatively predict the effective charge of colloidal particles with either acidic or basic surface groups. The predictions of the theory for the model are found to be in excellent agreement with the results of Monte Carlo simulations. This theory is further extended to treat colloidal particles with a mixture of both acidic and basic surface groups.
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Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS, Brazil.
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26
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Baek J, Schwahn AB, Lin S, Pohl CA, De Pra M, Tremintin SM, Cook K. New Insights into the Chromatography Mechanisms of Ion-Exchange Charge Variant Analysis: Dispelling Myths and Providing Guidance for Robust Method Optimization. Anal Chem 2020; 92:13411-13419. [DOI: 10.1021/acs.analchem.0c02775] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Julia Baek
- Thermo Fisher Scientific, 1228 Titan Way, Sunnyvale, California 94085, United States of America
| | | | - Shanhua Lin
- Thermo Fisher Scientific, 1228 Titan Way, Sunnyvale, California 94085, United States of America
| | - Christopher A. Pohl
- Thermo Fisher Scientific, 1228 Titan Way, Sunnyvale, California 94085, United States of America
| | - Mauro De Pra
- Thermo Fisher Scientific, Dornierstrasse 4, Germering 82110, Germany
| | - Stacy M. Tremintin
- Thermo Fisher Scientific, 1228 Titan Way, Sunnyvale, California 94085, United States of America
| | - Ken Cook
- Thermo Fisher Scientific, Stafford House, 1 Boundary Park, Hemel Hempstead HP2 7GE, U.K
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27
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Zhang F, You S, Huang T, Wang JZ, Zhu LL, Wang B, Ye WS, Herman RA, Luo H, Wang J. Dual promoter strategy enhances co-expression of α-L-rhamnosidase and enhanced fluorescent protein for whole-cell catalysis and bioresource valorization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 722:137865. [PMID: 32192973 DOI: 10.1016/j.scitotenv.2020.137865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/17/2020] [Accepted: 03/10/2020] [Indexed: 06/10/2023]
Abstract
Developing circular economy is the only way to improve the efficiency of resource utilization. Whole-cell catalysis is an effective method to recycle enzymes, improve catalytic efficiency, and reduce production costs. The enzyme, α-L-rhamnosidase has considerable application prospects in the field of biocatalysis as it can hydrolyze a variety of α-L rhamnoses. In the present study, the genes for α-L-rhamnosidase (rhaB1) and enhanced fluorescent protein (EGFP) were co-expressed using a bi-promoter expression vector pRSFDuet1 and their enzymatic properties were evaluated. To our knowledge, this study has established an effective rhamnosidase-fluorescent indicator and whole-cell catalytic system for the first time. Moreover, we analyzed the change in the activity of the crude rhaB1-EGFP as well as its whole-cell during the biocatalysis process using fluorescence intensity. Recombinant rhaB1-EGFP as a product which contains rhaB1 and EGFP showed higher thermal stability, pH stability, and conversion efficiency than rhaB1, and its optimum temperature for rutin catalysis was ideal for industrial applications. Moreover, under the optimal conditions of a rutin concentration of 0.05 g/L, pH of 6.0, temperature of 40 °C, a yield of 92.5% was obtained. Furthermore, we demonstrated the relationship between the fluorescence intensity and enzyme activity. This study established a highly efficient whole-cell catalytic system whose activity can be evaluated by fluorescence intensity, providing a reference for enzyme recycling.
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Affiliation(s)
- Fan Zhang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Shuai You
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, PR China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Zhenjiang 212018, PR China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Zhenjiang 212018, PR China
| | - Ting Huang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Jin-Zheng Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Lin-Lin Zhu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Bo Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Wang-Sheng Ye
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Richard Ansah Herman
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China
| | - Heng Luo
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, PR China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Zhenjiang 212018, PR China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Zhenjiang 212018, PR China
| | - Jun Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, PR China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, PR China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Zhenjiang 212018, PR China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Zhenjiang 212018, PR China.
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Izadi S, Patapoff TW, Walters BT. Multiscale Coarse-Grained Approach to Investigate Self-Association of Antibodies. Biophys J 2020; 118:2741-2754. [PMID: 32416079 DOI: 10.1016/j.bpj.2020.04.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/12/2020] [Accepted: 04/13/2020] [Indexed: 11/20/2022] Open
Abstract
Self-association of therapeutic monoclonal antibodies (mabs) are thought to modulate the undesirably high viscosity observed in their concentrated solutions. Computational prediction of such a self-association behavior is advantageous early during mab drug candidate selection when material availability is limited. Here, we present a coarse-grained (CG) simulation method that enables microsecond molecular dynamics simulations of full-length antibodies at high concentrations. The proposed approach differs from others in two ways: first, charges are assigned to CG beads in an effort to reproduce molecular multipole moments and charge asymmetry of full-length antibodies instead of only localized charges. This leads to great improvements in the agreement between CG and all-atom electrostatic fields. Second, the distinctive hydrophobic character of each antibody is incorporated through empirical adjustments to the short-range van der Waals terms dictated by cosolvent all-atom molecular dynamics simulations of antibody variable regions. CG simulations performed on a set of 15 different mabs reveal that diffusion coefficients in crowded environments are markedly impacted by intermolecular interactions. Diffusion coefficients computed from the simulations are in correlation with experimentally measured observables, including viscosities at a high concentration. Further, we show that the evaluation of electrostatic and hydrophobic characters of the mabs is useful in predicting the nonuniform effect of salt on the viscosity of mab solutions. This CG modeling approach is particularly applicable as a material-free screening tool for selecting antibody candidates with desirable viscosity properties.
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Affiliation(s)
- Saeed Izadi
- Pharmaceutical Development, Genentech, South San Francisco, California.
| | - Thomas W Patapoff
- Pharmaceutical Development, Genentech, South San Francisco, California
| | - Benjamin T Walters
- Biochemical and Cellular Pharmacology, Genentech, South San Francisco, California.
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29
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Ince-Coskun AE, Ozdestan-Ocak O. Effects of salt ions and heating on the behaviour of whey protein particle dispersions. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2019.105433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Konevtsova OV, Roshal DS, Lošdorfer BoŽič A, Podgornik R, Rochal S. Hidden symmetry of the anomalous bluetongue virus capsid and its role in the infection process. SOFT MATTER 2019; 15:7663-7671. [PMID: 31490506 DOI: 10.1039/c9sm01335k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Clear understanding of the principles that control the arrangement of proteins and their self-assembly into viral shells is very important for the development of antiviral strategies. Here we consider the structural peculiarities and hidden symmetry of the anomalous bluetongue virus (BTV) capsid. Each of its three concentric shells violates the paradigmatic geometrical model of Caspar and Klug, which is otherwise well suited to describe most of the known icosahedral viral shells. As we show, three icosahedral spherical lattices, which are commensurate with each other and possess locally hexagonal (primitive or honeycomb) order, underlie the proteinaceous shells of the BTV capsid. This interpretation of the multishelled envelope allows us to discuss the so-called "symmetry mismatch" between its layers. We also analyze the structural stability of the considered spherical lattices on the basis of the classical theory of spherical packing and relate the proximity of the outer spherical lattice to destabilization with the fact that during infection of the cell VP2 trimers are detached from the surface of the BTV capsid. An electrostatic mechanism that can assist in this detachment is discussed in detail.
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Affiliation(s)
- Olga V Konevtsova
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - Daria S Roshal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
| | - AnŽe Lošdorfer BoŽič
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Rudolf Podgornik
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia and School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sergey Rochal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia.
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31
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Klijn ME, Vormittag P, Bluthardt N, Hubbuch J. High-throughput computational pipeline for 3-D structure preparation and in silico protein surface property screening: A case study on HBcAg dimer structures. Int J Pharm 2019; 563:337-346. [PMID: 30935914 DOI: 10.1016/j.ijpharm.2019.03.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 02/06/2023]
Abstract
Knowledge-based experimental design can aid biopharmaceutical high-throughput screening (HTS) experiments needed to identify critical manufacturability parameters. Prior knowledge can be obtained via computational methods such as protein property extraction from 3-D protein structures. This study presents a high-throughput 3-D structure preparation and refinement pipeline that supports structure screenings with an automated and data-dependent workflow. As a case study, three chimeric virus-like particle (VLP) building blocks, hepatitis B core antigen (HBcAg) dimers, were constructed. Molecular dynamics (MD) refinement quality, speed, stability, and correlation to zeta potential data was evaluated using different MD simulation settings. Settings included 2 force fields (YASARA2 and AMBER03) and 2 pKa computation methods (YASARA and H++). MD simulations contained a data-dependent termination via identification of a 2 ns Window of Stability, which was also used for robust descriptor extraction. MD simulation with YASARA2, independent of pKa computation method, was found to be most stable and computationally efficient. These settings resulted in a fast refinement (6.6-37.5 h), a good structure quality (-1.17--1.13) and a strong linear dependence between dimer surface charge and complete chimeric HBcAg VLP zeta potential. These results indicate the computational pipeline's applicability for early-stage candidate assessment and design optimization of HTS manufacturability or formulability experiments.
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Affiliation(s)
- Marieke E Klijn
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Baden-Wuerttemberg, Germany
| | - Philipp Vormittag
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Baden-Wuerttemberg, Germany
| | - Nicolai Bluthardt
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Baden-Wuerttemberg, Germany
| | - Jürgen Hubbuch
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Baden-Wuerttemberg, Germany.
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32
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Roshal D, Konevtsova O, Lošdorfer Božič A, Podgornik R, Rochal S. pH-induced morphological changes of proteinaceous viral shells. Sci Rep 2019; 9:5341. [PMID: 30926857 PMCID: PMC6440952 DOI: 10.1038/s41598-019-41799-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 02/21/2019] [Indexed: 01/19/2023] Open
Abstract
Changes in environmental pH can induce morphological changes in empty proteinaceous shells of bacteriophages in vitro that are very similar to changes occurring in viral capsids in vivo after encapsidation of DNA. These changes in capsid shape and size cannot be explained with a simple elastic model alone. We propose a new theoretical framework that combines the elasticity of thin icosahedral shells with the pH dependence of capsid charge distribution. Minimization of the sum of elastic and electrostatic free energies leads to equilibrium shapes of viral shells that depend on a single elastic parameter and the detailed configuration of the imbedded protein charges. Based on the in vitro shell reconstructions of bacteriophage HK97 we elucidate the details of how the reversible transition between Prohead II and Expansion Intermediate II states of the HK97 procapsid is induced by pH changes, as well as some other features of the bacteriophage maturation.
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Affiliation(s)
- D Roshal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia
| | - O Konevtsova
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia
| | - A Lošdorfer Božič
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia
| | - R Podgornik
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia.
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000, Ljubljana, Slovenia.
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
| | - S Rochal
- Physics Faculty, Southern Federal University, Rostov-on-Don, Russia
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33
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Hydrodynamic and Electrophoretic Properties of Trastuzumab/HER2 Extracellular Domain Complexes as Revealed by Experimental Techniques and Computational Simulations. Int J Mol Sci 2019; 20:ijms20051076. [PMID: 30832287 PMCID: PMC6429128 DOI: 10.3390/ijms20051076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 11/18/2022] Open
Abstract
The combination of hydrodynamic and electrophoretic experiments and computer simulations is a powerful approach to study the interaction between proteins. In this work, we present hydrodynamic and electrophoretic experiments in an aqueous solution along with molecular dynamics and hydrodynamic modeling to monitor and compute biophysical properties of the interactions between the extracellular domain of the HER2 protein (eHER2) and the monoclonal antibody trastuzumab (TZM). The importance of this system relies on the fact that the overexpression of HER2 protein is related with the poor prognosis breast cancers (HER2++ positives), while the TZM is a monoclonal antibody for the treatment of this cancer. We have found and characterized two different complexes between the TZM and eHER2 proteins (1:1 and 1:2 TZM:eHER2 complexes). The conformational features of these complexes regulate their hydrodynamic and electrostatic properties. Thus, the results indicate a high degree of molecular flexibility in the systems that ultimately leads to higher values of the intrinsic viscosity, as well as lower values of diffusion coefficient than those expected for simple globular proteins. A highly asymmetric charge distribution is detected for the monovalent complex (1:1 complex), which has strong implications in correlations between the experimental electrophoretic mobility and the modeled net charge. In order to understand the dynamics of these systems and the role of the specific domains involved, it is essential to find biophysical correlations between dynamics, macroscopic transport and electrostatic properties. The results should be of general interest for researchers working in this area.
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34
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Poveda-Cuevas S, Etchebest C, Barroso da Silva FL. Insights into the ZIKV NS1 Virology from Different Strains through a Fine Analysis of Physicochemical Properties. ACS OMEGA 2018; 3:16212-16229. [PMID: 31458257 PMCID: PMC6643396 DOI: 10.1021/acsomega.8b02081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/14/2018] [Indexed: 05/02/2023]
Abstract
The flavivirus genus has several organisms responsible for generating various diseases in humans. Recently, especially in tropical regions, Zika virus (ZIKV) has raised great health concerns due to the high number of cases affecting the area during the last years that has been accompanied by a rise in the cases of the Guillain-Barré syndrome and fetal and neonatal microcephaly. Diagnosis is still difficult since the clinical symptoms between ZIKV and other flaviviruses (e.g., dengue and yellow fever) are highly similar. The understanding of their common physicochemical properties that are pH-dependent and biomolecular interaction features and their differences sheds light on the relation strain-virulence and might suggest alternative strategies toward differential serological diagnostics and therapeutic intervention. Due to their immunogenicity, the primary focus of this study was on the ZIKV nonstructural proteins 1 (NS1). By means of computational studies and semiquantitative theoretical analyses, we calculated the main physicochemical properties of this protein from different strains that are directly responsible for the biomolecular interactions and, therefore, can be related to the differential infectivity of the strains. We also mapped the electrostatic differences at both the sequence and structural levels for the strains from Uganda to Brazil, which could suggest possible molecular mechanisms for the increase of the virulence of ZIKV in Brazil. Exploring the interfaces used by NS1 to self-associate in some different oligomeric states and interact with membranes and the antibody, we could map the strategy used by the ZIKV during its evolutionary process. This indicates possible molecular mechanisms that can be correlated with the different immunological responses. By comparing with the known antibody structure available for the West Nile virus, we demonstrated that this antibody would have difficulties to neutralize the NS1 from the Brazilian strain. The present study also opens up perspectives to computationally design high-specificity antibodies.
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Affiliation(s)
- Sergio
A. Poveda-Cuevas
- Programa
Interunidades em Bioinformática, Universidade de São Paulo, São Paulo 05508-090, Brazil
- Departamento
de Física e Química, Faculdade de Ciências Farmacêuticas
de Ribeirão Preto, Universidade de
São Paulo, Ribeirão Preto, São Paulo 14040-903, Brazil
- University
of São Paulo and Université Sorbonne Paris Cité
Joint International Laboratory in Structural Bioinformatics
| | - Catherine Etchebest
- Institut
National de la Transfusion Sanguine, Paris 75015, France
- Biologie
Intégrée du Globule Rouge, Equipe 2, Dynamique des Structures
et des Interactions Moléculaires, Institut National de la Santé et de la Recherche Médicale,
UMR_S 1134, Paris 75015, France
- Université
Sorbonne Paris Cité and Université Paris Diderot, 75013 Paris, France
- University
of São Paulo and Université Sorbonne Paris Cité
Joint International Laboratory in Structural Bioinformatics
| | - Fernando L. Barroso da Silva
- Programa
Interunidades em Bioinformática, Universidade de São Paulo, São Paulo 05508-090, Brazil
- Departamento
de Física e Química, Faculdade de Ciências Farmacêuticas
de Ribeirão Preto, Universidade de
São Paulo, Ribeirão Preto, São Paulo 14040-903, Brazil
- University
of São Paulo and Université Sorbonne Paris Cité
Joint International Laboratory in Structural Bioinformatics
- Department
of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
- E-mail: and
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35
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Yuan Y, Zhang Z, Mills MJL, Hu R, Zhang R. Assessing Force Field Potential Energy Function Accuracy via a Multipolar Description of Atomic Electrostatic Interactions in RNA. J Chem Inf Model 2018; 58:2239-2254. [PMID: 30362754 DOI: 10.1021/acs.jcim.8b00328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Computational investigations of RNA properties often rely on a molecular mechanical approach to define molecular potential energy. Force fields for RNA typically employ a point charge model of electrostatics, which does not provide a realistic quantum-mechanical picture. In reality, electron distributions around nuclei are not spherically symmetric and are geometry dependent. A multipole expansion method which allows for incorporation of polarizability and anisotropy in a force field is described, and its applicability to modeling the behavior of RNA molecules is investigated. Transferability of the model, critical for force field development, is also investigated.
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Affiliation(s)
- Yongna Yuan
- School of Information Science & Engineering , Lanzhou University , Lanzhou , Gansu 730000 , China
| | - Zhuangzhuang Zhang
- School of Information Science & Engineering , Lanzhou University , Lanzhou , Gansu 730000 , China
| | | | - Rongjing Hu
- School of Information Science & Engineering , Lanzhou University , Lanzhou , Gansu 730000 , China
| | - Ruisheng Zhang
- School of Information Science & Engineering , Lanzhou University , Lanzhou , Gansu 730000 , China
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36
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Lošdorfer Božič A, Podgornik R. Anomalous multipole expansion: Charge regulation of patchy inhomogeneously charged spherical particles. J Chem Phys 2018; 149:163307. [DOI: 10.1063/1.5037044] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Anže Lošdorfer Božič
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Rudolf Podgornik
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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37
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Podgornik R. General theory of charge regulation and surface differential capacitance. J Chem Phys 2018; 149:104701. [PMID: 30219025 DOI: 10.1063/1.5045237] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A generalization of the mean-field approach will be derived that will take into account the ion-ion as well as ion-surface non-electrostatic effects on an equal footing, being based on the bulk and surface equations of state in the absence of electrostatic interactions. This approach will be applied to the analysis of a single planar surface with dissociable sites with several models of the specific ion-surface non-electrostatic interactions, providing a general thermodynamic insight into the characteristics of the surface differential capacitance. The ion-surface interactions and ion-ion packing considerations at the surface will be shown to be more relevant than the bulk packing constraints for ions vicinal to the surface, as well as to set in prior to the conditions where the bulk packing constraints would become relevant.
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Affiliation(s)
- Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia; and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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38
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Avni Y, Markovich T, Podgornik R, Andelman D. Charge regulating macro-ions in salt solutions: screening properties and electrostatic interactions. SOFT MATTER 2018; 14:6058-6069. [PMID: 29985507 DOI: 10.1039/c8sm00728d] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We revisit the charge-regulation mechanism of macro-ions and apply it to mobile macro-ions in a bathing salt solution. In particular, we examine the effects of correlation between various adsorption/desorption sites and analyze the collective behavior in terms of the solution effective screening properties. We show that such a behavior can be quantified in terms of the charge asymmetry of the macro-ions, defined by their preference for a non-zero effective charge, and their donor/acceptor propensity for exchanging salt ions with the bathing solution. Asymmetric macro-ions tend to increase the screening, while symmetric macro-ions can in some cases decrease it. Macro-ions that are classified as donors display a rather regular behavior, while those that behave as acceptors exhibit an anomalous non-monotonic Debye length. The screening properties, in their turn, engender important modifications to the disjoining pressure between two charged surfaces. Our findings are in particular relevant for solutions of proteins, whose exposed amino acids can undergo charge dissociation/association processes to/from the bathing solution, and can be considered as a solution of charged regulated macro-ions, as analyzed here.
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Affiliation(s)
- Yael Avni
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel.
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39
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Lošdorfer BoŽič A. From discrete to continuous description of spherical surface charge distributions. SOFT MATTER 2018; 14:1149-1161. [PMID: 29345714 DOI: 10.1039/c7sm02207g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The importance of electrostatic interactions in soft matter and biological systems can often be traced to non-uniform charge effects, which are commonly described using a multipole expansion of the corresponding charge distribution. The standard approach when extracting the charge distribution of a given system is to treat the constituent charges as points. This can, however, lead to an overestimation of multipole moments of high order, such as dipole, quadrupole, and higher moments. Focusing on distributions of charges located on a spherical surface - characteristic of numerous biological macromolecules, such as globular proteins and viral capsids, as well as of inverse patchy colloids - we develop a novel way of representing spherical surface charge distributions based on the von Mises-Fisher distribution. This approach takes into account the finite spatial extension of individual charges, and leads to a simple yet powerful way of describing surface charge distributions and their multipole expansions. In this manner, we analyze charge distributions and the derived multipole moments of a number of different spherical configurations of identical charges with various degrees of symmetry. We show how the number of charges, their size, and the geometry of their configuration influence the behavior and relative importance of multipole magnitudes of different order. Importantly, we clearly demonstrate how neglecting the effect of charge size leads to an overestimation of high-order multipoles. The results of our work can be applied to construct analytical models of electrostatic interactions and multipole expansion of charged particles in diverse soft matter and biological systems.
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40
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Lošdorfer Božič A, Podgornik R. Varieties of charge distributions in coat proteins of ssRNA+ viruses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:024001. [PMID: 29182522 PMCID: PMC7104810 DOI: 10.1088/1361-648x/aa9ded] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/21/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
A major part of the interactions involved in the assembly and stability of icosahedral, positive-sense single-stranded RNA (ssRNA+) viruses is electrostatic in nature, as can be inferred from the strong pH- and salt-dependence of their assembly phase diagrams. Electrostatic interactions do not act only between the capsid coat proteins (CPs), but just as often provide a significant contribution to the interactions of the CPs with the genomic RNA, mediated to a large extent by positively charged, flexible N-terminal tails of the CPs. In this work, we provide two clear and complementary definitions of an N-terminal tail of a protein, and use them to extract the tail sequences of a large number of CPs of ssRNA+ viruses. We examine the pH-dependent interplay of charge on both tails and CPs alike, and show that-in contrast to the charge on the CPs-the net positive charge on the N-tails persists even to very basic pH values. In addition, we note a limit to the length of the wild-type genomes of those viruses which utilize positively charged tails, when compared to viruses without charged tails and similar capsid size. At the same time, we observe no clear connection between the charge on the N-tails and the genome lengths of the viruses included in our study.
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Affiliation(s)
- Anže Lošdorfer Božič
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Rudolf Podgornik
- Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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