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1.
J Chromatogr A ; 1732: 465170, 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39098099

RESUMO

This paper employs a high-throughput parallel batch (microtiter plate) adsorption screen with sequential salt step increases to rapidly generate protein elution profiles for multiple resins at different pHs using a protein library. The chromatographic set used in this work includes single mode, multimodal anion-exchange (MMA), and multimodal cation-exchange (MMC) resins. The protein library consists of proteins with isoelectric points ranging from 5.1 to 11.4 with varying hydrophobicities as determined by their retention on hydrophobic interaction chromatography. The batch sequential experiments are carried out using one protein at a time with a wide set of resins at multiple pH conditions, thus enabling simple microtiter plate detection. A mathematical formulation is then used to determine the first moment of the distributions from each chromatogram (sequential step elution) generated in the parallel batch experiments. Batch data first moments (expressed in salt concentration) are then compared to results obtained from column linear salt gradient elution, and the techniques are shown to be consistent. In addition, first moment data are used to calculate one-resin separability scores, which are a measure of a resin's ability, at a specified pH, to separate the entire set of proteins in the library from one another. Again, the results from the batch and column experiments are shown to be comparable. The first moment data sets were then employed to calculate the two-resin separability scores, which are a measure of the ability of two resins to synergistically separate the entire set of proteins in the library. Importantly, these results based on the two-resin separability performances derived from the batch and column experiments were again shown to be consistent. This approach for rapidly screening large numbers of chromatographic resins and mobile phase conditions for their elution behavior may prove useful for enabling the rapid discovery of new chromatographic ligands and resins.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Proteínas , Cromatografia por Troca Iônica/métodos , Concentração de Íons de Hidrogênio , Proteínas/análise , Proteínas/química , Proteínas/isolamento & purificação , Ensaios de Triagem em Larga Escala/métodos , Resinas de Troca de Cátion/química , Resinas de Troca Aniônica/química , Adsorção , Ponto Isoelétrico
2.
Anal Methods ; 16(31): 5450-5458, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39042476

RESUMO

Imaged capillary isoelectric focusing (icIEF) is a preferred analytical method for determining isoelectric points (pIs) and charge heterogeneity profiles in biotherapeutic proteins. In this study, we optimized the icIEF method for an in-house IgG1κ monoclonal antibody (mAb-1) and assessed its reproducibility, robustness, and autosampler stability. The optimized method was used to evaluate batch-to-batch consistency in pIs for multiple lots of mAb-1 and determine the relative percentages of charge variants. We also tested the method's performance using multiple lots of another IgG1 mAb, commercially available as Herceptin (trastuzumab). Additionally, we designed and assessed native and denaturing platform icIEF methods for 11 other marketed mAbs, with pIs ranging from 6.0 (eculizumab) to 9.22 (tocilizumab).


Assuntos
Anticorpos Monoclonais , Focalização Isoelétrica Capilar , Humanos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/análise , Focalização Isoelétrica Capilar/métodos , Imunoglobulina G/química , Imunoglobulina G/análise , Ponto Isoelétrico , Reprodutibilidade dos Testes , Trastuzumab/química , Trastuzumab/análise
3.
Pharmazie ; 79(3): 57-63, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38872273

RESUMO

Human gonadotropins are glycoprotein hormones with a highly complex structure, which demands the application of sophisticated analytical methodologies to assess their quality. The principal objective of this study was a comparative evaluation of gel electrophoretic techniques and mass spectrometry-based methods for the quality study of the two urinary-derived, highly purified, human menopausal gonadotropin preparations, Menopur 75/75 I. U. and Meriofert 75 I. U. Molecular mass (Mr), isoelectric point (pI), and isoform pattern of studied compounds were estimated via SDS-PAGE and 2D gel electrophoresis, whereas matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for the downstream characterization of peptides obtained after in-gel tryptic digestion of selected protein spots. Additionally, for the estimation of the glycosylation pattern of these biologics, the enzymatic release of oligosaccharides was performed, and the isoform pattern was studied. Gel electrophoresis showed a typical electrophoretic behaviour for protein biotherapeutics medicines consisting of extremely complex spot patterns migrating at different masses and pIs. MS analysis proved to be a powerful tool for the identification and detailed characterization of the gonadotropins and the relevant peptides were identified with high sequence coverages. The results of this study are not only useful for the quality assessment of this class of complex biopharmaceuticals but may also serve as a supporting platform for further development of biopharmaceuticals based on modulation of the glycosylation pattern to enhance efficacy or reduce side effects.


Assuntos
Eletroforese em Gel de Poliacrilamida , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Feminino , Gonadotropinas , Eletroforese em Gel Bidimensional/métodos , Controle de Qualidade , Isoformas de Proteínas , Ponto Isoelétrico , Glicosilação , Peso Molecular , Espectrometria de Massas/métodos
4.
Nanomedicine ; 60: 102758, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38852881

RESUMO

The clinical application of tumor necrosis factor-α (TNF-α) is limited by its short half-life, subeffective concentration in the targeted area and severe systemic toxicity. In this study, the recombinant polypeptide S4-TNF-α was constructed and coupled with chitosan-modified superparamagnetic iron oxide nanoparticles (S4-TNF-α-SPIONs) to achieve pH-sensitive controlled release and active tumor targeting activity. The isoelectric point (pI) of S4-TNF-α was reconstructed to approach the pH of the tumor microenvironment. The negative-charge S4-TNF-α was adsorbed to chitosan-modified superparamagnetic iron oxide nanoparticles (CS-SPIONs) with a positive charge through electrostatic adsorption at physiological pH. The acidic tumor microenvironment endowed S4-TNF-α with a zero charge, which accelerated S4-TNF-α release from CS-SPIONs. Our studies showed that S4-TNF-α-SPIONs displayed an ideal pH-sensitive controlled release capacity and improved antitumor effects. Our study presents a novel approach to enhance the pH-sensitive controlled-release of genetically engineered drugs by adjusting their pI to match the pH of the tumor microenvironment.


Assuntos
Preparações de Ação Retardada , Fator de Necrose Tumoral alfa , Fator de Necrose Tumoral alfa/metabolismo , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Humanos , Animais , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Camundongos , Nanopartículas Magnéticas de Óxido de Ferro/química , Quitosana/química , Microambiente Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral , Camundongos Endogâmicos BALB C
5.
Food Chem ; 450: 138833, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-38653053

RESUMO

The instability and discoloration of (-)-epigallocatechin-3-gallate (EGCG) constrain its application in functional dairy products. Concurrently, challenges persist in the separation and utilization of whey in the dairy industry. By harnessing the interactions between polyphenols and whey proteins or their hydrolysates, this study proposed a method that involved limited enzymatic hydrolysis followed by the addition of EGCG and pH adjustment around the isoelectric point to obtain whey protein hydrolysates (WPH)-EGCG. Over 92 % of protein-EGCG complexes recovered from whey while ensuring the preservation of α-lactalbumin. The combination between EGCG and WPH depended on hydrogen bonding and hydrophobic interactions, significantly enhanced the thermal stability and storage stability of EGCG. Besides, the intestinal phase retention rate of EGCG in WPH-EGCG complex was significantly increased by 23.67 % compared to free EGCG. This work represents an exploratory endeavor in the improvement of EGCG stability and expanding the utilization approaches of whey.


Assuntos
Catequina , Polifenóis , Proteínas do Soro do Leite , Catequina/química , Catequina/análogos & derivados , Proteínas do Soro do Leite/química , Polifenóis/química , Hidrólise , Hidrolisados de Proteína/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Ponto Isoelétrico
6.
J Colloid Interface Sci ; 665: 801-813, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38555748

RESUMO

The co-assembly of polyelectrolytes (PE) with proteins offers a promising approach for designing complex structures with customizable morphologies, charge distribution, and stability for targeted cargo delivery. However, the complexity of protein structure limits our ability to predict the properties of the formed nanoparticles, and our goal is to identify the key triggers of the morphological transition in protein/PE complexes and evaluate their ability to encapsulate multivalent ionic drugs. A positively charged PE can assemble with a protein at pH above isoelectric point due to the electrostatic attraction and disassemble at pH below isoelectric point due to the repulsion. The additional hydrophilic block of the polymer should stabilize the particles in solution and enable them to encapsulate a negatively charged drug in the presence of PE excess. We demonstrated that diblock copolymers, poly(ethylene oxide)-block-poly(N,N-dimethylaminoethyl methacrylate) and poly(ethylene oxide)-block-poly(N,N,N-trimethylammonioethyl methacrylate), consisting of a polycation block and a neutral hydrophilic block, reversibly co-assemble with insulin in pH range between 5 and 8. Using small-angle neutron and X-ray scattering (SANS, SAXS), we showed that insulin arrangement within formed particles is controlled by intermolecular electrostatic forces between protein molecules, and can be tuned by varying ionic strength. For the first time, we observed by fluorescence that formed protein/PE complexes with excess of positive charges exhibited potential for encapsulating and controlled release of negatively charged bivalent drugs, protoporphyrin-IX and zinc(II) protoporphyrin-IX, enabling the development of nanocarriers for combination therapies with adjustable charge, stability, internal structure, and size.


Assuntos
Insulina , Protoporfirinas , Polieletrólitos , Óxido de Etileno , Espalhamento a Baixo Ângulo , Difração de Raios X , Polímeros/química , Proteínas , Ponto Isoelétrico
7.
MAbs ; 16(1): 2303781, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38475982

RESUMO

Early identification of antibody candidates with drug-like properties is essential for simplifying the development of safe and effective antibody therapeutics. For subcutaneous administration, it is important to identify candidates with low self-association to enable their formulation at high concentration while maintaining low viscosity, opalescence, and aggregation. Here, we report an interpretable machine learning model for predicting antibody (IgG1) variants with low viscosity using only the sequences of their variable (Fv) regions. Our model was trained on antibody viscosity data (>100 mg/mL mAb concentration) obtained at a common formulation pH (pH 5.2), and it identifies three key Fv features of antibodies linked to viscosity, namely their isoelectric points, hydrophobic patch sizes, and numbers of negatively charged patches. Of the three features, most predicted antibodies at risk for high viscosity, including antibodies with diverse antibody germlines in our study (79 mAbs) as well as clinical-stage IgG1s (94 mAbs), are those with low Fv isoelectric points (Fv pIs < 6.3). Our model identifies viscous antibodies with relatively high accuracy not only in our training and test sets, but also for previously reported data. Importantly, we show that the interpretable nature of the model enables the design of mutations that significantly reduce antibody viscosity, which we confirmed experimentally. We expect that this approach can be readily integrated into the drug development process to reduce the need for experimental viscosity screening and improve the identification of antibody candidates with drug-like properties.


Assuntos
Anticorpos Monoclonais , Imunoglobulina G , Anticorpos Monoclonais/química , Viscosidade , Imunoglobulina G/química , Mutação , Ponto Isoelétrico
8.
MAbs ; 16(1): 2318817, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38444390

RESUMO

Bispecific antibodies (BsAbs) capable of recognizing two distinct epitopes or antigens offer promising therapeutic options for various diseases by targeting multiple pathways. The favorable pharmacokinetic (PK) properties of monoclonal antibodies (mAbs) are crucial, as they directly influence patient safety and therapeutic efficacy. For numerous mAb therapeutics, optimization of neonatal Fc receptor (FcRn) interactions and elimination of unfavorable molecular properties have led to improved PK properties. However, many BsAbs exhibit unfavorable PK, which has precluded their development as drugs. In this report, we present studies on the molecular determinants underlying the distinct PK profiles of three IgG1-scFv BsAbs. Our study indicated that high levels of nonspecific interactions, elevated isoelectric point (pI), and increased number of positively charged patches contributed to the fast clearance of IgG1-scFv. FcRn chromatography results revealed specific scFv-FcRn interactions that are unique to the IgG1-scFv, which was further supported by molecular dynamics (MD) simulation. These interactions likely stabilize the BsAb FcRn interaction at physiological pH, which in turn could disrupt FcRn-mediated BsAb recycling. In addition to the empirical observations, we also evaluated the impact of in silico properties, including pI differential between the Fab and scFv and the ratio of dipole moment to hydrophobic moment (RM) and their correlation with the observed clearance. These findings highlight that the PK properties of BsAbs may be governed by novel determinants, owing to their increased structural complexity compared to immunoglobulin G (IgG) 1 antibodies.


Assuntos
Anticorpos Biespecíficos , Recém-Nascido , Humanos , Anticorpos Monoclonais , Epitopos , Imunoglobulina G , Ponto Isoelétrico
9.
MAbs ; 16(1): 2313737, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38332713

RESUMO

Therapeutic mAbs show a specific "charge fingerprint" that may affect safety and efficacy, and, as such, it is often identified as a critical quality attribute (CQA). Capillary iso-electric focusing (cIEF), commonly used for the evaluation of such CQA, provides an analytical tool to investigate mAb purity and identity across the product lifecycle. Here, we discuss the results of an analysis of a panel of antibody products by conventional and whole-column imaging cIEF systems performed as part of European Pharmacopoeia activities related to development of "horizontal standards" for the quality control of monoclonal antibodies (mAbs). The study aimed at designing and verifying an independent and transversal cIEF procedure for the reliable analysis of mAbs charge variants. Despite the use of comparable experimental conditions, discrepancies in the charge profile and measured isoelectric points emerged between the two cIEF systems. These data suggest that the results are method-dependent rather than absolute, an aspect known to experts in the field and pharmaceutical industry, but not suitably documented in the literature. Critical implications from analytical and regulatory perspectives, are herein thoughtfully discussed, with a special focus on the context of market surveillance and identification of falsified medicines.


Assuntos
Anticorpos Monoclonais , Eletroforese Capilar , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais/análise , Focalização Isoelétrica/métodos , Eletroforese Capilar/métodos , Ponto Isoelétrico , Controle de Qualidade
10.
RNA Biol ; 21(1): 1-18, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38361426

RESUMO

Protein aggregation, a consequence of misfolding and impaired proteostasis, can lead to cellular malfunctions such as various proteinopathies. The mechanisms protecting proteins from aggregation in complex cellular environments have long been investigated, often from a protein-centric viewpoint. However, our study provides insights into a crucial, yet overlooked actor: RNA. We found that depleting RNAs from Escherichia coli lysates induces global protein aggregation. Our quantitative mass spectrometry analysis identified over 900 statistically significant proteins from the Escherichia coli proteome whose solubility depends on RNAs. Proteome-wide characterization showed that the RNA dependency is particularly enriched among acidic proteins, intrinsically disordered proteins, and structural hub proteins. Moreover, we observed distinct differences in RNA-binding mode and Gene Ontology categories between RNA-dependent acidic and basic proteins. Notably, the solubility of key molecular chaperones [Trigger factor, DnaJ, and GroES] is largely dependent on RNAs, suggesting a yet-to-be-explored hierarchical relationship between RNA-based chaperone (termed as chaperna) and protein-based chaperones, both of which constitute the whole chaperone network. These findings provide new insights into the RNA-centric role in maintaining healthy proteome solubility in vivo, where proteins associate with a variety of RNAs, either stably or transiently.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Proteoma/metabolismo , Dobramento de Proteína , RNA/metabolismo , Solubilidade , Proteômica , Ponto Isoelétrico , Agregados Proteicos , Proteínas de Escherichia coli/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Espectrometria de Massas
11.
J Med Chem ; 67(2): 1406-1420, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38214909

RESUMO

Matrix metalloproteinase-7 (MMP-7) has been shown to play an important role in pathophysiological processes such as cancer and fibrosis. We previously discovered selective MMP-7 inhibitors by molecular hybridization and structure-based drug design. However, the systemic clearance (CLtot) of the biologically active lead compound was very high. Because our studies revealed that hepatic uptake by organic anion transporting polypeptide (OATP) was responsible for the high CLtot, we found a novel approach to reducing their uptake based on isoelectric point (IP) values as an indicator for substrate recognition by OATP1B1/1B3. Our "IP shift strategy" to adjust the IP values culminated in the discovery of TP0628103 (18), which is characterized by reduced in vitro OATP-mediated hepatic uptake and in vivo CLtot. Our in vitro-in vivo extrapolation of OATP-mediated clearance and the "IP shift strategy" provide crucial insights for a new medicinal chemistry approach to reducing the systemic clearance of OATP1B1/1B3 substrates.


Assuntos
Metaloproteinase 7 da Matriz , Transportadores de Ânions Orgânicos , Transportador 1 de Ânion Orgânico Específico do Fígado , Ponto Isoelétrico , Fígado , Interações Medicamentosas , Hepatócitos
12.
J Phys Chem B ; 128(1): 371-380, 2024 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-38156604

RESUMO

This study explores the impact of network functionalization and chemical composition on the pH-responsive behavior of polymer nanogels and their adsorption of proteins. Using a thermodynamic theory informed by a molecular model, this work evaluates the interactions of three proteins with varying isoelectric points (insulin, myoglobin, and cytochrome c) and pH-responsive nanogels based on methacrylic acid or allylamine motifs. Three different functionalization strategies are considered, with pH-responsive segments distributed randomly, at the center, or on the surface of the polymer network. Our results show that the spatial distribution of functional units affects both the nanogels' mechanical response to pH changes and the level and localization of adsorbed proteins. The dependence of protein adsorption on the salt concentration is also investigated, with the conclusion that it is best to encapsulate proteins at low salt concentrations and aim for release at high salt concentrations. These results provide valuable information for the design of pH-responsive nanogels as vehicles for protein encapsulation, transport, and administration.


Assuntos
Polímeros , Polímeros/química , Nanogéis , Adsorção , Concentração de Íons de Hidrogênio , Ponto Isoelétrico
13.
Sci Rep ; 13(1): 19862, 2023 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-37963965

RESUMO

Ferritin is a ubiquitous intracellular iron storage protein that plays a crucial role in iron homeostasis. Animal tissue ferritins consist of multiple isoforms (or isoferritins) with different proportions of H and L subunits that contribute to their structural and compositional heterogeneity, and thus physiological functions. Using size exclusion and anion exchange chromatography, capillary isoelectric focusing (cIEF), and SDS-capillary gel electrophoresis (SDS-CGE), we reveal for the first time a significant variation in ferritin subunit composition and isoelectric points, in both recombinant and native ferritins extracted from animal organs. Our results indicate that subunits composition is the main determinant of the mean pI of recombinant ferritin heteropolymers, and that ferritin microheterogeneity is a common property of both natural and recombinant proteins and appears to be an intrinsic feature of the cellular machinery during ferritin expression, regulation, post-translational modifications, and post-subunits assembly. The functional significance and physiological implications of ferritin heterogeneity in terms of iron metabolism, response to oxidative stress, tissue-specific functions, and pathological processes are discussed.


Assuntos
Ferritinas , Ferro , Animais , Ferritinas/metabolismo , Focalização Isoelétrica , Eletroforese em Gel de Poliacrilamida , Ferro/metabolismo , Ponto Isoelétrico
14.
Soft Matter ; 19(46): 9027-9035, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-37971365

RESUMO

Collagen/hyaluronan hydrogels with physical properties well suited for biomedical applications are challenging to synthesize due to the formation of polyionic complexes (PICs). A systematic physicochemical study was thus performed to determine novel conditions to inhibit the formation of collagen/hyaluronan PICs and obtain composite hydrogels with high physical properties. Using a range of pH from 1 to 5.5 and the addition of NaCl, type I collagen and tyramine-substituted hyaluronic acid (THA) solutions were mixed and analyzed by cryo-scanning electron microscopy and ATR-FTIR. PIC formation was inhibited at pH 1 without salt and at pH 2.5 and 5.5 in the presence of 400 mM NaCl. Interestingly, collagen fibrils were observed in solution at pH 5.5 before mixing with THA. After collagen gelling by pH increase, a homogeneous hydrogel consisting of collagen fibrils was only observed when PICs were inhibited. Then, the THA gelling performed by photo-crosslinking increased the rheological properties by four when hydrogels were formed with collagen/THA mixtures at pH 1 or 5.5 with salt. Taken together, these results show that a pH of 5.5, close to the collagen isoelectric point, enables the formation of collagen fibrils in solution, inhibits the PICs formation, and allows the formation of homogenous collagen/THA composite hydrogels compatible with cell survival.


Assuntos
Ácido Hialurônico , Hidrogéis , Ácido Hialurônico/química , Ponto Isoelétrico , Hidrogéis/química , Cloreto de Sódio , Colágeno/química
15.
Amino Acids ; 55(10): 1371-1379, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37668712

RESUMO

Peptides are short linear molecules consisting of amino acids that play an essential role in most biological processes. They can treat diseases by working as a vaccine or antimicrobial agent and serves as a cancer molecule to deliver the drug to the target site for the treatment of cancer. They have the potential to solve the drawbacks of current medications and can be industrially produced in large quantities at low cost. However, poor chemical and physical stability, short circulating plasma half-life, and solubility are some issues that need solutions before they can be used as therapeutics. PepAnalyzer tool is a user-friendly tool that predicts 15 different properties such as binding potential, half-life, transmembrane patterns, test tube stability, charge, isoelectric point, molecular weights, and molar extinction coefficients only using the sequence. The tool is designed using BioPython utility and has even results with standard tools, such as Expasy, EBI, Genecorner, and Geneinfinity. The tool assists students, researchers, and the pharmaceutical sector. The PepAnalyzer tool's online platform is accessible at the link: http://www.iksmbrlabdu.in/peptool .


Assuntos
Anti-Infecciosos , Peptídeos , Humanos , Peptídeos/química , Aminoácidos/química , Anti-Infecciosos/química , Ponto Isoelétrico , Peso Molecular
16.
Anal Chem ; 95(37): 13941-13948, 2023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37653711

RESUMO

Isoelectric focusing (IEF) is a powerful tool for resolving complex protein samples, which generates IEF patterns consisting of multiplex analyte bands. However, the interpretation of IEF patterns requires the careful selection of isoelectric point (pI) markers for profiling the pH gradient and a trivial process of pI labeling, resulting in low IEF efficiency. Here, we for the first time proposed a marker-free IEF method for the efficient and accurate classification of IEF patterns by using a convolutional neural network (CNN) model. To verify our method, we identified 21 meat samples whose IEF patterns comprised different bands of meat hemoglobin, myoglobin, and their oxygen-binding variants but no pI marker. Thanks to the high throughput and short assay time of the microstrip IEF, we efficiently collected 1449 IEF patterns to construct the data set for model training. Despite the absence of pI markers, we experimentally introduced the severe pH gradient drift into 189 IEF patterns in the data set, thereby omitting the need for profiling the pH gradient. To enhance the model robustness, we further employed data augmentation during the model training to mimic pH gradient drift. With the advantages of simple preprocessing, a rapid inference of 50 ms, and a high accuracy of 97.1%, the CNN model outperformed the traditional algorithm for simultaneously identifying meat species and cuts of meat of 105 IEF patterns, suggesting its great potential of being combined with microstrip IEF for large-scale IEF analyses of complicated protein samples.


Assuntos
Aprendizado Profundo , Focalização Isoelétrica , Ponto Isoelétrico , Algoritmos , Carne
17.
Proc Natl Acad Sci U S A ; 120(33): e2305704120, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37549277

RESUMO

Biocompatible and morphable hydrogels capable of multimode reprogrammable, and adaptive shape changes are potentially useful for diverse biomedical applications. However, existing morphable systems often rely on complicated structural designs involving cumbersome and energy-intensive fabrication processes. Here, we report a simple electric-field-activated protein network migration strategy to reversibly program silk-protein hydrogels with controllable and reprogrammable complex shape transformations. The application of a low electric field enables the convergence of net negatively charged protein cross-linking networks toward the anode (isoelectric point plane) due to the pH gradient generated in the process, facilitating the formation of a gradient network structure and systems suitable for three-dimensional shape change. These tunable protein networks can be reprogrammed or permanently fixed by control of the polymorphic transitions. We show that these morphing hydrogels are capable of conformally interfacing with biological tissues by programming the shape changes and a bimorph structure consisting of aligned carbon nanotube multilayers and the silk hydrogels was assembled to illustrate utility as an implantable bioelectronic device for localized low-voltage electrical stimulation of the sciatic nerve in a rabbit.


Assuntos
Hidrogéis , Seda , Animais , Coelhos , Seda/química , Hidrogéis/química , Ponto Isoelétrico , Materiais Biocompatíveis/química
18.
Biotechnol Prog ; 39(6): e3381, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37531360

RESUMO

Elastin-like polypeptides (ELPs) are peptide-based biomaterials with residue sequence (VPGXG)n where X is any residue except proline. ELPs are a useful modality for delivering biologically active proteins (growth factors, protease inhibitors, anti-inflammatory peptides, etc.) as fusion proteins (ELP-FP). ELP-FPs are particularly cost-effective because they can be rapidly purified using Inverse Temperature Cycling (ITC) via the reversible formation and precipitation of entropically driven aggregates above a transition temperature (Tt ). When ELP fusion proteins (ELP-FPs) contain significant charge density at physiological pH, electrostatic repulsion between them severely inhibits aggregate formation. The literature does not currently describe methods for purifying ELP-FPs containing charged proteins on either side of the ELP sequence as fusion partners without organic solvents. Here, the isoelectric point (pI) of ELP-FPs is discussed as a means of neutralizing surface charges on ELP-FPs and increasing ITC yield to dramatically high levels. We use pI-based phase separation (pI-BPS) to purify ELP-FPs containing cationic and anionic fusion proteins. We report a dramatic increase in protein yield when using pI-BPS for purification of ELP-FPs. Proteins purified by this method also retain the functional activity of the protein present in the ELP-FP. Techniques developed here enable significant diversification of possible fusion proteins delivered by ELPs as ELP-FPs by allowing them to be produced and purified at higher quantities and yields.


Assuntos
Polipeptídeos Semelhantes à Elastina , Elastina , Ponto Isoelétrico , Elastina/química , Separação de Fases , Peptídeos/química , Proteínas Recombinantes de Fusão/genética
19.
MAbs ; 15(1): 2232087, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37408314

RESUMO

Optimal pharmacokinetic (PK) properties of therapeutic monoclonal antibodies (mAbs) are essential to achieve the desired pharmacological benefits in patients. To accomplish this, we followed an approach comprising structure-based mAb charge engineering in conjunction with the use of relevant preclinical models to screen and select humanized candidates with PK suitable for clinical development. Murine mAb targeting TDP-43, ACI-5891, was humanized on a framework (VH1-3/VK2-30) selected based on the highest sequence homology. Since the initial humanized mAb (ACI-5891.1) presented a fast clearance in non-human primates (NHPs), reiteration of humanization on a less basic human framework (VH1-69-2/VK2-28) while retaining high sequence homology was performed. The resulting humanized variant, ACI-5891.9, presented a six-fold reduction in clearance in NHPs resulting in a significant increase in half-life. The observed reduced clearance of ACI-5891.9 was attributed not only to the overall reduction in isoelectric point (pI) by 2 units, but importantly to a more even surface potential. These data confirm the importance and contribution of surface charges to mAb disposition in vivo. Consistent low clearance of ACI-5891.9 in Tg32 mice, a human FcRn transgenic mouse model, further confirmed its utility for early assessment and prediction of human PK. These data demonstrate that mAb surface charge is an important parameter for consideration during the selection and screening of humanized candidates in addition to maintaining the other key physiochemical and target binding characteristics.


Assuntos
Anticorpos Monoclonais , Receptores Fc , Camundongos , Humanos , Animais , Camundongos Transgênicos , Taxa de Depuração Metabólica , Ponto Isoelétrico , Antígenos de Histocompatibilidade Classe I
20.
J Colloid Interface Sci ; 650(Pt B): 2065-2074, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37355354

RESUMO

In food manufacturing and particular biomedical products selected proteins are often required. Obtaining the desired proteins in a pure form from natural resources is therefore important, but often very challenging. Herein, we design a sequential coacervation process that allows to efficiently isolate and purify proteins with different isoelectric points (pIs) from a mixed solution, namely Bovine Serum Albumin (BSA, pI = 4.9) and Peroxidase from Horseradish (HRP, pI = 7.2). The key to separation is introducing a suitable polyelectrolyte that causes selective complex coacervation at appropriate pH and ionic strength. Specifically, polyethyleneimine (PEI), when added into the mixture at pH 6.0, produces a coacervation which exclusively contains BSA, leading to a supernatant solution containing 100 % HRP with a purity of 91 %. After separating the dilute and dense phases, BSA is recovered by adding poly(acrylic acid) (PAA) to the concentrated phase, which displaces BSA from the complex because it interacts more strongly with PEI. The supernatant phase after this step contains approximately 75 % of the initial amount of BSA with a purity of 99 %. Our results confirm that coacervation under well-defined conditions can be selective, enabling separation of proteins with adequate purity. Therefore, the established approach demonstrates a facile and sustainable strategy with potential for protein separation at industrial scale.


Assuntos
Polietilenoimina , Soroalbumina Bovina , Concentração de Íons de Hidrogênio , Soroalbumina Bovina/metabolismo , Polieletrólitos , Ponto Isoelétrico
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