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Rahban M, Ahmad F, Piatyszek MA, Haertlé T, Saso L, Saboury AA. Stabilization challenges and aggregation in protein-based therapeutics in the pharmaceutical industry. RSC Adv 2023; 13:35947-35963. [PMID: 38090079 PMCID: PMC10711991 DOI: 10.1039/d3ra06476j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/30/2023] [Indexed: 04/26/2024] Open
Abstract
Protein-based therapeutics have revolutionized the pharmaceutical industry and become vital components in the development of future therapeutics. They offer several advantages over traditional small molecule drugs, including high affinity, potency and specificity, while demonstrating low toxicity and minimal adverse effects. However, the development and manufacturing processes of protein-based therapeutics presents challenges related to protein folding, purification, stability and immunogenicity that should be addressed. These proteins, like other biological molecules, are prone to chemical and physical instabilities. The stability of protein-based drugs throughout the entire manufacturing, storage and delivery process is essential. The occurrence of structural instability resulting from misfolding, unfolding, and modifications, as well as aggregation, poses a significant risk to the efficacy of these drugs, overshadowing their promising attributes. Gaining insight into structural alterations caused by aggregation and their impact on immunogenicity is vital for the advancement and refinement of protein therapeutics. Hence, in this review, we have discussed some features of protein aggregation during production, formulation and storage as well as stabilization strategies in protein engineering and computational methods to prevent aggregation.
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Affiliation(s)
- Mahdie Rahban
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences Kerman Iran
| | - Faizan Ahmad
- Department of Biochemistry, School of Chemical & Life Sciences, Jamia Hamdard New Delhi-110062 India
| | | | | | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University Rome Italy
| | - Ali Akbar Saboury
- Institute of Biochemistry and Biophysics, University of Tehran Tehran 1417614335 Iran +9821 66404680 +9821 66956984
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2
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Zeunik R, Ryuzoji AF, Peariso A, Wang X, Lannan M, Spindler LJ, Knierman M, Copeland V, Patel C, Wen Y. Investigation of immune responses to oxidation, deamidation, and isomerization in therapeutic antibodies using preclinical immunogenicity risk assessment assays. J Pharm Sci 2022; 111:2217-2229. [DOI: 10.1016/j.xphs.2022.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/07/2022] [Accepted: 05/08/2022] [Indexed: 01/30/2023]
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3
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Austerberry J, Edwards J, Eyes T, Derrick JP. Use of Peptide Microarrays for Fast and Informative Profiling of Therapeutic Antibody Formulation Conditions. Mol Pharm 2021; 18:4131-4139. [PMID: 34658237 DOI: 10.1021/acs.molpharmaceut.1c00543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methods to optimize the solution behavior of therapeutic proteins are frequently time-consuming, provide limited information, and often use milligram quantities of material. Here, we present a simple, versatile method that provides valuable information to guide the identification and comparison of formulation conditions for, in principle, any biopharmaceutical drug. The subject protein is incubated with a designed synthetic peptide microarray; the extent of binding to each peptide is dependent on the solution conditions. The array is washed, and the adhesion of the subject protein is detected using a secondary antibody. We exemplify the method using a well-characterized human single-chain Fv and a selection of human monoclonal antibodies. Correlations of peptide adhesion profiles can be used to establish quantitative relationships between different solution conditions, allowing subgrouping into dendrograms. Multidimensional reduction methods, such as t-distributed stochastic neighbor embedding, can be applied to compare how different monoclonals vary in their adhesion properties under different solution conditions. Finally, we screened peptide binding profiles using a selection of monoclonal antibodies for which a range of biophysical measurements were available under specified buffer conditions. We used a neural network method to train the data against aggregation temperature, kD, percentage recovery after incubation at 25 °C, and melting temperature. The results demonstrate that peptide binding profiles can indeed be effectively trained on these indicators of protein stability and self-association in solution. The method opens up multiple possibilities for the application of machine learning methods in therapeutic protein formulation.
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Affiliation(s)
- James Austerberry
- School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - John Edwards
- School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Tim Eyes
- School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Jeremy P Derrick
- School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PT, United Kingdom
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4
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Lundahl MLE, Fogli S, Colavita PE, Scanlan EM. Aggregation of protein therapeutics enhances their immunogenicity: causes and mitigation strategies. RSC Chem Biol 2021; 2:1004-1020. [PMID: 34458822 PMCID: PMC8341748 DOI: 10.1039/d1cb00067e] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/04/2021] [Indexed: 12/25/2022] Open
Abstract
Protein aggregation in biotherapeutics has been identified to increase immunogenicity, leading to immune-mediated adverse effects, such as severe allergic responses including anaphylaxis. The induction of anti-drug antibodies (ADAs) moreover enhances drug clearance rates, and can directly block therapeutic function. In this review, identified immune activation mechanisms triggered by protein aggregates are discussed, as well as physicochemical properties of aggregates, such as size and shape, which contribute to immunogenicity. Furthermore, factors which contribute to protein stability and aggregation are considered. Lastly, with these factors in mind, we encourage an innovative and multidisciplinary approach with regard to further research in the field, with the overall aim to avoid immunogenic aggregation in future drug development.
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Affiliation(s)
- Mimmi L E Lundahl
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin 2 Ireland
| | - Silvia Fogli
- Glycome Biopharma, Unit 4, Joyce House, Barrack Square, Ballincollig Co Cork P31 HW35 Ireland
| | - Paula E Colavita
- School of Chemistry and Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin 2 Ireland
| | - Eoin M Scanlan
- School of Chemistry and Trinity Biomedical Sciences Institute, Trinity College Dublin Dublin 2 Ireland
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5
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Golam Kibria M, Akazawa-Ogawa Y, Hagihara Y, Kuroda Y. Immune response with long-term memory triggered by amorphous aggregates of misfolded anti-EGFR V HH-7D12 is directed against the native V HH-7D12 as well as the framework of the analogous V HH-9G8. Eur J Pharm Biopharm 2021; 165:13-21. [PMID: 33971271 DOI: 10.1016/j.ejpb.2021.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 02/06/2023]
Abstract
We previously demonstrated that amorphous aggregates of misfolded VHH-7D12 antibodies (VHH-Mis), a potential anti-EGFR drug, can generate a robust serum IgG response. Here we investigate the immunogenic nature, especially the specificity of the immune response induced by VHH-Mis. To this end, we used two natively folded and 77% identical anti-EGFR VHHs (VHH-7D12 and VHH-9G8) that possess a common framework but distinct complementarity determining regions (CDRs). In 60% of mice immunized with VHH-Mis, the anti-VHH-7D12 IgG titer was stronger than the anti-VHH-9G8 titer (Group-1). In the remaining mice (40%; Group-2), the anti-VHH-7D12 and anti-VHH-9G8 titer were almost identical. We rationalized these results by hypothesizing that mice in Group-1 produced IgG mostly against the VHH-7D12's CDRs, whereas in Group-2 mice, they targeted the VHH's framework. The IgG specificity against VHH-7D12 and VHH-9G8 was essentially unchanged over 17 weeks in both groups. Further, in all mice (Group-1&2) re-immunized with native VHH-7D12, the IgG titer against VHH-7D12 increased sharply but not against VHH-9G8. On the other hand, none of the three Group-1 mice re-immunized with native VHH-9G8 showed immunogenicity against VHH-7D12 nor VHH-9G8. Whereas, in Group-2 mice (three/three) re-immunized with VHH-9G8, the IgG titers against both VHHs increased but slowly. Flow-cytometric studies showed that VHH-Mis immunized mice generated a higher number of effector and central memory T-cells. Overall, these observations indicate that amorphous aggregates made of a misfolded VHH can induce serum IgG against its natively folded self and analogous VHHs having a similar framework but distinct CDRs. Furthermore, a robust long-term immune response with memory was established against its natively folded self but with a nil-to-moderate immune response against natively folded VHH analogs.
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Affiliation(s)
- Md Golam Kibria
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan
| | - Yoko Akazawa-Ogawa
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan
| | - Yoshihisa Hagihara
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan
| | - Yutaka Kuroda
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan.
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6
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Immunogenicity Challenges Associated with Subcutaneous Delivery of Therapeutic Proteins. BioDrugs 2021; 35:125-146. [PMID: 33523413 PMCID: PMC7848667 DOI: 10.1007/s40259-020-00465-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 12/12/2022]
Abstract
The subcutaneous route of administration has provided convenient and non-inferior delivery of therapeutic proteins compared to intravenous infusion, but there is potential for enhanced immunogenicity toward subcutaneously administered proteins in a subset of patients. Unwanted anti-drug antibody response toward proteins or monoclonal antibodies upon repeated administration is shown to impact the pharmacokinetics and efficacy of multiple biologics. Unique immunogenicity challenges of the subcutaneous route have been realized through various preclinical and clinical examples, although subcutaneous delivery has often demonstrated comparable immunogenicity to intravenous administration. Beyond route of administration as a treatment-related factor of immunogenicity, certain product-related risk factors are particularly relevant to subcutaneously administered proteins. This review attempts to provide an overview of the mechanism of immune response toward proteins administered subcutaneously (subcutaneous proteins) and comments on product-related risk factors related to protein structure and stability, dosage form, and aggregation. A two-wave mechanism of antigen presentation in the immune response toward subcutaneous proteins is described, and interaction with dynamic antigen-presenting cells possessing high antigen processing efficiency and migratory activity may drive immunogenicity. Mitigation strategies for immunogenicity are discussed, including those in general use clinically and those currently in development. Mechanistic insights along with consideration of risk factors involved inspire theoretical strategies to provide antigen-specific, long-lasting effects for maintaining the safety and efficacy of therapeutic proteins.
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The Impact of Product and Process Related Critical Quality Attributes on Immunogenicity and Adverse Immunological Effects of Biotherapeutics. J Pharm Sci 2020; 110:1025-1041. [PMID: 33316242 DOI: 10.1016/j.xphs.2020.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 02/07/2023]
Abstract
The pharmaceutical industry has experienced great successes with protein therapeutics in the last two decades and with novel modalities, including cell therapies and gene therapies, more recently. Biotherapeutics are complex in structure and present challenges for discovery, development, regulatory, and life cycle management. Biotherapeutics can interact with the immune system that may lead to undesired immunological responses, including immunogenicity, hypersensitivity reactions (HSR), injection site reactions (ISR), and others. Many product and process related critical quality attributes (CQAs) have the potential to trigger or augment such immunological responses to the product. Tremendous efforts, both clinically and preclinically, have been invested to understand the impact of product and process related CQAs on adverse immunological effects. The information and knowledge are critical for the implementation of Quality by Design (QbD), which requires risk assessment and establishment of specifications and control strategies for CQAs. A quality target product profile (QTPP) that identifies the key CQAs through process development can help assign severity scores based on safety, immunogenicity, pharmacokinetics (PK) and pharmacodynamics (PD) of the molecule. Gaps and future directions related to biotherapeutics and emerging novel modalities are presented.
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8
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Hasan MM, Khatun MS, Kurata H. iLBE for Computational Identification of Linear B-cell Epitopes by Integrating Sequence and Evolutionary Features. GENOMICS PROTEOMICS & BIOINFORMATICS 2020; 18:593-600. [PMID: 33099033 PMCID: PMC8377379 DOI: 10.1016/j.gpb.2019.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 01/13/2019] [Accepted: 04/19/2019] [Indexed: 12/17/2022]
Abstract
Linear B-cell epitopes are critically important for immunological applications, such as vaccine design, immunodiagnostic test, and antibody production, as well as disease diagnosis and therapy. The accurate identification of linear B-cell epitopes remains challenging despite several decades of research. In this work, we have developed a novel predictor, Identification of Linear B-cell Epitope (iLBE), by integrating evolutionary and sequence-based features. The successive feature vectors were optimized by a Wilcoxon-rank sum test. Then the random forest (RF) algorithm using the optimal consecutive feature vectors was applied to predict linear B-cell epitopes. We combined the RF scores by the logistic regression to enhance the prediction accuracy. iLBE yielded an area under curve score of 0.809 on the training dataset and outperformed other prediction models on a comprehensive independent dataset. iLBE is a powerful computational tool to identify the linear B-cell epitopes and would help to develop penetrating diagnostic tests. A web application with curated datasets for iLBE is freely accessible at http://kurata14.bio.kyutech.ac.jp/iLBE/.
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Affiliation(s)
- Md Mehedi Hasan
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan
| | - Mst Shamima Khatun
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan
| | - Hiroyuki Kurata
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Biomedical Informatics R&D Center, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
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9
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Nabhan M, Pallardy M, Turbica I. Immunogenicity of Bioproducts: Cellular Models to Evaluate the Impact of Therapeutic Antibody Aggregates. Front Immunol 2020; 11:725. [PMID: 32431697 PMCID: PMC7214678 DOI: 10.3389/fimmu.2020.00725] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
Patients treated with bioproducts (BPs) frequently develop anti-drug antibodies (ADAs) with potential neutralizing capacities leading to loss of clinical response or potential hypersensitivity reactions. Many factors can influence BP immunogenicity and could be related to the patient, the treatment, as well as to the product itself. Among these latter factors, it is now well accepted that BP aggregation is associated with an increased potential for immunogenicity, as aggregates seem to be correlated with ADA development. Moreover, the presence of high-affinity ADAs suggests a CD4 T-cell dependent adaptive immune response and therefore a pivotal role for antigen-presenting cells (APCs), such as dendritic cells (DCs). In this review, we address the in vitro methods developed to evaluate how monoclonal antibodies could trigger the immunization process by focusing on the role of aggregated antibodies in the establishment of this response. In particular, we will present the different cell-based assays that have been used to assess the potential of antibodies and their aggregates to modulate cellular mechanisms leading to activation and the biological parameters (cellular activation markers, proliferation and secreted molecules) that can be measured to evaluate the different cell activation stages and their consequences in the propagation of the immune response. Indeed, the use of such strategies could help evaluate the risk of BP immunogenicity and their role in mitigating this risk.
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Affiliation(s)
- Myriam Nabhan
- Inserm, Inflammation, Microbiome and Immunosurveillance, Université Paris-Saclay, Châtenay-Malabry, France
| | - Marc Pallardy
- Inserm, Inflammation, Microbiome and Immunosurveillance, Université Paris-Saclay, Châtenay-Malabry, France
| | - Isabelle Turbica
- Inserm, Inflammation, Microbiome and Immunosurveillance, Université Paris-Saclay, Châtenay-Malabry, France
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Willis LF, Kumar A, Jain T, Caffry I, Xu Y, Radford SE, Kapur N, Vásquez M, Brockwell DJ. The uniqueness of flow in probing the aggregation behavior of clinically relevant antibodies. ENGINEERING REPORTS : OPEN ACCESS 2020; 2:e12147. [PMID: 34901768 PMCID: PMC8638667 DOI: 10.1002/eng2.12147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 06/10/2023]
Abstract
The development of therapeutic monoclonal antibodies (mAbs) can be hindered by their tendency to aggregate throughout their lifetime, which can illicit immunogenic responses and render mAb manufacturing unfeasible. Consequently, there is a need to identify mAbs with desirable thermodynamic stability, solubility, and lack of self-association. These behaviors are assessed using an array of in silico and in vitro assays, as no single assay can predict aggregation and developability. We have developed an extensional and shear flow device (EFD), which subjects proteins to defined hydrodynamic forces which mimic those experienced in bioprocessing. Here, we utilize the EFD to explore the aggregation propensity of 33 IgG1 mAbs, whose variable domains are derived from clinical antibodies. Using submilligram quantities of material per replicate, wide-ranging EFD-induced aggregation (9-81% protein in pellet) was observed for these mAbs, highlighting the EFD as a sensitive method to assess aggregation propensity. By comparing the EFD-induced aggregation data to those obtained previously from 12 other biophysical assays, we show that the EFD provides distinct information compared with current measures of adverse biophysical behavior. Assessing a candidate's liability to hydrodynamic force thus adds novel insight into the rational selection of developable mAbs that complements other assays.
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Affiliation(s)
- Leon F. Willis
- School of Molecular and Cellular Biology, Faculty of Biological SciencesUniversity of LeedsLeedsUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUK
| | - Amit Kumar
- School of Molecular and Cellular Biology, Faculty of Biological SciencesUniversity of LeedsLeedsUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUK
- Department of Life SciencesImperial College LondonLondonUK
| | | | - Isabelle Caffry
- Adimab LLCLebanonNew HampshireUSA
- Cornell Johnson Graduate School of ManagementIthacaNew YorkUSA
| | - Yingda Xu
- Adimab LLCLebanonNew HampshireUSA
- Biotheus Inc.ZhuhaiGuangdong ProvinceChina
| | - Sheena E. Radford
- School of Molecular and Cellular Biology, Faculty of Biological SciencesUniversity of LeedsLeedsUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUK
| | - Nikil Kapur
- School of Mechanical Engineering, Faculty of EngineeringUniversity of LeedsLeedsUK
| | | | - David J. Brockwell
- School of Molecular and Cellular Biology, Faculty of Biological SciencesUniversity of LeedsLeedsUK
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUK
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Rahman N, Islam MM, Unzai S, Miura S, Kuroda Y. Nanometer-Sized Aggregates Generated Using Short Solubility Controlling Peptide Tags Do Increase the In Vivo Immunogenicity of a Nonimmunogenic Protein. Mol Pharm 2020; 17:1629-1637. [DOI: 10.1021/acs.molpharmaceut.0c00071] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Nafsoon Rahman
- Department of Biotechnology and Life Sciences, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan
| | - Mohammad Monirul Islam
- Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong 4331, Bangladesh
| | - Satoru Unzai
- Department of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584, Japan
| | - Shiho Miura
- Department of Biotechnology and Life Sciences, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan
| | - Yutaka Kuroda
- Department of Biotechnology and Life Sciences, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan
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12
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Pongprayoon P, Niramitranon J, Kaewhom P, Kaewmongkol S, Suwan E, Stich RW, Jittapalapong S. Dynamic and structural insights into tick serpin from Ixodes ricinus. J Biomol Struct Dyn 2019; 38:2296-2303. [PMID: 31215334 DOI: 10.1080/07391102.2019.1630003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ixodid ticks have a crucial impact on people and domestic animals worldwide. These parasites also pose a serious threat to livestock. To date, vaccination of hosts against ticks is a safer, more sustainable alternative to chemical control of ticks and the disease agents they transmit. Because of their roles in tick physiology, serpins (serine protease inhibitors) from tick saliva are among the candidates for anti-tick vaccines. Inhibitory serpins employ a suicide inhibition mechanism to inhibit proteases, where the serpin reactive centre loop (RCL) is cleaved, by the targeted protease, and then inserted into the main β-sheet of the serpin. This causes a massive conformational change called the 'stressed to relaxed' (S→R) transition, leading to the breakdown of serpin into two regions (core domain and cleaved polypeptide). Recently, the first tick serpin crystal structure from Ixodes ricinus in R-state was reported. We thus employed molecular dynamics simulations to better understand serpin structure and dynamics in atomic detail. Overall, R-state serpin showed high rigidity, especially the core domain. The most flexible region is the terminal of the cleaved polypeptide, due to its high-water exposure, while the rest of the cleaved polypeptide is stably trapped behind the core domain. T363, D367 and N375 are found to play a vital role in protein-protein attachment. This finding can be used to explain the high stability of the R-state serpin at the atomic level and provides insight into this tick serpin which will be useful for rational anti-tick vaccine development. AbbreviationsMDMolecular DynamicsRCLReactive centre loopCommunicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Prapasiri Pongprayoon
- Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand.,Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, KU Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - Jitti Niramitranon
- Department of Computer Engineering, Faculty of Engineering, Kasetsart University, Chatuchak, Bangkok, Thailand
| | - Phaitoon Kaewhom
- Faculty of Agricultural Technology, Burapha University, Sakaeo Campus, Sakaeo, Thailand
| | | | - Eukote Suwan
- Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
| | - Roger W Stich
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
| | - Sathaporn Jittapalapong
- Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand.,Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
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