1
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Dao TNP, Onikanni SA, Fadaka AO, Klein A, Tran VD, Le MH, Wang CH, Chang HH. In silico identification of compounds from Piper sarmentosum Roxb leaf fractionated extract inhibit interleukin-6 to prevent rheumatoid arthritis. Front Pharmacol 2024; 15:1358037. [PMID: 38576490 PMCID: PMC10991700 DOI: 10.3389/fphar.2024.1358037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/07/2024] [Indexed: 04/06/2024] Open
Abstract
Objective: Medicinal herbs with a phytonutrient background has been applied globally as major alternatives to ameliorate the continuous increase in rheumatoid arthritis cases worldwide. We herein aimed to critically examine the bioactive components of the medicinal herb Piper sarmentosum Roxb leaf fractionated extract for its potential to inhibit the influx of interleukin-6 (IL-6) in rheumatoid arthritis. Methods: The Schrödinger platform was employed as the main computational acumen for the screening of bioactive compounds identified and reference compounds subjected to molecular simulation (MDS) for analyzing the stability of docked complexes to assess fluctuations and conformational changes during protein-ligand interactions. Results: The values of the simulatory properties and principal component analysis (PCA) revealed the good stability of these phytochemicals in the active pocket of interleukin-6 (IL-6). Discussion: Our findings reveal new strategies in which these phytochemicals are potential inhibitory agents that can be modified and further evaluated to develop more effective agents for the management of rheumatoid arthritis, thereby providing a better understanding and useful model for the reproduction and/or discovery of new drugs for the management of rheumatoid arthritis and its complications.
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Affiliation(s)
- Tran Nhat Phong Dao
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan
- Faculty of Traditional Medicine, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam
| | - Sunday Amos Onikanni
- College of Medicine, Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
- Department of Chemical Sciences, Biochemistry Unit, Afe-Babalola University, Ado-Ekiti, Nigeria
| | | | - Ashwil Klein
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa
| | - Van De Tran
- Department of Health Organization and Management, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam
| | - Minh Hoang Le
- Faculty of Traditional Medicine, Can Tho University of Medicine and Pharmacy, Can Tho, Vietnam
| | - Chih-Hao Wang
- College of Medicine, Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
- Graduate Institute of Cell Biology, China Medical University, Taichung, Taiwan
| | - Hen-Hong Chang
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan
- Chinese Medicine Research Center, China Medical University, Taichung, Taiwan
- Department of Chinese Medicine, China Medical University Hospital, Taichung, Taiwan
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2
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Schweipert M, Nehls T, Frühauf A, Debarnot C, Kumar A, Knapp S, Lermyte F, Meyer‐Almes F. The catalytic domain of free or ligand bound histone deacetylase 4 occurs in solution predominantly in closed conformation. Protein Sci 2024; 33:e4917. [PMID: 38358265 PMCID: PMC10868454 DOI: 10.1002/pro.4917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Human histone deacetylase 4 (HDAC4) is a key epigenetic regulator involved in a number of important cellular processes. This makes HDAC4 a promising target for the treatment of several cancers and neurodegenerative diseases, in particular Huntington's disease. HDAC4 is highly regulated by phosphorylation and oxidation, which determine its nuclear or cytosolic localization, and exerts its function through multiple interactions with other proteins, forming multiprotein complexes of varying composition. The catalytic domain of HDAC4 is known to interact with the SMRT/NCOR corepressor complex when the structural zinc-binding domain (sZBD) is intact and forms a closed conformation. Crystal structures of the HDAC4 catalytic domain have been reported showing an open conformation of HDAC4 when bound to certain ligands. Here, we investigated the relevance of this HDAC4 conformation under physiological conditions in solution. We show that proper zinc chelation in the sZBD is essential for enzyme function. Loss of the structural zinc ion not only leads to a massive decrease in enzyme activity, but it also has serious consequences for the overall structural integrity and stability of the protein. However, the Zn2+ free HDAC4 structure in solution is incompatible with the open conformation. In solution, the open conformation of HDAC4 was also not observed in the presence of a variety of structurally divergent ligands. This suggests that the open conformation of HDAC4 cannot be induced in solution, and therefore cannot be exploited for the development of HDAC4-specific inhibitors.
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Affiliation(s)
- Markus Schweipert
- Department of Chemical Engineering and BiotechnologyUniversity of Applied SciencesDarmstadtGermany
| | - Thomas Nehls
- Department of ChemistryClemens‐Schöpf‐Institute of Chemistry and Biochemistry, Technical University of DarmstadtDarmstadtGermany
| | - Anton Frühauf
- Department of Chemical Engineering and BiotechnologyUniversity of Applied SciencesDarmstadtGermany
| | - Cecilé Debarnot
- Department of Chemical Engineering and BiotechnologyUniversity of Applied SciencesDarmstadtGermany
| | - Adarsh Kumar
- Fachbereich Biochemie, Chemie und PharmazieInstitut für Pharmazeutische Chemie, Goethe‐University FrankfurtFrankfurt Am MainGermany
| | - Stefan Knapp
- Fachbereich Biochemie, Chemie und PharmazieInstitut für Pharmazeutische Chemie, Goethe‐University FrankfurtFrankfurt Am MainGermany
| | - Frederik Lermyte
- Department of ChemistryClemens‐Schöpf‐Institute of Chemistry and Biochemistry, Technical University of DarmstadtDarmstadtGermany
| | - Franz‐Josef Meyer‐Almes
- Department of Chemical Engineering and BiotechnologyUniversity of Applied SciencesDarmstadtGermany
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3
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Wang Y, Liu J, Zhang Z, Meng X, Yang T, Shi W, He R, Ma H. Insights into Ultrasonication Treatment on the Characteristics of Cereal Proteins: Functionality, Conformational and Physicochemical Characteristics. Foods 2023; 12:foods12050971. [PMID: 36900488 PMCID: PMC10000784 DOI: 10.3390/foods12050971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND It would be impossible to imagine a country where cereals and their byproducts were not at the peak of foodstuff systems as a source of food, fertilizer, or for fiber and fuel production. Moreover, the production of cereal proteins (CPs) has recently attracted the scientific community's interest due to the increasing demands for physical wellbeing and animal health. However, the nutritional and technological enhancements of CPs are needed to ameliorate their functional and structural properties. Ultrasonic technology is an emerging nonthermal method to change the functionality and conformational characteristics of CPs. Scope and approach: This article briefly discusses the effects of ultrasonication on the characteristics of CPs. The effects of ultrasonication on the solubility, emulsibility, foamability, surface-hydrophobicity, particle-size, conformational-structure, microstructural, enzymatic-hydrolysis, and digestive properties are summarized. CONCLUSIONS The results demonstrate that ultrasonication could be used to enhance the characteristics of CPs. Proper ultrasonic treatment could improve functionalities such as solubility, emulsibility, and foamability, and is a good method for altering protein structures (including surface hydrophobicity, sulfhydryl and disulfide bonds, particle size, secondary and tertiary structures, and microstructure). In addition, ultrasonic treatment could effectively promote the enzymolytic efficiency of CPs. Furthermore, the in vitro digestibility was enhanced after suitable sonication treatment. Therefore, ultrasonication technology is a useful method to modify cereal protein functionality and structure for the food industry.
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Affiliation(s)
- Yang Wang
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Jiarui Liu
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Zhaoli Zhang
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
- Correspondence: (Z.Z.); (R.H.); Tel.: +86-(511)-8878-0174 (R.H.)
| | - Xiangren Meng
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Tingxuan Yang
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Wangbin Shi
- College of Tourism and Cooking & College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Ronghai He
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
- Correspondence: (Z.Z.); (R.H.); Tel.: +86-(511)-8878-0174 (R.H.)
| | - Haile Ma
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
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4
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Onikanni SA, Lawal B, Fadaka AO, Bakare O, Adewole E, Taher M, Khotib J, Susanti D, Oyinloye BE, Ajiboye BO, Ojo OA, Sibuyi NRS. Computational and Preclinical Prediction of the Antimicrobial Properties of an Agent Isolated from Monodora myristica: A Novel DNA Gyrase Inhibitor. Molecules 2023; 28:molecules28041593. [PMID: 36838579 PMCID: PMC9966190 DOI: 10.3390/molecules28041593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/22/2023] [Accepted: 01/27/2023] [Indexed: 02/11/2023] Open
Abstract
The African nutmeg (Monodora myristica) is a medically useful plant. We, herein, aimed to critically examine whether bioactive compounds identified in the extracted oil of Monodora myristica could act as antimicrobial agents. To this end, we employed the Schrödinger platform as the computational tool to screen bioactive compounds identified in the oil of Monodora myristica. Our lead compound displayed the highest potency when compared with levofloxacin based on its binding affinity. The hit molecule was further subjected to an Absorption, Distribution, Metabolism, Excretion (ADME) prediction, and a Molecular Dynamics (MD) simulation was carried out on molecules with PubChem IDs 529885 and 175002 and on three standards (levofloxacin, cephalexin, and novobiocin). The MD analysis results demonstrated that two molecules are highly compact when compared to the native protein; thereby, this suggests that they could affect the protein on a structural and a functional level. The employed computational approach demonstrates that conformational changes occur in DNA gyrase after the binding of inhibitors; thereby, this resulted in structural and functional changes. These findings expand our knowledge on the inhibition of bacterial DNA gyrase and could pave the way for the discovery of new drugs for the treatment of multi-resistant bacterial infections.
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Affiliation(s)
- Sunday Amos Onikanni
- College of Medicine, Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Biochemistry Unit, Department of Chemical Sciences, Afe Babalola University, Ado-Ekiti 360101, Nigeria
- Correspondence: or (S.A.O.); (J.K.); (B.O.A.)
| | - Bashir Lawal
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | | - Oluwafemi Bakare
- Department of Biochemistry, Faculty of Science, Adekunle Ajasin University, Akungba Akoko 342111, Nigeria
| | - Ezekiel Adewole
- Industrial Chemistry Unit, Department of Chemical Sciences, Afe Babalola University, Ado-Ekiti 360101, Nigeria
| | - Muhammad Taher
- Department of Pharmaceutical Technology, Kulliyyah of Pharmacy, International Islamic University Malaysia, Kuantan 25200, Pahang, Malaysia
- Pharmaceutics and Translational Research Group, Kulliyyah of Pharmacy, International Islamic University Malaysia, Kuantan 25200, Pahang, Malaysia
| | - Junaidi Khotib
- Department of Pharmacy Practice, Faculty of Pharmacy, Airlangga University, Surabaya 60115, Indonesia
- Correspondence: or (S.A.O.); (J.K.); (B.O.A.)
| | - Deny Susanti
- Department of Chemistry, Kulliyyah of Science, International Islamic University Malaysia, Kuantan 25200, Pahang, Malaysia
| | - Babatunji Emmanuel Oyinloye
- Biochemistry Unit, Department of Chemical Sciences, Afe Babalola University, Ado-Ekiti 360101, Nigeria
- Biotechnology and Structural Biology (BSB) Group, Department of Biochemistry and Microbiology, University of Zululand, Kwadlangezwa 3886, South Africa
- Institute of Drug Research and Development, SE Bogoro Center, Afe Babalola University, PMB 5454, Ado-Ekiti 360001, Nigeria
| | - Basiru Olaitan Ajiboye
- Institute of Drug Research and Development, SE Bogoro Center, Afe Babalola University, PMB 5454, Ado-Ekiti 360001, Nigeria
- Phytomedicine and Molecular Toxicology Research Laboratory, Department of Biochemistry, Federal University Oye-Ekiti, Oye-Ekiti 371104, Nigeria
- Correspondence: or (S.A.O.); (J.K.); (B.O.A.)
| | - Oluwafemi Adeleke Ojo
- Phytomedicine, Molecular Toxicology, and Computational Biochemistry Research Laboratory (PMTCB-RL), Department of Biochemistry, Bowen University, Iwo 232101, Nigeria
| | - Nicole Remaliah Samantha Sibuyi
- Department of Biotechnology, University of the Western Cape, Bellville 7530, South Africa
- Health Platform, Advanced Materials Division, Mintek, Randburg 2194, South Africa
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5
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Abstract
Large-molecule antibody biologics have revolutionized medicine owing to their superior target specificity, pharmacokinetic and pharmacodynamic properties, safety and toxicity profiles, and amenability to versatile engineering. In this review, we focus on preclinical antibody developability, including its definition, scope, and key activities from hit to lead optimization and selection. This includes generation, computational and in silico approaches, molecular engineering, production, analytical and biophysical characterization, stability and forced degradation studies, and process and formulation assessments. More recently, it is apparent these activities not only affect lead selection and manufacturability, but ultimately correlate with clinical progression and success. Emerging developability workflows and strategies are explored as part of a blueprint for developability success that includes an overview of the four major molecular properties that affect all developability outcomes: 1) conformational, 2) chemical, 3) colloidal, and 4) other interactions. We also examine risk assessment and mitigation strategies that increase the likelihood of success for moving the right candidate into the clinic.
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Affiliation(s)
- Carl Mieczkowski
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Xuejin Zhang
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Dana Lee
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Khanh Nguyen
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Wei Lv
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Yanling Wang
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Yue Zhang
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Jackie Way
- Department of Protein Sciences, Hengenix Biotech, Inc, Milpitas, CA, USA
| | - Jean-Michel Gries
- President, Discovery Research, Hengenix Biotech, Inc, Milpitas, CA, USA
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6
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Patterson-Orazem AC, Qerqez AN, Azouz LR, Ma MT, Hill SE, Ku Y, Schildmeyer LA, Maynard JA, Lieberman RL. Recombinant antibodies recognize conformation-dependent epitopes of the leucine zipper of misfolding-prone myocilin. J Biol Chem 2021; 297:101067. [PMID: 34384785 PMCID: PMC8408531 DOI: 10.1016/j.jbc.2021.101067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 11/11/2022] Open
Abstract
Recombinant antibodies with well-characterized epitopes and known conformational specificities are critical reagents to support robust interpretation and reproducibility of immunoassays across biomedical research. For myocilin, a protein prone to misfolding that is associated with glaucoma and an emerging player in other human diseases, currently available antibodies are unable to differentiate among the numerous disease-associated protein states. This fundamentally constrains efforts to understand the connection between myocilin structure, function, and disease. To address this concern, we used protein engineering methods to develop new recombinant antibodies that detect the N-terminal leucine zipper structural domain of myocilin and that are cross-reactive for human and mouse myocilin. After harvesting spleens from immunized mice and in vitro library panning, we identified two antibodies, 2A4 and 1G12. 2A4 specifically recognizes a folded epitope while 1G12 recognizes a range of conformations. We matured antibody 2A4 for improved biophysical properties, resulting in variant 2H2. In a human IgG1 format, 2A4, 1G12, and 2H2 immunoprecipitate full-length folded myocilin present in the spent media of human trabecular meshwork (TM) cells, and 2H2 can visualize myocilin in fixed human TM cells using fluorescence microscopy. These new antibodies should find broad application in glaucoma and other research across multiple species platforms.
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Affiliation(s)
| | - Ahlam N Qerqez
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Laura R Azouz
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Minh Thu Ma
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Shannon E Hill
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Yemo Ku
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Lisa A Schildmeyer
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA.
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA.
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7
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Sellner M, Fischer A, Don CG, Smieško M. Conformational Landscape of Cytochrome P450 Reductase Interactions. Int J Mol Sci 2021; 22:1023. [PMID: 33498551 PMCID: PMC7864194 DOI: 10.3390/ijms22031023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 01/05/2023] Open
Abstract
Oxidative reactions catalyzed by Cytochrome P450 enzymes (CYPs), which constitute the most relevant group of drug-metabolizing enzymes, are enabled by their redox partner Cytochrome P450 reductase (CPR). Both proteins are anchored to the membrane of the endoplasmic reticulum and the CPR undergoes a conformational change in order to interact with the respective CYP and transfer electrons. Here, we conducted over 22 microseconds of molecular dynamics (MD) simulations in combination with protein-protein docking to investigate the conformational changes necessary for the formation of the CPR-CYP complex. While some structural features of the CPR and the CPR-CYP2D6 complex that we highlighted confirmed previous observations, our simulations revealed additional mechanisms for the conformational transition of the CPR. Unbiased simulations exposed a movement of the whole protein relative to the membrane, potentially to facilitate interactions with its diverse set of redox partners. Further, we present a structural mechanism for the susceptibility of the CPR to different redox states based on the flip of a glycine residue disrupting the local interaction network that maintains inter-domain proximity. Simulations of the CPR-CYP2D6 complex pointed toward an additional interaction surface of the FAD domain and the proximal side of CYP2D6. Altogether, this study provides novel structural insight into the mechanism of CPR-CYP interactions and underlying conformational changes, improving our understanding of this complex machinery Cytochrome P450 reductase; CPR; conformational; dynamicsrelevant for drug metabolism.
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Affiliation(s)
| | | | | | - Martin Smieško
- Computational Pharmacy, Departement of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland; (M.S.); (A.F.); (C.G.D.)
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8
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Lou W, Stimple SD, Desai AA, Makowski EK, Kalyoncu S, Mogensen JE, Spang LT, Asgreen DJ, Staby A, Duus K, Amstrup J, Zhang Y, Tessier PM. Directed evolution of conformation-specific antibodies for sensitive detection of polypeptide aggregates in therapeutic drug formulations. Biotechnol Bioeng 2020; 118:797-808. [PMID: 33095442 DOI: 10.1002/bit.27610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 12/22/2022]
Abstract
Biologics such as peptides and proteins possess a number of attractive attributes that make them particularly valuable as therapeutics, including their high activity, high specificity, and low toxicity. However, one of the key challenges associated with this class of drugs is their propensity to aggregate. Given the safety and immunogenicity concerns related to polypeptide aggregates, it is particularly important to sensitively detect aggregates in therapeutic drug formulations as part of the quality control process. Here, we report the development of conformation-specific antibodies that recognize polypeptide aggregates composed of a GLP-1 receptor agonist (liraglutide) and their integration into a sensitive immunoassay for detecting liraglutide amyloid fibrils. We sorted single-chain antibody libraries against liraglutide fibrils using yeast surface display and magnetic-activated cell sorting, and identified several antibodies with high conformational specificity. Interestingly, these antibodies cross-react with amyloid fibrils formed by several other polypeptides, revealing that they recognize molecular features common to different types of fibrils. Moreover, we find that our immunoassay using these antibodies is >50-fold more sensitive than the conventional method for detecting liraglutide aggregation (Thioflavin T fluorescence). We expect that our systematic approach for generating a sensitive, aggregate-specific immunoassay can be readily extended to other biologics to improve the quality and safety of formulated drug products.
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Affiliation(s)
- Wenjia Lou
- Department of Pharmaceutical Sciences, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA.,Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Samuel D Stimple
- Department of Pharmaceutical Sciences, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA.,Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Alec A Desai
- Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Emily K Makowski
- Department of Pharmaceutical Sciences, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Sibel Kalyoncu
- Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | | | | | | | | | | | | | - Yulei Zhang
- Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter M Tessier
- Department of Pharmaceutical Sciences, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA.,Department of Chemical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA.,Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA.,Department of Biomedical Engineering, Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, USA
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9
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Wu C, Bates D, Sangtarash S, Ferri N, Thomas A, Higgins SJ, Robertson CM, Nichols RJ, Sadeghi H, Vezzoli A. Folding a Single-Molecule Junction. Nano Lett 2020; 20:7980-7986. [PMID: 33047599 PMCID: PMC7662913 DOI: 10.1021/acs.nanolett.0c02815] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Stimuli-responsive molecular junctions, where the conductance can be altered by an external perturbation, are an important class of nanoelectronic devices. These have recently attracted interest as large effects can be introduced through exploitation of quantum phenomena. We show here that significant changes in conductance can be attained as a molecule is repeatedly compressed and relaxed, resulting in molecular folding along a flexible fragment and cycling between an anti and a syn conformation. Power spectral density analysis and DFT transport calculations show that through-space tunneling between two phenyl fragments is responsible for the conductance increase as the molecule is mechanically folded to the syn conformation. This phenomenon represents a novel class of mechanoresistive molecular devices, where the functional moiety is embedded in the conductive backbone and exploits intramolecular nonbonding interactions, in contrast to most studies where mechanoresistivity arises from changes in the molecule-electrode interface.
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Affiliation(s)
- Chuanli Wu
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
- School
of Chemistry and Materials Science, Nanjing
Normal University, Nanjing 210023, People’s Republic
of China
| | - Demetris Bates
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Sara Sangtarash
- School
of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Nicoló Ferri
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Aidan Thomas
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Simon J. Higgins
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Craig M. Robertson
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Richard J. Nichols
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
| | - Hatef Sadeghi
- School
of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Andrea Vezzoli
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United
Kingdom
- Stephenson
Institute for Renewable Energy, University
of Liverpool, Peach Street, Liverpool L69 7ZF, United Kingdom
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10
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Abstract
With the increased global awareness and rise in food allergies, a multifold interest in food allergens is evident. The presence of undeclared food allergens results in expensive food recalls and increased risks of anaphylaxis for the sensitive individuals. Regardless of the allergenic food, the immunogen needs to be identified and detected before making any efforts to inactivate/eliminate it. In type I food allergies, protein immunogen cross-links immunoglobulin E, leading to basophil/mast cell degranulation, resulting in the symptoms that range from mild irritation to anaphylaxis. A portion/part of the protein, known as the epitope, can interact with either antibodies to elicit allergic reactions or T-cell receptors to initiate allergic sensitization. Antibody-recognized epitopes can be either a linear sequence of amino acids (linear epitope) or a three-dimensional motif (conformational epitope), while T-cell-receptor-recognized epitopes are exclusively linear peptides. Identifying and characterizing human-allergy-relevant epitopes are important for allergy diagnosis/prognosis, immunotherapy, and developing food processing methods that can reduce/eliminate immunogencity/immunoreactivity of the allergen.
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Affiliation(s)
- Changqi Liu
- School of Exercise and Nutritional Sciences, College of Health and Human Services , San Diego State University , 308 ENS Building, 5500 Campanile Drive , San Diego , California 92182-7251 , United States
| | - Shridhar K Sathe
- Department of Nutrition, Food & Exercise Sciences, College of Human Sciences , Florida State University , 402 SAN, 120 Convocation Way , Tallahassee , Florida 32306-1493 , United States
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11
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Godsey MH, Davulcu O, Nix JC, Skalicky JJ, Brüschweiler RP, Chapman MS. The Sampling of Conformational Dynamics in Ambient-Temperature Crystal Structures of Arginine Kinase. Structure 2016; 24:1658-1667. [PMID: 27594681 DOI: 10.1016/j.str.2016.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 01/26/2023]
Abstract
Arginine kinase provides a model for functional dynamics, studied through crystallography, enzymology, and nuclear magnetic resonance. Structures are now solved, at ambient temperature, for the transition state analog (TSA) complex. Analysis of quasi-rigid sub-domain displacements show that differences between the two TSA structures average about 5% of changes between substrate-free and TSA forms, and they are nearly co-linear. Small backbone hinge rotations map to sites that also flex on substrate binding. Anisotropic atomic displacement parameters (ADPs) are refined using rigid-body TLS constraints. Consistency between crystal forms shows that they reflect intrinsic molecular properties more than crystal lattice effects. In many regions, the favored directions of thermal/static displacement are appreciably correlated with movements on substrate binding. Correlation between ADPs and larger substrate-associated movements implies that the latter approximately follow paths of low-energy intrinsic motions.
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Affiliation(s)
- Michael H Godsey
- Department of Math/Science, Concordia University, Portland, OR 97211, USA
| | - Omar Davulcu
- Department Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jay C Nix
- Molecular Biology Consortium, Lawrence Berkeley Natl. Lab., Berkeley, CA 94720, USA
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 8412, USA
| | - Rafael P Brüschweiler
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Michael S Chapman
- Department Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
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Mikles DC, Bhat V, Schuchardt BJ, McDonald CB, Farooq A. Effect of osmolytes on the binding of EGR1 transcription factor to DNA. Biopolymers 2016; 103:74-87. [PMID: 25269753 DOI: 10.1002/bip.22556] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 08/16/2014] [Accepted: 08/19/2014] [Indexed: 11/11/2022]
Abstract
Osmolytes play a key role in maintaining protein stability and mediating macromolecular interactions within the intracellular environment of the cell. Herein, we show that osmolytes such as glycerol, sucrose, and polyethylene glycol 400 (PEG400) mitigate the binding of early growth response (protein) 1 (EGR1) transcription factor to DNA in a differential manner. Thus, while physiological concentrations of glycerol only moderately reduce the binding affinity, addition of sucrose and PEG400 is concomitant with a loss in the binding affinity by an order of magnitude. This salient observation suggests that EGR1 is most likely subject to conformational equilibrium and that the osmolytes exert their effect via favorable interactions with the unliganded conformation. Consistent with this notion, our analysis reveals that while EGR1 displays rather high structural stability in complex with DNA, the unliganded conformation becomes significantly destabilized in solution. In particular, while liganded EGR1 adopts a well-defined arc-like architecture, the unliganded protein samples a comparatively large conformational space between two distinct states that periodically interconvert between an elongated rod-like shape and an arc-like conformation on a submicrosecond time scale. Consequently, the ability of osmolytes to favorably interact with the unliganded conformation so as to stabilize it could account for the negative effect of osmotic stress on EGR1-DNA interaction observed here. Taken together, our study sheds new light on the role of osmolytes in modulating a key protein-DNA interaction.
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Affiliation(s)
- David C Mikles
- Department of Biochemistry and Molecular Biology, Leonard Miller School of Medicine, University of Miami, Miami, FL, 33136
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Abstract
Most biological reactions rely on interplay between binding and changes in both macromolecular structure and dynamics. Practical understanding of this interplay requires detection of critical intermediates and determination of their binding and conformational characteristics. However, many of these species are only transiently present and they have often been overlooked in mechanistic studies of reactions that couple binding to conformational change. We monitored the kinetics of ligand-induced conformational changes in a small protein using six different ligands. We analyzed the kinetic data to simultaneously determine both binding affinities for the conformational states and the rate constants of conformational change. The approach we used is sufficiently robust to determine the affinities of three conformational states and detect even modest differences in the protein's affinities for relatively similar ligands. Ligand binding favors higher-affinity conformational states by increasing forward conformational rate constants and/or decreasing reverse conformational rate constants. The amounts by which forward rate constants increase and reverse rate constants decrease are proportional to the ratio of affinities of the conformational states. We also show that both the affinity ratio and another parameter, which quantifies the changes in conformational rate constants upon ligand binding, are strong determinants of the mechanism (conformational selection and/or induced fit) of molecular recognition. Our results highlight the utility of analyzing the kinetics of conformational changes to determine affinities that cannot be determined from equilibrium experiments. Most importantly, they demonstrate an inextricable link between conformational dynamics and the binding affinities of conformational states.
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