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Liu W, Huang Z, Chen X, Ding S, Xiang Q, Huang Y, Li H. Human collagen sequence polypeptides mediated biomineralization and its molecular mechanism. J Mech Behav Biomed Mater 2024; 158:106687. [PMID: 39137580 DOI: 10.1016/j.jmbbm.2024.106687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 08/06/2024] [Accepted: 08/08/2024] [Indexed: 08/15/2024]
Abstract
Biotechnology provides alternatives for regenerative medicine with more controllable functions. Herein, the polypeptides encoded with human collagen I amino-acid sequences were studied for the first time to modulate biomimetic hydroxyapatite (HAP). With a length of 50-100 nm and a width of 20-30 nm, the HAP crystal formed was plate-like. The interaction of the human collagen sequence polypeptide on the (001), (100), and (211) crystal faces of HAP crystal had been studied using Molecular Dynamics (MD) simulations, respectively. Based on MD simulations, van der Waals forces and hydrogen bonds are the main interactions between polypeptides and HAP through the -NH2, -CH2-, -OH, and -COOH, respectively. According to the calculated results, der Waals forces might be the main interaction. The human collagen sequence polypeptides exhibited the highest adsorption energy on the (001) plane of HAP, significantly higher than any of the adsorption energy on the (100) and (211) planes. Therefore, the growth of the (001) would be inhibited, which kept accurate with the result of images from the Transmission Electron Microscope (TEM). Study results provide a basis for rational designing of peptides with human collagen sequences to regenerate hard tissues.
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Affiliation(s)
- Wangzi Liu
- College of Chemistry Materials and Science, Jinan University, Guangzhou, 510632, China; Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, 510632, China
| | - Zhilin Huang
- College of Chemistry Materials and Science, Jinan University, Guangzhou, 510632, China; Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, 510632, China
| | - Xiaohui Chen
- College of Chemistry Materials and Science, Jinan University, Guangzhou, 510632, China; Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, 510632, China
| | - Shan Ding
- College of Chemistry Materials and Science, Jinan University, Guangzhou, 510632, China; Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, 510632, China
| | - Qi Xiang
- Institute of Biomedicine and Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou, 510632, China
| | - Yadong Huang
- Institute of Biomedicine and Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou, 510632, China
| | - Hong Li
- College of Chemistry Materials and Science, Jinan University, Guangzhou, 510632, China; Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou, 510632, China.
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Crago M, Lee A, Hoang TP, Talebian S, Naficy S. Protein adsorption on blood-contacting surfaces: A thermodynamic perspective to guide the design of antithrombogenic polymer coatings. Acta Biomater 2024; 180:46-60. [PMID: 38615811 DOI: 10.1016/j.actbio.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. Thrombosis is fundamentally initiated by the nonspecific adsorption of proteins to the material surface, which is strongly governed by thermodynamic factors established by the nature of the interaction between the material surface, surrounding water molecules, and the protein itself. Along these lines, different surface materials (such as polymeric, metallic, ceramic, or composite) induce different entropic and enthalpic changes at the surface-protein interface, with material wettability significantly impacting this behavior. Consequently, protein adsorption on medical devices can be modulated by altering their wettability and surface energy. A plethora of polymeric coating modifications have been utilized for this purpose; hydrophobic modifications may promote or inhibit protein adsorption determined by van der Waals forces, while hydrophilic materials achieve this by mainly relying on hydrogen bonding, or unbalanced/balanced electrostatic interactions. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications. STATEMENT OF SIGNIFICANCE: Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. A plethora of polymeric coating modifications have been utilized for addressing this issue. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications.
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Affiliation(s)
- Matthew Crago
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Aeryne Lee
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Thanh Phuong Hoang
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Sepehr Talebian
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia.
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia.
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Xue J, Ji M, Lu Y, Pan D, Yang X, Yang X, Xu Z. The impact of chemical properties of the solid-liquid-adsorbate interfaces on the entropy-enthalpy compensation involved in adsorption. Phys Chem Chem Phys 2024; 26:8704-8715. [PMID: 38415756 DOI: 10.1039/d3cp05669d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Despite extensive studies on the thermodynamic mechanism governing molecular adsorption at the solid-water interface, a comprehensive understanding of the crucial role of interface properties in mediating the entropy-enthalpy compensation during adsorption is lacking, particularly at a quantitative level. Herein, we employed two types of surface models (hydroxyapatite and graphene) along with a series of amino acids to successfully elucidate how distinct interfacial features dictate the delicate balance between entropy and enthalpy variations. The adsorption of all amino acids on the hydroxyapatite surface is an enthalpy-dominated process, where the water-induced enthalpic component of the free energy and the surface-adsorbate electrostatic interaction term alternatively act as the driving force for adsorption in different regions of the surface. Although favorable interactions are observed between amino acids and the graphene surface, the entropy-enthalpy compensation exhibits dependence on the molecular size of the adsorbates. For small amino acids, favorable enthalpy changes predominantly determine their adsorption behavior; however, larger amino acids tend to bind more tightly with the graphene surface, which is thermodynamically dominated by the entropy variations despite the structural characteristics of amino acids. This study reveals specific entropy-enthalpy mechanisms underlying amino acid adsorption at the solid-liquid interface, providing guidance for surface design and synthesis of new biomolecules.
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Affiliation(s)
- Jinling Xue
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Mingyu Ji
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Yuanyuan Lu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Dan Pan
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Xiao Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Xiaoning Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Zhijun Xu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
- Zhangjiagang Institute of Nanjing Tech University, Zhangjiagang 215699, China
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Maurer J, Grouzmann E, Eugster PJ. Tutorial review for peptide assays: An ounce of pre-analytics is worth a pound of cure. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1229:123904. [PMID: 37832388 DOI: 10.1016/j.jchromb.2023.123904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023]
Abstract
The recent increase in peptidomimetic-based medications and the growing interest in peptide hormones has brought new attention to the quantification of peptides for diagnostic purposes. Indeed, the circulating concentrations of peptide hormones in the blood provide a snapshot of the state of the body and could eventually lead to detecting a particular health condition. Although extremely useful, the quantification of such molecules, preferably by liquid chromatography coupled to mass spectrometry, might be quite tricky. First, peptides are subjected to hydrolysis, oxidation, and other post-translational modifications, and, most importantly, they are substrates of specific and nonspecific proteases in biological matrixes. All these events might continue after sampling, changing the peptide hormone concentrations. Second, because they include positively and negatively charged groups and hydrophilic and hydrophobic residues, they interact with their environment; these interactions might lead to a local change in the measured concentrations. A phenomenon such as nonspecific adsorption to lab glassware or materials has often a tremendous effect on the concentration and needs to be controlled with particular care. Finally, the circulating levels of peptides might be low (pico- or femtomolar range), increasing the impact of the aforementioned effects and inducing the need for highly sensitive instruments and well-optimized methods. Thus, despite the extreme diversity of these peptides and their matrixes, there is a common challenge for all the assays: the need to keep concentrations unchanged from sampling to analysis. While significant efforts are often placed on optimizing the analysis, few studies consider in depth the impact of pre-analytical steps on the results. By working through practical examples, this solution-oriented tutorial review addresses typical pre-analytical challenges encountered during the development of a peptide assay from the standpoint of a clinical laboratory. We provide tips and tricks to avoid pitfalls as well as strategies to guide all new developments. Our ultimate goal is to increase pre-analytical awareness to ensure that newly developed peptide assays produce robust and accurate results.
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Affiliation(s)
- Jonathan Maurer
- Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Eric Grouzmann
- Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Philippe J Eugster
- Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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Huang Z, Wang C, Chen X, Ding S, Xiang Q, Xie M, Huang Y, Li H. Regulation of recombinant humanized collagen on HAP growth and its molecule simulation. RSC Adv 2023; 13:26031-26040. [PMID: 37664193 PMCID: PMC10472339 DOI: 10.1039/d3ra03810f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/13/2023] [Indexed: 09/05/2023] Open
Abstract
Hydroxyapatite (HAP) in natural bone is formed under the regulation of natural collagen I. Here, we report how recombinant humanized collagen I (rhCol I) regulates the growth of HAP nanocrystals in a long belt shape 100-150 nm in width and 200-300 nm in length. MD simulation results showed that the interactions between rhCol I and the (001), (100), and (211) planes of HAP mainly contributed to the electrostatic force and van der Waals forces via COO⋯Ca, -NH⋯Ca, CH⋯OPO3, and NH⋯OPO3 bonds, respectively. On the (001) plane, the interaction between -COO- and Ca was stronger than on the (100) and (211) planes, resulting in a large electrostatic force, which inhibited the growth of the (001) plane. The lowest energy of adsorption to the (211) plane resulted in the preferential growth of the (211) plane due to the weakest interaction with rhCol I. The detailed correlation between HAP and rhCol I could explain HAP growth under regulation by rhCol I. This study provides a reference for the bio-application of recombinant collagen.
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Affiliation(s)
- Zhilin Huang
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Engineering Research Center of Artificial Organs and Materials, Ministry of Education Guangzhou 510632 China
| | - Chucheng Wang
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Engineering Research Center of Artificial Organs and Materials, Ministry of Education Guangzhou 510632 China
| | - Xiaohui Chen
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Engineering Research Center of Artificial Organs and Materials, Ministry of Education Guangzhou 510632 China
| | - Shan Ding
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Engineering Research Center of Artificial Organs and Materials, Ministry of Education Guangzhou 510632 China
| | - Qi Xiang
- Institute of Biomedicine and Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University Guangzhou 510632 China
| | - Mo Xie
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications Guangzhou 510632 China
| | - Yadong Huang
- Institute of Biomedicine and Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University Guangzhou 510632 China
| | - Hong Li
- College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
- Engineering Research Center of Artificial Organs and Materials, Ministry of Education Guangzhou 510632 China
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Yang X, Zhang C, Yang X, Xu Z. Free energy reconstruction/decomposition from WHAM, force integration and free energy perturbation for an umbrella sampling simulation. Chem Phys 2023. [DOI: 10.1016/j.chemphys.2022.111736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Mitchell W, Tamucci JD, Ng EL, Liu S, Birk AV, Szeto HH, May ER, Alexandrescu AT, Alder NN. Structure-activity relationships of mitochondria-targeted tetrapeptide pharmacological compounds. eLife 2022; 11:75531. [PMID: 35913044 PMCID: PMC9342957 DOI: 10.7554/elife.75531] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 07/03/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondria play a central role in metabolic homeostasis, and dysfunction of this organelle underpins the etiology of many heritable and aging-related diseases. Tetrapeptides with alternating cationic and aromatic residues such as SS-31 (elamipretide) show promise as therapeutic compounds for mitochondrial disorders. In this study, we conducted a quantitative structure-activity analysis of three alternative tetrapeptide analogs, benchmarked against SS-31, that differ with respect to aromatic side chain composition and sequence register. We present the first structural models for this class of compounds, obtained with Nuclear Magnetic Resonance (NMR) and molecular dynamics approaches, showing that all analogs except for SS-31 form compact reverse turn conformations in the membrane-bound state. All peptide analogs bound cardiolipin-containing membranes, yet they had significant differences in equilibrium binding behavior and membrane interactions. Notably, analogs had markedly different effects on membrane surface charge, supporting a mechanism in which modulation of membrane electrostatics is a key feature of their mechanism of action. The peptides had no strict requirement for side chain composition or sequence register to permeate cells and target mitochondria in mammalian cell culture assays. All four peptides were pharmacologically active in serum withdrawal cell stress models yet showed significant differences in their abilities to restore mitochondrial membrane potential, preserve ATP content, and promote cell survival. Within our peptide set, the analog containing tryptophan side chains, SPN10, had the strongest impact on most membrane properties and showed greatest efficacy in cell culture studies. Taken together, these results show that side chain composition and register influence the activity of these mitochondria-targeted peptides, helping provide a framework for the rational design of next-generation therapeutics with enhanced potency.
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Affiliation(s)
- Wayne Mitchell
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Jeffrey D Tamucci
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Emery L Ng
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Shaoyi Liu
- Social Profit Network, Menlo Park, CA, United States
| | - Alexander V Birk
- Department of Biology, York College of CUNY, New York, NY, United States
| | - Hazel H Szeto
- Social Profit Network, Menlo Park, CA, United States
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Andrei T Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
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Yang X, Ji M, Zhang C, Yang X, Xu Z. Physical insight into the entropy-driven ion association. J Comput Chem 2022; 43:1621-1632. [PMID: 35801676 DOI: 10.1002/jcc.26963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
The ion association is widely believed to be dominated by the favorable entropy change arising from the release of water molecules from ion hydration shells. However, no direct thermodynamic evidence exists to validate the reliability and suitability of this view. Herein, we employ complicated free energy calculations to rigorously split the free energy including its entropic and enthalpic components into the water-induced contributions and ion-ion interaction terms for several ion pairs from monatomic to polyatomic ions, spanning the size range from small kosmotropes to large chaotropes (Na+ , Cs+ , Ca2+ , F- , I- , CO3 2- , and HPO4 2- ). Our results successfully reveal that though ion associations are indeed determined by a delicate balance between the favorable entropy variation and the repulsive enthalpy change, the entropy gain dominated by the solvent occurs only for the monatomic ion pairing. The water-induced entropic contribution significantly goes against the ion pairing between polyatomic anion and cation, which is, alternatively, dominated by the favorable entropy from the ion-ion interaction term, due to the configurational arrangement of polyatomic anions involved in ion association. The structural and dynamic analysis demonstrates that the entropy penalty from the water phase is primarily ascribed to the enhanced stability of water molecules around the cation imposed by the incoming anion. Our study successfully provides a fundamental understanding of water-mediated ion associations and highlights disparate lengthscale dependencies of the dehydration thermodynamics on the specific types of ions.
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Affiliation(s)
- Xiao Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Mingyu Ji
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Cong Zhang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Xiaoning Yang
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China
| | - Zhijun Xu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, China.,Zhangjiagang Institute of Nanjing Tech University, Zhangjiagang, China
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Ma Y, Hua T, Trinh TA, Wang R, Chew JW. Molecular dynamics simulation of the competitive adsorption behavior of effluent organic matters by heated aluminum oxide particles (HAOPs). Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120961] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Du J, Yang C, Ma X, Li Q. Insights into the conformation changes of SARS-CoV-2 spike receptor-binding domain on graphene. APPLIED SURFACE SCIENCE 2022; 578:151934. [PMID: 34866721 PMCID: PMC8627288 DOI: 10.1016/j.apsusc.2021.151934] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/24/2021] [Accepted: 11/14/2021] [Indexed: 05/13/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been widely spread in the world, causing more than two million deaths and seriously threatening human life. Effective protection measures are important to prevent the infection and spreading of the virus. To explore the effects of graphene on the virus adsorption and its biological properties, the adsorption process of the receptor binding domain (RBD) of SARS-CoV-2 on graphene has been investigated by molecular dynamics simulations in this paper. The results show that RBD can be quickly adsorbed onto the surface of graphene due to π - π stacking and hydrophobic interactions. Residue PHE486 with benzene ring has stronger adsorption force and the maximum contact area with graphene. Graphene significantly affects the secondary structure of RBD area, especially on the three key sites of binding with human ACE2, GLY476, PHE486 and ASN487. The binding free energy of RBD and graphene shows that the adsorption is irreversible. Undoubtedly, these changes will inevitably affect the pathogenicity of the virus. Therefore, this study provides a theoretical basis for the application of graphene in the protection of SARS-CoV-2, and also provides a reference for the potential application of graphene in the biomedical field.
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Affiliation(s)
- Jianbin Du
- College of Science, Langfang Normal University, Langfang 065000, China
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Chunmei Yang
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Xiangyun Ma
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Qifeng Li
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
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Laity PR, Holland C. Seeking Solvation: Exploring the Role of Protein Hydration in Silk Gelation. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020551. [PMID: 35056868 PMCID: PMC8781151 DOI: 10.3390/molecules27020551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/31/2021] [Accepted: 01/11/2022] [Indexed: 02/05/2023]
Abstract
The mechanism by which arthropods (e.g., spiders and many insects) can produce silk fibres from an aqueous protein (fibroin) solution has remained elusive, despite much scientific investigation. In this work, we used several techniques to explore the role of a hydration shell bound to the fibroin in native silk feedstock (NSF) from Bombyx mori silkworms. Small angle X-ray and dynamic light scattering (SAXS and DLS) revealed a coil size (radius of gyration or hydrodynamic radius) around 12 nm, providing considerable scope for hydration. Aggregation in dilute aqueous solution was observed above 65 °C, matching the gelation temperature of more concentrated solutions and suggesting that the strength of interaction with the solvent (i.e., water) was the dominant factor. Infrared (IR) spectroscopy indicated decreasing hydration as the temperature was raised, with similar changes in hydration following gelation by freezing or heating. It was found that the solubility of fibroin in water or aqueous salt solutions could be described well by a relatively simple thermodynamic model for the stability of the protein hydration shell, which suggests that the affected water is enthalpically favoured but entropically penalised, due to its reduced (vibrational or translational) dynamics. Moreover, while the majority of this investigation used fibroin from B. mori, comparisons with published work on silk proteins from other silkworms and spiders, globular proteins and peptide model systems suggest that our findings may be of much wider significance.
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Ma Y, Velioğlu S, Yin Z, Wang R, Chew JW. Molecular dynamics investigation of membrane fouling in organic solvents. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119329] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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