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Inoue M, Hayashi T, Yasuda S, Kato M, Ikeguchi M, Murata T, Kinoshita M. Statistical-Mechanics Analyses on Thermodynamics of Protein Folding Constructed by Privalov and Co-Workers. J Phys Chem B 2024; 128:10110-10125. [PMID: 39376155 DOI: 10.1021/acs.jpcb.4c05811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Privalov and co-workers estimated the changes in hydration enthalpy and entropy upon ubiquitin unfolding and their temperature dependences denoted by ΔHhyd(T) and ΔShyd(T), respectively, from experimentally measured enthalpies and entropies of transfer of various model compounds from gaseous phase to water. We calculate ΔHhyd(T) and ΔShyd(T) for ubiquitin by our statistical-mechanics theory where molecular and atomistic models are employed for water and protein structure, respectively. ΔHhyd(T) and ΔShyd(T) calculated are in remarkably good agreement with those estimated by Privalov and co-workers. By examining relative magnitudes and signs of the changes in a variety of constituents of ΔHhyd(T) and ΔShyd(T), we confirm that the hydrophobic effect is an essential force driving a protein to fold. Detailed and comprehensive explanations are given for our claim that the prevailing views of the hydrophobic effect are not capable of elucidating its weakening at low temperatures, whereas our updated view is. We find out problematic points of the changes in enthalpy and entropy upon protein unfolding denoted by ΔH°(T) and ΔS°(T), respectively, which are measured using the differential scanning calorimetry at low pH, suggesting a theoretical method of calculating ΔH°(T) and ΔS°(T) at pH ∼ 7.
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Affiliation(s)
- Masao Inoue
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomohiko Hayashi
- Interdisciplinary Program of Biomedical Engineering, Assistive Technology, and Art and Sports Sciences, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan
| | - Satoshi Yasuda
- Graduate School of Science and Membrane Protein Research Center, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
| | - Minoru Kato
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- RIKEN Medical Sciences Innovation Hub Program, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takeshi Murata
- Graduate School of Science and Membrane Protein Research Center, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
| | - Masahiro Kinoshita
- Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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2
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Pietrzak A, Wojciechowski J, Nowak P, Gacki M, Ochocki J, Wolf WM. Ambiguous Faces of Water-Based Inclusion Compounds: L4(4)8(8) Intercalato-Clathrate Hydrate of Pt(II) Complex. Chemistry 2024; 30:e202303483. [PMID: 38656538 DOI: 10.1002/chem.202303483] [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: 10/23/2023] [Revised: 04/10/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Clathrate hydrates are among the most intensively studied H-bond inclusion compounds. Despite the broad definition for this class of compounds, their meaning commonly refers to closed polyhedral nanocages that encapsulate small guest molecules. On the other hand, larger solutes enforce another type of encapsulation because of the solute size effect. Herein, we report a series of structures containing various molecules encapsulated by intercalated water layers constructed of polycyclic moieties of L4(4)8(8) topology. We parametrized the corrugation of individual layers and characterized interactions governing their formation. We suggested that these could be categorized as two-dimensional clathrates based on the character of intra-layer interactions and the effects observed between entrapped molecules and water-based intercalators.
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Affiliation(s)
- Anna Pietrzak
- Institute of General and Ecological Chemistry, Faculty of Chemistry, Łódź University of Technology, Żeromskiego 116, 90-924, Łódź, Poland
| | | | - Przemysław Nowak
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Łódź, Poland
- Bio-Med-Chem Doctoral School of University of Lodz and Lodz Institutes of the Polish Academy of Sciences, University of Łódź, Matejki 21/23, 90-237, Łódź, Poland
| | - Michał Gacki
- Institute of General and Ecological Chemistry, Faculty of Chemistry, Łódź University of Technology, Żeromskiego 116, 90-924, Łódź, Poland
| | - Justyn Ochocki
- Department of Bioinorganic Chemistry, Medical University of Łódź, Muszyńskiego 1, 90-151, Łódź, Poland
| | - Wojciech M Wolf
- Institute of General and Ecological Chemistry, Faculty of Chemistry, Łódź University of Technology, Żeromskiego 116, 90-924, Łódź, Poland
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Yang T, Zhang Y, Guo L, Li D, Liu A, Bilal M, Xie C, Yang R, Gu Z, Jiang D, Wang P. Antifreeze Polysaccharides from Wheat Bran: The Structural Characterization and Antifreeze Mechanism. Biomacromolecules 2024; 25:3877-3892. [PMID: 38388358 DOI: 10.1021/acs.biomac.3c00958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Exploring a novel natural cryoprotectant and understanding its antifreeze mechanism allows the rational design of future sustainable antifreeze analogues. In this study, various antifreeze polysaccharides were isolated from wheat bran, and the antifreeze activity was comparatively studied in relation to the molecular structure. The antifreeze mechanism was further revealed based on the interactions of polysaccharides and water molecules through dynamic simulation analysis. The antifreeze polysaccharides showed distinct ice recrystallization inhibition activity, and structural analysis suggested that the polysaccharides were arabinoxylan, featuring a xylan backbone with a majority of Araf and minor fractions of Manp, Galp, and Glcp involved in the side chain. The antifreeze arabinoxylan, characterized by lower molecular weight, less branching, and more flexible conformation, could weaken the hydrogen bonding of the surrounding water molecules more evidently, thus retarding the transformation of water molecules into the ordered ice structure.
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Affiliation(s)
- Tao Yang
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- National Technique Innovation Center for Regional Wheat Production/Key Laboratory of Crop Physiology, Ecology, and Management, Ministry of Agriculture/National Engineering and Technology Center for Information Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Yining Zhang
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Li Guo
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, People's Republic of China
| | - Dandan Li
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
| | - Anqi Liu
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Muhammad Bilal
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Chong Xie
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
| | - Runqiang Yang
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
| | - Zhenxin Gu
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
| | - Dong Jiang
- National Technique Innovation Center for Regional Wheat Production/Key Laboratory of Crop Physiology, Ecology, and Management, Ministry of Agriculture/National Engineering and Technology Center for Information Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
| | - Pei Wang
- College of Food Science and Technology, Whole Grain Food Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- National Technique Innovation Center for Regional Wheat Production/Key Laboratory of Crop Physiology, Ecology, and Management, Ministry of Agriculture/National Engineering and Technology Center for Information Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
- The Sanya Institute of Nanjing Agricultural University, Sanya 572024, People's Republic of China
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4
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Dandurand J, Monné M, Samouillan V, Rosa M, Laurita A, Pistone A, Bisaccia D, Matera I, Bisaccia F, Ostuni A. The 75-99 C-Terminal Peptide of URG7 Protein Promotes α-Synuclein Disaggregation. Int J Mol Sci 2024; 25:1135. [PMID: 38256207 PMCID: PMC10816444 DOI: 10.3390/ijms25021135] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024] Open
Abstract
Up Regulation Gene seven (URG7) is the pseudogene 2 of the transporter ABCC6. The translated URG7 protein is localized with its single transmembrane α-helix in the endoplasmic reticulum (ER) membrane, orienting the N- and C-terminal regions in the lumen and cytoplasm, respectively, and it plays a crucial role in the folding of ER proteins. Previously, the C-terminal region of URG7 (PU, residues 75-99) has been shown to modify the aggregation state of α-synuclein in the lysate of HepG2 cells. PU analogs were synthesized, and their anti-aggregation potential was tested in vitro on α-synuclein obtained using recombinant DNA technology. Circular dichroism (CD), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and microscopic techniques were used to assess the sample's behavior. The results show that the peptides studied by themselves are prone to clathrate-like structure formation of variable stability. Aggregation of α-synuclein is accompanied by desolvation of its peptide chain and an increase in intermolecular β-sheets. The PU analogs all interact with α-synuclein aggregates and those possessing the most stable clathrate-like structures have the highest disaggregating effect. These findings suggest that the C-terminal region of URG7 may have a role in interacting and modulating α-synuclein structures and could be used to generate interesting therapeutic candidates as disaggregators of α-synuclein.
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Affiliation(s)
- Jany Dandurand
- CIRIMAT Physique des Polymères, Université Toulouse 3, Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France; (J.D.); (V.S.)
| | - Magnus Monné
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | - Valérie Samouillan
- CIRIMAT Physique des Polymères, Université Toulouse 3, Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France; (J.D.); (V.S.)
| | - Martina Rosa
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | - Alessandro Laurita
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | - Alessandro Pistone
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | | | - Ilenia Matera
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | - Faustino Bisaccia
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
| | - Angela Ostuni
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy; (M.M.); (M.R.); (A.L.); (A.P.); (I.M.)
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Fujii S, Sakaguchi R, Oki H, Kawahara K, Ohkubo T, Fujiyoshi S, Sambongi Y. Contribution of a surface salt bridge to the protein stability of deep-sea Shewanella benthica cytochrome c'. J Struct Biol 2023; 215:108031. [PMID: 37758155 DOI: 10.1016/j.jsb.2023.108031] [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: 03/14/2023] [Revised: 09/05/2023] [Accepted: 09/23/2023] [Indexed: 10/03/2023]
Abstract
Two homologous cytochromes c', SBCP and SVCP, from deep-sea Shewanella benthica and Shewanella violacea respectively exhibit only nine surface amino acid substitutions, along with one at the N-terminus. Despite the small sequence difference, SBCP is thermally more stable than SVCP. Here, we examined the thermal stability of SBCP variants, each containing one of the nine substituted residues in SVCP, and found that the SBCP K87V variant was the most destabilized. We then determined the X-ray crystal structure of the SBCP K87V variant at a resolution of 2.1 Å. The variant retains a four-helix bundle structure similar to the wild-type, but notable differences are observed in the hydration structure around the mutation site. Instead of forming of the intrahelical salt bridge between Lys-87 and Asp-91 in the wild-type, a clathrate-like hydration around Val-87 through a hydrogen bond network with the nearby amino acid residues is observed. This network potentially enhances the ordering of surrounding water molecules, leading to an entropic destabilization of the protein. These results suggest that the unfavorable hydrophobic hydration environment around Val-87 and the inability to form the Asp-91-mediated salt bridge contribute to the observed difference in stability between SBCP and SVCP. These findings will be useful in future protein engineering for controlling protein stability through the manipulation of surface intrahelical salt bridges.
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Affiliation(s)
- Sotaro Fujii
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan; Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, UK.
| | - Riku Sakaguchi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Hiroya Oki
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamadaoka, Suita, Osaka, Japan; Research Institute for Microbial Diseases, Osaka University, Yamadaoka, Suita, Osaka, Japan
| | - Kazuki Kawahara
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamadaoka, Suita, Osaka, Japan
| | - Tadayasu Ohkubo
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamadaoka, Suita, Osaka, Japan
| | - So Fujiyoshi
- The IDEC Institute, Hiroshima University, Higashi-Hiroshima, Japan; Seto Inland Sea Carbon-neutral Research Center, Hiroshima University, Higashi-Hiroshima, Japan
| | - Yoshihiro Sambongi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan; Seto Inland Sea Carbon-neutral Research Center, Hiroshima University, Higashi-Hiroshima, Japan.
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6
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Aich R, Pal P, Chakraborty S, Jana B. Preferential Ordering and Organization of Hydration Water Favor Nucleation of Ice by Ice-Nucleating Proteins over Antifreeze Proteins. J Phys Chem B 2023; 127:6038-6048. [PMID: 37395194 DOI: 10.1021/acs.jpcb.3c01641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Bacteria containing ice-nucleating proteins (INPs) evolved in nature to nucleate ice at the high sub-zero ambiance. The ability of the INPs to induce order in the hydration layer and their aggregation propensity appear to be key factors of their ice nucleation abilities. However, the mechanism of the process of ice nucleation by INPs is yet to be understood clearly. Here, we have performed all-atom molecular dynamics simulations and analyzed the structure and dynamics of the hydration layer around the proposed ice-nucleating surface of a model INP. Results are compared with the hydration of a topologically similar non-ice-binding protein (non-IBP) and another ice-growth inhibitory antifreeze protein (sbwAFP). We observed that the hydration structure around the ice-nucleating surface of INP is highly ordered and the dynamics of the hydration water are slower, compared to the non-IBP. Even the ordering of the hydration layer is more evident around the ice-binding surface of INP, compared to the antifreeze protein sbwAFP. Particularly with increasing repeat units of INP, we observe an increased population of ice-like water. Interestingly, the distances between the hydroxyl groups of the threonine ladder and its associated channel water of the ice-binding surface (IBS) of INP in the X and Y direction mimic the oxygen atom distances of the basal plane of hexagonal ice. However, the structural synergies between the hydroxyl group distances of the threonine ladder and its associated channel water of the IBS of sbwAFP and oxygen atom distances of the basal plane are less evident. This difference makes the IBS of the INP a better template for ice nucleation than AFP, although both of them bind to the ice surface efficiently.
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Affiliation(s)
- Rahul Aich
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Prasun Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sandipan Chakraborty
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institution of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 5000046, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Belosludov RV, Gets KV, Zhdanov RK, Bozhko YY, Belosludov VR, Chen LJ, Kawazoe Y. Molecular Dynamics Study of Clathrate-like Ordering of Water in Supersaturated Methane Solution at Low Pressure. Molecules 2023; 28:2960. [PMID: 37049727 PMCID: PMC10095827 DOI: 10.3390/molecules28072960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
Using molecular dynamics, the evolution of a metastable solution for "methane + water" was studied for concentrations of 3.36, 6.5, 9.45, 12.2, and 14.8 mol% methane at 270 K and 1 bar during 100 ns. We have found the intriguing behavior of the system containing over 10,000 water molecules: the formation of hydrate-like structures is observed at 6.5 and 9.45 mol% concentrations throughout the entire solution volume. This formation of "blobs" and the following amorphous hydrate were studied. The creation of a metastable methane solution through supersaturation is the key to triggering the collective process of hydrate formation under low pressure. Even the first stage (0-1 ns), before the first fluctuating cavities appear, is a collective process of H-bond network reorganization. The formation of fluctuation cavities appears before steady hydrate growth begins and is associated with a preceding uniform increase in the water molecule's tetrahedrality. Later, the constantly presented hydrate cavities become the foundation for a few independent hydrate nucleation centers, this evolution is consistent with the labile cluster and local structure hypotheses. This new mechanism of hydrogen-bond network reorganization depends on the entropy of the cavity arrangement of the guest molecules in the hydrate lattice and leads to hydrate growth.
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Affiliation(s)
| | - Kirill V. Gets
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Ravil K. Zhdanov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Yulia Y. Bozhko
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Vladimir R. Belosludov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Li-Jen Chen
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Yoshiyuki Kawazoe
- New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan
- Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kattankurathur 603203, India
- School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
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Pal P, Aich R, Chakraborty S, Jana B. Molecular Factors of Ice Growth Inhibition for Hyperactive and Globular Antifreeze Proteins: Insights from Molecular Dynamics Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15132-15144. [PMID: 36450094 DOI: 10.1021/acs.langmuir.2c02149] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The molecular mechanism behind the ice growth inhibition by antifreeze proteins (AFPs) is yet to be understood completely. Also, what physical parameters differentiate between the AFP and non-AFP are largely unknown. Thus, to get an atomistic overview of the differential antifreeze activities of different classes of AFPs, we have studied ice growth from different ice surfaces in the presence of a moderately active globular type III AFP and a hyperactive spruce budworm (sbw) AFP. Results are compared with the observations of ice growth simulations in the presence of topologically similar non-AFPs using all-atom molecular dynamics simulations. Simulation data suggest that the ice surface coverage is a critical factor in ice growth inhibition. Due to the presence of an ice binding surface (IBS), AFPs form a high affinity complex with ice, accompanied by a transition of hydration water around the IBS from clathrate-like to ice-like. Several residues around the periphery of the IBS anchor the AFP to the curved ice surface mediated by multiple strong hydrogen bonds, stabilizing the complex immensely. In the high surface coverage regime, the slow unbinding kinetics dominates over the ice growth kinetics and thus facilitates the ice growth inhibition. Due to the non-availability of a proper IBS, non-AFPs form a low-affinity complex with the growing ice surface. As a result, the non-AFPs are continuously repelled by the surface. If the concentration of AFPs is low, then the effective surface coverage is reduced significantly. In this low surface coverage regime, AFPs can also behave like impurities and are engulfed by the growing ice crystal.
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Affiliation(s)
- Prasun Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Rahul Aich
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sandipan Chakraborty
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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9
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Parui S, Jana B. Cold denaturation induced helix-to-helix transition and its implication to activity of helical antifreeze protein. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Li J, Lu H, Zhou X. Electric field triggered release of gas from a quasi-one-dimensional hydrate in the carbon nanotube. NANOSCALE 2020; 12:12801-12808. [PMID: 32432277 DOI: 10.1039/d0nr01113d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We systematically investigate the effects of an axial electric field on the formation and decomposition of quasi-one-dimensional nitrogen gas hydrates within a single-walled carbon nanotube (SWNT) by using molecular dynamics (MD) simulations. We find that the nitrogen hydrate in the SWNT undergoes a series of structure phase transitions with increasing electric field. Corresponding to the structure transition, the nitrogen gas releases from the carbon nanotube in the electric field range of 1 V nm-1 to 2 V nm-1. However, nitrogen molecules are trapped as guest molecules, forming a molecule wire, in the ice nanotube when the electric field is less than 1 V nm-1 or larger than 2 V nm-1. Our simulations indicate that the nanotube is an excellent tiny gas tank that can be used to trap gas molecules and control their release triggered sensitively by electric signals. The key to this phenomenon is the change in orientations of water dipoles induced by the electric field, which leads to the structural change in the hydrogen-bonding network and the change in the diffusion coefficient of the water molecules. Our findings here may help understanding the mechanism of the electrorelease of gas from hydrates confined in the nanoscale space.
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Affiliation(s)
- Jiaxian Li
- College of Physics and Electronic Information Engineering, Zhejiang Normal University, Jinhua 321004, China.
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11
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Pal P, Chakraborty S, Jana B. Deciphering the Role of the Non-ice-binding Surface in the Antifreeze Activity of Hyperactive Antifreeze Proteins. J Phys Chem B 2020; 124:4686-4696. [PMID: 32425044 DOI: 10.1021/acs.jpcb.0c01206] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Antifreeze proteins (AFPs) show thermal hysteresis through specific interaction with the ice crystal. Hyperactive AFPs interact with the ice surface through a threonine-rich motif present at their ice-binding surface (IBS). Ordering of water around the IBS was extensively investigated. However, the role of non-IBS in ice growth inhibition is yet to be understood completely. The present study explores the nature of hydration and its length-scale evaluation around the non-IBS for hyperactive AFPs. We observed that the hydration layer of non-IBS is liquid-like, even in highly supercooled conditions, and the nature of hydration is drastically different from the hydration pattern of non-AFP surfaces. In similar conditions, the hydration layer around the IBS is ice-like ordered. Non-IBS of the hyperactive AFP exposes toward the bulk and is able to maintain the liquid-like character of its hydration water up to 15 Å. We also find that the amino acid compositions and their spatial distribution on the non-IBS are markedly different from those of the IBS and non-AFP surfaces. These results elucidate the combined role of IBS and non-IBS in ice-growth inhibition. While IBS is required to adsorb on ice efficiently, the exposed non-IBS may prevent ice nucleation/growth on top of the bound AFPs.
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Affiliation(s)
- Prasun Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | | | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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Hebert MJ, Russell DH. Hydration of Guanidinium Ions: An Experimental Search for Like-Charged Ion Pairs. J Phys Chem Lett 2019; 10:1349-1354. [PMID: 30840463 DOI: 10.1021/acs.jpclett.9b00268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Guanidinium ions (GdmH+) are reported to form stable complexes (GdmH+/GdmH+) in aqueous solution despite strong repulsive interactions between the like-charged centers. These complexes are thought to play important roles in protein folding, membrane penetration, and formation of protein dimers. Although GdmH+ ions are weakly hydrated, semiempirical calculations provide evidence that these like-charged complexes are stabilized by water molecules, which serve important structural and energetic roles. Specifically, water molecules bridge between the GdmH+ ions of GdmH+/GdmH+ complexes as well as complexes involving the guanidinium side chains of arginine. Potential biological significances of like-charged complexes have been largely confirmed by ab initio molecular dynamics simulations and indirect experimental evidence. We report cryo-ion mobility-mass spectrometry results for the GdmH+/GdmH+ ion pair confined in a nanodroplet- the first direct experimental observation of this like-charged complex. A second like-charged complex, described as a water-mediated complex involving GdmH+ and H3O+, was also observed.
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Affiliation(s)
- Michael J Hebert
- Department of Chemistry Texas A&M University College Station , Texas 77843 , United States
| | - David H Russell
- Department of Chemistry Texas A&M University College Station , Texas 77843 , United States
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