1
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Berhanu S, Majumder S, Müntener T, Whitehouse J, Berner C, Bera AK, Kang A, Liang B, Khan N, Sankaran B, Tamm LK, Brockwell DJ, Hiller S, Radford SE, Baker D, Vorobieva AA. Sculpting conducting nanopore size and shape through de novo protein design. Science 2024; 385:282-288. [PMID: 39024453 DOI: 10.1126/science.adn3796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 06/03/2024] [Indexed: 07/20/2024]
Abstract
Transmembrane β-barrels have considerable potential for a broad range of sensing applications. Current engineering approaches for nanopore sensors are limited to naturally occurring channels, which provide suboptimal starting points. By contrast, de novo protein design can in principle create an unlimited number of new nanopores with any desired properties. Here we describe a general approach to designing transmembrane β-barrel pores with different diameters and pore geometries. Nuclear magnetic resonance and crystallographic characterization show that the designs are stably folded with structures resembling those of the design models. The designs have distinct conductances that correlate with their pore diameter, ranging from 110 picosiemens (~0.5 nanometer pore diameter) to 430 picosiemens (~1.1 nanometer pore diameter). Our approach opens the door to the custom design of transmembrane nanopores for sensing and sequencing applications.
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Affiliation(s)
- Samuel Berhanu
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Sagardip Majumder
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | | | - James Whitehouse
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - Carolin Berner
- Structural Biology Brussel, Vrije Universiteit Brussel, Brussels, Belgium
- VUB-VIB Center for Structural Biology, Brussels, Belgium
| | - Asim K Bera
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Binyong Liang
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
| | - Nasir Khan
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lukas K Tamm
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | | | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - David Baker
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Anastassia A Vorobieva
- Structural Biology Brussel, Vrije Universiteit Brussel, Brussels, Belgium
- VUB-VIB Center for Structural Biology, Brussels, Belgium
- VIB Center for AI and Computational Biology, Belgium
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2
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Bose HS. Dry molten globule conformational state of CYP11A1 (SCC) regulates the first step of steroidogenesis in the mitochondrial matrix. iScience 2024; 27:110039. [PMID: 38868187 PMCID: PMC11167429 DOI: 10.1016/j.isci.2024.110039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/18/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024] Open
Abstract
Multiple metabolic events occur in mitochondria. Mitochondrial protein translocation from the cytoplasm across compartments depends on the amino acid sequence within the precursor. At the mitochondria associated-ER membrane, misfolding of a mitochondrial targeted protein prior to import ablates metabolism. CYP11A1, cytochrome P450 cholesterol side chain cleavage enzyme (SCC), is imported from the cytoplasm to mitochondrial matrix catalyzing cholesterol to pregnenolone, an essential step for metabolic processes and mammalian survival. Multiple steps regulate the availability of an actively folded SCC; however, the mechanism is unknown. We identified that a dry molten globule state of SCC exists in the matrix by capturing intermediate protein folding steps dictated by its C-terminus. The intermediate dry molten globule state in the mitochondrial matrix of living cells is stable with a limited network of interaction and is inactive. The dry molten globule is activated with hydrogen ions availability, triggering cleavage of cholesterol sidechain, and initiating steroidogenesis.
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Affiliation(s)
- Himangshu S. Bose
- Laboratory of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
- Anderson Cancer Institute, Memorial University Medical Center, Savannah, GA 31404, USA
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3
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Khaykelson D, Asor R, Zhao Z, Schlicksup CJ, Zlotnick A, Raviv U. Guanidine Hydrochloride-Induced Hepatitis B Virus Capsid Disassembly Hysteresis. Biochemistry 2024; 63:1543-1552. [PMID: 38787909 PMCID: PMC11191408 DOI: 10.1021/acs.biochem.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/20/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024]
Abstract
Hepatitis B virus (HBV) displays remarkable self-assembly capabilities that interest the scientific community and biotechnological industries as HBV is leading to an annual mortality of up to 1 million people worldwide (especially in Africa and Southeast Asia). When the ionic strength is increased, hepatitis B virus-like particles (VLPs) can assemble from dimers of the first 149 residues of the HBV capsid protein core assembly domain (Cp149). Using solution small-angle X-ray scattering, we investigated the disassembly of the VLPs by titrating guanidine hydrochloride (GuHCl). Measurements were performed with and without 1 M NaCl, added either before or after titrating GuHCl. Fitting the scattering curves to a linear combination of atomic models of Cp149 dimer (the subunit) and T = 3 and T = 4 icosahedral capsids revealed the mass fraction of the dimer in each structure in all the titration points. Based on the mass fractions, the variation in the dimer-dimer association standard free energy was calculated as a function of added GuHCl, showing a linear relation between the interaction strength and GuHCl concentration. Using the data, we estimated the energy barriers for assembly and disassembly and the critical nucleus size for all of the assembly reactions. Extrapolating the standard free energy to [GuHCl] = 0 showed an evident hysteresis in the assembly process, manifested by differences in the dimer-dimer association standard free energy obtained for the disassembly reactions compared with the equivalent assembly reactions. Similar hysteresis was observed in the energy barriers for assembly and disassembly and the critical nucleus size. The results suggest that above 1.5 M, GuHCl disassembled the capsids by attaching to the protein and adding steric repulsion, thereby weakening the hydrophobic attraction.
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Affiliation(s)
- Daniel Khaykelson
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Roi Asor
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Zhongchao Zhao
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Christopher John Schlicksup
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Adam Zlotnick
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Uri Raviv
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
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4
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Strachan M, Mashapa T, Gildenhuys S. Spectroscopic analysis of the bacterially expressed head domain of rotavirus VP6. Biosci Rep 2024; 44:BSR20232178. [PMID: 38592735 PMCID: PMC11065646 DOI: 10.1042/bsr20232178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 04/10/2024] Open
Abstract
The rotavirus capsid protein VP6 forms the middle of three protein layers and is responsible for many critical steps in the viral life cycle. VP6 as a structural protein can be used in various applications including as a subunit vaccine component. The head domain of VP6 (VP6H) contains key sequences that allow the protein to trimerize and that represent epitopes that are recognized by human antibodies in the viral particle. The domain is rich in β-sheet secondary structures. Here, VP6H was solubilised from bacterial inclusion bodies and purified using a single affinity chromatography step. Spectral (far-UV circular dichroism and intrinsic tryptophan fluorescence) analysis revealed that the purified domain had native-like secondary and tertiary structures. The domain could maintain structure up to 44°C during thermal denaturation following which structural changes result in an intermediate forming and finally irreversible aggregation and denaturation. The chemical denaturation with urea and guanidinium hydrochloride produces intermediates that represent a loss in the cooperativity. The VP6H domain is stable and can fold to produce its native structure in the absence of the VP6 base domain but cannot be defined as an independent folding unit.
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Affiliation(s)
- Milaan Simone Strachan
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
| | - Tshepo Mashapa
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
| | - Samantha Gildenhuys
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida, Roodepoort 1710, South Africa
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5
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Olgenblum GI, Hutcheson BO, Pielak GJ, Harries D. Protecting Proteins from Desiccation Stress Using Molecular Glasses and Gels. Chem Rev 2024; 124:5668-5694. [PMID: 38635951 PMCID: PMC11082905 DOI: 10.1021/acs.chemrev.3c00752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 02/18/2024] [Accepted: 02/22/2024] [Indexed: 04/20/2024]
Abstract
Faced with desiccation stress, many organisms deploy strategies to maintain the integrity of their cellular components. Amorphous glassy media composed of small molecular solutes or protein gels present general strategies for protecting against drying. We review these strategies and the proposed molecular mechanisms to explain protein protection in a vitreous matrix under conditions of low hydration. We also describe efforts to exploit similar strategies in technological applications for protecting proteins in dry or highly desiccated states. Finally, we outline open questions and possibilities for future explorations.
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Affiliation(s)
- Gil I. Olgenblum
- Institute
of Chemistry, Fritz Haber Research Center, and The Harvey M. Krueger
Family Center for Nanoscience & Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Brent O. Hutcheson
- Department
of Chemistry, University of North Carolina
at Chapel Hill (UNC-CH), Chapel
Hill, North Carolina 27599, United States
| | - Gary J. Pielak
- Department
of Chemistry, University of North Carolina
at Chapel Hill (UNC-CH), Chapel
Hill, North Carolina 27599, United States
- Department
of Chemistry, Department of Biochemistry & Biophysics, Integrated
Program for Biological & Genome Sciences, Lineberger Comprehensive
Cancer Center, University of North Carolina
at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Daniel Harries
- Institute
of Chemistry, Fritz Haber Research Center, and The Harvey M. Krueger
Family Center for Nanoscience & Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
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6
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Bjarnason S, McIvor JAP, Prestel A, Demény KS, Bullerjahn JT, Kragelund BB, Mercadante D, Heidarsson PO. DNA binding redistributes activation domain ensemble and accessibility in pioneer factor Sox2. Nat Commun 2024; 15:1445. [PMID: 38365983 PMCID: PMC10873366 DOI: 10.1038/s41467-024-45847-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 02/01/2024] [Indexed: 02/18/2024] Open
Abstract
More than 1600 human transcription factors orchestrate the transcriptional machinery to control gene expression and cell fate. Their function is conveyed through intrinsically disordered regions (IDRs) containing activation or repression domains but lacking quantitative structural ensemble models prevents their mechanistic decoding. Here we integrate single-molecule FRET and NMR spectroscopy with molecular simulations showing that DNA binding can lead to complex changes in the IDR ensemble and accessibility. The C-terminal IDR of pioneer factor Sox2 is highly disordered but its conformational dynamics are guided by weak and dynamic charge interactions with the folded DNA binding domain. Both DNA and nucleosome binding induce major rearrangements in the IDR ensemble without affecting DNA binding affinity. Remarkably, interdomain interactions are redistributed in complex with DNA leading to variable exposure of two activation domains critical for transcription. Charged intramolecular interactions allowing for dynamic redistributions may be common in transcription factors and necessary for sensitive tuning of structural ensembles.
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Affiliation(s)
- Sveinn Bjarnason
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland
| | - Jordan A P McIvor
- School of Chemical Science, University of Auckland, Auckland, New Zealand
| | - Andreas Prestel
- Department of Biology, REPIN and Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen, Denmark
| | - Kinga S Demény
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland
| | - Jakob T Bullerjahn
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Birthe B Kragelund
- Department of Biology, REPIN and Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen, Denmark
| | - Davide Mercadante
- School of Chemical Science, University of Auckland, Auckland, New Zealand.
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland.
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7
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Doharey PK, Verma P, Dubey A, Singh SK, Kumar M, Tripathi T, Alonazi M, Siddiqi NJ, Sharma B. Biophysical and in-silico studies on the structure-function relationship of Brugia malayi protein disulfide isomerase. J Biomol Struct Dyn 2024; 42:1533-1543. [PMID: 37079006 DOI: 10.1080/07391102.2023.2201849] [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: 11/14/2022] [Accepted: 04/03/2023] [Indexed: 04/21/2023]
Abstract
Human Lymphatic filariasis is caused by parasitic nematodes Wuchereria bancrofti, Brugia malayi, and Brugia timori. Protein disulfide isomerase (PDI), a redox-active enzyme, helps to form and isomerize the disulfide bonds, thereby acting as a chaperone. Such activity is essential for activating many essential enzymes and functional proteins. Brugia malayi protein disulfide isomerase (BmPDI) is crucial for parasite survival and an important drug target. Here, we used a combination of spectroscopic and computational analysis to study the structural and functional changes in the BmPDI during unfolding. Tryptophan fluorescence data revealed two well-separated transitions during the unfolding process, suggesting that the unfolding of the BmPDI is non-cooperative. The binding of the fluorescence probe 8-anilino-1-naphthalene sulfonic acid dye (ANS) validated the results obtained by the pH unfolding. The dynamics of molecular simulation performed at different pH conditions revealed the structural basis of BmPDI unfolding. Detailed analysis suggested that under different pH, both the global structure and the conformational dynamics of the active site residues were differentially altered. Our multiparametric study reveals the differential dynamics and collective motions of BmPDI unfolding, providing insights into its structure-function relationship.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Pravesh Verma
- Biochemistry Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Amit Dubey
- Computational Chemistry and Drug discovery Division, Quanta calculus Pvt. Ltd, Kushinagar, India
- Department of Pharmacology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Sudhir Kumar Singh
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Manish Kumar
- Department of Biochemistry, University of Allahabad, Allahabad, India
| | - Timir Tripathi
- Department of Biochemistry, North-Eastern Hill University, Umshing, India
| | - Mona Alonazi
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nikhat Jamal Siddiqi
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Bechan Sharma
- Department of Biochemistry, University of Allahabad, Allahabad, India
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8
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Byrne EL, Madhukailya S, Alderman OLG, Blesic M, Holbrey JD. The role of urea in formation of the sodium acetate trihydrate (SAT)-urea eutectic liquid: a neutron diffraction and isotopic substitution study. Phys Chem Chem Phys 2024; 26:3051-3059. [PMID: 38180076 DOI: 10.1039/d3cp05516g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Neutron diffraction with isotopic substitution has been used to investigate the structure of the liquid sodium acetate trihydrate-urea eutectic (mole fraction (χurea) of 0.60) at 50 °C. Urea competes with acetate anions and water molecules in the solvation of sodium ions, displacing water and, simultaneously, stabilising the liberated 'excess' water through hydrogen bonding between water and urea molecules in the eutectic liquid. This provides a direct insight into the role of urea as both denaturant and hydrogen-bond network former in generating eutectic liquids.
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Affiliation(s)
- Emily L Byrne
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK.
| | - Sanskrita Madhukailya
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK.
| | - Oliver L G Alderman
- ISIS, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Marijana Blesic
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK.
| | - John D Holbrey
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK.
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9
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Berhanu S, Majumder S, Müntener T, Whitehouse J, Berner C, Bera AK, Kang A, Liang B, Khan GN, Sankaran B, Tamm LK, Brockwell DJ, Hiller S, Radford SE, Baker D, Vorobieva AA. Sculpting conducting nanopore size and shape through de novo protein design. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572500. [PMID: 38187764 PMCID: PMC10769293 DOI: 10.1101/2023.12.20.572500] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Transmembrane β-barrels (TMBs) are widely used for single molecule DNA and RNA sequencing and have considerable potential for a broad range of sensing and sequencing applications. Current engineering approaches for nanopore sensors are limited to naturally occurring channels such as CsgG, which have evolved to carry out functions very different from sensing, and hence provide sub-optimal starting points. In contrast, de novo protein design can in principle create an unlimited number of new nanopores with any desired properties. Here we describe a general approach to the design of transmembrane β-barrel pores with different diameter and pore geometry. NMR and crystallographic characterization shows that the designs are stably folded with structures close to the design models. We report the first examples of de novo designed TMBs with 10, 12 and 14 stranded β-barrels. The designs have distinct conductances that correlate with their pore diameter, ranging from 110 pS (~0.5 nm pore diameter) to 430 pS (~1.1 nm pore diameter), and can be converted into sensitive small-molecule sensors with high signal to noise ratio. The capability to generate on demand β-barrel pores of defined geometry opens up fundamentally new opportunities for custom engineering of sequencing and sensing technologies.
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Affiliation(s)
- Samuel Berhanu
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Sagardip Majumder
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | | | - James Whitehouse
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - Carolin Berner
- Structural Biology Brussel, Vrije Universiteit Brussel, Brussels, Belgium
- VUB-VIB Center for Structural Biology, Brussels, Belgium
| | - Asim K. Bera
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Binyong Liang
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA 22903, USA
| | - G Nasir Khan
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lukas K. Tamm
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA 22903, USA
| | - David J. Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | | | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT
| | - David Baker
- Department of Biochemistry, The University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Anastassia A. Vorobieva
- Structural Biology Brussel, Vrije Universiteit Brussel, Brussels, Belgium
- VUB-VIB Center for Structural Biology, Brussels, Belgium
- VIB Center for AI and Computational Biology, Belgium
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10
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Bhowal P, Roy B, Ganguli S, Igloi GL, Banerjee R. Elucidating the structure-function attributes of a trypanosomal arginyl-tRNA synthetase. Mol Biochem Parasitol 2023; 256:111597. [PMID: 37852416 DOI: 10.1016/j.molbiopara.2023.111597] [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: 08/06/2023] [Revised: 09/20/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are fundamental components of the protein translation machinery. In light of their pivotal role in protein synthesis and structural divergence among species, they have always been considered potential targets for the development of antimicrobial compounds. Arginyl-tRNA synthetase from Trypanosoma cruzi (TcArgRS), the parasite responsible for causing Chagas Disease, contains a 100-amino acid insertion that was found to be completely absent in the human counterpart of similar length, as ascertained from multiple sequence alignment results. Thus, we were prompted to perform a preliminary characterization of TcArgRS using biophysical, biochemical, and bioinformatics tools. We expressed the protein in E. coli and validated its in-vitro enzymatic activity. Additionally, analysis of DTNB kinetics, Circular dichroism (CD) spectra, and ligand-binding studies using intrinsic tryptophan fluorescence measurements aided us to understand some structural features in the absence of available crystal structures. Our study indicates that TcArgRS can discriminate between L-arginine and its analogues. Among the many tested substrates, only L-canavanine and L-thioarginine, a synthetic arginine analogue exhibited notable activation. The binding of various substrates was also determined using in silico methods. This study may provide a viable foundation for studying small compounds that can be targeted against TcArgRS.
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Affiliation(s)
- Pratyasha Bhowal
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Sayak Ganguli
- Post Graduate Department of Biotechnology, St. Xavier's College (Autonomous), 30, Park Street, Mullick Bazar, Kolkata 700 016, India.
| | - Gabor L Igloi
- Institute of Biology III, University of Freiburg, Schänzlestr 1, D-79104 Freiburg, Germany
| | - Rajat Banerjee
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India.
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11
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Olgenblum GI, Carmon N, Harries D. Not Always Sticky: Specificity of Protein Stabilization by Sugars Is Conferred by Protein-Water Hydrogen Bonds. J Am Chem Soc 2023; 145:23308-23320. [PMID: 37845197 PMCID: PMC10603812 DOI: 10.1021/jacs.3c08702] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Solutes added to buffered solutions directly impact protein folding. Protein stabilization by cosolutes or crowders has been shown to be largely driven by protein-cosolute volume exclusion complemented by chemical and soft interactions. By contrast to previous studies that indicate the invariably destabilizing role of soft protein-sugar attractions, we show here that soft interactions with sugar cosolutes are protein-specific and can be stabilizing or destabilizing. We experimentally follow the folding of two model miniproteins that are only marginally stable but in the presence of sugars and polyols fold into representative and distinct secondary structures: β-hairpin or α-helix. Our mean-field model reveals that while protein-sugar excluded volume interactions have a similar stabilizing effect on both proteins, the soft interactions add a destabilizing contribution to one miniprotein but further stabilize the other. Using molecular dynamics simulations, we link the soft protein-cosolute interactions to the weakening of direct protein-water hydrogen bonding due to the presence of sugars. Although these weakened hydrogen bonds destabilize both the native and denatured states of the two proteins, the resulting contribution to the folding free energy can be positive or negative depending on the amino acid sequence. This study indicates that the significant variation between proteins in their soft interactions with sugar determines the specific response of different proteins, even to the same sugar.
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Affiliation(s)
- Gil I Olgenblum
- The Fritz Haber Research Center, and the Harvey M. Kruger Center for Nanoscience & Nanotechnology, Institute of Chemistry, The Hebrew University, Jerusalem 9190401, Israel
| | - Neta Carmon
- The Fritz Haber Research Center, and the Harvey M. Kruger Center for Nanoscience & Nanotechnology, Institute of Chemistry, The Hebrew University, Jerusalem 9190401, Israel
| | - Daniel Harries
- The Fritz Haber Research Center, and the Harvey M. Kruger Center for Nanoscience & Nanotechnology, Institute of Chemistry, The Hebrew University, Jerusalem 9190401, Israel
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12
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Seelig J, Seelig A. Chemical Protein Unfolding - A Simple Cooperative Model. J Phys Chem B 2023; 127:8296-8304. [PMID: 37735883 PMCID: PMC10561279 DOI: 10.1021/acs.jpcb.3c03558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/08/2023] [Indexed: 09/23/2023]
Abstract
Chemical unfolding with guanidineHCl or urea is a common method to study the conformational stability of proteins. The analysis of unfolding isotherms is usually performed with an empirical linear extrapolation method (LEM). A large positive free energy is assigned to the native protein, which is usually considered to be a minimum of the free energy. The method thus contradicts common expectations. Here, we present a multistate cooperative model that addresses specifically the binding of the denaturant to the protein and the cooperativity of the protein unfolding equilibrium. The model is based on a molecular statistical-mechanical partition function of the ensemble, but simple solutions for the calculation of the binding isotherm and the associated free energy are presented. The model is applied to 23 published unfolding isotherms of small and large proteins. For a given denaturant, the binding constant depends on temperature and pH but shows little protein specificity. Chemical unfolding is less cooperative than thermal unfolding. The cooperativity parameter σ is at least 2 orders of magnitude larger than that of thermal unfolding. The multistate cooperative model predicts zero free energy for the native protein, which becomes strongly negative beyond the midpoint concentration of unfolding. The free energy to unfold a cooperative unit corresponds exactly to the diffusive energy of the denaturant concentration gradient necessary for unfolding. The temperature dependence of unfolding isotherms yields the denaturant-induced unfolding entropy and, in turn, the unfolding enthalpy. The multistate cooperative model provides molecular insight and is as simple to apply as the LEM but avoids the conceptual difficulties of the latter.
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Affiliation(s)
- Joachim Seelig
- Biozentrum, University
of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Anna Seelig
- Biozentrum, University
of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
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13
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Vendra VPR, Ostrowski C, Dyba MA, Tarasov SG, Hejtmancik JF. Human γS-Crystallin Mutation F10_Y11delinsLN in the First Greek Key Pair Destabilizes and Impairs Tight Packing Causing Cortical Lamellar Cataract. Int J Mol Sci 2023; 24:14332. [PMID: 37762633 PMCID: PMC10531703 DOI: 10.3390/ijms241814332] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023] Open
Abstract
Aromatic residues forming tyrosine corners within Greek key motifs are critical for the folding, stability, and order of βγ-crystallins and thus lens transparency. To delineate how a double amino acid substitution in an N-terminal-domain tyrosine corner of the CRYGS mutant p.F10_Y11delinsLN causes juvenile autosomal dominant cortical lamellar cataracts, human γS-crystallin c-DNA was cloned into pET-20b (+) and a p.F10_Y11delinsLN mutant was generated via site-directed mutagenesis, overexpressed, and purified using ion-exchange and size-exclusion chromatography. Structure, stability, and aggregation properties in solution under thermal and chemical stress were determined using spectrofluorimetry and circular dichroism. In benign conditions, the p.F10_Y11delinsLN mutation does not affect the protein backbone but alters its tryptophan microenvironment slightly. The mutant is less stable to thermal and GuHCl-induced stress, undergoing a two-state transition with a midpoint of 60.4 °C (wild type 73.1 °C) under thermal stress and exhibiting a three-state transition with midpoints of 1.25 and 2.59 M GuHCl (wild type: two-state transition with Cm = 2.72 M GuHCl). The mutant self-aggregates upon heating at 60 °C, which is inhibited by α-crystallin and reducing agents. Thus, the F10_Y11delinsLN mutation in human γS-crystallin impairs the protein's tryptophan microenvironment, weakening its stability under thermal and chemical stress, resulting in self-aggregation, lens opacification, and cataract.
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Affiliation(s)
- Venkata Pulla Rao Vendra
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; (V.P.R.V.)
| | - Christian Ostrowski
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; (V.P.R.V.)
| | - Marzena A. Dyba
- Biophysics Resource in the Center for Structural Biology, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (M.A.D.); (S.G.T.)
| | - Sergey G. Tarasov
- Biophysics Resource in the Center for Structural Biology, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; (M.A.D.); (S.G.T.)
| | - J. Fielding Hejtmancik
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; (V.P.R.V.)
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14
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Khan S, Khan M, Lohani M, Ahmad S, Sherwani S, Bhagwath S, Khan MWA, Wahid M, Aqil F, Haque S. NADP/H binding nearly doubles the stability of a Mycobacterium drug target: an unfolding study. J Biomol Struct Dyn 2023; 41:8018-8025. [PMID: 36166625 DOI: 10.1080/07391102.2022.2127910] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/17/2022] [Indexed: 10/14/2022]
Abstract
Mycobacterium Aspartate beta semialdehyde dehydrogenase (ASADH) was studied using various spectroscopic techniques and size exclusion chromatography to examine the unfolding of free (apo) and NADP/H-bound (holo) forms of ASADH. Non-cooperative guanidinium chloride (GdnHCl)-induced unfolding of the apo ASADH was discovered, and no partially folded intermediate structures were stabilized. On the other hand, it was observed that GdnHCl's unfolding of holoenzyme was a cooperative process without any stable intermediate structure. The native form of holoenzyme is found to be stable against the lower concentration of GdnHCl only (namely up to 1.25 M GdnHCl). The tryptophan environment appears to unfold cooperatively in case of the holoenzyme and is in well coordination with the overall unfolding of the holoenzyme. The presence of NADP/H shows a stabilizing effect on the tryptophan environment as well as on the native NADP/H-bound enzyme. Δ G Solvent o values reveal nearly two-fold (∼1.9) conformationally more stable folded holoenzyme compared to its native apo state. The Cm for the apo and holo forms of ASADH are 1.3 and 1.9 M, respectively. Novel drug leads targeting the NADP/H binding domain of ASADH could offer promising drugs against extremely infective Mycobacterium tuberculosis.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Saif Khan
- Department of Basic Dental and Medical Sciences, College of Dentistry, Ha'il University, Ha'il, Saudi Arabia
| | - Mahvish Khan
- Department of Biology, College of Science, University of Ha'il, Ha'il, Saudi Arabia
| | - Mohtashim Lohani
- Department of Emergency Medical Services, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Saheem Ahmad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Hail, Hail, Saudi Arabia
| | - Subuhi Sherwani
- Department of Biology, College of Science, University of Ha'il, Ha'il, Saudi Arabia
| | - Sundeep Bhagwath
- Department of Basic Dental and Medical Sciences, College of Dentistry, Ha'il University, Ha'il, Saudi Arabia
| | - Mohd Wajid A Khan
- Department of Chemistry, College of Sciences, University of Ha'il, Ha'il, Saudi Arabia
| | - Mohd Wahid
- Research and Scientific Studies Unit, College of Nursing & Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Farrukh Aqil
- Department of Medicine and James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing & Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
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15
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Pennacchietti V, Pagano L, Malagrinò F, Diop A, Di Felice M, Di Matteo S, Marcocci L, Pietrangeli P, Toto A, Gianni S. Characterization of the folding and binding properties of the PTB domain of FRS2 with phosphorylated and unphosphorylated ligands. Arch Biochem Biophys 2023; 745:109703. [PMID: 37543351 DOI: 10.1016/j.abb.2023.109703] [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: 06/01/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/07/2023]
Abstract
PTB (PhosphoTyrosine Binding) domains are protein domains that exert their function by binding phosphotyrosine residues on other proteins. They are commonly found in a variety of signaling proteins and are important for mediating protein-protein interactions in numerous cellular processes. PTB domains can also exhibit binding to unphosphorylated ligands, suggesting that they have additional binding specificities beyond phosphotyrosine recognition. Structural studies have reported that the PTB domain from FRS2 possesses this peculiar feature, allowing it to interact with both phosphorylated and unphosphorylated ligands, such as TrkB and FGFR1, through different topologies and orientations. In an effort to elucidate the dynamic and functional properties of these protein-protein interactions, we provide a complete characterization of the folding mechanism of the PTB domain of FRS2 and the binding process to peptides mimicking specific regions of TrkB and FGFR1. By analyzing the equilibrium and kinetics of PTB folding, we propose a mechanism implying the presence of an intermediate along the folding pathway. Kinetic binding experiments performed at different ionic strengths highlighted the electrostatic nature of the interaction with both peptides. The specific role of single amino acids in early and late events of binding was pinpointed by site-directed mutagenesis. These results are discussed in light of previous experimental works on these protein systems.
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Affiliation(s)
- Valeria Pennacchietti
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Livia Pagano
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Francesca Malagrinò
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Awa Diop
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Mariana Di Felice
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Sara Di Matteo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Lucia Marcocci
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Paola Pietrangeli
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Angelo Toto
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy.
| | - Stefano Gianni
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, P.le Aldo Moro 5, 00185, Rome, Italy.
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16
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Chou Y, Hsieh C, Chen Y, Wang T, Wu W, Hwang C. Characterization of the pH-dependent protein stability of 3α-hydroxysteroid dehydrogenase/carbonyl reductase by differential scanning fluorimetry. Protein Sci 2023; 32:e4710. [PMID: 37354013 PMCID: PMC10357940 DOI: 10.1002/pro.4710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/21/2023] [Accepted: 06/21/2023] [Indexed: 06/25/2023]
Abstract
The characterization of protein stability is essential for understanding the functions of proteins. Hydroxysteroid dehydrogenase is involved in the biosynthesis of steroid hormones and the detoxification of xenobiotic carbonyl compounds. However, the stability of hydroxysteroid dehydrogenases has not yet been characterized in detail. Here, we determined the changes in Gibbs free energy, enthalpy, entropy, and heat capacity of unfolding for 3α-hydroxysteroid dehydrogenase/carbonyl reductase (3α-HSD/CR) by varying the pH and urea concentration through differential scanning fluorimetry and presented pH-dependent protein stability as a function of temperature. 3α-HSD/CR shows the maximum stability of 30.79 kJ mol-1 at 26.4°C, pH 7.6 and decreases to 7.74 kJ mol-1 at 25.7°C, pH 4.5. The change of heat capacity of 30.25 ± 1.38 kJ mol-1 K-1 is obtained from the enthalpy of denaturation as a function of melting temperature at varied pH. Two proton uptakes are linked to protein unfolding from residues with differential pKa of 4.0 and 6.5 in the native and denatured states, respectively. The large positive heat capacity change indicated that hydrophobic interactions played an important role in the folding of 3α-HSD/CR. These studies reveal the mechanism of protein unfolding in HSD and provide a convenient method to extract thermodynamic parameters for characterizing protein stability using differential scanning fluorimetry.
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Affiliation(s)
- Yun‐Hao Chou
- Graduate Institute of Medicine, College of MedicineKaohsiung Medical UniversityKaohsiungTaiwan
| | - Chia‐Lin Hsieh
- Graduate Institute of Medicine, College of MedicineKaohsiung Medical UniversityKaohsiungTaiwan
| | - Yan‐Liang Chen
- Graduate Institute of Medicine, College of MedicineKaohsiung Medical UniversityKaohsiungTaiwan
| | - Tzu‐Pin Wang
- Department of Medicinal and Applied ChemistryKaohsiung Medical UniversityKaohsiungTaiwan
| | - Wen‐Jeng Wu
- Department of Urology, Chung‐Ho Memorial HospitalKaohsiung Medical UniversityKaohsiungTaiwan
| | - Chi‐Ching Hwang
- Graduate Institute of Medicine, College of MedicineKaohsiung Medical UniversityKaohsiungTaiwan
- Department of Biochemistry, Faculty of Medicine, College of MedicineKaohsiung Medical UniversityKaohsiungTaiwan
- Department of Medical ResearchKaohsiung Medical University HospitalKaohsiungTaiwan
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17
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Vendra VPR, Ostrowski C, Clark R, Dyba M, Tarasov SG, Hejtmancik JF. The Y46D Mutation Destabilizes Dense Packing of the Second Greek Key Pair of Human γC-Crystallin Causing Congenital Nuclear Cataracts. Biochemistry 2023; 62:1864-1877. [PMID: 37184593 PMCID: PMC10758276 DOI: 10.1021/acs.biochem.2c00628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The γ-crystallins are highly expressed structural lens proteins comprising four Greek key motifs arranged in two domains. Their globular structure and short-range spatial ordering are essential for lens transparency. Aromatic residues play a vital role in stabilizing Greek key folds by forming Greek key or non-Greek key pairs or tyrosine corners. We investigated the effects of the cataractogenic Y46D mutation in the second Greek key pair (Y46-Y51) of human γC-crystallin on its stability and aggregation. Wild-type and Y46D mutant human γC-crystallin were overexpressed in E. coli BL-21(DE3) PLysS cells, purified using ion-exchange and size-exclusion chromatography, and analyzed by fluorescence spectroscopy and circular dichroism spectroscopy. The Y46D mutation does not affect the γC-crystallin backbone conformation under benign conditions but alters the tryptophan microenvironment, exposing hydrophobic residues to the surface. The Y46D mutant undergoes a three-state transition under thermal stress with midpoints of 54.6 and 67.7 °C while the wild type shows a two-state transition with a midpoint of 77.6 °C. The Y46D mutant also shows a three-state transition under GuHCl stress with Cm values of 0.9 and 2.1 M while the wild type shows a two-state transition with a Cm of 2.4 M GuHCl. Mutant but not wild-type γC-crystallin forms light scattering particles upon heating at 65 °C. Overall, the Y46D CRYGS mutation leaves the protein fold intact under benign conditions but destabilizes the molecule by altering the tryptophan microenvironment and exposing hydrophobic residues to its surface, thus increasing its susceptibility to thermal and chemical stress with resultant self-aggregation, light scattering, and cataract.
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Affiliation(s)
- Venkata Pulla Rao Vendra
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20852, United States
| | - Christian Ostrowski
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20852, United States
| | - Rebecca Clark
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20852, United States
| | - Marzena Dyba
- Biophysics Resource in the Center for Structural Biology, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702-4091, United States
| | - Sergey G Tarasov
- Biophysics Resource in the Center for Structural Biology, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702-4091, United States
| | - J Fielding Hejtmancik
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20852, United States
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18
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Mitra A, Sarkar N. Elucidating the inhibitory effects of rationally designed novel hexapeptide against hen egg white lysozyme fibrillation at acidic and physiological pH. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023; 1871:140899. [PMID: 36693516 DOI: 10.1016/j.bbapap.2023.140899] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/10/2023] [Accepted: 01/17/2023] [Indexed: 01/23/2023]
Abstract
Inhibition of highly ordered cross-β-sheet-rich aggregates of misfolded amyloid proteins using rationally designed sequence-based short peptides is a promising therapeutic strategy for the treatment of neurodegenerative diseases. Here, we have explored the anti-amyloidogenic potency of a rationally designed hexapeptide (Tyr-Pro-Gln-Ile-Pro-Asn) on in vitro hen egg white lysozyme (HEWL) amyloid fibril formation at acidic pH and physiological pH using computational docking as well as various biophysical techniques such as fluorescence spectroscopy, UV-vis spectroscopy, FTIR spectroscopy, confocal microscopy and TEM. The peptide was designed based on the aggregation-prone region (APR) of HEWL and thus referred to as SqP1 (Sequence-based Peptide 1). SqP1 showed over 70% inhibition of HEWL amyloid formation at pH 2.2 and approximately 50% inhibition at pH 7.5. We propose that SqP1 binds to the APR of HEWL and interacts strongly with the Trp62/Trp63, ultimately stabilizing monomeric HEWL at both the pH conditions and preventing conformation changes in the structure of HEWL, leading to the formation of amyloidogenic fibrillar structures. A sequence-based peptide inhibitor of HEWL amyloid formation was not reported previously, making this a critical study that will further emphasize the importance of short synthetic peptides as amyloid inhibitors.
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Affiliation(s)
- Amit Mitra
- Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Nandini Sarkar
- Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India.
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19
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Oepen K, Mater V, Schneider D. Unfolding Individual Domains of BmrA, a Bacterial ABC Transporter Involved in Multidrug Resistance. Int J Mol Sci 2023; 24:ijms24065239. [PMID: 36982314 PMCID: PMC10049088 DOI: 10.3390/ijms24065239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
The folding and stability of proteins are often studied via unfolding (and refolding) a protein with urea. Yet, in the case of membrane integral protein domains, which are shielded by a membrane or a membrane mimetic, urea generally does not induce unfolding. However, the unfolding of α-helical membrane proteins may be induced by the addition of sodium dodecyl sulfate (SDS). When protein unfolding is followed via monitoring changes in Trp fluorescence characteristics, the contributions of individual Trp residues often cannot be disentangled, and, consequently, the folding and stability of the individual domains of a multi-domain membrane protein cannot be studied. In this study, the unfolding of the homodimeric bacterial ATP-binding cassette (ABC) transporter Bacillus multidrug resistance ATP (BmrA), which comprises a transmembrane domain and a cytosolic nucleotide-binding domain, was investigated. To study the stability of individual BmrA domains in the context of the full-length protein, the individual domains were silenced by mutating the existent Trps. The SDS-induced unfolding of the corresponding constructs was compared to the (un)folding characteristics of the wild-type (wt) protein and isolated domains. The full-length variants BmrAW413Y and BmrAW104YW164A were able to mirror the changes observed with the isolated domains; thus, these variants allowed for the study of the unfolding and thermodynamic stability of mutated domains in the context of full-length BmrA.
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Affiliation(s)
- Kristin Oepen
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Veronika Mater
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
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20
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Impact of hydrogen peroxide on structure, stability, and aggregational properties of human γS-crystallin. J Biosci 2023. [DOI: 10.1007/s12038-023-00330-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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21
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Russell BL, Ntwasa M. Expression, purification, and characterisation of the p53 binding domain of Retinoblastoma binding protein 6 (RBBP6). PLoS One 2023; 18:e0277478. [PMID: 36763571 PMCID: PMC9916574 DOI: 10.1371/journal.pone.0277478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 10/28/2022] [Indexed: 02/11/2023] Open
Abstract
RBBP6 is a 250 kDa eukaryotic protein known to be a negative regulator of p53 and essential for embryonic development. Furthermore, RBBP6 is a critical element in carcinogenesis and has been identified as a potential biomarker for certain cancers. RBBP6's ability to interact with p53 and cause its degradation makes it a potential drug target in cancer therapy. Therefore, a better understating of the p53 binding domain of RBBP6 is needed. This study presents a three-part purification protocol for the polyhistidine-tagged p53 binding domain of RBBP6, expressed in Escherichia coli bacterial cells. The purified recombinant domain was shown to have structure and is functional as it could bind endogenous p53. We characterized it using clear native PAGE and far-UV CD and found that it exists in a single form, most likely monomer. We predict that its secondary structure is predominantly random coil with 19% alpha-helices, 9% beta-strand and 14% turns. When we exposed the recombinant domain to increasing temperature or known denaturants, our investigation suggested that the domain undergoes relatively small structural changes, especially with increased temperature. Moreover, we notice a high percentage recovery after returning the domain close to starting conditions. The outcome of this study is a pure, stable, and functional recombinant RBBP6-p53BD that is primarily intrinsically disordered.
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Affiliation(s)
- Bonnie L. Russell
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Florida, Roodepoort, South Africa
- Innovation Hub, Buboo (Pty) Ltd, Pretoria, South Africa
| | - Monde Ntwasa
- Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Florida, Roodepoort, South Africa
- * E-mail:
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22
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Anderson DM, Jayanthi LP, Gosavi S, Meiering EM. Engineering the kinetic stability of a β-trefoil protein by tuning its topological complexity. Front Mol Biosci 2023; 10:1021733. [PMID: 36845544 PMCID: PMC9945329 DOI: 10.3389/fmolb.2023.1021733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/02/2023] [Indexed: 02/11/2023] Open
Abstract
Kinetic stability, defined as the rate of protein unfolding, is central to determining the functional lifetime of proteins, both in nature and in wide-ranging medical and biotechnological applications. Further, high kinetic stability is generally correlated with high resistance against chemical and thermal denaturation, as well as proteolytic degradation. Despite its significance, specific mechanisms governing kinetic stability remain largely unknown, and few studies address the rational design of kinetic stability. Here, we describe a method for designing protein kinetic stability that uses protein long-range order, absolute contact order, and simulated free energy barriers of unfolding to quantitatively analyze and predict unfolding kinetics. We analyze two β-trefoil proteins: hisactophilin, a quasi-three-fold symmetric natural protein with moderate stability, and ThreeFoil, a designed three-fold symmetric protein with extremely high kinetic stability. The quantitative analysis identifies marked differences in long-range interactions across the protein hydrophobic cores that partially account for the differences in kinetic stability. Swapping the core interactions of ThreeFoil into hisactophilin increases kinetic stability with close agreement between predicted and experimentally measured unfolding rates. These results demonstrate the predictive power of readily applied measures of protein topology for altering kinetic stability and recommend core engineering as a tractable target for rationally designing kinetic stability that may be widely applicable.
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Affiliation(s)
| | - Lakshmi P. Jayanthi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Elizabeth M. Meiering
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada,*Correspondence: Elizabeth M. Meiering,
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23
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Housmans JAJ, Wu G, Schymkowitz J, Rousseau F. A guide to studying protein aggregation. FEBS J 2023; 290:554-583. [PMID: 34862849 DOI: 10.1111/febs.16312] [Citation(s) in RCA: 56] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/18/2021] [Accepted: 12/03/2021] [Indexed: 02/04/2023]
Abstract
Disrupted protein folding or decreased protein stability can lead to the accumulation of (partially) un- or misfolded proteins, which ultimately cause the formation of protein aggregates. Much of the interest in protein aggregation is associated with its involvement in a wide range of human diseases and the challenges it poses for large-scale biopharmaceutical manufacturing and formulation of therapeutic proteins and peptides. On the other hand, protein aggregates can also be functional, as observed in nature, which triggered its use in the development of biomaterials or therapeutics as well as for the improvement of food characteristics. Thus, unmasking the various steps involved in protein aggregation is critical to obtain a better understanding of the underlying mechanism of amyloid formation. This knowledge will allow a more tailored development of diagnostic methods and treatments for amyloid-associated diseases, as well as applications in the fields of new (bio)materials, food technology and therapeutics. However, the complex and dynamic nature of the aggregation process makes the study of protein aggregation challenging. To provide guidance on how to analyse protein aggregation, in this review we summarize the most commonly investigated aspects of protein aggregation with some popular corresponding methods.
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Affiliation(s)
- Joëlle A J Housmans
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Guiqin Wu
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Joost Schymkowitz
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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24
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Waseem R, Singh Yadav N, Khan T, Ahmad F, Naqui Kazim S, Hassan I, Prakash A, Islam A. Molecular Basis of Structural Stability of Irisin: A Combined Molecular Dynamics Simulation and In vitro Studies for Urea-induced Denaturation. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2022.121120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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25
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Ó'Fágáin C. Protein Stability: Enhancement and Measurement. Methods Mol Biol 2023; 2699:369-419. [PMID: 37647007 DOI: 10.1007/978-1-0716-3362-5_18] [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] [Indexed: 09/01/2023]
Abstract
This chapter defines protein stability, emphasizes its importance, and surveys the field of protein stabilization, with summary reference to a selection of 2014-2021 publications. One can enhance stability, particularly by protein engineering strategies but also by chemical modification and by other means. General protocols are set out on how to measure a given protein's (i) kinetic thermal stability and (ii) oxidative stability and (iii) how to undertake chemical modification of a protein in solution.
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Affiliation(s)
- Ciarán Ó'Fágáin
- School of Biotechnology, Dublin City University, Dublin, Ireland.
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26
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Varejão N, Reverter D. Using Intrinsic Fluorescence to Measure Protein Stability Upon Thermal and Chemical Denaturation. Methods Mol Biol 2023; 2581:229-241. [PMID: 36413321 DOI: 10.1007/978-1-0716-2784-6_16] [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] [Indexed: 06/16/2023]
Abstract
Understanding how point mutations affect the performance of protein stability has been the focus of several studies all over the years. Intrinsic fluorescence is commonly used to follow protein unfolding since during denaturation, progressive redshifts on tryptophan fluorescence emission are observed. Since the unfolding process (achieved by chemical or physical denaturants) can be considered as two-state N➔D, it is possible to utilize the midpoint unfolding curves (fU = 50%) as a parameter to evaluate if the mutation destabilizes wild-type protein. The idea is to determine the [D]1/2 or Tm values from both wild type and mutant and calculate the difference between them. Positive values indicate the mutant is less stable than wild type.
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Affiliation(s)
- Nathalia Varejão
- Institut de Biotecnologia i de Biomedicina (IBB) and Dept. de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
| | - David Reverter
- Institut de Biotecnologia i de Biomedicina (IBB) and Dept. de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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27
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Recombinant Globular Domain of TcpA Pilin from Vibrio cholerae El Tor: Recovery from Inclusion Bodies and Structural Characterization. Life (Basel) 2022; 12:life12111802. [DOI: 10.3390/life12111802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/28/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
The production of recombinant proteins in Escherichia coli cells is often hampered by aggregation of newly synthesized proteins and formation of inclusion bodies. Here we propose the use of transverse urea gradient electrophoresis (TUGE) in testing the capability of folding of a recombinant protein from inclusion bodies dissolved in urea. A plasmid encoding the amino acid sequence 55–224 of TcpA pilin (C-terminal globular domain: TcpA-C) from Vibrio cholerae El Tor enlarged by a His-tag on its N-terminus was expressed in E. coli cells. The major fraction (about 90%) of the target polypeptide was detected in cell debris. The polypeptide was isolated from the soluble fraction and recovered from inclusion bodies after their urea treatment. Some structural properties of the polypeptide from each sample proved identical. The refolding protocol was developed on the basis of TUGE data and successfully used for the protein large-scale recovery from inclusion bodies. Spectral, hydrodynamic, and thermodynamic characteristics of the recombinant TcpA recovered from inclusion bodies indicate the presence of a globular conformation with a pronounced secondary structure and a rigid tertiary structure, which is promising for the design of immunodiagnostics preparations aimed to assess the pilin level in different strains of V. cholerae and to develop cholera vaccines.
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28
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Gani K, Chirmade T, Ughade S, Thulasiram H, Bhambure R. Understanding unfolding and refolding of the antibody fragment (Fab) III: Mapping covalent and non-covalent interactions during in-vitro refolding of light chain, heavy chain, and Fab. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Conformational stability of ageritin, a metal binding ribotoxin-like protein of fungal origin. Int J Biol Macromol 2022; 221:1012-1021. [PMID: 36113585 DOI: 10.1016/j.ijbiomac.2022.09.103] [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: 05/25/2022] [Revised: 08/31/2022] [Accepted: 09/11/2022] [Indexed: 11/24/2022]
Abstract
Ageritin is a ribotoxin-like protein of biotechnological interest, belonging to a family of ribonucleases from edible mushrooms. Its enzymatic activity is explicated through the hydrolysis of a single phosphodiester bond, located in the sarcin/ricin loop of ribosomes. Unlike other ribotoxins, ageritin activity requires divalent cations (Zn2+). Here we investigated the conformational stability of ageritin in the pH range 4.0-7.4, using calorimetric and spectroscopic techniques. We observed a high protein thermal stability at all pHs with a denaturation temperature of 78 °C. At pH 5.0 we calculated a value of 36 kJ mol-1 for the unfolding Gibbs energy at 25 °C. We also analysed the thermodynamic and catalytic behaviour of S-pyridylethylated form, obtained by alkylating the single Cys18 residue, which is predicted to bind Zn2+. We show that this form possesses the same activity and structure of ageritin, but lower stability. In fact, the corresponding values of 52 °C and 14 kJ mol-1 were found. Conservation of activity is consistent with the location of alkylation site on the opposite site of the catalytic site cleft. Inasmuch as Cys18 is part of a structurally stabilizing zinc-binding site, disrupted by cysteine alkylation, our results point to an important role of metal ions in ageritin stability.
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30
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Liu X, Kouassi KGW, Vanbever R, Dumoulin M. Impact of the PEG length and PEGylation site on the structural, thermodynamic, thermal, and proteolytic stability of mono-PEGylated alpha-1 antitrypsin. Protein Sci 2022; 31:e4392. [PMID: 36040264 PMCID: PMC9375436 DOI: 10.1002/pro.4392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 11/11/2022]
Abstract
Conjugation to polyethylene glycol (PEG) is a widely used approach to improve the therapeutic value of proteins essentially by prolonging their body residence time. PEGylation may however induce changes in the structure and/or the stability of proteins and thus on their function(s). The effects of PEGylation on the thermodynamic stability can either be positive (stabilization), negative (destabilization), or neutral (no effect). Moreover, various factors such as the PEG length and PEGylation site can influence the consequences of PEGylation on the structure and stability of proteins. In this study, the effects of PEGylation on the structure, stability, and polymerization of alpha1-antitrypsin (AAT) were investigated, using PEGs with different lengths, different structures (linear or 2-armed) and different linking chemistries (via amine or thiol) at two distinct positions of the sequence. The results show that whatever the size, position, and structure of PEG chains, PEGylation (a) does not induce significant changes in AAT structure (either at the secondary or tertiary level); (b) does not alter the stability of the native protein upon both chemical- and heat-induced denaturation; and (c) does not prevent AAT to fully refold and recover its activity following chemical denaturation. However, the propensity of AAT to aggregate upon heat treatment was significantly decreased by PEGylation, although PEGylation did not prevent the irreversible inactivation of the enzyme. Moreover, conjugation to PEG, especially 2-armed 40 kDa PEG, greatly improved the proteolytic resistance of AAT. PEGylation of AAT could be a promising strategy to prolong its half-life after infusion in AAT-deficient patients and thereby decrease the frequency of infusions.
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Affiliation(s)
- Xiao Liu
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Kobenan G. W. Kouassi
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Rita Vanbever
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Mireille Dumoulin
- Department of Life SciencesInBios, Center for Protein Engineering, Nanobodies to Explore Protein Structure and Functions, University of LiègeLiègeBelgium
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31
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Abstract
Human health depends on the correct folding of proteins, for misfolding and aggregation lead to diseases. An unfolded (denatured) protein can refold to its original folded state. How does this occur is known as the protein folding problem. One of several related questions to this problem is that how much more stable is the folded state than the unfolded state. There are several measures of protein stability. In this article, protein stability is given a thermodynamic definition and is measured by Gibbs free energy change ( Δ G D 0 ) associated with the equilibrium, native (N) conformation ↔ denatured (D) conformation under the physiological condition usually taken as dilute buffer (or water) at 25 °C. We show that this thermodynamic quantity ( Δ G D 0 ), where subscript D represents transition between N and D states, and superscript 0 (zero) represents the fact that the transition occurs in the absence of denaturant, can be neither measured nor predicted under physiological conditions. However, Δ G D can be measured in the presence of strong chemical denaturants such as guanidinium chloride and urea which are shown to destroy all noncovalent interactions responsible for maintaining the folded structure. A problem with this measurement is that the estimate of Δ G D 0 comes from the analysis of the plot of Δ G D versus denaturant concentration, which requires a long extrapolation of values of Δ G D , and all the three methods of extrapolation give three different values of Δ G D 0 for a protein. Thus, our confidence in the authentic value of Δ G D 0 is eroded. Another problem with this in vitro measurement of Δ G D 0 is that it is done on the pure protein sample in dilute buffer which is a very large extrapolation of the in vivo conditions, for the crowding effect on protein stability is ignored.
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Affiliation(s)
- Faizan Ahmad
- Department of Biochemistry, SCLS, Jamia Hamdard, New Delhi, India
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32
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Idrees D, Naqvi AAT, Hassan MI, Ahmad F, Gourinath S. Insight into the Conformational Transitions of Serine Acetyl Transferase Isoforms in E. histolytica: Implications for Structural and Functional Balance. ACS OMEGA 2022; 7:24626-24637. [PMID: 35874230 PMCID: PMC9301732 DOI: 10.1021/acsomega.2c02467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Serine acetyl transferase (SAT) is one of the crucial enzymes in the cysteine biosynthetic pathway and an essential enzyme for the survival of Entamoeba histolytica, the causative agent of amoebiasis. E. histolytica expresses three isoforms of SAT, where SAT1 and SAT2 are inhibited by the final product cysteine, while SAT3 is not inhibited. SAT3 has a slightly elongated C-terminus compared to SAT1. To understand the stability and conformational transition between two secondary structures of proteins, we measured the effect of urea, a chemical denaturant, on two isoforms of SAT (SAT1 and SAT3) of E. histolytica. The effect of urea on the structure and stability of SAT1 and SAT3 was determined by measuring changes in their far-UV circular dichroism (CD), Trp fluorescence, and near-UV absorption spectra. The urea-induced normal transition curves suggested that the structural transition is reversible and follows a two-state process. Analysis of the urea-induced transition of all optical properties for the stability parameters ΔG D° (Gibbs free energy change (ΔG D) in the absence of urea), m (dependence of ΔG D on urea concentration), and C m (midpoint of urea transition) suggested that SAT1 is more stable than SAT3. Characterization of the end product of the urea-induced transition of both proteins by the far-UV CD and Trp-fluorescence and near-UV absorbance suggested that urea causes α-helix to β-sheet transition and burial of Trp residues, respectively. To support the in vitro findings, 100 ns molecular dynamics simulations (in silico study) were performed. Both the spectroscopic and molecular dynamics approaches clearly indicated that SAT1 is more stable than SAT3. SAT3 has evolved to escape the feedback inhibition to keep producing cysteine, but in the process, it compromises its structural stability relative to SAT1.
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Affiliation(s)
- Danish Idrees
- School
of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- Faculty
of Allied Health Sciences, Shree Guru Gobind
Tricentenary University, Gurugram, Harayana 122505, India
| | | | - Md Imtaiyaz Hassan
- Centre
for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi 110025, India
| | - Faizan Ahmad
- Department
of Biochemistry, Jamia Hamdard, New Delhi 110062, India
| | - Samudrala Gourinath
- School
of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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33
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Patrick C, Upadhyay V, Lucas A, Mallela KM. Biophysical Fitness Landscape of the SARS-CoV-2 Delta Variant Receptor Binding Domain. J Mol Biol 2022; 434:167622. [PMID: 35533762 PMCID: PMC9076029 DOI: 10.1016/j.jmb.2022.167622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/21/2022] [Accepted: 04/29/2022] [Indexed: 12/16/2022]
Abstract
Among the five known SARS-CoV-2 variants of concern, Delta is the most virulent leading to severe symptoms and increased mortality among infected people. Our study seeks to examine how the biophysical parameters of the Delta variant correlate to the clinical observations. Receptor binding domain (RBD) is the first point of contact with the human host cells and is the immunodominant form of the spike protein. Delta variant RBD contains two novel mutations L452R and T478K. We examined the effect of single as well as the double mutations on RBD expression in human Expi293 cells, RBD stability using urea and thermal denaturation, and RBD binding to angiotensin converting enzyme 2 (ACE2) receptor and to neutralizing antibodies using isothermal titration calorimetry. Delta variant RBD showed significantly higher expression compared to the wild-type RBD, and the increased expression is due to L452R mutation. Despite their non-conservative nature, none of the mutations significantly affected RBD structure and stability. All mutants showed similar binding affinity to ACE2 and to Class 1 antibodies (CC12.1 and LY-CoV016) as that of the wild-type. Delta double mutant L452R/T478K showed no binding to Class 2 antibodies (P2B-2F6 and LY-CoV555) and a hundred-fold weaker binding to a Class 3 antibody (REGN10987), and the decreased antibody binding is determined by the L452R mutation. These results indicate that the immune escape from neutralizing antibodies, rather than increased receptor binding, is the main biophysical parameter that determined the fitness landscape of the Delta variant RBD.
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Affiliation(s)
| | | | | | - Krishna M.G. Mallela
- Corresponding author at: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Blvd, MS C238-V20, Aurora, CO 80045, USA
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34
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Arsiccio A, Ganguly P, Shea JE. A Transfer Free Energy Based Implicit Solvent Model for Protein Simulations in Solvent Mixtures: Urea-Induced Denaturation as a Case Study. J Phys Chem B 2022; 126:4472-4482. [PMID: 35679169 DOI: 10.1021/acs.jpcb.2c00889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We developed a method for implicit solvent molecular dynamics simulations of proteins in solvent mixtures (model with implicit solvation thermodynamics, MIST). The MIST method introduces experimental group transfer free energies to the generalized Born formulation for generating molecular trajectories without the need for developing rigorous explicit-solvent force fields for multicomponent solutions. As a test case, we studied the urea-induced denaturation of the Trp-cage miniprotein in water. We demonstrate that our method allows efficient exploration of the conformational space of the protein in only a few hundreds of nanoseconds of all-atom unbiased simulations. Furthermore, selective implementation of the transfer free energies of specific peptide groups, backbone, and side chains enables us to decouple their specific energetic contributions to the conformational changes of the protein. The approach herein developed can readily be extended to the investigation of complex matrices as well as to the characterization of protein aggregation. The MIST method is implemented in Plumed (ver. 2.8) as a separate module called SASA.
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Affiliation(s)
- Andrea Arsiccio
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States.,Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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35
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The Denaturant- and Mutation-Induced Disassembly of Pseudomonas aeruginosa Hexameric Hfq Y55W Mutant. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123821. [PMID: 35744948 PMCID: PMC9228748 DOI: 10.3390/molecules27123821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 11/17/2022]
Abstract
Although oligomeric proteins are predominant in cells, their folding is poorly studied at present. This work is focused on the denaturant- and mutation-induced disassembly of the hexameric mutant Y55W of the Qβ host factor (Hfq) from mesophilic Pseudomonas aeruginosa (Pae). Using intrinsic tryptophan fluorescence, dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC), we show that the dissociation of Hfq Y55W occurs either under the effect of GuHCl or during the pre-denaturing transition, when the protein concentration is decreased, with both events proceeding through the accumulation of stable intermediate states. With an extremely low pH of 1.4, a low ionic strength, and decreasing protein concentration, the accumulated trimers and dimers turn into monomers. Also, we report on the structural features of monomeric Hfq resulting from a triple mutation (D9A/V43R/Y55W) within the inter-subunit surface of the protein. This globular and rigidly packed monomer displays a high thermostability and an oligomer-like content of the secondary structure, although its urea resistance is much lower.
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36
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Upadhyay V, Patrick C, Lucas A, Mallela KMG. Convergent Evolution of Multiple Mutations Improves the Viral Fitness of SARS-CoV-2 Variants by Balancing Positive and Negative Selection. Biochemistry 2022; 61:963-980. [PMID: 35511584 DOI: 10.1021/acs.biochem.2c00132] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Multiple mutations have been seen to undergo convergent evolution in SARS-CoV-2 variants of concern. One such evolution occurs in Beta, Gamma, and Omicron variants at three amino acid positions K417, E484, and N501 in the receptor binding domain of the spike protein. We examined the physical mechanisms underlying the convergent evolution of three mutations K417T/E484K/N501Y by delineating the individual and collective effects of mutations on binding to angiotensin converting enzyme 2 receptor, immune escape from neutralizing antibodies, protein stability, and expression. Our results show that each mutation serves a distinct function that improves virus fitness supporting its positive selection, even though individual mutations have deleterious effects that make them prone to negative selection. Compared to the wild-type, K417T escapes Class 1 antibodies and has increased stability and expression; however, it has decreased receptor binding. E484K escapes Class 2 antibodies; however, it has decreased receptor binding, stability, and expression. N501Y increases receptor binding; however, it has decreased stability and expression. When these mutations come together, the deleterious effects are mitigated due to the presence of compensatory effects. Triple mutant K417T/E484K/N501Y has increased receptor binding, escapes both Class 1 and Class 2 antibodies, and has similar stability and expression as that of the wild-type. These results show that the convergent evolution of multiple mutations enhances viral fitness on different fronts by balancing both positive and negative selection and improves the chances of selection of mutations together.
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Affiliation(s)
- Vaibhav Upadhyay
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Casey Patrick
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Alexandra Lucas
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Krishna M G Mallela
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
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37
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Camp OG, Bai D, Awonuga A, Goud P, Abu-Soud HM. Hypochlorous acid facilitates inducible nitric oxide synthase subunit dissociation: The link between heme destruction, disturbance of the zinc-tetrathiolate center, and the prevention by melatonin. Nitric Oxide 2022; 124:32-38. [PMID: 35513289 DOI: 10.1016/j.niox.2022.04.006] [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: 02/28/2022] [Revised: 04/20/2022] [Accepted: 04/29/2022] [Indexed: 11/25/2022]
Abstract
Inducible nitric oxide synthase (iNOS) is a zinc-containing hemoprotein composed of two identical subunits, each containing a reductase and an oxygenase domain. The reductase domain contains binding sites for NADPH, FAD, FMN, and tightly bound calmodulin and the oxygenase domain contains binding sites for heme, tetrahydrobiopterin (H4B), and l-arginine. The enzyme converts l-arginine into nitric oxide (NO) and citrulline in the presence of O2. It has previously been demonstrated that myeloperoxidase (MPO), which catalyzes formation of hypochlorous acid (HOCl) from hydrogen peroxide (H2O2) and chloride (Cl-), is enhanced in inflammatory diseases and could be a potent scavenger of NO. Using absorbance spectroscopy and gel filtration chromatography, we investigated the role of increasing concentrations of HOCl in mediating iNOS heme destruction and subsequent subunit dissociation and unfolding. The results showed that dimer iNOS dissociation between 15 and 100 μM HOCl was accompanied by loss of heme content and NO synthesis activity. The dissociated subunits-maintained cytochrome c and ferricyanide reductase activities. There was partial unfolding of the subunits at 300 μM HOCl and above, and the subunit unfolding transition was accompanied by loss of reductase activities. These events can be prevented when the enzyme is preincubated with melatonin prior to HOCl addition. Melatonin supplementation to patients experiencing low NO levels due to inflammatory diseases may be helpful to restore physiological NO functions.
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Affiliation(s)
- Olivia G Camp
- Departments of Obstetrics and Gynecology and Biochemistry and Molecular Biology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, 48201, USA; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - David Bai
- Departments of Obstetrics and Gynecology and Biochemistry and Molecular Biology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Awoniyi Awonuga
- Departments of Obstetrics and Gynecology and Biochemistry and Molecular Biology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Pravin Goud
- Division of Reproductive Endocrinology and Infertility & California IVF Fertility Center, Department of Obstetrics and Gynecology, University of California Davis, Sacramento, CA, 95833, USA; California Northstate University Medical College, Elk Grove, CA, 95757, USA
| | - Husam M Abu-Soud
- Departments of Obstetrics and Gynecology and Biochemistry and Molecular Biology, The C.S. Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, MI, 48201, USA; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA; Department of Microbiology, Immunology and Biochemistry, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
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38
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Thermodynamics of co-translational folding and ribosome-nascent chain interactions. Curr Opin Struct Biol 2022; 74:102357. [PMID: 35390638 DOI: 10.1016/j.sbi.2022.102357] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 11/03/2022]
Abstract
Proteins can begin the conformational search for their native structure in parallel with biosynthesis on the ribosome, in a process termed co-translational folding. In contrast to the reversible folding of isolated domains, as a nascent chain emerges from the ribosome exit tunnel during translation the free energy landscape it explores also evolves as a function of chain length. While this presents a substantially more complex measurement problem, this review will outline the progress that has been made recently in understanding, quantitatively, the process by which a nascent chain attains its full native stability, as well as the mechanisms through which interactions with the nearby ribosome surface can perturb or modulate this process.
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39
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Kumar A, Nimsarkar P, Singh S. Probing the Interactions Responsible for the Structural Stability of Trypanothione Reductase Through Computer Simulation and Biophysical Characterization. Protein J 2022; 41:230-244. [PMID: 35364760 DOI: 10.1007/s10930-022-10052-x] [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] [Accepted: 03/22/2022] [Indexed: 11/26/2022]
Abstract
With the necessity to develop antileishmanial drugs with substrate specificity, trypanothione reductase (TryR) has gained popularity in parasitology. TryR is unique to be present only in trypanosomatids and is functionally similar to glutathione in mammals. It protects against oxidative stress exerted by the host defense mechanism. The TryR enzyme is essential for the survival of Leishmania parasites in the host as it reduces trypanothione and aids in neutralizing hydrogen peroxide produced by the host macrophages during infection. Henceforth, it becomes vital to decipher their functional stability and behaviour in the presence of denaturants. Our study is focused on structural, functional and behavioural stability aspects of TryR with different concentrations of Urea, Guanidinium chloride, alcohol based compounds followed by extensive molecular dynamics simulations in a lipid bilayer system. The results obtained from the study reveal an interesting insight into the possible mechanisms of modulation of the structure, function and stability of the TryR protein.
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Affiliation(s)
- Anurag Kumar
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune, 411007, India
| | - Prajakta Nimsarkar
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune, 411007, India
| | - Shailza Singh
- National Centre for Cell Science, NCCS Complex, Ganeshkhind, SP Pune University Campus, Pune, 411007, India.
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40
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Protein folding stabilities are a major determinant of oxidation rates for buried methionine residues. J Biol Chem 2022; 298:101872. [PMID: 35346688 PMCID: PMC9062257 DOI: 10.1016/j.jbc.2022.101872] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 12/20/2022] Open
Abstract
The oxidation of protein-bound methionines to form methionine sulfoxides has a broad range of biological ramifications, making it important to delineate factors that influence methionine oxidation rates within a given protein. This is especially important for biopharmaceuticals, where oxidation can lead to deactivation and degradation. Previously, neighboring residue effects and solvent accessibility have been shown to impact the susceptibility of methionine residues to oxidation. In this study, we provide proteome-wide evidence that oxidation rates of buried methionine residues are also strongly influenced by the thermodynamic folding stability of proteins. We surveyed the Escherichia coli proteome using several proteomic methodologies and globally measured oxidation rates of methionine residues in the presence and absence of tertiary structure, as well as the folding stabilities of methionine-containing domains. These data indicated that buried methionines have a wide range of protection factors against oxidation that correlate strongly with folding stabilities. Consistent with this, we show that in comparison to E. coli, the proteome of the thermophile Thermus thermophilus is significantly more stable and thus more resistant to methionine oxidation. To demonstrate the utility of this correlation, we used native methionine oxidation rates to survey the folding stabilities of E. coli and T. thermophilus proteomes at various temperatures and propose a model that relates the temperature dependence of the folding stabilities of these two species to their optimal growth temperatures. Overall, these results indicate that oxidation rates of buried methionines from the native state of proteins can be used as a metric of folding stability.
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Hidalgo F, Nocka LM, Shah NH, Gorday K, Latorraca NR, Bandaru P, Templeton S, Lee D, Karandur D, Pelton JG, Marqusee S, Wemmer D, Kuriyan J. A saturation-mutagenesis analysis of the interplay between stability and activation in Ras. eLife 2022; 11:e76595. [PMID: 35272765 PMCID: PMC8916776 DOI: 10.7554/elife.76595] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 01/25/2022] [Indexed: 12/31/2022] Open
Abstract
Cancer mutations in Ras occur predominantly at three hotspots: Gly 12, Gly 13, and Gln 61. Previously, we reported that deep mutagenesis of H-Ras using a bacterial assay identified many other activating mutations (Bandaru et al., 2017). We now show that the results of saturation mutagenesis of H-Ras in mammalian Ba/F3 cells correlate well with the results of bacterial experiments in which H-Ras or K-Ras are co-expressed with a GTPase-activating protein (GAP). The prominent cancer hotspots are not dominant in the Ba/F3 data. We used the bacterial system to mutagenize Ras constructs of different stabilities and discovered a feature that distinguishes the cancer hotspots. While mutations at the cancer hotspots activate Ras regardless of construct stability, mutations at lower-frequency sites (e.g. at Val 14 or Asp 119) can be activating or deleterious, depending on the stability of the Ras construct. We characterized the dynamics of three non-hotspot activating Ras mutants by using NMR to monitor hydrogen-deuterium exchange (HDX). These mutations result in global increases in HDX rates, consistent with destabilization of Ras. An explanation for these observations is that mutations that destabilize Ras increase nucleotide dissociation rates, enabling activation by spontaneous nucleotide exchange. A further stability decrease can lead to insufficient levels of folded Ras - and subsequent loss of function. In contrast, the cancer hotspot mutations are mechanism-based activators of Ras that interfere directly with the action of GAPs. Our results demonstrate the importance of GAP surveillance and protein stability in determining the sensitivity of Ras to mutational activation.
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Affiliation(s)
- Frank Hidalgo
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Laura M Nocka
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Neel H Shah
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, Columbia UniversityNew YorkUnited States
| | - Kent Gorday
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Biophysics Graduate Group, University of California, BerkeleyBerkeleyUnited States
| | - Naomi R Latorraca
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Pradeep Bandaru
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Sage Templeton
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - David Lee
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Deepti Karandur
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Jeffrey G Pelton
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
| | - Susan Marqusee
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - David Wemmer
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - John Kuriyan
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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42
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Chetri PB, Shukla R, Khan JM, Padhi AK, Tripathi T. Unraveling the structural basis of urea-induced unfolding of Fasciola gigantica cytosolic malate dehydrogenase. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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McConnell KD, Fitzkee NC, Emerson JP. Metal Ion Binding Induces Local Protein Unfolding and Destabilizes Human Carbonic Anhydrase II. Inorg Chem 2022; 61:1249-1253. [PMID: 34989562 PMCID: PMC8919859 DOI: 10.1021/acs.inorgchem.1c03271] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human carbonic anhydrase II (HCA) is a robust metalloprotein and an excellent biological model system to study the thermodynamics of metal ion coordination. Apo-HCA binds one zinc ion or two copper ions. We studied these binding processes at five temperatures (15-35 °C) using isothermal titration calorimetry, yielding thermodynamic parameters corrected for pH and buffer effects. We then sought to identify binding-induced structural changes. Our data suggest that binding at the active site organizes 6-8 residues; however, copper binding near the N-terminus results in a net unfolding of 6-7 residues. This surprising destabilization was confirmed using circular dichroism and protein stability measurements. Metal binding induced unfolding may represent an important regulatory mechanism, but it may be easily missed by NMR and X-ray crystallography. Thus, in addition to highlighting a highly novel binding-induced unfolding event, we demonstrate the value of calorimetry for studying the structural implications of metal binding.
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Affiliation(s)
- Kayla D. McConnell
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Nicholas C. Fitzkee
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Joseph P. Emerson
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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Balanced Polymorphism at the Pgm-1 Locus of the Pompeii Worm Alvinella pompejana and Its Variant Adaptability Is Only Governed by Two QE Mutations at Linked Sites. Genes (Basel) 2022; 13:genes13020206. [PMID: 35205251 PMCID: PMC8872362 DOI: 10.3390/genes13020206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 11/16/2022] Open
Abstract
The polychaete Alvinella pompejana lives exclusively on the walls of deep-sea hydrothermal chimneys along the East Pacific Rise (EPR), and displays specific adaptations to withstand the high temperatures and hypoxia associated with this highly variable habitat. Previous studies have revealed the existence of a balanced polymorphism on the enzyme phosphoglucomutase associated with thermal variations, where allozymes 90 and 100 exhibit different optimal activities and thermostabilities. Exploration of the mutational landscape of phosphoglucomutase 1 revealed the maintenance of four highly divergent allelic lineages encoding the three most frequent electromorphs over the geographic range of A. pompejana. This polymorphism is only governed by two linked amino acid replacements, located in exon 3 (E155Q and E190Q). A two-niche model of selection, including ‘cold’ and ‘hot’ conditions, represents the most likely scenario for the long-term persistence of these isoforms. Using directed mutagenesis and the expression of the three recombinant variants allowed us to test the additive effect of these two mutations on the biochemical properties of this enzyme. Our results are coherent with those previously obtained from native proteins, and reveal a thermodynamic trade-off between protein thermostability and catalysis, which is likely to have maintained these functional phenotypes prior to the geographic separation of populations across the Equator about 1.2 million years ago.
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45
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Mukherjee M, Saha Sardar P, Basu Roy M, Mukherjee P, Ghosh R, Ghosh S. Tracking Zone-wise perturbation during unfolding of some globular proteins using Eu(III) complex of Tetracycline as a probe exhibiting Stark splitting. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 264:120231. [PMID: 34365134 DOI: 10.1016/j.saa.2021.120231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/14/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Enhanced 'Antenna effect' of a suitably designed ternary complex of Eu(III), Tetracycline hydrochloride (TC) and globular proteins viz bovine serum albumin (BSA), human serum albumin (HSA) and β-lactoglobulin A (BLGA) in aqueous medium is employed to characterize the different partially unfolded states along with investigation of the micro- heterogeneous environment of the proteins during their stepwise unfolding. The zone-wise perturbation for the proteins upon denaturation by Urea and Guanidine hydrochloride (Gdn. HCl) is followed by the emission of Eu(III) through 'Antenna Effect' and that of the tryptophan (Trp) residues of the proteins as a function of denaturants both by steady state and time resolved emission study. With Gdn. HCl as denaturant, both BSA and BLGA show quenching of Eu(III) emission compared to pure protein while HSA exhibits an enhancement of antenna effect during unfolding as compared to that in its absence. In the presence of Urea, HSA and BSA show enhancement of antenna effect accompanied by Stark splitting of the 5D0→7F2 transition of Eu(III) although BLGA follows the similar pattern of quenching of Eu(III) emission as observed with Gdn. HCl without any Stark splitting. The proteins exhibit a two state transition with ΔGD values of ~ 2-3 kcal mol-1. Thus the use of Eu(III) emission as an efficient probe is advocating here to rationalize the microenvironment of the proteins during their stepwise unfolding.
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Affiliation(s)
- Moumita Mukherjee
- Present Address: Sri Aurobindo Vidyamandir, Chandannagar, Hoogly, West Bengal, India
| | - Pinki Saha Sardar
- Department of Chemistry, The Bhawanipur Education Society College, Kolkata-700020, West Bengal, India
| | - Maitrayee Basu Roy
- Department of Chemistry, Vidyasagar College for Women, Kolkata-700006, West Bengal, India
| | - Priyanka Mukherjee
- Department of Chemistry and Biochemistry, Asutosh College, Kolkata-700026, India
| | - Rina Ghosh
- Department of Chemistry, St. Xavier's College, Kolkata-700013, India
| | - Sanjib Ghosh
- Department of Chemistry, Adamas University, Barasat, West Bengal, India.
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Tariq N, Kume T, Luo L, Cai Z, Dong S, Macgregor RB. Dimethyl sulfoxide (DMSO) as a stabilizing co-solvent for G-quadruplex DNA. Biophys Chem 2022; 282:106741. [DOI: 10.1016/j.bpc.2021.106741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/05/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022]
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Lamantia T, Jansch A, Marsee JD, Weiland MH, Miller JM. Engineered Sphingomonas sp. KT-1 PahZ1 monomers efficiently degrade poly(aspartic acid). Biophys Chem 2021; 281:106745. [PMID: 34953381 DOI: 10.1016/j.bpc.2021.106745] [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: 10/21/2021] [Revised: 12/03/2021] [Accepted: 12/16/2021] [Indexed: 12/01/2022]
Abstract
In recent years, there has been an effort toward creating and utilizing novel biodegradable polymeric materials. As products become available, it is necessary to concurrently search for novel biodegradation catalysts and further investigate the properties of known biodegradation enzymes. Regarding the latter, we recently reported the crystal structure of a dimeric enzyme, Sphingomonas sp. KT-1 PahZ1, capable of degrading poly(aspartic acid), a green alternative to non-biodegradable polycarboxylates. However, the role of the dimeric state in catalytic function remained unclear. Here we report PahZ1KT-1 constructs with either single or multiple mutation(s) at the dimer interface yield active monomers. Our data indicates PahZ1KT-1 monomers and dimers catalyze PAA degradation at equivalent rates. Unfolding experiments reveal differences where the activation energy for monomers is ~ 46 kJ mol-1 lower than for dimers despite similar thermodynamic properties. Characterization of this biodegradation enzyme and others is critical for future protein engineering efforts toward polymer remediation.
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Affiliation(s)
- Timothy Lamantia
- Middle Tennessee State University, Department of Chemistry, 1301 East Main Street, Murfreesboro, TN 37132, USA
| | - Amanda Jansch
- Georgia Southern University, Department of Chemistry and Biochemistry, 11935 Abercorn Street, Savannah 31419, Georgia
| | - Justin D Marsee
- Middle Tennessee State University, Department of Chemistry, 1301 East Main Street, Murfreesboro, TN 37132, USA
| | - Mitch H Weiland
- Georgia Southern University, Department of Chemistry and Biochemistry, 11935 Abercorn Street, Savannah 31419, Georgia
| | - Justin M Miller
- Middle Tennessee State University, Department of Chemistry, 1301 East Main Street, Murfreesboro, TN 37132, USA.
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Structural Characterization of Ectodomain G Protein of Respiratory Syncytial Virus and Its Interaction with Heparan Sulfate: Multi-Spectroscopic and In Silico Studies Elucidating Host-Pathogen Interactions. Molecules 2021; 26:molecules26237398. [PMID: 34885979 PMCID: PMC8658883 DOI: 10.3390/molecules26237398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 02/03/2023] Open
Abstract
The global burden of disease caused by a respiratory syncytial virus (RSV) is becoming more widely recognized in young children and adults. Heparan sulfate helps in attaching the virion through G protein with the host cell membrane. In this study, we examined the structural changes of ectodomain G protein (edG) in a wide pH range. The absorbance results revealed that protein maintains its tertiary structure at physiological and highly acidic and alkaline pH. However, visible aggregation of protein was observed in mild acidic pH. The intrinsic fluorescence study shows no significant change in the λmax except at pH 12.0. The ANS fluorescence of edG at pH 2.0 and 3.0 forms an acid-induced molten globule-like state. The denaturation transition curve monitored by fluorescence spectroscopy revealed that urea and GdmCl induced denaturation native (N) ↔ denatured (D) state follows a two-state process. The fluorescence quenching, molecular docking, and 50 ns simulation measurements suggested that heparan sulfate showed excellent binding affinity to edG. Our binding study provides a preliminary insight into the interaction of edG to the host cell membrane via heparan sulfate. This binding can be inhibited using experimental approaches at the molecular level leading to the prevention of effective host–pathogen interaction.
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Parray ZA, Naqvi AAT, Ahmad F, Hassan MI, Islam A. Characterization of different intermediate states in myoglobin induced by polyethylene glycol: A process of spontaneous molecular self-organization foresees the energy landscape theory via in vitro and in silico approaches. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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50
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Clinckspoor KJ, Okasaki FB, Sabadini E. Urea induces (unexpected) formation of lamellar gel-phase in low concentration of cationic surfactants. J Colloid Interface Sci 2021; 607:1014-1022. [PMID: 34571291 DOI: 10.1016/j.jcis.2021.09.018] [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: 04/12/2021] [Revised: 08/02/2021] [Accepted: 09/03/2021] [Indexed: 11/29/2022]
Abstract
HYPOTHESIS The unexpected formation of a lamellar structure with concomitant gelation in solutions containing high urea concentration (40 wt%) and relatively low amount of cationic surfactant (3 wt%), indicates that a hierarchically structured complex is formed by both molecules. EXPERIMENTS Gels formed by combination of aqueous solutions of urea and C12TAB, C14TAB or C16TAB were prepared in different proportions and their structures at microscopic and mesoscopic levels were investigated using XRD and SAXS, respectively. The elastic and viscous moduli and yield stress of the samples were determined and correlated with the composition and structuration of the gels. The lamellar structure is reversibly thermically destroyed and this process was investigated using DSC. FINDINGS XRD revealed that, at microscopic scale, the gels are formed through crystallization of adducts containing surfactant molecules loaded into the cavities of honeycomb-like urea assemblies. Such crystalline phase arranges itself in lamellae with interplanar distance around ∼20-30 nm, which were observed by SAXS. This hierarchical structure is independent of the chain length of the cationic surfactants. The blocks of lamellae dispersed in the continuous phase form a three-dimensional rigid particulate network structure, giving the characteristic rheological behavior of a hydrogel. DSC revealed a reversible thermal transition at around 20-25 °C, beyond which the adducts and the lamellar phase are destroyed and micelles are formed. The characteristic transition temperature is independent of the chain length of the surfactant, and thus, it is not associated with their Krafft temperatures. The structures of the gels indicate that they resemble alpha-gels formed by fatty-alcohols and surfactants, although they self-assemble by different driving forces.
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Affiliation(s)
- Karl Jan Clinckspoor
- Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, P.O. BOX 6154, 13084-862 Campinas, SP, Brazil
| | - Fernando Bonin Okasaki
- Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, P.O. BOX 6154, 13084-862 Campinas, SP, Brazil
| | - Edvaldo Sabadini
- Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, P.O. BOX 6154, 13084-862 Campinas, SP, Brazil.
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