1
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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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2
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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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3
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Lin GH, Yu TA, Chang CF, Hsu CH. Proline Isomerization and Molten Globular Property of TgPDCD5 Secreted from Toxoplasma gondii Confers Its Regulation of Heparin Sulfate Binding. JACS AU 2024; 4:1763-1774. [PMID: 38818051 PMCID: PMC11134355 DOI: 10.1021/jacsau.3c00577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 06/01/2024]
Abstract
Toxoplasmosis, caused by Toxoplasma gondii, poses risks to vulnerable populations. TgPDCD5, a secreted protein of T. gondii, induces apoptosis through heparan sulfate-mediated endocytosis. The entry mechanism of TgPDCD5 has remained elusive. Here, we present the solution structure of TgPDCD5 as a helical bundle with an extended N-terminal helix, exhibiting molten globule characteristics. NMR perturbation studies reveal heparin/heparan sulfate binding involving the heparan sulfate/heparin proteoglycans-binding motif and the core region, influenced by proline isomerization of P107 residue. The heterogeneous proline recruits a cyclophilin TgCyp18, accelerating interconversion between conformers and regulating heparan/heparin binding. These atomic-level insights elucidate the binary switch's functionality, expose novel heparan sulfate-binding surfaces, and illuminate the unconventional cellular entry of pathogenic TgPDCD5.
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Affiliation(s)
- Gloria
Meng-Hsuan Lin
- Department
of Agricultural Chemistry, National Taiwan
University, Taipei 10617, Taiwan
- Genome
and Systems Biology Degree Program, National
Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Tsun-Ai Yu
- Genomic
Research Center, Academia Sinica, Taipei 115201, Taiwan
| | - Chi-Fon Chang
- Genomic
Research Center, Academia Sinica, Taipei 115201, Taiwan
| | - Chun-Hua Hsu
- Department
of Agricultural Chemistry, National Taiwan
University, Taipei 10617, Taiwan
- Genome
and Systems Biology Degree Program, National
Taiwan University and Academia Sinica, Taipei 10617, Taiwan
- Institute
of Biochemical Sciences, National Taiwan
University, Taipei 115201, Taiwan
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4
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Nazir A, Shad M, Rehman HM, Azim N, Sajjad M. Application of SUMO fusion technology for the enhancement of stability and activity of lysophospholipase from Pyrococcus abyssi. World J Microbiol Biotechnol 2024; 40:183. [PMID: 38722449 DOI: 10.1007/s11274-024-03998-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 04/21/2024] [Indexed: 05/18/2024]
Abstract
Heterologous production of proteins in Escherichia coli has raised several challenges including soluble production of target proteins, high levels of expression and purification. Fusion tags can serve as the important tools to overcome these challenges. SUMO (small ubiquitin-related modifier) is one of these tags whose fusion to native protein sequence can enhance its solubility and stability. In current research, a simple, efficient and cost-effective method is being discussed for the construction of pET28a-SUMO vector. In order to improve the stability and activity of lysophospholipase from Pyrococcus abyssi (Pa-LPL), a 6xHis-SUMO tag was fused to N-terminal of Pa-LPL by using pET28a-SUMO vector. Recombinant SUMO-fused enzyme (6 H-S-PaLPL) works optimally at 35 °C and pH 6.5 with remarkable thermostability at 35-95 °C. Thermo-inactivation kinetics of 6 H-S-PaLPL were also studied at 35-95 °C with first order rate constant (kIN) of 5.58 × 10- 2 h-1 and half-life of 12 ± 0 h at 95 °C. Km and Vmax for the hydrolysis of 4-nitrophenyl butyrate were calculated to be 2 ± 0.015 mM and 3882 ± 22.368 U/mg, respectively. 2.4-fold increase in Vmax of Pa-LPL was observed after fusion of 6xHis-SUMO tag to its N-terminal. It is the first report on the utilization of SUMO fusion tag to enhance the overall stability and activity of Pa-LPL. Fusion of 6xHis-SUMO tag not only aided in the purification process but also played a crucial role in increasing the thermostability and activity of the enzyme. SUMO-fused enzyme, thus generated, can serve as an important candidate for degumming of vegetable oils at industrial scale.
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Affiliation(s)
- Arshia Nazir
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Mohsin Shad
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | | | - Naseema Azim
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Muhammad Sajjad
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
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5
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Sonkar KS, Pachauri M, Kumar A, Choudhary H, Jagannadham MV. Conformational stability of peroxidase from the latex of Artocarpus lakoocha: influence of pH, chaotropes, and temperature. FRONTIERS IN PLANT SCIENCE 2024; 15:1341454. [PMID: 38476686 PMCID: PMC10929713 DOI: 10.3389/fpls.2024.1341454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/02/2024] [Indexed: 03/14/2024]
Abstract
The latex of the medicinal plant Artocarpus lakoocha (A. lakoocha), which has been shown to have potential anti-inflammatory and wound-healing capabilities, contains a novel heme-peroxidase. This protein was subjected to activity assays, fluorescence spectroscopy, and far-UV circular dichroism to investigate its structure, dynamics, and stability. The results demonstrated the presence of three folding states: the native state (N) at neutral pH, intermediate states including molten globule (MG) at pH 2 and acid-unfolded (UA) at pH 1.5 or lower, and acid-refolded (A) at pH 0.5, along with alkaline denatured (UB) at pH 8-12 and the third denatured state (D) at GuHCl concentrations exceeding 5 M. Absorbance studies indicated the presence of loosely associated form of heme in the pH range of 1-2. The protein showed stability and structural integrity across a wide pH range (3-10), temperature (70°C), and high concentrations of GuHCl (5 M) and urea (8 M). This study is the first to report multiple 'partially folded intermediate states' of A. lakoocha peroxidase, with varying amounts of secondary structure, stability, and compactness. These results demonstrate the high stability of A. lakoocha peroxidase and its potential for biotechnological and industrial applications, making it a valuable model system for further studies on its structure-function relationship.
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Affiliation(s)
- Kirti Shila Sonkar
- Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | | | - Amit Kumar
- Department of Biochemistry, University of Delhi, New Delhi, India
| | - Himanshi Choudhary
- Molecular Pathology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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6
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Lidman J, Sallova Y, Matečko-Burmann I, Burmann BM. Structure and dynamics of the mitochondrial DNA-compaction factor Abf2 from S. cerevisiae. J Struct Biol 2023; 215:108008. [PMID: 37543301 DOI: 10.1016/j.jsb.2023.108008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/10/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023]
Abstract
Mitochondria are essential organelles that produce most of the energy via the oxidative phosphorylation (OXPHOS) system in all eukaryotic cells. Several essential subunits of the OXPHOS system are encoded by the mitochondrial genome (mtDNA) despite its small size. Defects in mtDNA maintenance and expression can lead to severe OXPHOS deficiencies and are amongst the most common causes of mitochondrial disease. The mtDNA is packaged as nucleoprotein structures, referred to as nucleoids. The conserved mitochondrial proteins, ARS-binding factor 2 (Abf2) in the budding yeast Saccharomyces cerevisiae (S. cerevisiae) and mitochondrial transcription factor A (TFAM) in mammals, are nucleoid associated proteins (NAPs) acting as condensing factors needed for packaging and maintenance of the mtDNA. Interestingly, gene knockout of Abf2 leads, in yeast, to the loss of mtDNA and respiratory growth, providing evidence for its crucial role. On a structural level, the condensing factors usually contain two DNA binding domains called high-mobility group boxes (HMG boxes). The co-operating mechanical activities of these domains are crucial in establishing the nucleoid architecture by bending the DNA strands. Here we used advanced solution NMR spectroscopy methods to characterize the dynamical properties of Abf2 together with its interaction with DNA. We find that the two HMG-domains react notably different to external cues like temperature and salt, indicating distinct functional properties. Biophysical characterizations show the pronounced difference of these domains upon DNA-binding, suggesting a refined picture of the Abf2 functional cycle.
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Affiliation(s)
- Jens Lidman
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Ylber Sallova
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Irena Matečko-Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden; Department of Psychiatry and Neurochemistry, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Björn M Burmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden.
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7
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Judy E, Kishore N. Prevention of insulin fibrillation by biocompatible choline-amino acid based ionic liquids: Biophysical insights. Biochimie 2023; 207:20-32. [PMID: 36471542 DOI: 10.1016/j.biochi.2022.11.013] [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: 08/08/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
We have synthesized biocompatible ionic liquids (ILs) with choline as cation and amino acids as anions to explore their potential towards prevention of fibrillation in insulin and the obtain corresponding mechanistic insights. This has been achieved by examining the effect of these ILs on insulin at the nucleation, elongation and maturation stages of the fibrillation process. A combination of high sensitivity isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) have been employed along with spectroscopy and microscopy to evaluate interaction of the ILs at each stage of fibrillation quantitatively. Choline glycinate is observed to provide maximum stabilization to insulin compared to that provided by choline prolinate, choline leucinate, and choline valinate. This increased thermal stabilization has direct correlation with the extent of reduction in the fibrillation of insulin by ILs determined using Thioflavin T and 8-anilinonaphthalene sulfonate based fluorescence assays. ITC has permitted understanding nature of interaction of the ILs with the protein at different fibrillation stages in terms of standard molar enthalpy of interaction whereas DSC has enabled understanding the extent of reduction in thermal stability of the protein at these stages. These ILs are able to completely inhibit formation of insulin aggregates at a concentration of 50 mM. Stabilization of proteins by ILs could be explained based on involvement of preferential hydration process. The work provides biocompatible IL based approach in achieving stability and prevention of fibrillation in insulin.
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Affiliation(s)
- Eva Judy
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Nand Kishore
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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8
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Pandey B, Sinha K, Dev A, Ganguly HK, Polley S, Chakrabarty S, Basu G. Phosphorylation-Competent Metastable State of Escherichia coli Toxin HipA. Biochemistry 2023; 62:989-999. [PMID: 36802529 DOI: 10.1021/acs.biochem.2c00614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Phosphorylation is a key post-translational modification that alters the functional state of many proteins. The Escherichia coli toxin HipA, which phosphorylates glutamyl-tRNA synthetase and triggers bacterial persistence under stress, becomes inactivated upon autophosphorylation of Ser150. Interestingly, Ser150 is phosphorylation-incompetent in the crystal structure of HipA since it is deeply buried ("in-state"), although in the phosphorylated state it is solvent exposed ("out-state"). To be phosphorylated, a minor population of HipA must exist in the phosphorylation-competent "out-state" (solvent-exposed Ser150), not detected in the crystal structure of unphosphorylated HipA. Here we report a molten-globule-like intermediate of HipA at low urea (∼4 kcal/mol unstable than natively folded HipA). The intermediate is aggregation-prone, consistent with a solvent exposed Ser150 and its two flanking hydrophobic neighbors (Val/Ile) in the "out-state". Molecular dynamics simulations showed the HipA "in-out" pathway to contain multiple free energy minima with an increasing degree of Ser150 solvent exposure with the free energy difference between the "in-state" and the metastable exposed state(s) to be ∼2-2.5 kcal/mol, with unique sets of hydrogen bonds and salt bridges associated with the metastable loop conformations. Together, the data clearly identify the existence of a phosphorylation-competent metastable state of HipA. Our results not only suggest a mechanism of HipA autophosphorylation but also add to a number of recent reports on unrelated protein systems where the common proposed mechanism for phosphorylation of buried residues is their transient exposure even without phosphorylation.
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Affiliation(s)
- Bhawna Pandey
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Krishnendu Sinha
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III Salt Lake, Kolkata 700106, India
| | - Aditya Dev
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Himal K Ganguly
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Smarajit Polley
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Suman Chakrabarty
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III Salt Lake, Kolkata 700106, India
| | - Gautam Basu
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
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9
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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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10
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Naidu KT, Prabhu NP. Polyols, increasing global stability of cytochrome c, destabilize the thermal unfolding intermediate. J Biomol Struct Dyn 2022; 40:11216-11228. [PMID: 34308796 DOI: 10.1080/07391102.2021.1956593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Studies on the intermediate states of proteins provide essential information on folding pathway and energy landscape of proteins. Osmolytes, known to alter the stability of proteins, might also affect the structure and energy states of folding intermediates. This was examined using cytochrome c (Cyt) as a model protein which forms a spectroscopically detectable intermediate during thermal denaturation transition. Most of the secondary structure and the native heme-ligation were intact in the intermediate state of the protein. Denaturants, urea and guanidinium hydrochloride, and ionic salt destabilizes the intermediate and drive the protein to follow two-state transition. The effect of polyol class of osmolytes, glycol, glycerol, erythritol, xylitol and sorbitol (with OH-groups two to six), on the intermediate was studied using Soret absorbance and far-UV circular dichroism. With the increasing concentration of any of the polyols, the transition-midpoint temperature (Tm) and the enthalpy change (ΔH) for native to intermediate transition were decreased. This indicated that the intermediate was destabilized by the polyols. However, the polyols increased the overall stability of the protein by increasing Tm and ΔH for intermediate to unfolded transition, except for glycol which destabilized the protein. These results show that the polyols could alter the energy state of the intermediate, and the effect of lower and higher polyols might be different on the stability and folding pathway of the protein.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- K Tejaswi Naidu
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - N Prakash Prabhu
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
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11
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Anjali, Kishore N. Influence of amino acids on alkaline pH induced partially folded molten globule like intermediate of bovine serum albumin: Conformational and thermodynamic insights. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Improvement of techno-functional properties of acidic subunit from amaranth 11S globulin modified by bioactive peptide insertions. ELECTRON J BIOTECHN 2022. [DOI: 10.1016/j.ejbt.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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13
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Bartelli NL, Passanisi VJ, Michalska K, Song K, Nhan DQ, Zhou H, Cuthbert BJ, Stols LM, Eschenfeldt WH, Wilson NG, Basra JS, Cortes R, Noorsher Z, Gabraiel Y, Poonen-Honig I, Seacord EC, Goulding CW, Low DA, Joachimiak A, Dahlquist FW, Hayes CS. Proteolytic processing induces a conformational switch required for antibacterial toxin delivery. Nat Commun 2022; 13:5078. [PMID: 36038560 PMCID: PMC9424206 DOI: 10.1038/s41467-022-32795-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 08/12/2022] [Indexed: 02/08/2023] Open
Abstract
Many Gram-negative bacteria use CdiA effector proteins to inhibit the growth of neighboring competitors. CdiA transfers its toxic CdiA-CT region into the periplasm of target cells, where it is released through proteolytic cleavage. The N-terminal cytoplasm-entry domain of the CdiA-CT then mediates translocation across the inner membrane to deliver the C-terminal toxin domain into the cytosol. Here, we show that proteolysis not only liberates the CdiA-CT for delivery, but is also required to activate the entry domain for membrane translocation. Translocation function depends on precise cleavage after a conserved VENN peptide sequence, and the processed ∆VENN entry domain exhibits distinct biophysical and thermodynamic properties. By contrast, imprecisely processed CdiA-CT fragments do not undergo this transition and fail to translocate to the cytoplasm. These findings suggest that CdiA-CT processing induces a critical structural switch that converts the entry domain into a membrane-translocation competent conformation.
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Affiliation(s)
- Nicholas L Bartelli
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Victor J Passanisi
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Karolina Michalska
- Midwest Center for Structural Genomics, Argonne National Laboratory, Lemont, IL, USA
- Center for Structural Genomics of Infectious Diseases, University of Chicago, Chicago, IL, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Kiho Song
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA
| | - Dinh Q Nhan
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Hongjun Zhou
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Bonnie J Cuthbert
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, USA
| | - Lucy M Stols
- Midwest Center for Structural Genomics, Argonne National Laboratory, Lemont, IL, USA
| | - William H Eschenfeldt
- Midwest Center for Structural Genomics, Argonne National Laboratory, Lemont, IL, USA
| | - Nicholas G Wilson
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Jesse S Basra
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Ricardo Cortes
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Zainab Noorsher
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Youssef Gabraiel
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Isaac Poonen-Honig
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Elizabeth C Seacord
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Celia W Goulding
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, USA
- Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - David A Low
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Andrzej Joachimiak
- Midwest Center for Structural Genomics, Argonne National Laboratory, Lemont, IL, USA
- Center for Structural Genomics of Infectious Diseases, University of Chicago, Chicago, IL, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Frederick W Dahlquist
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Christopher S Hayes
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA, USA.
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA.
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14
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Bhuvanachandra B, Sivaramakrishna D, Alim S, Swamy MJ, Podile AR. Deciphering the thermotolerance of chitinase O from Chitiniphilus shinanonensis by in vitro and in silico studies. Int J Biol Macromol 2022; 210:44-52. [PMID: 35537581 DOI: 10.1016/j.ijbiomac.2022.05.013] [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: 02/22/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 11/05/2022]
Abstract
Biochemical and biophysical studies revealed that chitinase O from Chitiniphilus shinanonensis (CsChiO) exhibits considerable thermotolerance, possibly due to the formation of a stable structural conformation. CsChiO is an exochitinase with a temperature optimum of 70 °C. The secondary structures of CsChiO and its catalytic domain (Cat-CsChiO) are only marginally affected upon heating up to 90 °C, as revealed by circular dichroism (CD) spectroscopy. Differential scanning calorimetric (DSC) studies revealed that CsChiO exhibits two endothermic transitions at ca. 51 °C (Tm1) and 59 °C (Tm2), whereas Cat-CsChiO shows a single endothermic transition at 52 °C. Together, the CD and DSC analyses suggested that the catalytic domain of CsChiO undergoes a thermotropic transition at ~52 °C from native state to another stable structural conformation. Results from molecular dynamic simulations corroborated that Cat-CsChiO adopts a stable structural conformation above 50 °C by partial unfolding. Thermotolerant CsChiO would be useful for the conversion of chitin, which is highly abundant, to biologically active COS. This study unveiled the adaptability of enzymes/proteins in nature to perform biological functions at elevated temperatures.
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Affiliation(s)
- Bhoopal Bhuvanachandra
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500 046, Telangana, India
| | - Dokku Sivaramakrishna
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500 046, Telangana, India
| | - Sk Alim
- School of Chemistry, University of Hyderabad, Gachibowli, Hyderabad 500 046, Telangana, India
| | - Musti J Swamy
- School of Chemistry, University of Hyderabad, Gachibowli, Hyderabad 500 046, Telangana, India
| | - Appa Rao Podile
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad 500 046, Telangana, India.
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15
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Hovan A, Sedláková D, Berta M, Bánó G, Sedlák E. Singlet oxygen quenching as a probe for cytochrome c molten globule state formation. Phys Chem Chem Phys 2022; 24:13317-13324. [PMID: 35608043 DOI: 10.1039/d2cp01281b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Singlet oxygen refers to the nonradical metastable excited state of molecular oxygen that readily oxidizes various cellular components. Its behavior in different biological systems has been studied for many years. Recently, we analyzed the effect of singlet oxygen quenching by heme cofactor in cytochrome c (cyt c). Here, we have exploited this effect in the investigation of conformational differences in the molten globule states of cyt c induced by different sodium anions, namely sulfate, chloride and perchlorate. The high efficiency of heme toward quenching singlet oxygen enabled us to use this property for the analysis of the otherwise experimentally difficult-to-determine parameter of heme upon exposure to solvents as highly similar conformational states of cyt c in the molten globule states are induced by different salts at acidic pH. Our results from singlet oxygen quenching experiments correlate well with other spectroscopic methods, such as circular dichroism and fluorescence measurements, and suggest increasing availability of heme in the order: perchlorate < chloride < sulfate. Based on our findings we propose that singlet oxygen phosphorescence measurements are useful in determining the differences in the protein conformation of their heme regions, particularly regarding the relative heme exposure to the solvent.
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Affiliation(s)
- Andrej Hovan
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Dagmar Sedláková
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
| | - Martin Berta
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Gregor Bánó
- Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
| | - Erik Sedlák
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovakia
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16
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Parray ZA, Shahid M, Islam A. Insights into Fluctuations of Structure of Proteins: Significance of Intermediary States in Regulating Biological Functions. Polymers (Basel) 2022; 14:polym14081539. [PMID: 35458289 PMCID: PMC9025146 DOI: 10.3390/polym14081539] [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: 02/23/2022] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023] Open
Abstract
Proteins are indispensable to cellular communication and metabolism. The structure on which cells and tissues are developed is deciphered from proteins. To perform functions, proteins fold into a three-dimensional structural design, which is specific and fundamentally determined by their characteristic sequence of amino acids. Few of them have structural versatility, allowing them to adapt their shape to the task at hand. The intermediate states appear momentarily, while protein folds from denatured (D) ⇔ native (N), which plays significant roles in cellular functions. Prolific effort needs to be taken in characterizing these intermediate species if detected during the folding process. Protein folds into its native structure through definite pathways, which involve a limited number of transitory intermediates. Intermediates may be essential in protein folding pathways and assembly in some cases, as well as misfolding and aggregation folding pathways. These intermediate states help to understand the machinery of proper folding in proteins. In this review article, we highlight the various intermediate states observed and characterized so far under in vitro conditions. Moreover, the role and significance of intermediates in regulating the biological function of cells are discussed clearly.
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Affiliation(s)
- Zahoor Ahmad Parray
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Department of Chemistry, Indian Institute of Technology Delhi, IIT Campus, Hauz Khas, New Delhi 110016, India
| | - Mohammad Shahid
- Department of Basic Medical Sciences, College of Medicine, Prince Sattam bin Abdulaziz University, Al Kharj 11942, Saudi Arabia;
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Correspondence: ; Tel.: +91-93-1281-2007
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17
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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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18
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Abstract
The natural function of many proteins depends on their ability to switch their conformation driven by environmental changes. In this work, we present a small, monomeric β-sheet peptide that switches between a molten globule and a folded state through Zn(II) binding. The solvent-exposed hydrophobic core on the β-sheet surface was substituted by a His3-site, whereas the internal hydrophobic core was left intact. Zn(II) is specifically recognized by the peptide relative to other divalent metal ions, binds in the lower micromolar range, and can be removed and re-added without denaturation of the peptide. In addition, the peptide is fully pH-switchable, has a pKa of about 6, and survives several cycles of acidification and neutralization. In-depth structural characterization of the switch was achieved by concerted application of circular dichroism (CD) and multinuclear NMR spectroscopy. Thus, this study represents a viable approach toward a globular β-sheet Zn(II) mini-receptor prototype.
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Affiliation(s)
- Truc Lam Pham
- Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Centre for Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Franziska Thomas
- Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Centre for Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
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19
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Li J, Li H. New insights into the folding–unfolding mechanism and conformations of cytochrome C. Chem Sci 2022; 13:7498-7508. [PMID: 35872809 PMCID: PMC9241957 DOI: 10.1039/d2sc01126c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/29/2022] [Indexed: 11/21/2022] Open
Abstract
Optical trapping experiments offer new insights into the folding and unfolding of cytochrome C.
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Affiliation(s)
- Jiayu Li
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Hongbin Li
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
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20
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Hayashi T, Kawasaki M, Kamatari YO, Oda M. Single-chain Fv antibody covalently linked to antigen peptides and its structural evaluation. Anal Biochem 2021; 629:114312. [PMID: 34302799 DOI: 10.1016/j.ab.2021.114312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 11/17/2022]
Abstract
The monoclonal antibody G2 specifically recognizes different peptides. The single-chain Fv (scFv) antibodies of G2 covalently linked to antigen peptides, Pep18mer and Pep395, via a flexible linker were expressed in Escherichia coli in the insoluble fraction, and were solubilized using guanidine HCl, followed by refolding. We analyzed the folding thermodynamics of the refolded proteins, purified as monomers using size-exclusion chromatography (SEC). The results of the differential scanning calorimetry (DSC) showed that the thermal stabilities of antigen peptide-linked G2 scFvs were higher than those of antigen-free G2 scFv in the absence or presence of antigen peptides. The folding thermodynamics further indicated how the antigen-antibody affinity affect the intramolecular interactions. The combination of SEC and DSC experiments could confirm the folding correctness of antigen peptide-linked G2 scFvs and could be applied for "structural screening" of refolded proteins in the case that the "functional screening" like antigen binding is difficult to apply. The present method to covalently link the peptide would contribute to the stable complex structure, and would be widely applied to other antibodies recognizing peptide antigens.
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Affiliation(s)
- Takahiro Hayashi
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto, 606-8522, Japan
| | - Maki Kawasaki
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto, 606-8522, Japan
| | - Yuji O Kamatari
- Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, Kyoto, 606-8522, Japan.
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21
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Telek E, Karádi K, Kardos J, Kengyel A, Fekete Z, Halász H, Nyitrai M, Bugyi B, Lukács A. The C-terminal tail extension of myosin 16 acts as a molten globule, including intrinsically disordered regions, and interacts with the N-terminal ankyrin. J Biol Chem 2021; 297:100716. [PMID: 33930467 PMCID: PMC8253979 DOI: 10.1016/j.jbc.2021.100716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 11/20/2022] Open
Abstract
The lesser-known unconventional myosin 16 protein is essential in proper neuronal functioning and has been implicated in cell cycle regulation. Its longer Myo16b isoform contains a C-terminal tail extension (Myo16Tail), which has been shown to play a role in the neuronal phosphoinositide 3-kinase signaling pathway. Myo16Tail mediates the actin cytoskeleton remodeling, downregulates the actin dynamics at the postsynaptic site of dendritic spines, and is involved in the organization of the presynaptic axon terminals. However, the functional and structural features of this C-terminal tail extension are not well known. Here, we report the purification and biophysical characterization of the Myo16Tail by bioinformatics, fluorescence spectroscopy, and CD. Our results revealed that the Myo16Tail is functionally active and interacts with the N-terminal ankyrin domain of myosin 16, suggesting an intramolecular binding between the C and N termini of Myo16 as an autoregulatory mechanism involving backfolding of the motor domain. In addition, the Myo16Tail possesses high structural flexibility and a solvent-exposed hydrophobic core, indicating the largely unstructured, intrinsically disordered nature of this protein region. Some secondary structure elements were also observed, indicating that the Myo16Tail likely adopts a molten globule-like structure. These structural features imply that the Myo16Tail may function as a flexible display site particularly relevant in post-translational modifications, regulatory functions such as backfolding, and phosphoinositide 3-kinase signaling.
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Affiliation(s)
- Elek Telek
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary
| | - Kristóf Karádi
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - József Kardos
- Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - András Kengyel
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - Zsuzsanna Fekete
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Henriett Halász
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary
| | - Miklós Nyitrai
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - Beáta Bugyi
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary.
| | - András Lukács
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary.
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22
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Velasco-Bolom JL, Domínguez L. Exploring the folding process of human βB2-crystallin using multiscale molecular dynamics and the Markov state model. Phys Chem Chem Phys 2021; 22:26753-26763. [PMID: 33205789 DOI: 10.1039/d0cp04136j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adequate knowledge of protein conformations is crucial for understanding their function and their association properties with other proteins. The cataract disease is correlated with conformational changes in key proteins called crystallins. These changes are due to mutations or post-translational modifications that may lead to protein unfolding, and thus the formation of aggregate states. Human βB2-crystallin (HβB2C) is found in high proportion in the eye lens, and its mutations are related to some cataracts. HβB2C also associates into dimers, tetramers, and other higher-order supramolecular complexes. However, it is the only protein of the βγ-crystallin family that has been found in an extended conformation. Therefore, we hypothesize that the extended conformation is not energetically favourable and that HβB2C may adopt a closed (completely folded) conformation, similar to the other members of the βγ-crystallin family. To corroborate this hypothesis, we performed extensive molecular dynamics simulations of HβB2C in its monomeric and dimeric conformations, using all-atom and coarse-grained scales. We employed Markov state model (MSM) analysis to characterize the conformational and kinetically relevant states in the folding process of monomeric HβB2C. The MSM analysis clearly shows that HβB2C adopts a completely folded structure, and this conformation is the most kinetically and energetically favourable one. In contrast, the extended conformations are kinetically unstable and energetically unfavourable. Our MSM analysis also reveals a key metastable state, which is particularly interesting because it is from this state that the folded state is reached. The folded state is stabilized by the formation of two salt bridges between the residue-pairs E74-R187 and R97-E166 and the two hydrophobic residue-pairs V59-L164 and V72-V151. Furthermore, free energy surface (FES) analysis revealed that the HβB2C dimer with both monomers in a closed conformation (face-en-face dimer) is energetically more stable than the domain-swapped dimer (crystallographic structure). The results presented in this report shed light on the molecular details of the folding mechanism of HβB2C in an aqueous environment and may contribute to interpreting different experimental findings. Finally, a detailed knowledge of HβB2C folding may be key to the rational design of potential molecules to treat cataract disease.
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Affiliation(s)
- José-Luis Velasco-Bolom
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico.
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23
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Novel insights in linking solvent relaxation dynamics and protein conformations utilizing red edge excitation shift approach. Emerg Top Life Sci 2021; 5:89-101. [PMID: 33416893 DOI: 10.1042/etls20200256] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/14/2020] [Accepted: 12/18/2020] [Indexed: 01/01/2023]
Abstract
Protein hydration dynamics plays an important role in many physiological processes since protein fluctuations, slow solvation, and the dynamics of hydrating water are all intrinsically related. Red edge excitation shift (REES) is a unique and powerful wavelength-selective (i.e. excitation-energy dependent) fluorescence approach that can be used to directly monitor the environment-induced restriction and dynamics around a polar fluorophore in a complex biological system. This review is mainly focused on recent applications of REES and a novel analysis of REES data to monitor the structural dynamics, functionally relevant conformational transitions and to unmask the structural ensembles in proteins. In addition, the novel utility of REES in imaging protein aggregates in a cellular context is discussed. We believe that the enormous potential of REES approach showcased in this review will engage more researchers, particularly from life sciences.
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24
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Cortez-Trejo MC, Mendoza S, Loarca-Piña G, Figueroa-Cárdenas JD. Physicochemical characterization of protein isolates of amaranth and common bean and a study of their compatibility with xanthan gum. Int J Biol Macromol 2020; 166:861-868. [PMID: 33157134 DOI: 10.1016/j.ijbiomac.2020.10.242] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/21/2020] [Accepted: 10/30/2020] [Indexed: 11/27/2022]
Abstract
Vegetables are considered to be a sustainable source of promising biomaterials such as proteins and polysaccharides. In this study, four protein isolates (amaranth protein isolate API, amaranth globulin-rich protein isolate AGR, bean protein isolate BPI, and bean phaseolin-rich protein isolate BPR) were structurally characterized under different pH conditions (2-12) and their compatibility behavior with xanthan gum (XG) in aqueous medium was described. All protein isolates showed β turn and β sheet (78.24-81.11%), as the major secondary structures without statistically significant difference under the pH conditions surveyed. Protein isolates show solubility at pH ≤ 3 (40.4-85.1%) and pH ≥ 8 (57.6-99.9%) and surface hydrophobicity results suggest protein denaturation at pH ≤ 3. In the compatibility study, API/XG ratios between 1:1 and 5:1 at pH from 7 to 9 and the BPI/XG ratios from 1:1 to 20:1 at pH 7 form gels that do not require heating nor crosslinking agent addition. Zeta potential results, on the other hand, evidenced that formation of gels is driven by attractive electrostatic interaction of the charged regions of both biopolymers and intermolecular interactions such as hydrogen bonds.
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Affiliation(s)
- M C Cortez-Trejo
- Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro, 76010 Santiago de Querétaro, Querétaro, Mexico
| | - S Mendoza
- Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro, 76010 Santiago de Querétaro, Querétaro, Mexico.
| | - G Loarca-Piña
- Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro, 76010 Santiago de Querétaro, Querétaro, Mexico
| | - J D Figueroa-Cárdenas
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Querétaro, 76230 Querétaro, Querétaro, Mexico
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25
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Manrrique JD, Powell ZK, Brock RM, Franklin CE, Coker AO. Room Temperature Intrinsic Emission Ratio of BSA Correlates With Percent Aggregates During Long-Term Storage. J Pharm Sci 2020; 110:1120-1129. [PMID: 33127426 DOI: 10.1016/j.xphs.2020.10.045] [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: 06/11/2020] [Revised: 08/04/2020] [Accepted: 10/22/2020] [Indexed: 10/23/2022]
Abstract
Successful formulation development hinges on the ability to screen and identify excipients that stabilize drug products during long-term storage. Biophysical and accelerated stability studies are used to screen for excipients that stabilize protein drug products. However, these studies are not always predictive of aggregation during long-term storage. In this study, we used multivariate experimentation to compare the effectiveness of intrinsic fluorescence and size exclusion chromatography accelerated stability parameters to predict excipients that stabilized bovine serum albumin (BSA) against aggregation on long-term storage at 4 °C. Emission intensity ratio (IR330/350) data was more sensitive than emission maxima (λmax) or intensity measurements in identifying significant factors and interactions. We observed the expected inverse correlation between the mid-points of fluorescence thermal transitions (Tms) and insoluble aggregates at 4 and 40 °C. However, there were positive correlations between Tms and % aggregates at 4 °C, indicating that if Tm was used as a predictive tool, it would select formulations that promoted soluble aggregates on long-term storage. Ambient temperature IR330/350 measurements identified excipients that reduced BSA soluble aggregates on long-term storage. The results show ambient temperature emission ratio measurements can be useful for protein formulation development.
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Affiliation(s)
- Joel D Manrrique
- University of the Incarnate Word Feik School of Pharmacy, Department of Pharmaceutical Sciences, San Antonio, TX, USA
| | - Zakiya K Powell
- University of the Incarnate Word Feik School of Pharmacy, Department of Pharmaceutical Sciences, San Antonio, TX, USA
| | - Ryan M Brock
- University of the Incarnate Word Feik School of Pharmacy, Department of Pharmaceutical Sciences, San Antonio, TX, USA
| | - Cynthia E Franklin
- University of the Incarnate Word Feik School of Pharmacy, Department of Pharmaceutical Sciences, San Antonio, TX, USA
| | - Adeola O Coker
- University of the Incarnate Word Feik School of Pharmacy, Department of Pharmaceutical Sciences, San Antonio, TX, USA.
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26
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Broersen K. Milk Processing Affects Structure, Bioavailability and Immunogenicity of β-lactoglobulin. Foods 2020; 9:foods9070874. [PMID: 32635246 PMCID: PMC7404694 DOI: 10.3390/foods9070874] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/24/2020] [Accepted: 06/26/2020] [Indexed: 12/15/2022] Open
Abstract
Bovine milk is subjected to various processing steps to warrant constant quality and consumer safety. One of these steps is pasteurization, which involves the exposure of liquid milk to a high temperature for a limited amount of time. While such heating effectively ameliorates consumer safety concerns mediated by pathogenic bacteria, these conditions also have an impact on one of the main nutritional whey constituents of milk, the protein β-lactoglobulin. As a function of heating, β-lactoglobulin was shown to become increasingly prone to denaturation, aggregation, and lactose conjugation. This review discusses the implications of such heat-induced modifications on digestion and adsorption in the gastro-intestinal tract, and the responses these conformations elicit from the gastro-intestinal immune system.
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Affiliation(s)
- Kerensa Broersen
- Department of Applied Stem Cell Technologies, TechMed Centre, University of Twente, Postbus 217, 7500 AE Enschede, The Netherlands
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27
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Ghosh DK, Ranjan A. The metastable states of proteins. Protein Sci 2020; 29:1559-1568. [PMID: 32223005 PMCID: PMC7314396 DOI: 10.1002/pro.3859] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/26/2022]
Abstract
The intriguing process of protein folding comprises discrete steps that stabilize the protein molecules in different conformations. The metastable state of protein is represented by specific conformational characteristics, which place the protein in a local free energy minimum state of the energy landscape. The native-to-metastable structural transitions are governed by transient or long-lived thermodynamic and kinetic fluctuations of the intrinsic interactions of the protein molecules. Depiction of the structural and functional properties of metastable proteins is not only required to understand the complexity of folding patterns but also to comprehend the mechanisms of anomalous aggregation of different proteins. In this article, we review the properties of metastable proteins in context of their stability and capability of undergoing atypical aggregation in physiological conditions.
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Affiliation(s)
- Debasish Kumar Ghosh
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and DiagnosticsUppal, HyderabadTelanganaIndia
| | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and DiagnosticsUppal, HyderabadTelanganaIndia
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28
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Abstract
The analysis of folding trajectories for proteins is an open challenge. One of the problems is how to describe the amount of folded secondary structure in a protein. We extend the use of Estradas' folding degree (Bioinformatics 2002, 18, 697) for the analysis of the evolution of the folding stage during molecular dynamics (MD) simulation. It is shown that residue contribution to the total folding degree is a predominantly local property, well-defined by the backbone dihedral angles at the given residue, without significant contribution from the backbone conformation of other residues. Moreover, the magnitude of this residue contribution can be quite easily associated with characteristic motifs of secondary protein structures such as the α-helix, β-sheet (hairpin), and so on by means of a Ramachandran-like plot as a function of backbone dihedral angles φ,ψ. Additionally, the understanding of the free energy profile associated with the folding process becomes much simpler. Often a 1D profile is sufficient to locate global minima and the corresponding structure for short peptides.
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Affiliation(s)
- Vladimir Sladek
- Institute of Chemistry - Centre for Glycomics, Dubravska cesta 9, 84538 Bratislava, Slovakia.,Agency for Medical Research and Development (AMED), Chiyoda-ku, Japan
| | - Ryuhei Harada
- Center for Computational Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan
| | - Yasuteru Shigeta
- Center for Computational Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan
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29
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Ishtikhar M, Siddiqui Z, Husain FM, Khan RA, Hassan I. Comparative refolding of guanidinium hydrochloride denatured bovine serum albumin assisted by cationic and anionic surfactants via artificial chaperone protocol: Biophysical insight. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 225:117510. [PMID: 31520999 DOI: 10.1016/j.saa.2019.117510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/28/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
In the present study, we report the cooperative refolding/renaturation behaviour of guanidinium hydrochloride (GdnHCl) denatured bovine serum albumin (BSA) in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB), anionic surfactant sodium dodecyl sulphate (SDS) and their catanionic mixture in the solution of 60 mM sodium phosphate buffer of physiological pH 7.4, using artificial chaperone-assisted two-step method. Here, we have employed biophysical techniques to characterize the refolding mechanism of denatured BSA after 200 times of dilution in the presence of cationic, anionic surfactants and their catanionic mixture, separately. We have found that minimum refolding of diluted BSA in the presence of 1:1 rational mixture of CTAB and SDS (CTAB/SDS = 50/50), it may be due to the micelles formation which is responsible for the unordered microstructure aggregate formation. Other mixtures (CTAB/SDS = 20/80 and 80/20) slightly played an effective role during refolding process in the presence of methyl-β-cyclodextrin. On other hand, CTAB and SDS are more effective and reflect a good renaturation tendency of denatured BSA solution separately and in existence of methyl-β-cyclodextrin as compare to their mixture compositions. But overall, CTAB has the better renaturation tendency as compare to SDS in the existence of methyl-β-cyclodextrin. These results ascribed the presence of charge head group and length of hydrophobic tail of CTAB surfactant that plays an important task during electrostatic and hydrophobic interactions at pH 7.4 at which BSA carries negative charge on their surface. These biophysical parameters suggest that, CTAB surfactant assisted artificial chaperone protocol may be utilized in the protein renaturation/refolding studies, which may address the associated problems of biotechnological industries for the development of efficient and inexpensive folding aides, which may also be used to produced genetically engineered cells related diseases, resulting from protein misfolding/aggregation.
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Affiliation(s)
- Mohd Ishtikhar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Zeba Siddiqui
- Department of Biosciences, Integral University, Lucknow 226026, India
| | - Fohad Mabood Husain
- Department of Food Science and Nutrition, College of Food and Agricultural Sciences, King Saud University, 2460, Riyadh 11451, Saudi Arabia
| | - Rais Ahmad Khan
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Iftekhar Hassan
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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Uversky VN, Finkelstein AV. Life in Phases: Intra- and Inter- Molecular Phase Transitions in Protein Solutions. Biomolecules 2019; 9:E842. [PMID: 31817975 PMCID: PMC6995567 DOI: 10.3390/biom9120842] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 02/06/2023] Open
Abstract
Proteins, these evolutionarily-edited biological polymers, are able to undergo intramolecular and intermolecular phase transitions. Spontaneous intramolecular phase transitions define the folding of globular proteins, whereas binding-induced, intra- and inter- molecular phase transitions play a crucial role in the functionality of many intrinsically-disordered proteins. On the other hand, intermolecular phase transitions are the behind-the-scenes players in a diverse set of macrosystemic phenomena taking place in protein solutions, such as new phase nucleation in bulk, on the interface, and on the impurities, protein crystallization, protein aggregation, the formation of amyloid fibrils, and intermolecular liquid-liquid or liquid-gel phase transitions associated with the biogenesis of membraneless organelles in the cells. This review is dedicated to the systematic analysis of the phase behavior of protein molecules and their ensembles, and provides a description of the major physical principles governing intramolecular and intermolecular phase transitions in protein solutions.
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Affiliation(s)
- Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Moscow, Russia
| | - Alexei V. Finkelstein
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow, Russia
- Biology Department, Lomonosov Moscow State University, 119192 Moscow, Russia
- Bioltechnogy Department, Lomonosov Moscow State University, 142290 Pushchino, Moscow, Russia
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31
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Sekhon G, Singh R. Human aldose reductase unfolds through an intermediate. F1000Res 2019; 8:564. [PMID: 31723418 PMCID: PMC6844136 DOI: 10.12688/f1000research.18963.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/22/2019] [Indexed: 11/26/2022] Open
Abstract
Background: Human aldose reductase (hAR) is the first and rate-limiting enzyme of the polyol pathway. For the development of secondary complications of diabetes in chronic hyperglycemic conditions, one of the critical factors is the increased flux of glucose through the polyol pathway. Due to this clinical implication, hAR attracted considerable attention from the drug discovery perspective. In spite of extensive characterization in the context of biochemical and structural aspects, we know very little about the unfolding behavior of hAR. This study reports equilibrium unfolding studies of hAR. Methods: We carried out thermal denaturation and chemical-induced equilibrium unfolding studies of hAR monitored by circular dichroism and fluorescence spectroscopy. Results: Thermal denaturation studies presented a classical picture of two-state unfolding from native to the denatured state. The data was used to derive thermodynamic parameters and study the thermostability of hAR. Chemical induced equilibrium unfolding studies led us to discover an intermediate state, which gets populated at 3.5-4.0 M and 0.7-2.0 M of urea and GuHCl, respectively. Thermodynamic parameters derived from chemical-induced unfolding are in agreement with those obtained from thermal denaturation of hAR. Conclusion: This study revealed that aldose reductase unfolds from native to the unfolded state via an intermediate. Assessment of the thermodynamic stability of native, intermediate, and unfolded states shows that significant energy barriers separate these states, which ensures the cooperativity of unfolding. As hAR functions in cells that are under osmotic and oxidative stress, these
in vitro findings may have implications for its native conformation under the physiological state.
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Affiliation(s)
- Gurprit Sekhon
- Department cum National Center for Human Genome Studies and Research, Panjab University, Chandigarh, 160014, India
| | - Ranvir Singh
- Department cum National Center for Human Genome Studies and Research, Panjab University, Chandigarh, 160014, India
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Prasanthan P, Kishore N. Alkali induced unique partially folded state of bovine serum albumin: qualitative and quantitative insights. Int J Biol Macromol 2019; 138:252-261. [DOI: 10.1016/j.ijbiomac.2019.07.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 01/31/2023]
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33
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Battle AR, Norton RS, Böcking T, Noji H, Kim KK, Nagayama K. Editorial: Special issue of Biophysical Reviews dedicated to the joint 10th Asian Biophysics Association Symposium and 42nd Australian Society for Biophysics Meeting, Melbourne, Australia, December 2-6, 2018. Biophys Rev 2019; 11:245-247. [PMID: 31115863 PMCID: PMC6557946 DOI: 10.1007/s12551-019-00553-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Andrew R Battle
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, 4000, Australia.
- Translational Research Institute and Institute for Biomedical Innovation (QUT), 37 Kent Street, Woolloongabba, 4102, Australia.
- The University of Queensland Diamantina Institute, Faculty of Medicine, The University of Queensland, Brisbane, 4102, Australia.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Hiroyuki Noji
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, School of Medicine, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Kuniaki Nagayama
- National Institute for Physiological Sciences, Myodaiji-cho, Okazaki, 444-8585, Japan
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