1
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Ooka K, Arai M. Accurate prediction of protein folding mechanisms by simple structure-based statistical mechanical models. Nat Commun 2023; 14:6338. [PMID: 37857633 PMCID: PMC10587348 DOI: 10.1038/s41467-023-41664-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/10/2023] [Indexed: 10/21/2023] Open
Abstract
Recent breakthroughs in highly accurate protein structure prediction using deep neural networks have made considerable progress in solving the structure prediction component of the 'protein folding problem'. However, predicting detailed mechanisms of how proteins fold into specific native structures remains challenging, especially for multidomain proteins constituting most of the proteomes. Here, we develop a simple structure-based statistical mechanical model that introduces nonlocal interactions driving the folding of multidomain proteins. Our model successfully predicts protein folding processes consistent with experiments, without the limitations of protein size and shape. Furthermore, slight modifications of the model allow prediction of disulfide-oxidative and disulfide-intact protein folding. These predictions depict details of the folding processes beyond reproducing experimental results and provide a rationale for the folding mechanisms. Thus, our physics-based models enable accurate prediction of protein folding mechanisms with low computational complexity, paving the way for solving the folding process component of the 'protein folding problem'.
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Affiliation(s)
- Koji Ooka
- Department of Physics, Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
- Komaba Organization for Educational Excellence, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
| | - Munehito Arai
- Department of Physics, Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
- Komaba Organization for Educational Excellence, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
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2
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Malik A, Khan JM, Alhomida AS, Ola MS, Alokail MS, Khan MS, Alenad AM, Altwaijry N, Alafaleq NO, Odeibat H. Agitation does not induce fibrillation in reduced hen egg-white lysozyme at physiological temperature and pH. J Mol Recognit 2023; 36:e3009. [PMID: 36841950 DOI: 10.1002/jmr.3009] [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: 10/10/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023]
Abstract
Several proteins and peptides tend to form an amyloid fibril, causing a range of unrelated diseases, from neurodegenerative to certain types of cancer. In the native state, these proteins are folded and soluble. However, these proteins acquired β-sheet amyloid fibril due to unfolding and aggregation. The conversion mechanism from well-folded soluble into amorphous or amyloid fibril is not well understood yet. Here, we induced unfolding and aggregation of hen egg-white lysozyme (HEWL) by reducing agent dithiothreitol and applied mechanical sheering force by constant shaking (1000 rpm) on the thermostat for 7 days. Our turbidity results showed that reduced HEWL rapidly formed aggregates, and a plateau was attained in nearly 5 h of incubation in both shaking and non-shaking conditions. The turbidity was lower in the shaking condition than in the non-shaking condition. The thioflavin T binding and transmission electron micrographs showed that reduced HEWL formed amorphous aggregates in both conditions. Far-UV circular dichroism results showed that reduced HEWL lost nearly all alpha-helical structure, and β-sheet secondary structure was not formed in both conditions. All the spectroscopic and microscopic results showed that reduced HEWL formed amorphous aggregates under both conditions.
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Affiliation(s)
- Ajamaluddin Malik
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Javed Masood Khan
- Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah S Alhomida
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad Shamsul Ola
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Majed S Alokail
- Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohd Shahnawaz Khan
- Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Amal M Alenad
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nojood Altwaijry
- Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nouf Omar Alafaleq
- Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hamza Odeibat
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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3
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Effects of Molecular Crowding and Betaine on HSPB5 Interactions, with Target Proteins Differing in the Quaternary Structure and Aggregation Mechanism. Int J Mol Sci 2022; 23:ijms232315392. [PMID: 36499725 PMCID: PMC9737104 DOI: 10.3390/ijms232315392] [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: 11/17/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
The aggregation of intracellular proteins may be enhanced under stress. The expression of heat-shock proteins (HSPs) and the accumulation of osmolytes are among the cellular protective mechanisms in these conditions. In addition, one should remember that the cell environment is highly crowded. The antiaggregation activity of HSPB5 and the effect on it of either a crowding agent (polyethylene glycol (PEG)) or an osmolyte (betaine), or their mixture, were tested on the aggregation of two target proteins that differ in the order of aggregation with respect to the protein: thermal aggregation of glutamate dehydrogenase and DTT-induced aggregation of lysozyme. The kinetic analysis of the dynamic light-scattering data indicates that crowding can decrease the chaperone-like activity of HSPB5. Nonetheless, the analytical ultracentrifugation shows the protective effect of HSPB5, which retains protein aggregates in a soluble state. Overall, various additives may either improve or impair the antiaggregation activity of HSPB5 against different protein targets. The mixed crowding arising from the presence of PEG and 1 M betaine demonstrates an extraordinary effect on the oligomeric state of protein aggregates. The shift in the equilibrium of HSPB5 dynamic ensembles allows for the regulation of its antiaggregation activity. Crowding can modulate HSPB5 activity by affecting protein-protein interactions.
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4
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Wang X, Bowman J, Tu S, Nykypanchuk D, Kuksenok O, Minko S. Polyethylene Glycol Crowder's Effect on Enzyme Aggregation, Thermal Stability, and Residual Catalytic Activity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8474-8485. [PMID: 34236863 DOI: 10.1021/acs.langmuir.1c00872] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Protein stability and performance in various natural and artificial systems incorporating many other macromolecules for therapeutic, diagnostic, sensor, and biotechnological applications attract increasing interest with the expansion of these technologies. Here we address the catalytic activity of lysozyme protein (LYZ) in the presence of a polyethylene glycol (PEG) crowder in a broad range of concentrations and temperatures in aqueous solutions of two different molecular mass PEG samples (Mw = 3350 and 10000 g/mol). The phase behavior of PEG-protein solutions is examined by using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS), while the enzyme denaturing is monitored by using an activity assay (AS) and circular dichroism (CD) spectroscopy. Molecular dynamic (MD) simulations are used to illustrate the effect of PEG concentration on protein stability at high temperatures. The results demonstrate that LYZ residual activity after 1 h incubation at 80 °C is improved from 15% up to 55% with the addition of PEG. The improvement is attributed to two underlying mechanisms. (i) Primarily, the stabilizing effect is due to the suppression of the enzyme aggregation because of the stronger PEG-protein interactions caused by the increased hydrophobicity of PEG and lysozyme at elevated temperatures. (ii) The MD simulations showed that the addition of PEG to some degree stabilizes the secondary structures of the enzyme by delaying unfolding at elevated temperatures. The more pronounced effect is observed with an increase in PEG concentration. This trend is consistent with CD and AS experimental results, where the thermal stability is strengthened with increasing of PEG concentration and molecular mass. The results show that the highest stabilizing effect is approached at the critical overlap concentration of PEG.
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Affiliation(s)
- Xue Wang
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Jeremy Bowman
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Sidong Tu
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Olga Kuksenok
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sergiy Minko
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
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5
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Fabra D, Matesanz AI, Herrero JM, Alvarez C, Balsa LM, Leon IE, Quiroga AG. Two Different Thiosemicarbazone Tauto‐Conformers Coordinate to Palladium (II). Stability and Biological Studies of the Final Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202001066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- David Fabra
- Inorganic Chemistry Department Universidad Autónoma de Madrid Madrid 28049 Spain
| | - Ana I. Matesanz
- Inorganic Chemistry Department Universidad Autónoma de Madrid Madrid 28049 Spain
| | - Jorge M. Herrero
- Inorganic Chemistry Department Universidad Autónoma de Madrid Madrid 28049 Spain
| | - Cristina Alvarez
- Inorganic Chemistry Department Universidad Autónoma de Madrid Madrid 28049 Spain
| | - Lucia M. Balsa
- Centro de Química Inorgánica (CEQUINOR CONICET-UNLP) Facultad de Ciencias Exactas Universidad Nacional de La Plata Bv 120 1465 1900 La Plata Argentina
| | - Ignacio E. Leon
- Centro de Química Inorgánica (CEQUINOR CONICET-UNLP) Facultad de Ciencias Exactas Universidad Nacional de La Plata Bv 120 1465 1900 La Plata Argentina
| | - Adoracion G. Quiroga
- Inorganic Chemistry Department Universidad Autónoma de Madrid Madrid 28049 Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem) Universidad Autónoma de Madrid Madrid 28049 Spain
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6
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Narayan M. Revisiting the Formation of a Native Disulfide Bond: Consequences for Protein Regeneration and Beyond. Molecules 2020; 25:molecules25225337. [PMID: 33207635 PMCID: PMC7697891 DOI: 10.3390/molecules25225337] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/16/2022] Open
Abstract
Oxidative protein folding involves the formation of disulfide bonds and the regeneration of native structure (N) from the fully reduced and unfolded protein (R). Oxidative protein folding studies have provided a wealth of information on underlying physico-chemical reactions by which disulfide-bond-containing proteins acquire their catalytically active form. Initially, we review key events underlying oxidative protein folding using bovine pancreatic ribonuclease A (RNase A), bovine pancreatic trypsin inhibitor (BPTI) and hen-egg white lysozyme (HEWL) as model disulfide bond-containing folders and discuss consequential outcomes with regard to their folding trajectories. We re-examine the findings from the same studies to underscore the importance of forming native disulfide bonds and generating a “native-like” structure early on in the oxidative folding pathway. The impact of both these features on the regeneration landscape are highlighted by comparing ideal, albeit hypothetical, regeneration scenarios with those wherein a native-like structure is formed relatively “late” in the R→N trajectory. A special case where the desired characteristics of oxidative folding trajectories can, nevertheless, stall folding is also discussed. The importance of these data from oxidative protein folding studies is projected onto outcomes, including their impact on the regeneration rate, yield, misfolding, misfolded-flux trafficking from the endoplasmic reticulum (ER) to the cytoplasm, and the onset of neurodegenerative disorders.
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Affiliation(s)
- Mahesh Narayan
- The Department of Chemistry and Biochemistry, The University of Texas as El Paso, El Paso, TX 79968, USA
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7
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Trehalose Effect on the Aggregation of Model Proteins into Amyloid Fibrils. Life (Basel) 2020; 10:life10050060. [PMID: 32414105 PMCID: PMC7281244 DOI: 10.3390/life10050060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/13/2022] Open
Abstract
Protein aggregation into amyloid fibrils is a phenomenon that attracts attention from a wide and composite part of the scientific community. Indeed, the presence of mature fibrils is associated with several neurodegenerative diseases, and in addition these supramolecular aggregates are considered promising self-assembling nanomaterials. In this framework, investigation on the effect of cosolutes on protein propensity to aggregate into fibrils is receiving growing interest, and new insights on this aspect might represent valuable steps towards comprehension of highly complex biological processes. In this work we studied the influence exerted by the osmolyte trehalose on fibrillation of two model proteins, that is, lysozyme and insulin, investigated during concomitant variation of the solution ionic strength due to NaCl. In order to monitor both secondary structures and the overall tridimensional conformations, we have performed UV spectroscopy measurements with Congo Red, Circular Dichroism, and synchrotron Small Angle X-ray Scattering. For both proteins we describe the effect of trehalose in changing the fibrillation pattern and, as main result, we observe that ionic strength in solution is a key factor in determining trehalose efficiency in slowing down or blocking protein fibrillation. Ionic strength reveals to be a competitive element with respect to trehalose, being able to counteract its inhibiting effects toward amyloidogenesis. Reported data highlight the importance of combining studies carried out on cosolutes with valuation of other physiological parameters that may affect the aggregation process. Also, the obtained experimental results allow to hypothesize a plausible mechanism adopted by the osmolyte to preserve protein surface and prevent protein fibrillation.
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8
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Muttathukattil AN, Singh PC, Reddy G. Role of Disulfide Bonds and Topological Frustration in the Kinetic Partitioning of Lysozyme Folding Pathways. J Phys Chem B 2019; 123:3232-3241. [PMID: 30913878 DOI: 10.1021/acs.jpcb.9b00739] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Disulfide bonds in proteins can strongly influence the folding pathways by constraining the conformational space. Lysozyme has four disulfide bonds and is widely studied for its antibacterial properties. Experiments on lysozyme infer that the protein folds through a fast and a slow pathway. However, the reasons for the kinetic partitioning in the folding pathways are not completely clear. Using a coarse-grained protein model and simulations, we show that two out of the four disulfide bonds, which are present in the α-domain of lysozyme, are responsible for the slow folding pathway. In this pathway, a kinetically trapped intermediate state, which is close to the native state, is populated. In this state, the orientations of α-helices present in the α-domain are misaligned relative to each other. The protein in this state has to partially unfold by breaking down the interhelical contacts between the misaligned helices to fold to the native state. However, the topological constraints due to the two disulfide bonds present in the α-domain make the protein less flexible, and it is trapped in this conformation for hundreds of milliseconds. On disabling these disulfide bonds, we find that the kinetically trapped intermediate state and the slow folding pathway disappear. Simulations mimicking the folding of protein without disulfide bonds under oxidative conditions show that the native disulfide bonds are formed as the protein folds, indicating that folding guides the formation of disulfide bonds. The sequence of formation of the disulfide bonds is Cys64-Cys80 → Cys76-Cys94 → Cys30-Cys115 → Cys6-Cys127. Any disulfide bond that forms before its precursor in the sequence has to break and follow the sequence for the protein to fold. These results show that lysozyme also serves as a very good model system to probe the role of disulfide bonds and topological frustration in protein folding. The predictions from the simulations can be verified by single-molecule fluorescence resonance energy transfer or single-molecule pulling experiments, which can probe heterogeneity in the folding pathways.
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Affiliation(s)
- Aswathy N Muttathukattil
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bengaluru 560012 , Karnataka , India
| | - Prashant Chandra Singh
- School of Chemical Science , Indian Association for the Cultivation of Science , 2A & 2B, Raja S.C. Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bengaluru 560012 , Karnataka , India
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10
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Coacervates and coaggregates: Liquid–liquid and liquid–solid phase transitions by native and unfolded protein complexes. Int J Biol Macromol 2018; 120:10-18. [DOI: 10.1016/j.ijbiomac.2018.08.063] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/11/2018] [Accepted: 08/13/2018] [Indexed: 11/23/2022]
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11
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Singh AK, Burada PS, Bhattacharya S, Bag S, Bhattacharya A, Dasgupta S, Roy A. Microwave-radiation-induced molecular structural rearrangement of hen egg-white lysozyme. Phys Rev E 2018; 97:052416. [PMID: 29906821 DOI: 10.1103/physreve.97.052416] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Indexed: 11/07/2022]
Abstract
We have investigated the nonthermal effect of 10 GHz/22 dBm microwave radiation on hen egg-white lysozyme (HEWL) over different irradiation times, ranging from 2 min to 1 h. To ensure a control over the radiation parameters, a pair of microwave rectangular waveguides is used to irradiate the samples. Optical spectroscopic measurements, which include UV-visible absorption spectroscopy, Raman spectroscopy, and far UV CD spectroscopy, reveal the exposure of the buried tryptophan (Trp) residues of the native molecule between 15 and 30 min of radiation. The higher duration of the perturbation leads to a compact structure of the protein and Trp residues are buried again. Interestingly, we do not find any change in the secondary structure of the protein even for 1 h duration of radiation. The relaxation dynamics of the irradiated molecules also has been discussed. We have shown that the molecules relax to their native configuration in 7-8 h after the radiation field is turned off. The structural rearrangement over the above timescale has further been probed by a model calculation, based on a modified Langevin equation. Our coarse-grained simulation approach utilizes the mean of atomic positions and net atomic charge of each amino acid of native HEWL to mimic the initial conformation of the molecule. The modified positions of the residues are then calculated for the given force fields. The simulation results reveal the nonmonotonous change in overall size of the molecule, as observed experimentally. The radiation parameters used in our experiments are very similar to those of some of the electronic devices we often come across. Thus, we believe that the results of our studies on a simple protein structure may help us in understanding the effect of radiation on complex biological systems as well.
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Affiliation(s)
- Anang K Singh
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
| | - P S Burada
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
| | | | - Sudipta Bag
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Amitabha Bhattacharya
- Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721302, India
| | - Swagata Dasgupta
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Anushree Roy
- Department of Physics, Indian Institute of Technology, Kharagpur 721302, India
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12
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Impact of disulfide bonds on the folding and refolding capability of a novel thermostable GH45 cellulase. Appl Microbiol Biotechnol 2018; 102:9183-9192. [DOI: 10.1007/s00253-018-9256-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/08/2018] [Accepted: 07/13/2018] [Indexed: 12/22/2022]
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13
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Zegota MM, Wang T, Seidler C, Wah Ng DY, Kuan SL, Weil T. "Tag and Modify" Protein Conjugation with Dynamic Covalent Chemistry. Bioconjug Chem 2018; 29:2665-2670. [PMID: 29949347 DOI: 10.1021/acs.bioconjchem.8b00358] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The development of small protein tags that exhibit bioorthogonality, bond stability, and reversibility, as well as biocompatibility, holds great promise for applications in cellular environments enabling controlled drug delivery or for the construction of dynamic protein complexes in biological environments. Herein, we report the first application of dynamic covalent chemistry both for purification and for reversible assembly of protein conjugates using interactions of boronic acid with diols and salicylhydroxamates. Incorporation of the boronic acid (BA) tag was performed in a site-selective fashion by applying disulfide rebridging strategy. As an example, a model protein enzyme (lysozyme) was modified with the BA tag and purified using carbohydrate-based column chromatography. Subsequent dynamic covalent "click-like" bioconjugation with a salicylhydroxamate modified fluorescent dye (BODIPY FL) was accomplished while retaining its original enzymatic activity.
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Affiliation(s)
- Maksymilian Marek Zegota
- Max-Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.,Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany
| | - Tao Wang
- Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany.,School of Materials Science and Engineering , Southwest Jiaotong University , 610031 Chengdu , P.R. China
| | - Christiane Seidler
- Max-Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.,Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany
| | - David Yuen Wah Ng
- Max-Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.,Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany
| | - Seah Ling Kuan
- Max-Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.,Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany
| | - Tanja Weil
- Max-Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany.,Institute of Inorganic Chemistry I , University of Ulm , Albert-Einstein-Allee 11 , 89081 Ulm , Germany
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14
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Watanabe K, Ohshima T. Bioconjugation with Thiols by Benzylic Substitution. Chemistry 2018; 24:3959-3964. [PMID: 29457301 DOI: 10.1002/chem.201706149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 12/11/2022]
Abstract
A benzylic substitution of 3-indolyl(hydroxyl)acetate derivatives with thiols proceeded specifically in the presence of amino, carboxy, and phosphate groups in weakly acidic aqueous solutions under nearly physiological condition, while no reaction occurred at pH over 7. Kinetic studies revealed that the reaction followed second-order kinetics (first-order in the reactant and first-order in thiol) in contrast with the SN 1 mechanism of common benzylic substitution of alcohols. The utility of the present method for functionalization of biomacromolecules was demonstrated using several model proteins, such as lysozyme, insulin, trypsin, and serum albumin. The catalytic bioactivity of lysozyme in lysis of Micrococcus lysodeikticus cells was completely retained after the modification.
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Affiliation(s)
- Kenji Watanabe
- Graduate School of Pharmaceutical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takashi Ohshima
- Graduate School of Pharmaceutical Sciences, Kyushu University, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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15
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Safari MS, Byington MC, Conrad JC, Vekilov PG. Polymorphism of Lysozyme Condensates. J Phys Chem B 2017; 121:9091-9101. [DOI: 10.1021/acs.jpcb.7b05425] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mohammad S. Safari
- Department
of Chemical and Biomolecular Engineering, University of Houston, 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Michael C. Byington
- Department
of Chemical and Biomolecular Engineering, University of Houston, 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Jacinta C. Conrad
- Department
of Chemical and Biomolecular Engineering, University of Houston, 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Peter G. Vekilov
- Department
of Chemical and Biomolecular Engineering, University of Houston, 4726 Calhoun Road, Houston, Texas 77204-4004, United States
- Department
of Chemistry, University of Houston, 3585 Cullen Blvd., Houston, Texas 77204-5003, United States
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16
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Yang Z, Luo S, Zeng Y, Shi C, Li R. Albumin-Mediated Biomineralization of Shape-Controllable and Biocompatible Ceria Nanomaterials. ACS APPLIED MATERIALS & INTERFACES 2017; 9:6839-6848. [PMID: 28150935 DOI: 10.1021/acsami.6b15442] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Although ceria-based nanostructures have emerged as fascinating materials with diverse biological activities, developing a facile, rapid, and biocompatible method of their preparation remains a major challenge. Herein we describe bovine serum albumin (BSA) protein-directed synthesis of ceria-based nanostructures, including ceria nanoclusters (CNLs), nanoparticles (CNPs), and nanochains (CNHs). Their preparation is simple, one-pot, and performed in a mild reaction condition with a "green" synthetic approach. Most importantly, these three kinds of ceria-based nanostructures can be synthesized in a shape and size controllable manner by tuning the reaction time, temperature, and molar ratio. The formation mechanism shows that growth of these ceria nanostructures is mediated by Ce3+/Ce4+ switchable redox system, reducible disulfide bonds, and unique spatial structures in albumin proteins. More importantly, these albumin-based ceria nanostructures exhibit high superoxide dismutase (SOD) mimetic activity and good biocompatibility, providing a promising prospect in biomedical application.
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Affiliation(s)
- Zhangyou Yang
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing Engineering Research Center for Nanomedicine, Department of Preventive Medicine, Third Military Medical University , Chongqing, 400038, China
| | - Shenglin Luo
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing Engineering Research Center for Nanomedicine, Department of Preventive Medicine, Third Military Medical University , Chongqing, 400038, China
| | - Yiping Zeng
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing Engineering Research Center for Nanomedicine, Department of Preventive Medicine, Third Military Medical University , Chongqing, 400038, China
| | - Chunmeng Shi
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing Engineering Research Center for Nanomedicine, Department of Preventive Medicine, Third Military Medical University , Chongqing, 400038, China
| | - Rong Li
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Chongqing Engineering Research Center for Nanomedicine, Department of Preventive Medicine, Third Military Medical University , Chongqing, 400038, China
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17
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Byington MC, Safari MS, Conrad JC, Vekilov PG. Protein Conformational Flexibility Enables the Formation of Dense Liquid Clusters: Tests Using Solution Shear. J Phys Chem Lett 2016; 7:2339-2345. [PMID: 27267087 DOI: 10.1021/acs.jpclett.6b00822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
According to recently proposed two-step nucleation mechanisms, crystal nuclei form within preexisting dense liquid clusters. Clusters with radii about 100 nm, which capture from 10(-7) to 10(-3) of the total protein, have been observed with numerous proteins and shown to host crystal nucleation. Theories aiming to understand the mesoscopic size and small protein fraction held in the clusters have proposed that in solutions of single-chain proteins, the clusters consist of partially misfolded protein molecules. To test this conjecture, we perturb the protein conformation by shearing solutions of the protein lysozyme. We demonstrate that shear rates greater than a threshold applied for longer than 1 h reduce the volume of the cluster population. The likely mechanism of the observed response involves enhanced partial unfolding of lysozyme molecules, which exposes hydrophobic surfaces between the constituent domains to the aqueous solution.
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Affiliation(s)
- Michael C Byington
- Department of Chemical and Biomolecular Engineering and ‡Department of Chemistry, University of Houston , 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Mohammad S Safari
- Department of Chemical and Biomolecular Engineering and ‡Department of Chemistry, University of Houston , 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Jacinta C Conrad
- Department of Chemical and Biomolecular Engineering and ‡Department of Chemistry, University of Houston , 4726 Calhoun Road, Houston, Texas 77204-4004, United States
| | - Peter G Vekilov
- Department of Chemical and Biomolecular Engineering and ‡Department of Chemistry, University of Houston , 4726 Calhoun Road, Houston, Texas 77204-4004, United States
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18
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Zhu W, Silvers R, Schwalbe H, Keiderling TA. Reduced and mutant lysozyme refolding with lipid vesicles. Model study of disulfide impact on equilibria and dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1083-1092. [PMID: 27240304 DOI: 10.1016/j.bbapap.2016.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/24/2016] [Accepted: 05/25/2016] [Indexed: 11/26/2022]
Abstract
The recovery of secondary structure in disordered, disulfide-reduced hen egg white lysozyme (HEWL) upon interaction with lipid vesicles was studied using circular dichroism (CD), fluorescence and infrared (IR) spectroscopic techniques. Lipid vesicles having negative head groups, such as DMPG, interact with reduced HEWL to induce formation of more helical structure than in native HEWL, but no stable tertiary structure was evident. Changes in tertiary structure, as evidenced by local environment of the tryptophan residues, were monitored by fluorescence. Spectra for oxidized HEWL, reduced HEWL and mutants with no or just one disulfide bond developed variable degrees of increased helicity when added to negatively charged lipid vesicles, mostly depending on packing of tails. When mixed with zwitterionic lipid vesicles, reduced HEWL developed β-sheet structure with no change in helicity, indicating an altered interaction mechanism. Stopped flow CD and fluorescence dynamics, were fit to multi-exponential forms, consistent with refolding to metastable intermediates of increasing helicity for HEWL interacting with lipid vesicles. Formation of an intermediate after rapid interaction of the lipid vesicles and the protein is supported by the correlation of faster steps in CD and fluorescence kinetics, and largely appears driven by electrostatic interaction. In subsequent slower steps, the partially refolded intermediate further alters structure, gaining helicity and modifying tryptophan packing, as driven by hydrophobic interactions.
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Affiliation(s)
- Weiying Zhu
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., m/c 111, Chicago, IL 60607-7061, USA
| | - Robert Silvers
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt,, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt,, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Timothy A Keiderling
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., m/c 111, Chicago, IL 60607-7061, USA.
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19
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Coughlan HD, Darmanin C, Phillips NW, Hofmann F, Clark JN, Harder RJ, Vine DJ, Abbey B. Radiation damage in a micron-sized protein crystal studied via reciprocal space mapping and Bragg coherent diffractive imaging. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:041704. [PMID: 26798804 PMCID: PMC4711611 DOI: 10.1063/1.4919641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 04/22/2015] [Indexed: 05/11/2023]
Abstract
For laboratory and synchrotron based X-ray sources, radiation damage has posed a significant barrier to obtaining high-resolution structural data from biological macromolecules. The problem is particularly acute for micron-sized crystals where the weaker signal often necessitates the use of higher intensity beams to obtain the relevant data. Here, we employ a combination of techniques, including Bragg coherent diffractive imaging to characterise the radiation induced damage in a micron-sized protein crystal over time. The approach we adopt here could help screen for potential protein crystal candidates for measurement at X-ray free election laser sources.
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Affiliation(s)
| | - C Darmanin
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe University , Melbourne 3086, Australia
| | | | - F Hofmann
- Department of Engineering Science, University of Oxford , Oxford OX1 3PJ, United Kingdom
| | | | - R J Harder
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, USA
| | - D J Vine
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, USA
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20
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Yang M, Dutta C, Tiwari A. Disulfide-bond scrambling promotes amorphous aggregates in lysozyme and bovine serum albumin. J Phys Chem B 2015; 119:3969-81. [PMID: 25689578 DOI: 10.1021/acs.jpcb.5b00144] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Disulfide bonds are naturally formed in more than 50% of amyloidogenic proteins, but the exact role of disulfide bonds in protein aggregation is still not well-understood. The intracellular reducing agents and/or improper use of antioxidants in extracellular environment can break proteins disulfide bonds, making them unstable and prone to misfolding and aggregation. In this study, we report the effect of disulfide-reducing agent dithiothreitol (DTT) on hen egg white lysozyme (lysozyme) and bovine serum albumin (BSA) aggregation at pH 7.2 and 37 °C. BSA and lysozyme proteins treated with disulfide-reducing agents form very distinct amorphous aggregates as observed by scanning electron microscope. However, proteins with intact disulfide bonds were stable and did not aggregate over time. BSA and lysozyme aggregates show unique but measurable differences in 8-anilino-1-naphthalenesulfonic acid (ANS) and 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) fluorescence, suggesting a loose and flexible aggregate structure for lysozyme but a more compact aggregate structure for BSA. Scrambled disulfide-bonded protein aggregates were observed by nonreducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for both proteins. Similar amorphous aggregates were also generated using a nonthiol-based reducing agent, tris(2-carboxyethyl)phosphine (TCEP), at pH 7.2 and 37 °C. In summary, formation of distinct amorphous aggregates by disulfide-reduced BSA and lysozyme suggests an alternate pathway for protein aggregation that may be relevant to several proteins.
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Affiliation(s)
- Mu Yang
- Department of Chemistry, Michigan Technological University , Houghton, Michigan 49931, United States
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21
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Refolding of Laccase in Dilution Additive Mode with Copper-Based Ionic Liquid. Appl Biochem Biotechnol 2013; 171:1289-98. [DOI: 10.1007/s12010-013-0422-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 08/05/2013] [Indexed: 11/25/2022]
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22
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Reinvestigation of the oxidative folding pathways of hen egg white lysozyme: switching of the major pathways by temperature control. Int J Mol Sci 2013; 14:13194-212. [PMID: 23803654 PMCID: PMC3742182 DOI: 10.3390/ijms140713194] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/04/2013] [Accepted: 06/04/2013] [Indexed: 11/16/2022] Open
Abstract
It has been well established that in the oxidative folding of hen egg white lysozyme (HEL), which has four SS linkages in the native state (N), three des intermediates, i.e., des[76-94], des[64-80], and des [6-127], are populated at 20 °C and N is dominantly formed by the oxidation of des[64-80] and des[6-127]. To elucidate the temperature effects, the oxidative folding pathways of HEL were reinvestigated at 5-45 °C in the presence of 2 M urea at pH 8.0 by using a selenoxide reagent, DHSox. When reduced HEL was reacted with 1-4 equivalents of DHSox, 1S, 2S, 3S, and 4S intermediate ensembles with 1-4 SS linkages, respectively, were produced within 1 min. After the oxidation, 3S was slowly converted to the des intermediates with formation of the native structures through SS rearrangement. At 5 °C, des[76-94] was populated in the largest amount, but the oxidation to N was slower than that of des[64-80] and des[6-127]. At 35 °C, on the other hand, des[64-80] and des[6-127] were no longer stable, and only des[76-94] was populated. The results suggested that the major folding pathways of HEL can be switched from one to the other by temperature control.
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23
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Xie JB, Cao Y, Pan H, Qin M, Yan ZQ, Xiong X, Wang W. Photoinduced fibrils formation of chicken egg white lysozyme under native conditions. Proteins 2012; 80:2501-13. [DOI: 10.1002/prot.24132] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/09/2012] [Accepted: 05/25/2012] [Indexed: 11/06/2022]
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24
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Sugimoto H, Noda Y, Segawa SI. NMR analysis of a kinetically trapped intermediate of a disulfide-deficient mutant of the starch-binding domain of glucoamylase. J Mol Biol 2011; 412:304-15. [PMID: 21801731 DOI: 10.1016/j.jmb.2011.07.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 07/07/2011] [Accepted: 07/14/2011] [Indexed: 11/15/2022]
Abstract
A thermally unfolded disulfide-deficient mutant of the starch-binding domain of glucoamylase refolds into a kinetically trapped metastable intermediate when subjected to a rapid lowering of temperature. We attempted to characterise this intermediate using multidimensional NMR spectroscopy. The (1)H-(15)N heteronuclear single quantum coherence spectrum after a rapid temperature decrease (the spectrum of the intermediate) showed good chemical shift dispersion but was significantly different from that of the native state, suggesting that the intermediate adopts a nonnative but well-structured conformation. Large chemical shift changes for the backbone amide protons between the native and the intermediate states were observed for residues in the β-sheet consisting of strands 2, 3, 5, 6, and 7 as well as in the C-terminal region. These residues were found to be in close proximity to aromatic residues, suggesting that the chemical shift changes are mainly due to ring current shifts caused by the aromatic residues. The two-dimensional nuclear Overhauser enhancement (NOE) spectroscopy experiments showed that the intermediate contained substantial, native-like NOE connectivities, although there were fewer cross peaks in the spectrum of the intermediate compared with that of the native state. It was also shown that there were native-like interresidue NOEs for residues buried in the protein, whereas many of the NOE cross peaks were lost for the residues involved in a surface-exposed aromatic cluster. These results suggest that, in the intermediate, the aromatic cluster at the surface is structurally less organised, whereas the interior of the protein has relatively rigid, native-like side-chain packing.
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Affiliation(s)
- Hayuki Sugimoto
- Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
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25
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Sugimoto H, Nakaura M, Nishimura S, Karita S, Miyake H, Tanaka A. Kinetically trapped metastable intermediate of a disulfide-deficient mutant of the starch-binding domain of glucoamylase. Protein Sci 2009; 18:1715-23. [PMID: 19530230 DOI: 10.1002/pro.188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Refolding of a thermally unfolded disulfide-deficient mutant of the starch-binding domain of glucoamylase was investigated using differential scanning calorimetry, isothermal titration calorimetry, CD, and (1)H NMR. When the protein solution was rapidly cooled from a higher temperature, a kinetic intermediate was formed during refolding. The intermediate was unexpectedly stable compared with typical folding intermediates that have short half-lives. It was shown that this intermediate contained substantial secondary structure and tertiary packing and had the same binding ability with beta-cyclodextrin as the native state, suggesting that the intermediate is highly-ordered and native-like on the whole. These characteristics differ from those of partially folded intermediates such as molten globule states. Far-UV CD spectra showed that the secondary structure was once disrupted during the transition from the intermediate to the native state. These results suggest that the intermediate could be an off-pathway type, possibly a misfolded state, that has to undergo unfolding on its way to the native state.
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Affiliation(s)
- Hayuki Sugimoto
- Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan
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26
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Gurbhele-Tupkar MC, Perez LR, Silva Y, Lees WJ. Rate enhancement of the oxidative folding of lysozyme by the use of aromatic thiol containing redox buffers. Bioorg Med Chem 2008; 16:2579-90. [DOI: 10.1016/j.bmc.2007.11.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 11/13/2007] [Accepted: 11/16/2007] [Indexed: 10/22/2022]
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27
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Collins ES, Wirmer J, Hirai K, Tachibana H, Segawa SI, Dobson CM, Schwalbe H. Characterisation of disulfide-bond dynamics in non-native states of lysozyme and its disulfide deletion mutants by NMR. Chembiochem 2006; 6:1619-27. [PMID: 16138305 DOI: 10.1002/cbic.200500196] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This report describes NMR-spectroscopic investigations of the conformational dynamics of disulfide bonds in hen-egg-white lysozyme substitution mutants. The following four systems have been investigated: 2SS(alpha), a lysozyme variant that contains C64A, C76A, C80A and C94A substitutions, was studied in water at pH 2 and 3.8 and in urea (8 M, pH 2); 2SS(beta) lysozyme, which has C6S, C30A, C115A and C127A substitutions, was studied in water (pH 2) and urea (8 M, pH 2). The NMR analysis of heteronuclear 15N-relaxation rates shows that the barrier to disulfide-bond isomerisation can vary substantially in different lysozyme mutants and depends on the residual structure present in these states. The investigations reveal cooperativity in the modulation of micro- to millisecond dynamics that is due to the presence of multiple disulfide bridges in lysozyme. Mutation of cysteines in one of the two structural domains substantially diminishes the barrier to rotational isomerisation in the other domain. However, the interactions between hydrophobic clusters within and across the domains remains intact.
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Affiliation(s)
- Emily S Collins
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Johann Wolfgang Goethe University, Marie-Curie-Strasse 11, 60439 Frankfurt am Main, Germany
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28
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Zhou H, Wang W, Luo Y. Contributions of Disulfide Bonds in a Nested Pattern to the Structure, Stability, and Biological Functions of Endostatin. J Biol Chem 2005; 280:11303-12. [PMID: 15634676 DOI: 10.1074/jbc.m412072200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endostatin can inhibit the proliferation and migration of endothelial cells. It contains two pairs of disulfide bonds in a nested pattern. We constructed three mutants, C33A/C173A, C135A/C165A, and all-Ala, to evaluate the contributions of individual disulfide bonds to the structure, stability, and biological functions of endostatin. Both tryptophan emission fluorescence spectrum and 1H nuclear magnetic resonance spectrum show that C135A/C165A and all-Ala, the two mutants lacking disulfide bond Cys135-Cys165, lost nearly their entire tertiary structure. Although C33A/C173A appears to retain some native-like structures, it is less stable and has a higher helical content, which confirms our earlier hypothesis that the polypeptide backbone of endostatin has a high helical propensity. C135A/C165A and all-Ala mutants lost most of their inhibitory activities both on the migration and proliferation of human microvascular endothelial cells, whereas C33A/C173A is partially active. The mutants without disulfide bond Cys135-Cys165 can hardly be internalized and localized to cytoskeleton and nucleus in the cell, which probably contributes to their loss of inhibition on the migration and proliferation of endothelial cells. Our studies provide a structural basis for the two disulfide bonds on the biological functions of endostatin.
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Affiliation(s)
- Hao Zhou
- Laboratory of Protein Chemistry, Ministry of Education Laboratory of Protein Science, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
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29
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Jarrett NM, Djavadi-Ohaniance L, Willson RC, Tachibana H, Goldberg ME. Immunochemical pulsed-labeling characterization of intermediates during hen lysozyme oxidative folding. Protein Sci 2002; 11:2584-95. [PMID: 12381842 PMCID: PMC2373722 DOI: 10.1110/ps.0221802] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2002] [Revised: 08/13/2002] [Accepted: 08/15/2002] [Indexed: 10/27/2022]
Abstract
Previous studies have shown that reduced hen egg white lysozyme refolds and oxidizes according to a linear model, in which the number of disulfide bonds increases sequentially. In this study, we describe the kinetics of native tertiary structure formation during the oxidative-renaturation of reduced hen egg white lysozyme, as monitored using an immunochemical pulsed-labeling method based on enzyme-linked immunosorbent assay (ELISA) in conjunction with two monoclonal antibodies (mAb). Each of these antibodies recognizes a separate face of the native lysozyme surface and, more importantly, each epitope is composed of discontinuous regions of the polypeptide chain. Renaturation kinetics were studied under the same refolding conditions as previous investigations of the kinetics of the regain of far-UV CD, fluorescence, enzymatic activity, and disulfide bonds. Comparison of our results with the results from those studies showed that the immunoreactivity (i.e., the native fold) of the alpha-domain appeared in intermediates containing two SS bonds only (C6-C127 and C30-C115), while the immunoreactivity of the beta-domain appeared together with the formation of the third SS bond (C64-C80). Thus, the alpha-domain folds before the beta-domain during the oxidative folding of reduced lysozyme.
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Affiliation(s)
- Nicole M Jarrett
- Unité de Repliement et Modélisation des Protéines (CNRS URA 2185), Institut Pasteur, 75254 Paris Cedex 15, France
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