1
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MAREKHA B, Hunger J. A single methyl group drastically changes urea's hydration dynamics. J Chem Phys 2022; 156:164504. [DOI: 10.1063/5.0085461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The amphiphilicity and denaturation efficiency of urea can be tuned via alkylation. Although the interaction of alkylureas with water and proteins has been studied in detail, the hydration of 1-methylurea has remained elusive, precluding the isolation of the effect of an individual methyl group. Here, we study water dynamics in the hydration shell of 1-methylurea (1-MU) using infrared absorption and ultrafast infrared spectroscopies. We find that 1-MU hardly affects the hydrogen-bond distribution of water as probed by the OD stretching vibration of HOD molecules. Polarization resolved infrared pump-probe experiments reveal that 1-MU slows down the rotational dynamics of up to 3 water molecules in its hydration shell. Comparison to earlier results for other alkylureas suggests that further alkylation does not necessarily slow down the rotational dynamics of additional water molecules. Two-dimensional infrared experiments show that 1-MU markedly slows down the hydrogen-bond fluctuation dynamics of water, yet similar to what has been found for urea and dimethylureas. Remarkably, (alkyl-) ureas that share a similar effect on water's hydrogen-bond fluctuation dynamics share a similar (modest) protein denaturation tendency. As such, not only the hydrophobicity but also hydration of hydrophilic fragments of alkylureas may be relevant to explain their function towards biomolecules.
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Affiliation(s)
- Bogdan MAREKHA
- Max-Planck-Institute for Medical Research Department of Biomolecular Mechanisms, Germany
| | - Johannes Hunger
- Molecular Spectroscopy, Max Planck Institute for Polymer Research, Germany
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2
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Sha F, Chen Y, Drout RJ, Idrees KB, Zhang X, Farha OK. Stabilization of an enzyme cytochrome c in a metal-organic framework against denaturing organic solvents. iScience 2021; 24:102641. [PMID: 34151233 PMCID: PMC8192563 DOI: 10.1016/j.isci.2021.102641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/05/2021] [Accepted: 05/20/2021] [Indexed: 01/30/2023] Open
Abstract
Enzymes are promising catalysts with high selectivity and activity under mild reaction conditions. However, their practical application has largely been hindered by their high cost and poor stability. Metal-organic frameworks (MOFs) as host materials show potential in protecting proteins against denaturing conditions, but a systematic study investigating the stabilizing mechanism is still lacking. In this study, we stabilized enzyme cytochrome c (cyt c) by encapsulating it in a hierarchical mesoporous zirconium-based MOF, NU-1000 against denaturing organic solvents. Cyt c@NU-1000 showed a significantly enhanced activity compared to the native enzyme, and the composite retained this enhanced activity after treatment with five denaturing organic solvents. Moreover, the composite was recyclable without activity loss for at least three cycles. Our cyt c@NU-1000 model system demonstrates that enzyme@MOF composites prepared via post-synthetic encapsulation offer a promising route to overcome the challenges of enzyme stability and recyclability that impede the widespread adoption of biocatalysis.
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Affiliation(s)
- Fanrui Sha
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | - Yijing Chen
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | - Riki J. Drout
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | - Karam B. Idrees
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | - Xuan Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | - Omar K. Farha
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
- International Institute for Nanotechnology (IIN), Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
- Department of Chemical & Biological Engineering, Northwestern University, Evanston, IL 60208, USA
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3
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Edmans JG, Murdoch C, Santocildes-Romero ME, Hatton PV, Colley HE, Spain SG. Incorporation of lysozyme into a mucoadhesive electrospun patch for rapid protein delivery to the oral mucosa. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 112:110917. [DOI: 10.1016/j.msec.2020.110917] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/04/2020] [Accepted: 03/31/2020] [Indexed: 11/16/2022]
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4
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Chen Q, Man H, Zhu L, Guo Z, Wang X, Tu J, Jin G, Lou J, Zhang L, Ci L. Enhanced plant antioxidant capacity and biodegradation of phenol by immobilizing peroxidase on amphoteric nitrogen-doped carbon dots. CATAL COMMUN 2020. [DOI: 10.1016/j.catcom.2019.105847] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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5
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Marekha BA, Hunger J. Hydrophobic pattern of alkylated ureas markedly affects water rotation and hydrogen bond dynamics in aqueous solution. Phys Chem Chem Phys 2019; 21:20672-20677. [PMID: 31508638 DOI: 10.1039/c9cp04108g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alkylated ureas are frequently used amphiphiles to mediate biomolecule water interactions, yet their hydrophobic substitution pattern critically affects their function. These differences can be traced back to their hydration, which is poorly understood. Here, we investigate subtle effects of the hydrophobic pattern of ureas on hydration dynamics using a combination of linear and non-linear infrared spectroscopies on the OD stretching vibration of HDO. Isomeric 1,3-dimethylurea (1,3-DMU), 1,1-dimethylurea (1,1-DMU) and 1-ethylurea (1-EU) exhibit very similar and rather weak modulation of the water hydrogen-bond strength distribution. Yet, only 1,3-DMU and 1,1-DMU enhance the hydrogen-bond heterogeneity and slow-down its fluctuation dynamics. In turn, rotational dynamics of water molecules, which is dominated by hydrogen bond switches, is significantly impeded in the presence of 1,3-DMU and only weakly by 1,1-DMU and 1-EU. These marked differences can be explained by both excluded volume effects in hydration and self-aggregation, which may be the key to their biotechnological function.
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Affiliation(s)
- Bogdan A Marekha
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Johannes Hunger
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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6
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Sen S, Udgaonkar JB. Binding-induced folding under unfolding conditions: Switching between induced fit and conformational selection mechanisms. J Biol Chem 2019; 294:16942-16952. [PMID: 31582563 DOI: 10.1074/jbc.ra119.009742] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/14/2019] [Indexed: 12/11/2022] Open
Abstract
The chemistry of protein-ligand binding is the basis of virtually every biological process. Ligand binding can be essential for a protein to function in the cell by stabilizing or altering the conformation of a protein, particularly for partially or completely unstructured proteins. However, the mechanisms by which ligand binding impacts disordered proteins or influences the role of disorder in protein folding is not clear. To gain insight into this question, the mechanism of folding induced by the binding of a Pro-rich peptide ligand to the SH3 domain of phosphatidylinositol 3-kinase unfolded in the presence of urea has been studied using kinetic methods. Under strongly denaturing conditions, folding was found to follow a conformational selection (CS) mechanism. However, under mildly denaturing conditions, a ligand concentration-dependent switch in the mechanism was observed. The folding mechanism switched from being predominantly a CS mechanism at low ligand concentrations to being predominantly an induced fit (IF) mechanism at high ligand concentrations. The switch in the mechanism manifests itself as an increase in the reaction flux along the IF pathway at high ligand concentrations. The results indicate that, in the case of intrinsically disordered proteins too, the folding mechanism is determined by the concentration of the ligand that induces structure formation.
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Affiliation(s)
- Sreemantee Sen
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India Indian Institute of Science Education and Research, Pune, Pashan, Pune 411 008, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India Indian Institute of Science Education and Research, Pune, Pashan, Pune 411 008, India
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7
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Ding B, Yang L, Mukherjee D, Chen J, Gao Y, Gai F. Microscopic Insight into the Protein Denaturation Action of Urea and Its Methyl Derivatives. J Phys Chem Lett 2018; 9:2933-2940. [PMID: 29767523 DOI: 10.1021/acs.jpclett.8b00960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We employ site-specific, linear and nonlinear infrared spectroscopic techniques as well as fluorescence spectroscopy and molecular dynamics simulations to investigate the binding interactions of urea and three of its derivatives, methylurea, 1,3-dimethylurea, and tetramethylurea, with protein aromatic and polar side chains. We find that (1) urea methylation leads to preferential interactions between the cosolvent molecules and aromatic side chains with an affinity that increases with the number of methyl groups; (2) interactions with tetramethylurea cause significant dehydration of aromatic side chains and the effect is most pronounced for tryptophan; and (3) while neither urea nor tetramethylurea shows preferential accumulation around a polar side chain, the number of hydrogen-bond donors around this side chain is significantly decreased in the presence of tetramethylurea. Taken together, our findings suggest that these urea derivatives, especially tetramethylurea, can effectively disrupt hydrophobic interactions in proteins. Additionally, tetramethylurea can promote intramolecular hydrogen-bond formation and hence induce α-helix folding in peptides, as observed.
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Affiliation(s)
| | - Lijiang Yang
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | | | | | - Yiqin Gao
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
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8
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Ahmed A, Shamsi A, Khan MS, Husain FM, Bano B. Methylglyoxal induced glycation and aggregation of human serum albumin: Biochemical and biophysical approach. Int J Biol Macromol 2018; 113:269-276. [PMID: 29481950 DOI: 10.1016/j.ijbiomac.2018.02.137] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/15/2018] [Accepted: 02/22/2018] [Indexed: 11/15/2022]
Abstract
Serum protein glycation and formation of advanced glycation end products (AGEs) correlates with many diseases viz. diabetes signifying the importance of studying the glycation pattern of serum proteins. In our present study, methylglyoxal was investigated for its effect on the structure of human serum albumin (HSA); exploring the formation of AGEs and aggregates of HSA. The analytical tools employed includes intrinsic and extrinsic fluorescence, UV spectroscopy, far UV circular dichroism, Thioflavin T fluorescence, congo red binding, polyacrylamide gel electrophoresis (PAGE). UV and fluorescence spectroscopy revealed the structural transition of native HSA evident by new peaks and increased absorbance in UV spectra and quenched fluorescence in the presence of MG. Far UV CD spectroscopy revealed MG induced secondary structural alteration evident by reduced α-helical content. AGEs formation was confirmed by AGEs specific fluorescence. Increased ThT fluorescence and CR absorbance of 10mM MG incubated HSA suggests that glycated HSA results in the formation of aggregates of HSA. SEM and TEM were reported to have an insight of these aggregates. Molecular docking was also utilized to see site specific interaction of MG-HSA. This study is clinically significant as HSA is a clinically relevant protein which plays a crucial role in many diseases.
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Affiliation(s)
- Azaj Ahmed
- Department of Biochemistry, F/O Life Sciences, Aligarh Muslim University, Aligarh, India
| | - Anas Shamsi
- Department of Biochemistry, F/O Life Sciences, Aligarh Muslim University, Aligarh, India
| | - Mohd Shahnawaz Khan
- Protein Research Chair, Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Fohad Mabood Husain
- Department of Food Science and Nutrition, Faculty of Food and Agricultural Sciences, King Saud University, 2460, Riyadh 11451, Saudi Arabia
| | - Bilqees Bano
- Department of Biochemistry, F/O Life Sciences, Aligarh Muslim University, Aligarh, India.
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9
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10
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Shamsi A, Ahmed A, Bano B. Glyoxal induced structural transition of buffalo kidney cystatin to molten globule and aggregates: Anti-fibrillation potency of quinic acid. IUBMB Life 2016; 68:156-66. [DOI: 10.1002/iub.1471] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 12/20/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Anas Shamsi
- Department of Biochemistry, Faculty of Life Sciences; Aligarh Muslim University; Aligarh Uttar Pradesh India
| | - Azaj Ahmed
- Department of Biochemistry, Faculty of Life Sciences; Aligarh Muslim University; Aligarh Uttar Pradesh India
| | - Bilqees Bano
- Department of Biochemistry, Faculty of Life Sciences; Aligarh Muslim University; Aligarh Uttar Pradesh India
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11
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Chollangi S, Parker R, Singh N, Li Y, Borys M, Li Z. Development of robust antibody purification by optimizing protein-A chromatography in combination with precipitation methodologies. Biotechnol Bioeng 2015; 112:2292-304. [DOI: 10.1002/bit.25639] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 01/17/2023]
Affiliation(s)
- Srinivas Chollangi
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
| | - Ray Parker
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
| | - Nripen Singh
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
| | - Yi Li
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
| | - Michael Borys
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
| | - Zhengjian Li
- Bristol-Myers Squibb; Biologics Development; Global Manufacturing & Supply; Hopkinton Massachusetts
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12
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Amadei A, Marracino P. Theoretical–computational modelling of the electric field effects on protein unfolding thermodynamics. RSC Adv 2015. [DOI: 10.1039/c5ra15605j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this paper we present a general theoretical–computational approach to model the protein unfolding thermodynamics response to intense electric fields.
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Affiliation(s)
- A. Amadei
- Dipartimento di Scienze e Tecnologie Chimiche
- Università degli studi di Roma Tor Vergata
- 00031 Rome
- Italy
| | - P. Marracino
- Dipartimento di Ingegneria dell'Informazione
- Elettronica e Telecomunicazioni
- Sapienza Universitaà di Roma
- 00184 Rome
- Italy
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13
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Kim SJ, Joo JC, Kim HS, Kwon I, Song BK, Yoo YJ, Kim YH. Development of the radical-stable Coprinus cinereus peroxidase (CiP) by blocking the radical attack. J Biotechnol 2014; 189:78-85. [DOI: 10.1016/j.jbiotec.2014.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/23/2014] [Accepted: 08/27/2014] [Indexed: 11/26/2022]
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14
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Wei H, Xie J, Jiang X, Ye T, Chang A, Wu W. Synthesis and Characterization of Dextran–Tyramine-Based H2O2-Sensitive Microgels. Macromolecules 2014. [DOI: 10.1021/ma5013368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hua Wei
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, The Key Laboratory
for Chemical Biology of Fujian Province, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Jianda Xie
- School
of Materials Science and Engineering, Xiamen University of Technology, Xiamen 361024, Fujian, China
| | - Xiaomei Jiang
- Clinical
Laboratory, Huli Center for Maternal and Child Health, Xiamen 361009, Fujian, China
| | - Ting Ye
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, The Key Laboratory
for Chemical Biology of Fujian Province, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Aiping Chang
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, The Key Laboratory
for Chemical Biology of Fujian Province, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Weitai Wu
- State
Key Laboratory for Physical Chemistry of Solid Surfaces, The Key Laboratory
for Chemical Biology of Fujian Province, and Department of Chemistry,
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
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15
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Amani S, Shamsi A, Rabbani G, Naim A. An insight into the biophysical characterization of insoluble collagen aggregates: implication for arthritis. J Fluoresc 2014; 24:1423-31. [PMID: 25011697 DOI: 10.1007/s10895-014-1424-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 06/23/2014] [Indexed: 11/25/2022]
Abstract
Misfolding and aggregation of proteins is involved in some of the most prevalent neurodegenerative disorders. The importance of collagen stems from the fact that it is one of the dominant component used for tissue engineering and drug delivery applications and is a major component of skin, tendon, bone and other connective tissues. A systematic investigation on the conformation of collagen at various concentrations of glyoxal is studied by various biophysical techniques such as Trp fluorescence, ANS binding, Circular dichroism (CD), ATR-FTIR, Congo red (CR) assay, Rayleigh light scattering and Turbidity measurements. At 60% (v/v) glyoxal, collagen retains native-like secondary structure, altered Trp environment and high ANS fluorescence, characteristic of molten globule (MG) state. At 80% (v/v) glyoxal, insoluble collagen aggregates are detected as confirmed by decrease in Trp and ANS fluorescence, increase in non-native β sheet structure as evident from far-UV CD and FTIR spectra, increase in Thioflavin T fluorescence, Rayleigh light scattering, Turbidity measurements, as well as red shift in CR absorbance.
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Affiliation(s)
- Samreen Amani
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India
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16
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Zheng J, Xu JL, Jin TBH, Wang JL, Zhang WQ, Hu YX, He PG, Fang YZ. Preparation of Magnetic Ordered Mesoporous Carbon Composite and Its Application in Direct Electrochemistry of Horseradish Peroxidase. ELECTROANAL 2013. [DOI: 10.1002/elan.201300220] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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17
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Kamal MZ, Yedavalli P, Deshmukh MV, Rao NM. Lipase in aqueous-polar organic solvents: activity, structure, and stability. Protein Sci 2013; 22:904-15. [PMID: 23625694 DOI: 10.1002/pro.2271] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 11/06/2022]
Abstract
Studying alterations in biophysical and biochemical behavior of enzymes in the presence of organic solvents and the underlying cause(s) has important implications in biotechnology. We investigated the effects of aqueous solutions of polar organic solvents on ester hydrolytic activity, structure and stability of a lipase. Relative activity of the lipase monotonically decreased with increasing concentration of acetone, acetonitrile, and DMF but increased at lower concentrations (upto ~20% v/v) of dimethylsulfoxide, isopropanol, and methanol. None of the organic solvents caused any appreciable structural change as evident from circular dichorism and NMR studies, thus do not support any significant role of enzyme denaturation in activity change. Change in 2D [15N, 1H]-HSQC chemical shifts suggested that all the organic solvents preferentially localize to a hydrophobic patch in the active-site vicinity and no chemical shift perturbation was observed for residues present in protein's core. This suggests that activity alteration might be directly linked to change in active site environment only. All organic solvents decreased the apparent binding of substrate to the enzyme (increased Km ); however significantly enhanced the kcat . Melting temperature (Tm ) of lipase, measured by circular dichroism and differential scanning calorimetry, altered in all solvents, albeit to a variable extent. Interestingly, although the effect of all organic solvents on various properties on lipase is qualitatively similar, our study suggest that magnitudes of effects do not appear to follow bulk solvent properties like polarity and the solvent effects are apparently dictated by specific and local interactions of solvent molecule(s) with the protein.
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Affiliation(s)
- Md Zahid Kamal
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
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18
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Sun W, Guo Y, Lu Y, Hu A, Shi F, Li T, Sun Z. Electrochemical biosensor based on graphene, Mg2Al layered double hydroxide and hemoglobin composite. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2012.12.088] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Park BW, Ko KA, Yoon DY, Kim DS. Enzyme activity assay for horseradish peroxidase encapsulated in peptide nanotubes. Enzyme Microb Technol 2012; 51:81-5. [DOI: 10.1016/j.enzmictec.2012.04.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 04/04/2012] [Accepted: 04/16/2012] [Indexed: 11/16/2022]
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20
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Zhan T, Guo Y, Xu L, Zhang W, Sun W, Hou W. Electrochemistry and electrocatalysis of myoglobin intercalated in Mg2Al–Cl layered double hydroxide and ionic liquid composite material. Talanta 2012; 94:189-94. [DOI: 10.1016/j.talanta.2012.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 03/03/2012] [Accepted: 03/06/2012] [Indexed: 11/15/2022]
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21
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Acetonitrile can promote formation of different structural intermediate states on aggregation pathway of immunoglobulin G from human and bovine. Int J Biol Macromol 2011; 49:71-8. [DOI: 10.1016/j.ijbiomac.2011.03.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Revised: 03/23/2011] [Accepted: 03/23/2011] [Indexed: 11/17/2022]
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22
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Meyer-Ilse J, Akimov D, Dietzek B. Femtosecond Coherence Spectroscopic Study of the Onset of Chemical Denaturation of Myoglobin upon Addition of Minor Amounts of Urea. Z PHYS CHEM 2011. [DOI: 10.1524/zpch.2011.0082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AbstractThe interaction of urea with myoglobin, as a benchmark system for heme-containing proteins, is studiedviafemtosecond coherence spectroscopy. The work focuses on the effect of urea on the appearance of low-wavenumber oscillations, which are a measure of the geometrical structure of the heme group and its interaction with the polypeptide chain. Pursuing this approach, structural alterations (i.e.changes in the vibrational dynamics of the heme group) are detected at denaturant concentrations below the full denaturation limit of 6 M urea for myoglobin. In particular, the low-wavenumber oscillation associated with the heme-doming (i.e.the out-off-plane vibration of the propyrin macrocycle) is found to appear spectrally shifted with a concentration of only 3 M urea. These results suggest that the local environment around the heme is already altered despite the fact that macroscopic unfolding as manifested in the thermodynamic properties of the polypeptide chain is not complete at these urea concentrations.
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Affiliation(s)
- Julia Meyer-Ilse
- Friedrich-Schiller-Univesrität Jena, Institute of Physical Chemistry, Jena, Deutschland
| | - Denis Akimov
- Institute of Photonic Technology Jena e.V., Jena, Deutschland
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23
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Electrochemical detection of phenolic compounds using composite film of multiwall carbon nanotube/surfactant/tyrosinase on a carbon paste electrode. J Solid State Electrochem 2011. [DOI: 10.1007/s10008-011-1355-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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24
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Direct electrochemistry and electrocatalysis of myoglobin immobilized on Fe2O3 nanoparticle–sodium alginate–ionic liquid composite-modified electrode. J Colloid Interface Sci 2010; 346:188-93. [DOI: 10.1016/j.jcis.2010.02.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/31/2010] [Accepted: 02/04/2010] [Indexed: 11/18/2022]
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25
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Xu H, Xiong HY, Zeng QX, Jia L, Wang Y, Wang SF. Direct electrochemistry and electrocatalysis of heme proteins immobilized in single-wall carbon nanotubes-surfactant films in room temperature ionic liquids. Electrochem commun 2009. [DOI: 10.1016/j.elecom.2008.11.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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26
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Zhang Y, Zheng J. Direct electrochemistry and electrocatalysis of myoglobin immobilized in hyaluronic acid and room temperature ionic liquids composite film. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2008.07.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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27
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Non-ionic Surfactants and Non-Catalytic Protein Treatment on Enzymatic Hydrolysis of Pretreated Creeping Wild Ryegrass. Appl Biochem Biotechnol 2007; 146:231-48. [DOI: 10.1007/s12010-007-8035-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 08/27/2007] [Indexed: 11/24/2022]
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28
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Ding SF, Wei W, Zhao GC. Direct electrochemical response of cytochrome c on a room temperature ionic liquid, N-butylpyridinium tetrafluoroborate, modified electrode. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.06.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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29
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Bao Z, Wang S, Shi W, Dong S, Ma H. Selective modification of Trp19 in beta-lactoglobulin by a new diazo fluorescence probe. J Proteome Res 2007; 6:3835-41. [PMID: 17705525 DOI: 10.1021/pr070284n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To obtain the local information on the tryptophan domain in a protein, the design and synthesis of a new fluorescent probe, 1,7-bis(4-hydroxy-3-methoxyphenyl)-4-diazo-1,6-heptadiene-3,5-dione, is reported for the selective modification of tryptophan residues. The probe comprises a curcumin fluorophore and a diazo labeling group, whose spectroscopic properties are characterized. The diazo group may be catalytically degraded by transition metal complexes such as Rh2(OAc)4, generating an active rhodium carbenoid intermediate, which can react selectively with tryptophan residues. By the use of the carbene's intermolecular reactions, the tryptophan residue (Trp19) of beta-lactoglobulin may be modified with the diazo curcumin probe. Furthermore, slight secondary but larger tertiary structural changes are detected after Trp19 is modified, and the Trp19 modification produces a great effect on the binding of 8-anilino-1-naphthalenesulfonic acid and retinol. These results indicate that the Trp19 residue plays an essential role in the structure and stability of beta-lactoglobulin, and the specific modification of this residue may have a potential use in further elucidating the relationship between the structure and function of the protein.
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Affiliation(s)
- Zhijuan Bao
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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30
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Activity and stability of horseradish peroxidase in hydrophilic room temperature ionic liquid and its application in non-aqueous biosensing. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.01.042] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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31
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Chen H, Wang Y, Liu Y, Wang Y, Qi L, Dong S. Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in Nafion-RTIL composite film. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2006.10.019] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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32
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Wang SF, Chen T, Zhang ZL, Shen XC, Lu ZX, Pang DW, Wong KY. Direct electrochemistry and electrocatalysis of heme proteins entrapped in agarose hydrogel films in room-temperature ionic liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:9260-6. [PMID: 16171360 DOI: 10.1021/la050947k] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The electrochemistry and electrocatalysis of a number of heme proteins entrapped in agarose hydrogel films in the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) have been investigated. UV-vis and FTIR spectroscopy show that the heme proteins retain their native structure in agarose film. The uniform distribution of hemoglobin in agarose-dimethylformamide film was demonstrated by atomic force microscopy. Cyclic voltammetry shows that direct electron transfer between the heme proteins and glassy carbon electrode is quasi-reversible in [bmim][PF(6)]. The redox potentials for hemoglobin, myoglobin, horseradish peroxidase, cytochrome c, and catalase were found to be more negative than those in aqueous solution. The charge-transfer coefficient and the apparent electron-transfer rate constant for these heme proteins in [bmim][PF(6)] were calculated from the peak-to-peak separation as a function of scan rate. The heme proteins catalyze the electroreduction of trichloroacetic acid and tert-butyl hydroperoxide in [bmim][PF(6)]. The kinetic parameter I(max) (maximum current at saturation concentration of substrate) and the apparent K(m) (Michaelis-Menten constant) for the electrocatalytic reactions were evaluated.
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Affiliation(s)
- Sheng-Fu Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
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33
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Panchagnula V, Kumar CV, Rusling JF. Ultrathin layered myoglobin-polyion films functional and stable at acidic pH values. J Am Chem Soc 2002; 124:12515-21. [PMID: 12381195 DOI: 10.1021/ja020683d] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cross-linking of myoglobin (Mb) promoted by 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide within films of polystyrene sulfonate after layer-by-layer self-assembly provided remarkable stabilization. Cross-linking greatly improved adhesion of the films to fused silica slides and allowed extensive optical studies over a wide pH range. Circular dichroism and visible absorbance spectra showed that Mb retained its native conformation when films were placed in solutions of pH as low as 2 and up to pH 11. Linear dichroism revealed an average orientation of the Mb iron heme cofactors of 58 degrees to the film normal. High concentrations of urea did denature the protein in the films, however. At pH 1, Mb in solution is fully unfolded but retained considerable alpha-helical content in the cross-linked films. Both the polyion film environment and cross-linking seem to play roles in stabilizing protein secondary structure and function at low pH. Cross-linked myoglobin-polyion films on pyrolytic graphite electrodes were used in strongly acidic solutions for the electrochemical catalytic reduction of trichloracetic acid, hydrogen peroxide, and oxygen. The pH-dependent catalytic reduction of trichloracetic acid was faster in 0.1 M HCl than in the medium pH range.
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Affiliation(s)
- Venkateswarlu Panchagnula
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, Connecticut 06269, USA
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34
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Dikshit KL, Raje M. Optimization of immunogold labeling TEM. An ELISA-based method for rapid and convenient simulation of processing conditions for quantitative detection of antigen. J Histochem Cytochem 2001; 49:355-68. [PMID: 11181739 DOI: 10.1177/002215540104900310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We developed an ELISA-based method for rapid optimization of various tissue processing parameters in immunogold labeling for electron microscopy. The effects of aldehyde fixation, tannic acid, postfixation, dehydration, temperature, and antigen retrieval on antibody binding activity of Vitreoscilla hemoglobin (VHb) expressed in E. coli cells were assayed by ELISA and the results confirmed by quantitative immunogold labeling transmission electron microscopy (TEM). Our results demonstrated that low concentrations (0.2%) of glutaraldehyde fixation caused minimal loss in total binding compared to higher concentrations. Dehydration in up to 70% ethanol resulted in some distortion of cellular ultrastructure but better antibody binding activity compared to dehydration up to 100%. Postfixation or incorporation of tannic acid in the primary fixative caused almost total loss of activity, whereas antigen retrieval of osmium-postfixed material resulted in approximately 90-100% recovery. The sensitivity of detection of proteins by immunogold labeling electron microscopy depends on the retention of antibody binding activity during tissue processing steps, e.g., fixation and dehydration. Our study indicated that an ELISA-based screening method of various tissue processing procedures could help in rapid selection and optimization of a suitable protocol for immunogold localization and quantification of antigen by TEM.
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35
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Wang ZQ, Wang YH, Qian W, Wang HH, Chunyu LJ, Xie Y, Huang ZX. Methanol-induced unfolding and refolding of cytochrome b5 and its P40V mutant monitored by UV-visible, CD, and fluorescence spectra. JOURNAL OF PROTEIN CHEMISTRY 1999; 18:547-55. [PMID: 10524772 DOI: 10.1023/a:1020699200092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In order to illustrate the structural importance of proline-40 of cytochrome b5 (Cyt b5), the P40V mutant gene was constructed. Unfolding and refolding of Cyt b5 induced by methanol was investigated by means of the UV-visible spectrum, circular dichroism, and the fluorescence spectrum. Methanol denaturation of Cyt b5 is a cooperative process, that is, the heme group dissociates from the heme pocket accompanied by unfolding of the polypeptide chain both in the secondary and tertiary structures. Substitution of proline by valine reduces the stability of the mutant under methanol denaturation. The unfolding process is almost reversible by dilution. During refolding, the denatured polypeptide must be folded to a more ordered structure prior to the heme capture. Pro40 plays an important role in modulating the protein's stability. The role of tyrosine in the unfolding and refolding of Cyt b5 is evaluated for the first time. A mechanism of methanol denaturation is also proposed.
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Affiliation(s)
- Z Q Wang
- Chemistry Department, Fudan University, Shanghai, China
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36
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Lvov YM, Lu Z, Schenkman JB, Zu X, Rusling JF. Direct Electrochemistry of Myoglobin and Cytochrome P450cam in Alternate Layer-by-Layer Films with DNA and Other Polyions. J Am Chem Soc 1998. [DOI: 10.1021/ja9737984] [Citation(s) in RCA: 416] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuri M. Lvov
- Contribution from the Chemistry Department, U-60, University of Connecticut, Storrs, Connecticut 06269-4060, and Department of Pharmacology, University of Connecticut Health Center, Farmington, Connecticut 06032
| | - Zhongqing Lu
- Contribution from the Chemistry Department, U-60, University of Connecticut, Storrs, Connecticut 06269-4060, and Department of Pharmacology, University of Connecticut Health Center, Farmington, Connecticut 06032
| | - John B. Schenkman
- Contribution from the Chemistry Department, U-60, University of Connecticut, Storrs, Connecticut 06269-4060, and Department of Pharmacology, University of Connecticut Health Center, Farmington, Connecticut 06032
| | - Xiaolin Zu
- Contribution from the Chemistry Department, U-60, University of Connecticut, Storrs, Connecticut 06269-4060, and Department of Pharmacology, University of Connecticut Health Center, Farmington, Connecticut 06032
| | - James F. Rusling
- Contribution from the Chemistry Department, U-60, University of Connecticut, Storrs, Connecticut 06269-4060, and Department of Pharmacology, University of Connecticut Health Center, Farmington, Connecticut 06032
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37
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Remmele RL, Nightlinger NS, Srinivasan S, Gombotz WR. Interleukin-1 receptor (IL-1R) liquid formulation development using differential scanning calorimetry. Pharm Res 1998; 15:200-8. [PMID: 9523304 DOI: 10.1023/a:1011902215383] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE To elucidate the solution conditions that confer stability of aqueous IL-1R using differential scanning calorimetry (DSC). METHODS Optimal pH conditions were determined by monitoring degradation products encountered during accelerated studies (at elevated temperatures) using SDS-PAGE. At the pH optimum, DSC screened for excipients that enhanced thermal stability by shifting the Tm to higher values. Using SEC the relationship between thermal unfolding and stability was investigated by considering if lower Tm's in the presence of preservatives correlated with degradation products at 37 degrees C over time. The degree of aggregation relative to that of a control determined the level of stability achieved. RESULTS Circular dichroism (CD) measurements confirmed molecular modeling studies showing IL-1R to be about 39% beta-sheet. Two major transitions characterized the DSC data with Tm's observed near 47 degrees C and 66 degrees C. Among 21 excipients screened, NaCl exhibited the greatest stabilizing influences based on shifting the low temperature transition to 53 degrees C. The low temperature transition was later found to comprise two transitions, yielding a total of three melting transitions for IL-1R. High Tm's arising from the presence of preservatives correlated with the order of stability (i.e., 0.065% phenol > 0.1% m-Cresol > 0.9% benzyl alcohol). CONCLUSIONS The three melting transitions are consistent in origin with the cooperative unfolding of three unique immunoglobulin-like domains of IL-1R. Optimal stability was achieved in 20 mM sodium citrate at pH 6 with sufficient NaCl to attain the tonicity of human serum. A correlation between the predicted ranking of stability and the extent of aggregation was demonstrated using DSC.
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Affiliation(s)
- R L Remmele
- Immunex Corporation, Seattle, WA 98101, USA.
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38
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39
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Nassar AEF, Zhang Z, Hu N, Rusling JF, Kumosinski TF. Proton-Coupled Electron Transfer from Electrodes to Myoglobin in Ordered Biomembrane-like Films. J Phys Chem B 1997. [DOI: 10.1021/jp962896t] [Citation(s) in RCA: 208] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alaa-Eldin F. Nassar
- Department of Chemistry, Box U-60, University of Connecticut, Storrs, Connecticut 06269-4060
| | - Zhe Zhang
- Department of Chemistry, Box U-60, University of Connecticut, Storrs, Connecticut 06269-4060
| | - Naifei Hu
- Department of Chemistry, Box U-60, University of Connecticut, Storrs, Connecticut 06269-4060
| | - James F. Rusling
- Department of Chemistry, Box U-60, University of Connecticut, Storrs, Connecticut 06269-4060
| | - Thomas F. Kumosinski
- Eastern Regional Research Center, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118
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40
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Zhang Z, Rusling JF. Electron transfer between myoglobin and electrodes in thin films of phosphatidylcholines and dihexadecylphosphate. Biophys Chem 1997; 63:133-46. [PMID: 9108688 DOI: 10.1016/s0301-4622(96)02216-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Myoglobin (Mb) in thin films of phosphatidyl cholines (PC) or dihexadecyl phosphate (DHP) gave direct, reversible electron transfer between pyrolytic graphite electrodes and the heme Fe(III)/Fe(II) redox couple of the protein. PC films incorporated much more Mb than DHP films. A model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fit square-wave voltammetric data at pulse heights > 50 mV. Electron transfer rate constants in PC and DHP films were significantly larger than for Mb in thin films of an insoluble cationic surfactant. The pH dependence of the formal potential of Mb in the PC films suggested that protonation, possibly inducing conformational change, accompanies electron transfer to MbFe(III) between pH 5 and 11. Mb in PC films was used for catalysis of the reduction of trichloroacetic acid.
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Affiliation(s)
- Z Zhang
- Department of Chemistry, University of Connecticut, Storrs 06268-4060, USA
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41
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Glandières JM, Calmettes P, Martel P, Zentz C, Massat A, Ramstein J, Alpert B. Solvent-induced structural distortions of horse metmyoglobin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 227:241-8. [PMID: 7851391 DOI: 10.1111/j.1432-1033.1995.tb20381.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Structural and dynamic constraints produced by the surrounding solvent on the aquometmyoglobin molecule were investigated by means of circular dichroism and Fourier-transform infrared spectroscopies, tritium/hydrogen exchange kinetics and small-angle neutron-scattering experiments. Formamide and ethanol were chosen as cosolvents because they are known to increase and decrease protein activity, respectively. The CD measurements in the Soret region show that no changes occur in the heme molecular structure nor in the protein near the heme. The results of proton-exchange kinetics experiments indicate that the conformational dynamics of aquometmyoglobin is only marginally affected by the cosolvents. However, the small-angle neutron-scattering spectra strongly suggest that these cosolvents induce some distortions of the tertiary conformation. According to the ultraviolet CD and Fourier-transform infrared data, the alteration of the tertiary conformation results from changes in both the number of intrachain hydrogen bonds and the structures of beta turns of type I' for formamide and of type II for either of the two cosolvents. The use of several techniques allows the present approach to demonstrates that the myoglobin structure is extremely sensitive to its environmental conditions.
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Affiliation(s)
- J M Glandières
- Laboratoire de Biologie Physico-Chimique, Université de Paris, France
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43
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Vazquez-Duhalt R, Semple KM, Westlake DW, Fedorak PM. Effect of water-miscible organic solvents on the catalytic activity of cytochrome c. Enzyme Microb Technol 1993; 15:936-43. [PMID: 7764253 DOI: 10.1016/0141-0229(93)90169-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of five water-miscible organic solvents (tetrahydrofuran, N,N-dimethylformamide, acetonitrile, 2-propanol, and methanol) on the oxidation of pinacyanol chloride (Quinaldine Blue) by horse heart cytochrome c was determined. Hydrogen peroxide was used as the oxidant, and a change in catalytic property of the dissolved protein was observed after a certain threshold concentration of the organic solvent had been reached. The maximum specific activity was correlated with the Dimroth-Reichardt parameter for the solvents, which is directly related to the free energy of the solvation process. The kinetic constants for the oxidation of pinacyanol chloride were determined in systems containing different proportions of tetrahydrofuran. The best catalytic efficiency (kcat/KM,app) was obtained in a system containing 50% tetrahydrofuran in phosphate buffer. In a mixture containing 90% tetrahydrofuran, cytochrome c showed 18% of its maximum activity. The inactivation of cytochrome c was mainly due to the presence of hydrogen peroxide, and a direct correlation was found between the inactivation constant and the concentration of hydrogen peroxide in the system. The chemical modifications and immobilization of cytochrome c were able to change its biocatalytic activity and stability in the organic solvent system. The kinetic constants and the inactivation of three other type c cytochromes, from Saccharomyces cerevisiae, Pseudomonas aeruginosa, and Desulfovibrio vulgaris Hildenborough in a system containing 90% tetrahydrofuran were compared with those of cytochrome c from horse heart. Cytochrome c551 from P. aeruginosa showed the best stability against hydrogen peroxide and a higher catalytic efficiency than that of horse heart cytochrome c.
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Affiliation(s)
- R Vazquez-Duhalt
- Department of Microbiology, University of Alberta, Edmonton, Canada
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44
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Khmelnitsky YL, Mozhaev VV, Belova AB, Sergeeva MV, Martinek K. Denaturation capacity: a new quantitative criterion for selection of organic solvents as reaction media in biocatalysis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 198:31-41. [PMID: 1645649 DOI: 10.1111/j.1432-1033.1991.tb15983.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The process of reversible denaturation of several proteins (alpha-chymotrypsin, trypsin, laccase, chymotrypsinogen, cytochrome c and myoglobin) by a broad series of organic solvents of different nature was investigated using both our own and literature data, based on the results of kinetic and spectroscopic measurements. In all systems studied, the denaturation proceeded in a threshold manner, i.e. an abrupt change in catalytic and/or spectroscopic properties of dissolved proteins was observed after a certain threshold concentration of the organic solvent had been reached. To account for the observed features of the denaturation process, a thermodynamic model of the reversible protein denaturation by organic solvents was developed, based on the widely accepted notion that an undisturbed water shell around the protein globule is a prerequisite for the retention of the native state of the protein. The quantitative treatment led to the equation relating the threshold concentration of the organic solvent with its physicochemical characteristics, such as hydrophobicity, solvating ability and molecular geometry. This equation described well the experimental data for all proteins tested. Based on the thermodynamic model of protein denaturation, a novel quantitative parameter characterizing the denaturing strength of organic solvents, called the denaturation capacity (DC), was suggested. Different organic solvents, arranged according to their DC values, form the DC scale of organic solvents which permits theoretical prediction of the threshold concentration of any organic solvent for a given protein. The validity of the DC scale for this kind of prediction was verified for all proteins tested and a large number of organic solvents. The experimental data for a few organic solvents, such as formamide and N-methylformamide, did not comply with equations describing the denaturation model. Such solvents form the group of so-called 'bad' solvents; reasons for the occurrence of 'bad' solvents are not yet clear. The DC scale was further extended to include also highly nonpolar solvents, in order to explain the well-known ability of enzymes to retain catalytic activity and stability in biphasic systems of the type water/water-immiscible organic solvent. It was quantitatively demonstrated that this ability is accounted for by the simple fact that nonpolar solvents are not sufficiently soluble in water to reach the inactivation threshold concentration.
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Mozhaev VV, Khmelnitsky YL, Sergeeva MV, Belova AB, Klyachko NL, Levashov AV, Martinek K. Catalytic activity and denaturation of enzymes in water/organic cosolvent mixtures. Alpha-chymotrypsin and laccase in mixed water/alcohol, water/glycol and water/formamide solvents. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 184:597-602. [PMID: 2806243 DOI: 10.1111/j.1432-1033.1989.tb15055.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The dependence of the catalytic activities of alpha-chymotrypsin and laccase on the concentration of organic cosolvents (alcohols, glycols and formamides) in mixed aqueous media has a pronounced threshold character: it does not change up to a critical concentration of the non-aqueous cosolvents added, yet further increase of the latter (by only a small percentage, by vol.) leads to an abrupt decrease in enzyme activity. Fluorescence studies indicate that the inactivation results from reversible conformational changes (denaturation) of the enzymes. There is a linear correlation between the critical concentration of residual water (at which the enzyme inactivation occurs in a threshold manner) and the hydrophobicity of the organic cosolvents added. A quantitative criterion is suggested for the selection of organic cosolvents to be used for enzymatic reactions in homogeneous water/organic solvent media.
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Affiliation(s)
- V V Mozhaev
- Chemistry Department, Moscow State University, USSR
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46
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Khmelnitsky Y, Levashov A, Klyachko N, Martinek K. Engineering biocatalytic systems in organic media with low water content. Enzyme Microb Technol 1988. [DOI: 10.1016/0141-0229(88)90115-9] [Citation(s) in RCA: 261] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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47
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Murakami K. Kinetics of the Denaturation of Ovalbumin and S-Ovalbumin by Alcohols. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1988. [DOI: 10.1246/bcsj.61.3043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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48
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Jager J, Engberts JB. Effects of aqueous non-electrolytes on the compact coil → random coil conformational transition of poly(methacrylic acid). Eur Polym J 1987. [DOI: 10.1016/0014-3057(87)90001-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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49
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Zerovnik E, Lapanje S. Interactions of myoglobin with urea and some alkylureas. I. Solvation in urea and alkylurea solutions. Biophys Chem 1986; 24:53-9. [PMID: 3741989 DOI: 10.1016/0301-4622(86)85059-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The interactions of myoglobin with urea, methyl-, N,N'-dimethyl- and ethylurea in aqueous solutions were studied by density measurements. From the densities at constant chemical potential and constant molality, the partial specific volumes of myoglobin in these solutions as well as the extent of preferential binding of urea and alkylurea to myoglobin were determined. It has been found that water and not the denaturant is preferentially bound in urea solutions and alkylurea solutions up to 4 M so that the Gibbs free energy of myoglobin, i.e., its chemical potential in a denaturant solution, is larger than in water. This behavior of myoglobin is different from that of other globular proteins for which preferential binding of urea has been found. It appears that preferential hydration of myoglobin is due to its high content of ionic groups.
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50
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Guillochon D, Esclade L, Thomas D. Effect of glutaraldehyde on haemoglobin: oxidation-reduction potentials and stability. Biochem Pharmacol 1986; 35:317-23. [PMID: 3080007 DOI: 10.1016/0006-2952(86)90532-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Glutaraldehyde is a reagent widely used for the cross-linking of haemoglobin for use as a blood substitute. Most of the previous studies were limited to oxygen binding equilibria of the glutaraldehyde-modified haemoglobin. This paper concerns the impact of glutaraldehyde on oxidation-reduction equilibria, autoxidation kinetics and stability towards heat and urea of haemoglobin cross-linked in the oxy, deoxy and ferri states. The oxidation-reduction potentials and homotropic effects were reduced; however, the oxidation Bohr effect was not significantly different when compared with native haemoglobin. Haemoglobin immobilized in the oxy or ferri state exhibited a lower redox potential than when immobilized in the deoxy state. The autoxidation rates were increased after cross-linking, particularly at basic pH. Cross-linking stabilizes ferrihaemoglobin better than oxy or deoxyhaemoglobin against thermal- and urea-induced denaturation. Glutaraldehyde cross-linking does not stabilize haemoglobin against urea-denaturation. The experimental results were interpreted as indicating a chemical modification of the protein without 'conformation freezing' and by an opening of the haem pocket to the aqueous solvent.
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