1
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Kitamura K, Oshima A, Sasaki F, Shiramasa Y, Yamamoto R, Kameda T, Kitazawa S, Kitahara R. Modulation of Biomolecular Liquid-Liquid Phase Separation by Preferential Hydration and Interaction of Small Osmolytes with Proteins. J Phys Chem Lett 2024; 15:7620-7627. [PMID: 39029245 DOI: 10.1021/acs.jpclett.4c01365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
We examined the effects of trimethylamine N-oxide (TMAO) and urea (known osmolytes) on the liquid-liquid phase separation (LLPS) of fused in sarcoma (FUS) and three FUS-LLPS states: LLPS states at atmospheric pressure with low- and high-salt concentrations and a re-entrant LLPS state above 2 kbar. Temperature- and pressure-scan turbidity measurements revealed that TMAO and urea contributed to stabilizing and destabilizing LLPS, respectively. These results can be attributed to the excluded volume effect of TMAO (preferential hydration) and preferential interaction of urea with proteins. Additionally, TMAO counteracted the effects of equimolar urea on LLPS, a phenomenon not previously reported. The concept of the m-value for osmolyte-induced protein folding and unfolding can be applied to the osmolyte's effects on LLPS. In conclusion, biomolecular LLPS can be modulated by preferential hydration and the interaction of small osmolytes with proteins, thereby facilitating LLPS formation, even in extreme environments characterized by high-salt, high-urea, and high-pressure conditions.
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Affiliation(s)
- Keiji Kitamura
- Graduate School of Pharmacy, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Ayano Oshima
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Fuka Sasaki
- Graduate School of Pharmacy, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Yutaro Shiramasa
- Graduate School of Pharmacy, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Ryu Yamamoto
- Graduate School of Pharmacy, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Tomoshi Kameda
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26, Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Soichiro Kitazawa
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Ryo Kitahara
- Graduate School of Pharmacy, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
- College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
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2
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Negi KS, Das N, Khan T, Sen P. Osmolyte induced protein stabilization: modulation of associated water dynamics might be a key factor. Phys Chem Chem Phys 2023; 25:32602-32612. [PMID: 38009208 DOI: 10.1039/d3cp03357k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
The mechanism of protein stabilization by osmolytes remains one of the most important and long-standing puzzles. The traditional explanation of osmolyte-induced stability through the preferential exclusion of osmolytes from the protein surface has been seriously challenged by the observations like the concentration-dependent reversal of osmolyte-induced stabilization/destabilization. The more modern explanation of protein stabilization/destabilization by osmolytes considers an indirect effect due to osmolyte-induced distortion of the water structure. It provides a general mechanism, but there are numerous examples of protein-specific effects, i.e., a particular osmolyte might stabilize one protein, but destabilize the other, that could not be rationalized through such an explanation. Herein, we hypothesized that osmolyte-induced modulation of associated water might be a critical factor in controlling protein stability in such a medium. Taking different osmolytes and papain as a protein, we proved that our proposal could explain protein stability in osmolyte media. Stabilizing osmolytes rigidify associated water structures around the protein, whereas destabilizing osmolytes make them flexible. The strong correlation between the stability and the associated water dynamics, and the fact that such dynamics are very much protein specific, established the importance of considering the modulation of associated water structures in explaining the osmolyte-induced stabilization/destabilization of proteins. More interestingly, we took another protein, bromelain, for which a traditionally stabilizing osmolyte, sucrose, acts as a stabilizer at higher concentrations but as a destabilizer at lower concentrations. Our proposal successfully explains such observations, which is probably impossible by any known mechanisms. We believe this report will trigger much research in this area.
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Affiliation(s)
- Kuldeep Singh Negi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh, India.
| | - Nilimesh Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh, India.
| | - Tanmoy Khan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh, India.
| | - Pratik Sen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh, India.
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3
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Malik R, Chandra A. Counteracting Effects of Trimethylamine N-Oxide against Urea in Aqueous Solutions: Insights from Theoretical Two-Dimensional Infrared Spectroscopy. J Phys Chem B 2023; 127:7372-7383. [PMID: 37566900 DOI: 10.1021/acs.jpcb.3c03864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
The study of small osmolytes in their aqueous solutions has gained significant attention because of their relevance to structure and thermodynamics of proteins in aqueous media. Special attention has been given to the binary and ternary aqueous solutions of urea and trimethylamine N-oxide (TMAO). Urea is a well-known protein denaturant, while TMAO protects proteins in their native states. Interestingly, TMAO counteracts urea's ability to denature proteins when present in solutions with approximately half of the concentration of urea. Vibrational spectroscopy can improve our understanding of the molecular origin of this counteracting effect because of its sensitivity to local structure and dynamics. We present results of theoretical linear vibrational and two-dimensional infrared (2DIR) spectroscopy of water in the binary and ternary aqueous solutions of TMAO and urea. The 2DIR spectra are calculated using the electronic structure/molecular dynamics approach. The non-Condon effects in spectral transitions are incorporated in the theoretical calculations of 2DIR spectra. It is found that TMAO disrupts the local structure of water, while urea leaves it essentially unaffected. The 2DIR results show that both TMAO and urea slow down the dynamics of spectral diffusion of water. The extent of slowing down is found to be particularly significant for both hydration and bulk water in the presence of TMAO which can be attributed to strong hydrogen bonds between the water and TMAO molecules. The water molecules present in the hydration layer of the solutes in the ternary solutions are found to relax at even slower rates compared to that in their binary solutions in water. The hydrogen bonds between TMAO and urea are found to be not stable. Thus, the counteracting effect of TMAO against urea is seen to take place mainly through water-mediated interactions. Such TMAO-induced effects giving rise to more structured and slower hydrogen-bonded network are successfully captured through 2DIR spectroscopic calculations.
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Affiliation(s)
- Ravi Malik
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
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4
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Nasralla M, Laurent H, Baker DL, Ries ME, Dougan L. A study of the interaction between TMAO and urea in water using NMR spectroscopy. Phys Chem Chem Phys 2022; 24:21216-21222. [PMID: 36040138 DOI: 10.1039/d2cp02475f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trimethylamine N-oxide (TMAO) and urea are small organic biological molecules. While TMAO is known as a protective osmolyte that promotes the native form of biomolecules, urea is a denaturant. An understanding of the impact of TMAO and urea on water structure may aid in uncovering the molecular mechanisms that underlie this activity. Here we investigate binary solutions of TMAO-water, urea-water and ternary solutions of TMAO-urea-water using NMR spectroscopy at 300 K. An enhancement of the total hydrogen bonding in water was found upon the addition of TMAO and this effect was neutralised by a mole ratio of 1-part TMAO to 4-parts urea. Urea was found to have little effect on the strength of water's hydrogen bonding network and the dynamics of water molecules. Evidence was found for a weak interaction between TMAO and urea. Taken together, these results suggest that TMAO's function as a protective osmolyte, and its counteraction of urea, may be driven by the strength of its hydrogen bond interactions with water, and by a secondary reinforcement of water's own hydrogen bond network. They also suggest that the TMAO-urea complex forms through the donation of a hydrogen bond by urea.
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Affiliation(s)
- Mazin Nasralla
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
| | - Harrison Laurent
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
| | - Daniel L Baker
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
| | - Michael E Ries
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
| | - Lorna Dougan
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
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5
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Sharma GS, Krishna S, Khan S, Dar TA, Khan KA, Singh LR. Protecting thermodynamic stability of protein: The basic paradigm against stress and unfolded protein response by osmolytes. Int J Biol Macromol 2021; 177:229-240. [PMID: 33607142 DOI: 10.1016/j.ijbiomac.2021.02.102] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 01/10/2023]
Abstract
Organic osmolytes are known to play important role in stress protection by stabilizing macromolecules and suppressing harmful effects on functional activity. There is existence of several reports in the literature regarding their effects on structural, functional and thermodynamic aspects of many enzymes and the interaction parameters with proteins have been explored. Osmolytes are compatible with enzyme function and therefore, can be accumulated up to several millimolar concentrations. From the thermodynamic point of view, osmolyte raises mid-point of thermal denaturation (Tm) of proteins while having no significant effect on ΔGD° (free energy change at physiological condition). Unfavorable interaction with the peptide backbone due to preferential hydration is the major driving force for folding of unfolded polypeptide in presence of osmolyte. However, the thermodynamic basis of stress protection and origin of compatibility paradigm has been a debatable issue. In the present manuscript, we attempt to elaborate the origin of stress protection and compatibility paradigm of osmolytes based on the effect on thermodynamic stability of proteins. We also infer that protective effects of osmolytes on ΔGD° (of proteins) could also indicate its potential involvement in unfolded protein response and overall stress biology on macromolecular level.
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Affiliation(s)
- Gurumayum Suraj Sharma
- Department of Botany, Bhaskaracharya College of Applied Sciences, University of Delhi, Delhi, India
| | - Snigdha Krishna
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Sheeza Khan
- School of Life Sciences, B. S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, India
| | - Tanveer A Dar
- Department of Clinical Biochemistry, University of Kashmir, Srinagar, J&K, India
| | - Khurshid A Khan
- School of Life Sciences, B. S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, India
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6
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Judy E, Kishore N. Quantitative calorimetric evidences into counteraction mechanism of denaturing effect of guanidine hydrochloride by citrulline and betaine. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Ganguly P, Polák J, van der Vegt NFA, Heyda J, Shea JE. Protein Stability in TMAO and Mixed Urea–TMAO Solutions. J Phys Chem B 2020; 124:6181-6197. [DOI: 10.1021/acs.jpcb.0c04357] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Pritam Ganguly
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Jakub Polák
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, Darmstadt 64287, Germany
| | - Jan Heyda
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, United States
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8
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Chettiyankandy P, Chowdhuri S. Ion solvation scenario in an aqueous solution mixture of counteracting osmolytes: Urea and trimethylamine-N-oxide (TMAO). J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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9
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Rani A, Venkatesu P. Changing relations between proteins and osmolytes: a choice of nature. Phys Chem Chem Phys 2018; 20:20315-20333. [DOI: 10.1039/c8cp02949k] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The stabilization and destabilization of the protein in the presence of any additive is mainly attributed to its preferential exclusion from protein surface and its preferential binding to the protein surface, respectively.
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Affiliation(s)
- Anjeeta Rani
- Department of Chemistry
- University of Delhi
- Delhi 110 007
- India
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10
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Ganguly P, Boserman P, van der Vegt NFA, Shea JE. Trimethylamine N-oxide Counteracts Urea Denaturation by Inhibiting Protein–Urea Preferential Interaction. J Am Chem Soc 2017; 140:483-492. [DOI: 10.1021/jacs.7b11695] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pritam Ganguly
- Department
of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Pablo Boserman
- Department
of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut
für Anorganische und Physikalische Chemie, Center of Smart
Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße
10, Darmstadt 64287, Germany
| | - Joan-Emma Shea
- Department
of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
- Department
of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, United States
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11
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Ghosh S, Dey S, Patel M, Chakrabarti R. Can an ammonium-based room temperature ionic liquid counteract the urea-induced denaturation of a small peptide? Phys Chem Chem Phys 2017; 19:7772-7787. [DOI: 10.1039/c6cp08842b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The folding/unfolding equilibrium of proteins in aqueous medium can be altered by adding small organic molecules generally termed as co-solvents.
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Affiliation(s)
- Soumadwip Ghosh
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
| | - Souvik Dey
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
| | - Mahendra Patel
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
| | - Rajarshi Chakrabarti
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
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12
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Ohto T, Hunger J, Backus EHG, Mizukami W, Bonn M, Nagata Y. Trimethylamine-N-oxide: its hydration structure, surface activity, and biological function, viewed by vibrational spectroscopy and molecular dynamics simulations. Phys Chem Chem Phys 2017; 19:6909-6920. [DOI: 10.1039/c6cp07284d] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vibrational spectroscopy and molecular simulations revealed the hydrophilicity and hydrophobicity of TMAO in aqueous solution.
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Affiliation(s)
- Tatsuhiko Ohto
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | | | | | - Wataru Mizukami
- Department of Energy and Material Sciences
- Faculty of Engineering Sciences
- Kyushu University
- Fukuoka
- Japan
| | - Mischa Bonn
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
- Department of Theoretical and Computational Molecular Science
- Institute for Molecular Science
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13
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Sarkar S, Ghosh S, Chakrabarti R. Ammonium based stabilizers effectively counteract urea-induced denaturation in a small protein: insights from molecular dynamics simulations. RSC Adv 2017. [DOI: 10.1039/c7ra10712a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Room temperature ionic liquids (IL) and deep eutectic solvents (DES) are known to aid the conformational stability and activity of proteins and enzymes in aqueous solutions.
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Affiliation(s)
- Soham Sarkar
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
| | - Soumadwip Ghosh
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
| | - Rajarshi Chakrabarti
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai – 400076
- India
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14
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Paul S, Paul S. Investigating the Counteracting Effect of Trehalose on Urea-Induced Protein Denaturation Using Molecular Dynamics Simulation. J Phys Chem B 2015; 119:10975-88. [DOI: 10.1021/acs.jpcb.5b01457] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Subrata Paul
- Department
of Chemistry, Indian Institute of Technology, Guwahati, Assam India-781039
| | - Sandip Paul
- Department
of Chemistry, Indian Institute of Technology, Guwahati, Assam India-781039
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15
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Rahman S, Warepam M, Singh LR, Dar TA. A current perspective on the compensatory effects of urea and methylamine on protein stability and function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 119:129-36. [PMID: 26095775 DOI: 10.1016/j.pbiomolbio.2015.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 11/16/2022]
Abstract
Urea is a strong denaturant and inhibits many enzymes but is accumulated intracellularly at very high concentrations (up to 3-4 M) in mammalian kidney and in many marine fishes. It is known that the harmful effects of urea on the macromolecular structure and function is offset by the accumulation of an osmolytic agent called methylamine. Intracellular concentration of urea to methylamines falls in the ratio of 2:1 to 3:2 (molar ratio). At this ratio, the thermodynamic effects of urea and methylamines on protein stability and function are believed to be algebraically additive. The mechanism of urea-methylamine counteraction has been widely investigated on various approaches including, thermodynamic, structural and functional aspects. Recent advances have also revealed atomic level insights of counteraction and various molecular dynamic simulation studies have yielded significant molecular level informations on the interaction between urea and methylamines with proteins. It is worthwhile that urea-methylamine system not only plays pivotal role for the survival and functioning of the renal medullary cells but also is a key osmoregulatory component of the marine elasmobranchs, holocephalans and coelacanths. Therefore, it is important to combine all discoveries and discuss the developments in context to physiology of the mammalian kidney and adaptation of the marine organisms. In this article we have for the first time reviewed all major developments on urea-counteraction systems to date. We have also discussed about other additional urea-counteraction systems discovered so far including urea-NaCl, urea-myoinsoitol and urea-molecular chaperone systems. Insights for the possible future research have also been highlighted.
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Affiliation(s)
- Safikur Rahman
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110 007, India
| | - Marina Warepam
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110 007, India
| | - Laishram R Singh
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110 007, India
| | - Tanveer Ali Dar
- Clinical Biochemistry, University of Kashmir, Srinagar, Jammu & Kashmir 190006, India.
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16
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Ganguly P, Hajari T, Shea JE, van der Vegt NFA. Mutual Exclusion of Urea and Trimethylamine N-Oxide from Amino Acids in Mixed Solvent Environment. J Phys Chem Lett 2015; 6:581-5. [PMID: 26262470 DOI: 10.1021/jz502634k] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We study the solvation of amino acids in pure-osmolyte and mixed-osmolyte urea and trimethylamine N-oxide (TMAO) solutions using molecular dynamics simulations. Analysis of Kirkwood-Buff integrals between the solution components provides evidence that in the mixed osmolytic solution, both urea and TMAO are mutually excluded from the amino acid surface, accompanied by an increase in osmolyte-osmolyte aggregation. Similar observations are made in simulations of a model protein backbone, represented by triglycine, and suggest that TMAO stabilizes proteins under urea denaturation conditions by effectively removing urea from the protein surface. The effects of the mixed osmolytes on the solvation of the amino acids and the backbone are found to be highly nonlinear in terms of the effects of the individual osmolytes and independent of differences in the strength of the TMAO-water interactions, as observed with different TMAO force fields.
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Affiliation(s)
- Pritam Ganguly
- §Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, Darmstadt 64287, Germany
| | - Timir Hajari
- §Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, Darmstadt 64287, Germany
| | | | - Nico F A van der Vegt
- §Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, Darmstadt 64287, Germany
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17
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Hunger J, Ottosson N, Mazur K, Bonn M, Bakker HJ. Water-mediated interactions between trimethylamine-N-oxide and urea. Phys Chem Chem Phys 2015; 17:298-306. [DOI: 10.1039/c4cp02709d] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The osmoprotectant trimethylamine-N-oxide (TMAO) interacts with the protein denaturant urea via the hydrogen-bonded water network.
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Affiliation(s)
| | | | - Kamila Mazur
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
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18
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Larini L, Shea JE. Double Resolution Model for Studying TMAO/Water Effective Interactions. J Phys Chem B 2013; 117:13268-77. [DOI: 10.1021/jp403635g] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Luca Larini
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
| | - Joan-Emma Shea
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
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19
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Kumar A, Attri P, Venkatesu P. Trehalose protects urea-induced unfolding of α-chymotrypsin. Int J Biol Macromol 2010; 47:540-5. [DOI: 10.1016/j.ijbiomac.2010.07.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 10/19/2022]
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20
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Venkatesu P, Lee MJ, Lin HM. Osmolyte counteracts urea-induced denaturation of alpha-chymotrypsin. J Phys Chem B 2009; 113:5327-38. [PMID: 19354310 DOI: 10.1021/jp8113013] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The stability of proteins is reduced by urea, which is methylamine and nonprotecting osmolyte; eventually urea destabilizes the activity and function and alters the structure of proteins, whereas the stability of proteins is raised by the osmolytes, which are not interfering with the functional activity of proteins. The deleterious effect of urea on proteins has been counteracted by methylamines (osmolytes), such as trimethylamine N-oxide (TMAO), betaine, and sarcosine. To distinctly enunciate the comparison of the counteracting effects between these methylamines on urea-induced denaturation of alpha-chymotrypsin (CT), we measured the hydrodynamic diameter (d(H)) and the thermodynamic properties (T(m), DeltaH, DeltaG(U), and DeltaC(p)) with dynamic light scattering (DLS) and differential scanning calorimeter (DSC), respectively. The present investigation compares the compatibility and counteracting hypothesis by determining the effects of methylamines and urea, as individual components and in combination at a concentration ratio of 1:2 (methylamine:urea) as well as various urea concentrations (0.5-5 M) in the presence of 1 M methylamine. The experimental results revealed that the naturally occurring osmolytes TMAO, betaine, and sarcosine strongly counteracted the urea actions on alpha-chymotrypsin. The results also indicated that TMAO counteracting the urea effects on CT was much stronger than betaine or sarcosine.
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Affiliation(s)
- Pannur Venkatesu
- Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106-07, Taiwan.
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21
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Chebotareva NA. Effect of molecular crowding on the enzymes of glycogenolysis. BIOCHEMISTRY (MOSCOW) 2007; 72:1478-90. [DOI: 10.1134/s0006297907130056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Villalobos ARA, Renfro JL. Trimethylamine oxide suppresses stress-induced alteration of organic anion transport in choroid plexus. J Exp Biol 2007; 210:541-52. [PMID: 17234624 DOI: 10.1242/jeb.02681] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe effect of physicochemical stress on organic anion transport across the vertebrate blood–cerebrospinal fluid (CSF) barrier in the presence and absence of an endogenous cytoprotectant, trimethylamine oxide (TMAO), was investigated in isolated IVth choroid plexus (CP) of spiny dogfish shark(Squalus acanthias), an animal with naturally high levels of TMAO(∼70 mmol l–1). Active transepithelial absorption of the organic anion, 2,4-dichlorophenoxyacetic acid (2,4-D), by IVth CP mounted in Ussing chambers was measured after in vitro stress, and a marker for the cellular stress response, inducible heat shock protein 70 (Hsp70), was assayed by immunoblot analysis. Transient heat stress (a shift from the normal 13.5°C to 23.5°C for 1 h) decreased 2,4-D transport by ∼66%;however, the same stress minus TMAO (isosmotic replacement with urea) had no effect on transport rate. In the absence of TMAO, stress-induced Hsp70 accumulation was more than double that seen in the presence of TMAO. Likewise,exposure to 50 μmol l–1 Zn for 6 h induced a twofold greater Hsp70 accumulation in the absence of TMAO than in its presence, and the higher Hsp70 level was associated with a higher 2,4-D transport rate. Heat stress and 50 μmol l–1 Zn also induced more pronounced increases in Hsp70 mRNA in the absence of TMAO. Thus, the cellular stress response can significantly alter CP organic anion transport capacity, and an endogenous osmolyte can suppress that response.
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Affiliation(s)
- Alice R A Villalobos
- Center for Membrane Toxicological Studies, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA.
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23
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Doan-Nguyen V, Loria JP. The effects of cosolutes on protein dynamics: the reversal of denaturant-induced protein fluctuations by trimethylamine N-oxide. Protein Sci 2006; 16:20-9. [PMID: 17123958 PMCID: PMC2222840 DOI: 10.1110/ps.062393707] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The protein stabilizing effects of the small molecule osmolyte, trimethylamine N-oxide, against chemical denaturant was investigated by NMR spin-relaxation measurements and model-free analysis. In the presence of 0.7 M guanidine hydrochloride increased picosecond-nanosecond dynamics are observed in the protein ribonuclease A. These increased fluctuations occur throughout the protein, but the most significant increases in flexibility occur at positions believed to be the first to unfold. Addition of 0.35 M trimethylamine N-oxide to this destabilized form of ribonuclease results in significant rigidification of the protein backbone as assessed by (1)H-(15)N order parameters. Statistically, these order parameters are the same as those measured in native ribonuclease indicating that TMAO reduces the amplitude of backbone fluctuations in a destabilized protein. These data suggest that TMAO restricts the bond vector motions on the protein energy landscape to resemble those motions that occur in the native protein and points to a relation between stability and dynamics in this enzyme.
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24
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Eronina TB, Chebotareva NA, Kurganov BI. Influence of Osmolytes on Inactivation and Aggregation of Muscle Glycogen Phosphorylase b by Guanidine Hydrochloride. Stimulation of Protein Aggregation under Crowding Conditions. BIOCHEMISTRY (MOSCOW) 2005; 70:1020-6. [PMID: 16266274 DOI: 10.1007/s10541-005-0219-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of the osmolytes trimethylamine-N-oxide (TMAO), betaine, proline, and glycine on the kinetics of inactivation and aggregation of rabbit skeletal muscle glycogen phosphorylase b by guanidine hydrochloride (GuHCl) have been studied. It is shown that the osmolytes TMAO and betaine exhibit the highest protective efficacy against phosphorylase b inactivation. A test system for studying the effects of macromolecular crowding induced by osmolytes on aggregation of proteins is proposed. TMAO and glycine increase the rate of phosphorylase b aggregation induced by GuHCl.
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Affiliation(s)
- T B Eronina
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia.
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25
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Mukherjee A, Santra MK, Beuria TK, Panda D. A natural osmolyte trimethylamine N-oxide promotes assembly and bundling of the bacterial cell division protein, FtsZ and counteracts the denaturing effects of urea. FEBS J 2005; 272:2760-72. [PMID: 15943810 DOI: 10.1111/j.1742-4658.2005.04696.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Assembly of FtsZ was completely inhibited by low concentrations of urea and its unfolding occurred in two steps in the presence of urea, with the formation of an intermediate [Santra MK & Panda D (2003) J Biol Chem278, 21336-21343]. In this study, using the fluorescence of 1-anilininonaphthalene-8-sulfonic acid and far-UV circular dichroism spectroscopy, we found that a natural osmolyte, trimethylamine N-oxide (TMAO), counteracted the denaturing effects of urea and guanidium chloride on FtsZ. TMAO also protected assembly and bundling of FtsZ protofilaments from the denaturing effects of urea and guanidium chloride. Furthermore, the standard free energy changes for unfolding of FtsZ were estimated to be 22.5 and 28.4 kJ.mol(-1) in the absence and presence of 0.6 M TMAO, respectively. The data are consistent with the view that osmolytes counteract denaturant-induced unfolding of proteins by destabilizing the unfolded states. Interestingly, TMAO was also found to affect the assembly properties of native FtsZ. TMAO increased the light-scattering signal of the FtsZ assembly, increased sedimentable polymer mass, enhanced bundling of FtsZ protofilaments and reduced the GTPase activity of FtsZ. Similar to TMAO, monosodium glutamate, a physiological osmolyte in bacteria, which induces assembly and bundling of FtsZ filaments in vitro[Beuria TK, Krishnakumar SS, Sahar S, Singh N, Gupta K, Meshram M & Panda D (2003) J Biol Chem278, 3735-3741], was also found to counteract the deleterious effects of urea on FtsZ. The results together suggested that physiological osmolytes may regulate assembly and bundling of FtsZ in bacteria and that they may protect the functionality of FtsZ under environmental stress conditions.
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Affiliation(s)
- Arnab Mukherjee
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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26
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Samuelsson LM, Bedford JJ, Smith RAJ, Leader JP. A comparison of the counteracting effects of glycine betaine and TMAO on the activity of RNase A in aqueous urea solution. Comp Biochem Physiol A Mol Integr Physiol 2005; 141:22-8. [PMID: 15886035 DOI: 10.1016/j.cbpb.2005.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 03/07/2005] [Accepted: 03/08/2005] [Indexed: 11/16/2022]
Abstract
Trimethylamine-N-oxide (TMAO) and glycine betaine are counteracting osmolytes found in cellular systems under osmotic stress, often in association with high urea concentrations. TMAO is a characteristic component of cartilaginous fish and marine molluscs, while glycine betaine is more widely distributed, occurring in plants, bacteria and the mammalian kidney. As part of a project to explain and understand the action of these methylamines, the RNase A-catalysed degradation of polyuridylic acid in the presence of urea and various osmolytes (0-1.0 M) was studied using (31)P Nuclear Magnetic Resonance spectroscopy. The decrease in reaction rate induced by urea could be fully recovered with 1 molar equivalent of trimethylamine-N-oxide or 1.4 molar equivalents of glycine betaine. These results indicate that the modification of RNase A activity induced by urea is not associated with gross irreversible structural changes and that both glycine betaine and trimethylamine-N-oxide have kinetically detectable counteracting effects.
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Affiliation(s)
- L M Samuelsson
- Department of Physiology, University of Otago Medical School, University of Otago, P.O. Box 913, Dunedin 9001, New Zealand
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27
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Chebotareva NA, Kurganov BI, Livanova NB. Biochemical effects of molecular crowding. BIOCHEMISTRY (MOSCOW) 2005; 69:1239-51. [PMID: 15627378 DOI: 10.1007/s10541-005-0070-y] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell cytoplasm contains high concentrations of high-molecular-weight components that occupy a substantial part of the volume of the medium (crowding conditions). The effect of crowding on biochemical processes proceeding in the cell (conformational transitions of biomacromolecules, assembling of macromolecular structures, protein folding, protein aggregation, etc.) is discussed in this review. The excluded volume concept, which allows the effects of crowding on biochemical reactions to be quantitatively described, is considered. Experimental data demonstrating the biochemical effects of crowding imitated by both low-molecular-weight and high-molecular-weight crowding agents are summarized.
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Affiliation(s)
- N A Chebotareva
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow 119071, Russia.
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28
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Gahl RF, Narayan M, Xu G, Scheraga HA. Trimethylamine-N-oxide modulates the reductive unfolding of onconase. Biochem Biophys Res Commun 2004; 325:707-10. [PMID: 15541346 DOI: 10.1016/j.bbrc.2004.10.088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Indexed: 11/13/2022]
Abstract
The physiological osmolyte trimethylamine-N-oxide (TMAO) stabilizes proteins by decreasing the entropy of the unfolded state through a solvophobic effect. Our studies on the effect of TMAO on the reductive unfolding of onconase (ONC) to form its reductive intermediate, des [30-75], indicate that TMAO diminishes the reductive unfolding rate of the protein although it does not significantly affect the stability of the native protein relative to its denatured state. Since the reductive unfolding of ONC is a local event, our studies provide direct evidence for a TMAO-induced local structural change that reduces the rate of redox-dependent protein unfolding. The implications of our findings for protein folding/unfolding are discussed.
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Affiliation(s)
- Robert F Gahl
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA
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29
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30
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Kast KM, Brickmann J, Kast SM, Berry RS. Binary Phases of Aliphatic N-Oxides and Water: Force Field Development and Molecular Dynamics Simulation. J Phys Chem A 2003. [DOI: 10.1021/jp027336a] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kristine M. Kast
- Physikalische Chemie I, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, and Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - Jürgen Brickmann
- Physikalische Chemie I, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, and Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - Stefan M. Kast
- Physikalische Chemie I, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, and Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - R. Stephen Berry
- Physikalische Chemie I, Technische Universität Darmstadt, Petersenstrasse 20, 64287 Darmstadt, Germany, and Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
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31
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Saïda F, Uzan M, Bontems F. The phage T4 restriction endoribonuclease RegB: a cyclizing enzyme that requires two histidines to be fully active. Nucleic Acids Res 2003; 31:2751-8. [PMID: 12771201 PMCID: PMC156712 DOI: 10.1093/nar/gkg377] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2003] [Revised: 04/01/2003] [Accepted: 04/01/2003] [Indexed: 11/14/2022] Open
Abstract
The regB gene, from the bacteriophage T4, codes for an endoribonuclease that controls the expression of a number of phage early genes. The RegB protein cleaves its mRNA substrates with an almost absolute specificity in the middle of the tertranucleotide GGAG, making it a unique well-defined restriction endoribonuclease. This striking protein has no homology to any known RNase and its catalytic mechanism has never been investigated. Here, we show, using 31P nuclear magnetic resonance (NMR), that RegB produces a cyclic 2',3'-phosphodiester product. In order to determine the residues crucial for its activity, we prepared all the histidine-to- alanine point mutants of RegB. The activity of these mutants was characterized both in vivo and in vitro. In addition, their binding capability was quantified by surface plasmon resonance and their structural integrity was probed by 1H/15N NMR correlation spectroscopy. The results obtained show that only the H48A and the H68A substitutions significantly reduce RegB activity without changing its ability to bind the substrate or affecting its overall structure. Altogether, our results define RegB as a new cyclizing RNase and present His48 and His68 as potent catalytic residues. The effect of the in vivo selected R52L mutation is also described and discussed.
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Affiliation(s)
- Fakhri Saïda
- Laboratoire ICSN-RMN, Institut de Chimie des Substances Naturelles, Ecole polytechnique, Route de Saclay, 91128 Palaiseau, France
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32
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Abstract
A key paradigm in the biology of adaptation holds that urea affects protein function by increasing the fluctuations of the native state, while trimethylamine N-oxide (TMAO) affects function in the opposite direction by decreasing the normal fluctuations of the native ensemble. Using urea and TMAO separately and together, hydrogen exchange (HX) studies on RNase A at pH* 6.35 were used to investigate the basic tenets of the urea:TMAO paradigm. TMAO (1 M) alone decreases HX rate constants of a select number of sites exchanging from the native ensemble, and low urea alone increases the rate constants of some of the same sites. Addition of TMAO to urea solutions containing RNase A also suppresses HX rate constants. The data show that urea and TMAO independently or in combination affect the dynamics of the native ensemble in opposing ways. The results provide evidence in support of the counteraction aspect of the urea:TMAO paradigm linking structural dynamics with protein function in urea-rich organs and organisms. RNase A is so resistant to urea denaturation at pH* 6.35 that even in the presence of 4.8 M urea, the native ensemble accounts for >99.5% of the protein. An essential test, devised to determine the HX mechanism of exchangeable protons, shows that over the 0-4.8 M urea concentration range nearly 80% of all observed sites convert from EX2 to EX1. The slow exchange sites are all EX1; they do not exhibit global exchange even at urea concentrations (5.8 M) well into the denaturation transition zone, and their energetically distinct activated complexes leading to exchange gives evidence of residual structure. Under these experimental conditions, the use of DeltaG(HX) as a basis for HX analysis of RNase A urea denaturation is invalid.
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Affiliation(s)
- Youxing Qu
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, 5.154 MRB, Galveston, Texas 77555-1052, USA
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33
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Hill CM, Bates IR, White GF, Hallett FR, Harauz G. Effects of the osmolyte trimethylamine-N-oxide on conformation, self-association, and two-dimensional crystallization of myelin basic protein. J Struct Biol 2002; 139:13-26. [PMID: 12372316 DOI: 10.1016/s1047-8477(02)00513-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The osmolyte trimethylamine-N-oxide (TMAO) is a naturally in vivo occurring "chemical chaperone" that has been shown to stabilise the folding of numerous proteins. Myelin basic protein (MBP) is a molecule that has not yet been suitably crystallized either in three dimensions for X-ray crystallography or in two dimensions for electron crystallography. Here, we describe lipid monolayer crystallization experiments of two species of recombinant murine MBP in the presence of TMAO. One protein was unmodified, whereas the other contained six Arg/Lys-->Gln substitutions to mimic the effects of deimination (i.e., the enzymatic modification of Arg to citrulline), which reduces the net positive charge. Planar arrays of both proteins were formed on binary lipid monolayers containing a nickel-chelating lipid and a phosphoinositide. In the presence of TMAO, the diffraction spots of these arrays became sharper and more distinct than in its absence, indicating some improvement of crystallinity. The osmolyte also induced the formation of epitaxial growth of protein arrays, especially with the mutant protein. However, none of these assemblies was sufficiently ordered to extract high-resolution structural information. Circular dichroic spectroscopy showed that MBP gained no increase in ordered secondary structure in the presence of TMAO in bulk solution, whereas it did in the presence of lipids. Dynamic light-scattering experiments confirmed that the MBP preparations were monomodal under the optimal crystallization conditions determined by electron microscopy trials. The salt and osmolyte concentrations used were shown to result in a largely unassociated population of MBP. The amino acid composition of MBP overwhelmingly favours a disordered state, and a neural-network-based scheme predicted large segments that would be unlikely to adopt a regular conformation. Thus, this protein has an inherently disordered nature, which mitigates strongly against its crystallization for high-resolution structure determination.
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Affiliation(s)
- Christopher M Hill
- Department of Molecular Biology and Genetics, University of Guelph, 50 Stone Road East, Guelph, Ont., Canada N1G 2W1
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Wojciechowski G, Ratajczak-Sitarz M, Katrusiak A, Brzezinski B. Shape of the proton potential in an intramolecular hydrogen-bonded system. Part II. J Mol Struct 2002. [DOI: 10.1016/s0022-2860(02)00074-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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35
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Wojciechowski G, Brzezinski B. Shape of the proton potential in an intramolecular hydrogen-bonded system. J Mol Struct 2001. [DOI: 10.1016/s0022-2860(01)00524-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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