1
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Roy UC, Bandyopadhyay P. Correlation between protein conformations and water structure and thermodynamics at high pressure: A molecular dynamics study of the Bovine Pancreatic Trypsin Inhibitor (BPTI) protein. J Chem Phys 2023; 158:095102. [PMID: 36889972 DOI: 10.1063/5.0124837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Pressure-induced perturbation of a protein structure leading to its folding-unfolding mechanism is an important yet not fully understood phenomenon. The key point here is the role of water and its coupling with protein conformations as a function of pressure. In the current work, using extensive molecular dynamics simulation at 298 K, we systematically examine the coupling between protein conformations and water structures of pressures of 0.001, 5, 10, 15, 20 kbar, starting from (partially) unfolded structures of the protein Bovine Pancreatic Trypsin Inhibitor (BPTI). We also calculate localized thermodynamics at those pressures as a function of protein-water distance. Our findings show that both protein-specific and generic effects of pressure are operating. In particular, we found that (1) the amount of increase in water density near the protein depends on the protein structural heterogeneity; (2) the intra-protein hydrogen bond decreases with pressure, while the water-water hydrogen bond per water in the first solvation shell (FSS) increases; protein-water hydrogen bonds also found to increase with pressure, (3) with pressure hydrogen bonds of waters in the FSS getting twisted; and (4) water's tetrahedrality in the FSS decreases with pressure, but it is dependent on the local environment. Thermodynamically, at higher pressure, the structural perturbation of BPTI is due to the pressure-volume work, while the entropy decreases with the increase of pressure due to the higher translational and rotational rigidity of waters in the FSS. The local and subtle effects of pressure, found in this work, are likely to be typical of pressure-induced protein structure perturbation.
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Affiliation(s)
- Umesh C Roy
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Pradipta Bandyopadhyay
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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2
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Tavagnacco L, Zaccarelli E, Chiessi E. Modeling Solution Behavior of Poly( N-isopropylacrylamide): A Comparison between Water Models. J Phys Chem B 2022; 126:3778-3788. [PMID: 35491838 PMCID: PMC9150113 DOI: 10.1021/acs.jpcb.2c00637] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
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Water is known to
play a fundamental role in determining the structure
and functionality of macromolecules. The same crucial contribution
is also found in the in silico description of polymer aqueous solutions.
In this work, we exploit the widely investigated synthetic polymer
poly(N-isopropylacrylamide) (PNIPAM) to understand
the effect of the adopted water model on its solution behavior and
to refine the computational setup. By means of atomistic molecular
dynamics simulations, we perform a comparative study of PNIPAM aqueous
solution using two advanced water models: TIP4P/2005 and TIP4P/Ice.
The conformation and hydration features of an atactic 30-mer at infinite
dilution are probed at a range of temperature and pressure suitable
to detect the coil-to-globule transition and to map the P–T
phase diagram. Although both water models can reproduce the temperature-induced
coil-to-globule transition at atmospheric pressure and the polymer
hydration enhancement that occurs with increasing pressure, the PNIPAM–TIP4P/Ice
solution shows better agreement with experimental findings. This result
can be attributed to a stronger interaction of TIP4P/Ice water with
both hydrophilic and hydrophobic groups of PNIPAM, as well as to a
less favorable contribution of the solvent entropy to the coil-to-globule
transition.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Emanuela Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, Rome 00133, Italy
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3
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Ou X, Lao Y, Xu J, Wutthinitikornkit Y, Shi R, Chen X, Li J. ATP Can Efficiently Stabilize Protein through a Unique Mechanism. JACS AU 2021; 1:1766-1777. [PMID: 34723279 PMCID: PMC8549052 DOI: 10.1021/jacsau.1c00316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Recent experiments suggested that ATP can effectively stabilize protein structure and inhibit protein aggregation when its concentration is less than 10 mM, which is significantly lower than cosolvent concentrations required in conventional mechanisms. The ultrahigh efficiency of ATP suggests a unique mechanism that is fundamentally different from previous models of cosolvents. In this work, we used molecular dynamics simulation and experiments to study the interactions of ATPs with three proteins: lysozyme, ubiquitin, and malate dehydrogenase. ATP tends to bind to the surface regions with high flexibility and high degree of hydration. These regions are also vulnerable to thermal perturbations. The bound ATPs further assemble into ATP clusters mediated by Mg2+ and Na+ ions. More interestingly, in Mg2+-free ATP solution, Na+ at higher concentration (150 mM under physiological conditions) can similarly mediate the formation of the ATP cluster on protein. The ATP cluster can effectively reduce the fluctuations of the vulnerable region and thus stabilize the protein against thermal perturbations. Both ATP binding and the considerable improvement of thermal stability of ATP-bound protein were verified by experiments.
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Affiliation(s)
- Xinwen Ou
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Yichong Lao
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Jingjie Xu
- Eye
Center of the Second Affiliated Hospital, Institute of Translational
Medicine, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Yanee Wutthinitikornkit
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Rui Shi
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Xiangjun Chen
- Eye
Center of the Second Affiliated Hospital, Institute of Translational
Medicine, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Jingyuan Li
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
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4
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Timpmann K, Linnanto JM, Yadav D, Kangur L, Freiberg A. Hydrostatic High-Pressure-Induced Denaturation of LH2 Membrane Proteins. J Phys Chem B 2021; 125:9979-9989. [PMID: 34460261 DOI: 10.1021/acs.jpcb.1c05789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The denaturation of globular proteins by high pressure is frequently associated with the release of internal voids and/or the exposure of the hydrophobic protein interior to a polar aqueous solvent. Similar evidence with respect to membrane proteins is not available. Here, we investigate the impact of hydrostatic pressures reaching 12 kbar on light-harvesting 2 integral membrane complexes of purple photosynthetic bacteria using two types of innate chromophores in separate strategic locations: bacteriochlorophyll-a in the hydrophobic interior and tryptophan at both protein-solvent interfacial gateways to internal voids. The complexes from mutant Rhodobacter sphaeroides with low resilience against pressure were considered in parallel with the naturally robust complexes of Thermochromatium tepidum. In the former case, a firm correlation was established between the abrupt blue shift of the bacteriochlorophyll-a exciton absorption, a known indicator of the breakage of tertiary structure pigment-protein hydrogen bonds, and the quenching of tryptophan fluorescence, a supposed result of further protein solvation. No such effects were observed in the reference complex. While these data may be naively taken as supporting evidence of the governing role of hydration, the analysis of atomistic model structures of the complexes confirmed the critical part of the structure in the pressure-induced denaturation of the membrane proteins studied.
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Affiliation(s)
- Kõu Timpmann
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
| | - Juha Matti Linnanto
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
| | - Dheerendra Yadav
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
| | - Liina Kangur
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
| | - Arvi Freiberg
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia.,Estonian Academy of Sciences, Kohtu Str. 6, Tallinn 10130, Estonia
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5
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Arsiccio A, Shea JE. Pressure Unfolding of Proteins: New Insights into the Role of Bound Water. J Phys Chem B 2021; 125:8431-8442. [PMID: 34310136 DOI: 10.1021/acs.jpcb.1c04398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
High pressures can be detrimental for protein stability, resulting in unfolding and loss of function. This phenomenon occurs because the unfolding transition is accompanied by a decrease in volume, which is typically attributed to the elimination of cavities that are present within the native state as a result of packing defects. We present a novel computational approach that enables the study of pressure unfolding in atomistically detailed protein models in implicit solvent. We include the effect of pressure using a transfer free energy term that allows us to decouple the effect of protein residues and bound water molecules on the volume change upon unfolding. We discuss molecular dynamics simulations results using this protocol for two model proteins, Trp-cage and staphylococcal nuclease (SNase). We find that the volume reduction of bound water is the key energetic term that drives protein denaturation under the effect of pressure, for both Trp-cage and SNase. However, we note differences in unfolding mechanisms between the smaller Trp-cage and the larger SNase protein. Indeed, the unfolding of SNase, but not Trp-cage, is seen to be further accompanied by a reduction in the volume of internal cavities. Our results indicate that, for small peptides, like Trp-cage, pressure denaturation is driven by the increase in solvent accessibility upon unfolding, and the subsequent increase in the number of bound water molecules. For larger proteins, like SNase, the cavities within the native fold act as weak spots, determining the overall resistance to pressure denaturation. Our simulations display a striking agreement with the pressure-unfolding profile experimentally obtained for SNase and represent a promising approach for a computationally efficient and accurate exploration of pressure-induced denaturation of proteins.
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Affiliation(s)
- Andrea Arsiccio
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Physics, University of California, Santa Barbara, California 93106, United States
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6
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Tavagnacco L, Chiessi E, Zaccarelli E. Molecular insights on poly( N-isopropylacrylamide) coil-to-globule transition induced by pressure. Phys Chem Chem Phys 2021; 23:5984-5991. [PMID: 33666621 PMCID: PMC8247264 DOI: 10.1039/d0cp06452a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/17/2021] [Indexed: 12/17/2022]
Abstract
By using extensive all-atom molecular dynamics simulations of an atactic linear polymer chain, we provide microscopic insights into poly(N-isopropylacrylamide) (PNIPAM) coil-to-globule transition addressing the roles played by both temperature and pressure. We detect a coil-to-globule transition up to large pressures, showing a reentrant behavior of the critical temperature with increasing pressure in agreement with experimental observations. Furthermore, again confirming the experimental findings, we report the existence at high pressures of a new kind of globular state. It is characterized by a more structured hydration shell that is closer to PNIPAM hydrophobic domains, as compared to the globular state observed at atmospheric pressure. Our results highlight that temperature and pressure induce a PNIPAM coil-to-globule transition through different molecular mechanisms, opening the way for a systematic use of both thermodynamic variables to tune the location of the transition and the properties of the associated swollen/collapsed states.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185, Rome, Italy.
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133, Rome, Italy.
| | - Emanuela Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185, Rome, Italy.
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7
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Inoue M, Hayashi T, Hikiri S, Ikeguchi M, Kinoshita M. Hydration properties of a protein at low and high pressures: Physics of pressure denaturation. J Chem Phys 2020; 152:065103. [PMID: 32061219 DOI: 10.1063/1.5140499] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Using experimentally determined structures of ubiquitin at 1 and 3000 bar, we generate sufficiently large ensembles of model structures in the native and pressure-induced (denatured) states by means of molecular dynamics simulations with explicit water. We calculate the values of a free-energy function (FEF), which comprises the hydration free energy (HFE) and the intramolecular (conformational) energy and entropy, for the two states at 1 and 3000 bar. The HFE and the conformational entropy, respectively, are calculated using our statistical-mechanical method, which has recently been shown to be accurate, and the Boltzmann-quasi-harmonic method. The HFE is decomposed into a variety of physically insightful components. We show that the FEF of the native state is lower than that of the denatured state at 1 bar, whereas the opposite is true at 3000 bar, thus being successful in reproducing the pressure denaturation. We argue that the following two quantities of hydration play essential roles in the denaturation: the WASA-dependent term in the water-entropy loss upon cavity creation for accommodating the protein (WASA is the water-accessible surface area of the cavity) and the protein-water Lennard-Jones interaction energy. At a high pressure, the mitigation of the serious water crowding in the system is the most important, and the WASA needs to be sufficiently enlarged with the increase in the excluded-volume being kept as small as possible. The denatured structure thus induced is characterized by the water penetration into the protein interior. The pressure denaturation is accompanied by a significantly large gain of water entropy.
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Affiliation(s)
- Masao Inoue
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tomohiko Hayashi
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Simon Hikiri
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Masahiro Kinoshita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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8
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Nakagawa H, Joti Y, Kitao A, Yamamuro O, Kataoka M. Universality and Structural Implications of the Boson Peak in Proteins. Biophys J 2019; 117:229-238. [PMID: 31255295 DOI: 10.1016/j.bpj.2019.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/19/2019] [Accepted: 06/05/2019] [Indexed: 12/12/2022] Open
Abstract
The softness and rigidity of proteins are reflected in the structural dynamics, which are in turn affected by the environment. The characteristic low-frequency vibrational spectrum of a protein, known as boson peak, is an indication of the structural rigidity of the protein at a cryogenic temperature or dehydrated conditions. In this article, the effect of hydration, temperature, and pressure on the boson peak and volumetric properties of a globular protein are evaluated by using inelastic neutron scattering and molecular dynamics simulation. Hydration, pressurization, and cooling shift the boson peak position to higher energy and depress the peak intensity and decreases the protein and cavity volumes. We found the correlation between the boson peak and cavity volume in a protein. A decrease of cavity volume means the increase of rigidity, which is the origin of the boson peak shift. Boson peak is the universal property of a protein, which is rationalized by the correlation.
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Affiliation(s)
- Hiroshi Nakagawa
- Hierarchical Structure Research Group, Materials Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan.
| | - Yasumasa Joti
- XFEL Utilization Division, Japan Synchrotron Radiation Research Institute, Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro, Tokyo, Japan
| | - Osamu Yamamuro
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba, Japan
| | - Mikio Kataoka
- Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, Tokai, Naka, Ibaraki, Japan.
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9
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Golub M, Pieper J, Peters J, Kangur L, Martin EC, Hunter CN, Freiberg A. Picosecond Dynamical Response to a Pressure-Induced Break of the Tertiary Structure Hydrogen Bonds in a Membrane Chromoprotein. J Phys Chem B 2019; 123:2087-2093. [PMID: 30739452 DOI: 10.1021/acs.jpcb.8b11196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We used elastic incoherent neutron scattering (EINS) to find out if structural changes accompanying local hydrogen bond rupture are also reflected in global dynamical response of the protein complex. Chromatophore membranes from LH2-only strains of the photosynthetic bacterium Rhodobacter sphaeroides, with spheroidenone or neurosporene as the major carotenoids, were subjected to high hydrostatic pressure at ambient temperature. Optical spectroscopy conducted at high pressure confirmed rupture of tertiary structure hydrogen bonds. In parallel, we used EINS to follow average motions of the hydrogen atoms in LH2, which reflect the flexibility of this complex. A decrease of the average atomic mean square displacements of hydrogen atoms was observed up to a pressure of 5 kbar in both carotenoid samples due to general stiffening of protein structures, while at higher pressures a slight increase of the displacements was detected in the neurosporene mutant LH2 sample only. These data show a correlation between the local pressure-induced breakage of H-bonds, observed in optical spectra, with the altered protein dynamics monitored by EINS. The slightly higher compressibility of the neurosporene mutant sample shows that even subtle alterations of carotenoids are manifested on a larger scale and emphasize a close connection between the local structure and global dynamics of this membrane protein complex.
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Affiliation(s)
- Maksym Golub
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , 50411 Tartu , Estonia
| | - Jörg Pieper
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , 50411 Tartu , Estonia
| | - Judith Peters
- Institut Laue Langevin , F-38042 Grenoble Cedex 9 , France.,University Grenoble Alpes, CNRS, LIPhy , 38000 Grenoble , France
| | - Liina Kangur
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , 50411 Tartu , Estonia
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology , University of Sheffield , S10 2TN Sheffield , U.K
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology , University of Sheffield , S10 2TN Sheffield , U.K
| | - Arvi Freiberg
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , 50411 Tartu , Estonia.,Institute of Molecular and Cell Biology , University of Tartu , Riia 23 , 51010 Tartu , Estonia
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10
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Mori Y, Okamoto Y. Conformational changes of ubiquitin under high pressure conditions: A pressure simulated tempering molecular dynamics study. J Comput Chem 2017; 38:1167-1173. [DOI: 10.1002/jcc.24767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 01/13/2017] [Accepted: 01/14/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Yoshiharu Mori
- Department of Physics, Graduate School of Science; Nagoya University; Nagoya Aichi 464-8602 Japan
| | - Yuko Okamoto
- Department of Physics, Graduate School of Science; Nagoya University; Nagoya Aichi 464-8602 Japan
- JST-CREST; Nagoya Aichi 464-8602 Japan
- Structural Biology Research Center, Graduate School of Science, Nagoya University; Nagoya Aichi 464-8602 Japan
- Center for Computational Science, Graduate School of Engineering, Nagoya University; Nagoya Aichi 464-8603 Japan
- Information Technology Center, Nagoya University; Nagoya Aichi 464-8601 Japan
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11
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Ramírez-Sarmiento CA, Baez M, Zamora RA, Balasubramaniam D, Babul J, Komives EA, Guixé V. The folding unit of phosphofructokinase-2 as defined by the biophysical properties of a monomeric mutant. Biophys J 2016; 108:2350-61. [PMID: 25954892 DOI: 10.1016/j.bpj.2015.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/01/2015] [Accepted: 04/02/2015] [Indexed: 10/23/2022] Open
Abstract
Escherichia coli phosphofructokinase-2 (Pfk-2) is an obligate homodimer that follows a highly cooperative three-state folding mechanism N2 ↔ 2I ↔ 2U. The strong coupling between dissociation and unfolding is a consequence of the structural features of its interface: a bimolecular domain formed by intertwining of the small domain of each subunit into a flattened β-barrel. Although isolated monomers of E. coli Pfk-2 have been observed by modification of the environment (changes in temperature, addition of chaotropic agents), no isolated subunits in native conditions have been obtained. Based on in silico estimations of the change in free energy and the local energetic frustration upon binding, we engineered a single-point mutant to destabilize the interface of Pfk-2. This mutant, L93A, is an inactive monomer at protein concentrations below 30 μM, as determined by analytical ultracentrifugation, dynamic light scattering, size exclusion chromatography, small-angle x-ray scattering, and enzyme kinetics. Active dimer formation can be induced by increasing the protein concentration and by addition of its substrate fructose-6-phosphate. Chemical and thermal unfolding of the L93A monomer followed by circular dichroism and dynamic light scattering suggest that it unfolds noncooperatively and that the isolated subunit is partially unstructured and marginally stable. The detailed structural features of the L93A monomer and the F6P-induced dimer were ascertained by high-resolution hydrogen/deuterium exchange mass spectrometry. Our results show that the isolated subunit has overall higher solvent accessibility than the native dimer, with the exception of residues 240-309. These residues correspond to most of the β-meander module and show the same extent of deuterium uptake as the native dimer. Our results support the idea that the hydrophobic core of the isolated monomer of Pfk-2 is solvent-penetrated in native conditions and that the β-meander module is not affected by monomerizing mutations.
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Affiliation(s)
| | - Mauricio Baez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Casilla 233, Santiago, Chile
| | - Ricardo A Zamora
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
| | - Deepa Balasubramaniam
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Jorge Babul
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California.
| | - Victoria Guixé
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
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12
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Mochizuki K, Sumi T, Koga K. Driving forces for the pressure-induced aggregation of poly(N-isopropylacrylamide) in water. Phys Chem Chem Phys 2016; 18:4697-703. [DOI: 10.1039/c5cp07674a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Driving forces for the pressure-induced aggregation of poly(N-isopropylacrylamide) in water are discussed.
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Affiliation(s)
- Kenji Mochizuki
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
| | - Tomonari Sumi
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
| | - Kenichiro Koga
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
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13
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Oshima H, Kinoshita M. Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: Comparison between hard-sphere solvent and water. J Chem Phys 2015; 142:145103. [DOI: 10.1063/1.4917075] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hiraku Oshima
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Masahiro Kinoshita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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14
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Kutálková E, Hrnčiřík J, Ingr M. Pressure induced structural changes and dimer destabilization of HIV-1 protease studied by molecular dynamics simulations. Phys Chem Chem Phys 2014; 16:25906-15. [DOI: 10.1039/c4cp03676j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Dias CL, Chan HS. Pressure-Dependent Properties of Elementary Hydrophobic Interactions: Ramifications for Activation Properties of Protein Folding. J Phys Chem B 2014; 118:7488-7509. [DOI: 10.1021/jp501935f] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Cristiano L. Dias
- Department
of Physics, New Jersey Institute of Technology, University Heights, Tiernan Hall, Room 463, Newark, New Jersey 07102, United States
- Departments
of Biochemistry, Molecular Genetics, and Physics, University of Toronto, 1 King’s College Circle, Toronto, Ontario Canada M5S 1A8
| | - Hue Sun Chan
- Departments
of Biochemistry, Molecular Genetics, and Physics, University of Toronto, 1 King’s College Circle, Toronto, Ontario Canada M5S 1A8
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16
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Abedi Karjiban R, Lim WZ, Basri M, Abdul Rahman MB. Molecular Dynamics of Thermoenzymes at High Temperature and Pressure: A Review. Protein J 2014; 33:369-76. [DOI: 10.1007/s10930-014-9568-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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17
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Abstract
Fluorescence is the most widely used technique to study the effect of pressure on biochemical systems. The use of pressure as a physical variable sheds light into volumetric characteristics of reactions. Here we focus on the effect of pressure on protein solutions using a simple unfolding example in order to illustrate the applications of the methodology. Topics covered in this review include the relationships between practical aspects and technical limitations; the effect of pressure and the study of protein cavities; the interpretation of thermodynamic and relaxation kinetics; and the study of relaxation amplitudes. Finally, we discuss the insights available from the combination of fluorescence and other methods adapted to high pressure, such as SAXS or NMR. Because of the simplicity and accessibility of high-pressure fluorescence, the technique is a starting point that complements appropriately multi-methodological approaches related to understanding protein function, disfunction, and folding from the volumetric point of view.
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18
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Oshima H, Kinoshita M. Effects of sugars on the thermal stability of a protein. J Chem Phys 2014; 138:245101. [PMID: 23822280 DOI: 10.1063/1.4811287] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It is experimentally known that the heat-denaturation temperature of a protein is raised (i.e., its thermal stability is enhanced) by sugar addition. In earlier works, we proposed a physical picture of thermal denaturation of proteins in which the measure of the thermal stability is defined as the solvent-entropy gain upon protein folding at 298 K normalized by the number of residues. A multipolar-model water was adopted as the solvent. The polyatomic structures of the folded and unfolded states of a protein were taken into account in the atomic detail. A larger value of the measure implies higher thermal stability. First, we show that the measure remains effective even when the model water is replaced by the hard-sphere solvent whose number density and molecular diameter are set at those of real water. The physical picture is then adapted to the elucidation of the effects of sugar addition on the thermal stability of a protein. The water-sugar solution is modeled as a binary mixture of hard spheres. The thermal stability is determined by a complex interplay of the diameter of sugar molecules dC and the total packing fraction of the solution η: dC is estimated from the volume per molecule in the sugar crystal and η is calculated using the experimental data of the solution density. We find that the protein is more stabilized as the sucrose or glucose concentration becomes higher and the stabilization effect is stronger for sucrose than for glucose. These results are in accord with the experimental observations. Using a radial-symmetric integral equation theory and the morphometric approach, we decompose the change in the measure upon sugar addition into two components originating from the protein-solvent pair and protein-solvent many-body correlations, respectively. Each component is further decomposed into the excluded-volume and solvent-accessible-surface terms. These decompositions give physical insights into the microscopic origin of the thermal-stability enhancement by sugar addition. As an example, the higher stability of the native state relative to that of the unfolded state is found to be attributable primarily to an increase in the solvent crowding caused by sugar addition. Due to the hydrophilicity of sugar molecules, the addition of sugar by a larger amount or that with a larger molecular size leads to an increase in η which is large enough to make the solvent crowding more serious.
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Affiliation(s)
- Hiraku Oshima
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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19
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Takahashi S, Sugimoto N. Effect of pressure on thermal stability of g-quadruplex DNA and double-stranded DNA structures. Molecules 2013; 18:13297-319. [PMID: 24172240 PMCID: PMC6270079 DOI: 10.3390/molecules181113297] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/05/2013] [Accepted: 10/24/2013] [Indexed: 11/16/2022] Open
Abstract
Pressure is a thermodynamic parameter that can induce structural changes in biomolecules due to a volumetric decrease. Although most proteins are denatured by pressure over 100 MPa because they have the large cavities inside their structures, the double-stranded structure of DNA is stabilized or destabilized only marginally depending on the sequence and salt conditions. The thermal stability of the G-quadruplex DNA structure, an important non-canonical structure that likely impacts gene expression in cells, remarkably decreases with increasing pressure. Volumetric analysis revealed that human telomeric DNA changed by more than 50 cm3 mol-1 during the transition from a random coil to a quadruplex form. This value is approximately ten times larger than that for duplex DNA under similar conditions. The volumetric analysis also suggested that the formation of G-quadruplex DNA involves significant hydration changes. The presence of a cosolute such as poly(ethylene glycol) largely repressed the pressure effect on the stability of G-quadruplex due to alteration in stabilities of the interactions with hydrating water. This review discusses the importance of local perturbations of pressure on DNA structures involved in regulation of gene expression and highlights the potential for application of high-pressure chemistry in nucleic acid-based nanotechnology.
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Affiliation(s)
- Shuntaro Takahashi
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan; E-Mail:
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan; E-Mail:
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-774-98-2580; Fax: +81-774-98-2585
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20
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Dellarole M, Roumestand C, Royer C, Lecomte JTJ. Volumetric properties underlying ligand binding in a monomeric hemoglobin: a high-pressure NMR study. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1910-22. [PMID: 23619242 DOI: 10.1016/j.bbapap.2013.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 04/09/2013] [Accepted: 04/15/2013] [Indexed: 11/16/2022]
Abstract
The 2/2 hemoglobin of the cyanobacterium Synechococcus sp. PCC 7002, GlbN, coordinates the heme iron with two histidines and exists either with a b heme or with a covalently attached heme. The binding of exogenous ligands displaces the distal histidine and induces a conformational rearrangement involving the reorganization of internal void volumes. The formation of passageways within the resulting conformation is thought to facilitate ligand exchange and play a functional role. Here we monitored the perturbation induced by pressure on the ferric bis-histidine and cyanide-bound states of GlbN using (1)H-(15)N HSQC NMR spectroscopy. We inspected the outcome with a statistical analysis of 170 homologous 2/2 hemoglobin sequences. We found that the compression landscape of GlbN, as represented by the variation of an average chemical shift parameter, was highly sensitive to ligand swapping and heme covalent attachment. Stabilization of rare conformers was observed at high pressures and consistent with cavity redistribution upon ligand binding. In all states, the EF loop was found to be exceptionally labile to pressure, suggesting a functional role as a semi-flexible hinge between the adjacent helices. Finally, coevolved clusters presented a common pattern of compensating pressure responses. The high-pressure dissection combined with protein sequence analysis established locations with volumetric signatures relevant to residual communication of 2/2 hemoglobins. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.
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Affiliation(s)
- Mariano Dellarole
- Centre de Biochimie Structurale, CNRS, UMR 5048, Montpellier, France
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21
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Sarma R, Paul S. Crucial Importance of Water Structure Modification on Trimethylamine N-Oxide Counteracting Effect at High Pressure. J Phys Chem B 2013; 117:677-89. [DOI: 10.1021/jp311102v] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rahul Sarma
- 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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22
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Effect of pressure on the solution structure and hydrogen bond properties of aqueous N-methylacetamide. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Dias CL. Unifying microscopic mechanism for pressure and cold denaturations of proteins. PHYSICAL REVIEW LETTERS 2012; 109:048104. [PMID: 23006112 DOI: 10.1103/physrevlett.109.048104] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Indexed: 06/01/2023]
Abstract
We study the stability of globular proteins as a function of temperature and pressure through NPT simulations of a coarse-grained model. We reproduce the elliptical stability of proteins and highlight a unifying microscopic mechanism for pressure and cold denaturations. The mechanism involves the solvation of nonpolar residues with a thin layer of water. These solvated states have lower volume and lower hydrogen-bond energy compared to other conformations of nonpolar solutes. Hence, these solvated states are favorable at high pressure and low temperature, and they facilitate protein unfolding under these thermodynamical conditions.
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Affiliation(s)
- Cristiano L Dias
- Fachbereich Physik, Freie Universität Berlin, Arnimalle 14, 14195 Berlin, Germany
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24
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Jankowska E, Stefanowicz P, Sosnowska M, Karpowicz P, Radziszewska K, Szewczuk Z, Szymańska A. Pressure as a denaturing agent in studies of single-point mutants of an amyloidogenic protein human cystatin c. Proteins 2012; 80:2417-25. [PMID: 22674847 DOI: 10.1002/prot.24126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 05/16/2012] [Accepted: 05/28/2012] [Indexed: 11/11/2022]
Abstract
Recently, we presented a convenient method combining a deuterium-hydrogen exchange and electrospray mass spectrometry for studying high-pressure denaturation of proteins (Stefanowicz et al., Biosci Rep 2009; 30:91-99). Here, we present results of pressure-induced denaturation studies of an amyloidogenic protein-the wild-type human cystatin C (hCC) and its single-point mutants, in which Val57 residue from the hinge region was substituted by Asn, Asp or Pro, respectively. The place of mutation and the substituting residues were chosen mainly on a basis of theoretical calculations. Observation of H/D isotopic exchange proceeding during pressure induced unfolding and subsequent refolding allowed us to detect differences in the proteins stability and folding dynamics. On the basis of the obtained results we can conclude that proline residue at the hinge region makes cystatin C structure more flexible and dynamic, what probably facilitates the dimerization process of this hCC variant. Polar asparagine does not influence stability of hCC conformation significantly, whereas charged aspartic acid in 57 position makes the protein structure slightly more prone to unfolding. Our experiments also point out pressure denaturation as a valuable supplementary method in denaturation studies of mutated proteins.
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25
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Protein crowding impedes pressure-induced unfolding of staphylococcal nuclease. Biochim Biophys Acta Gen Subj 2012; 1820:957-61. [DOI: 10.1016/j.bbagen.2012.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/29/2012] [Accepted: 03/30/2012] [Indexed: 11/17/2022]
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26
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Das P, Matysiak S. Direct Characterization of Hydrophobic Hydration during Cold and Pressure Denaturation. J Phys Chem B 2012; 116:5342-8. [DOI: 10.1021/jp211832c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Payel Das
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Silvina Matysiak
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742,
United States
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27
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Sarma R, Paul S. The effect of pressure on the hydration structure around hydrophobic solute: A molecular dynamics simulation study. J Chem Phys 2012; 136:114510. [DOI: 10.1063/1.3694834] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Zhang M, Wu Y. Pressure-induced structural and hydration changes of proteins in aqueous solutions. ANAL SCI 2012; 27:1139-42. [PMID: 22076342 DOI: 10.2116/analsci.27.1139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effects of elevated hydrostatic pressure on four representative proteins, lysozyme, human serum albumin, ubiquitin and RNase A, were investigated by using Fourier transform infrared (FTIR) spectroscopy, by principal component analysis (PCA) and by moving-window two-dimensional (MW2D) correlation analysis. In addition, we revealed the pressure-induced changes of secondary structure elements using curve fitting. With pressure increase, the amide I band shifted to lower wavenumbers, with a transition at 200 MPa, which was indicative of hydration enhancement. Moreover, the pressure-induced behavior of pure water was studied, similar transition pressure was observed with protein in aqueous solution, suggesting that structure change of water around 200 MPa caused a hydration enhancement of protein. Under pressure higher than 200 MPa, the structural changes of the four proteins were obviously different except for the common features shifting to lower wavenumbers with pressure, basically due to the distinct structural differences among them.
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Affiliation(s)
- Min Zhang
- State Key Laboratory for Supramolecular Structure and Materials, Jilin University, Changchun, P. R. China
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29
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Nagae T, Kawamura T, Chavas LMG, Niwa K, Hasegawa M, Kato C, Watanabe N. High-pressure-induced water penetration into 3-isopropylmalate dehydrogenase. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:300-9. [PMID: 22349232 PMCID: PMC3282623 DOI: 10.1107/s0907444912001862] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 01/16/2012] [Indexed: 11/30/2022]
Abstract
Hydrostatic pressure induces structural changes in proteins, including denaturation, the mechanism of which has been attributed to water penetration into the protein interior. In this study, structures of 3-isopropylmalate dehydrogenase (IPMDH) from Shewanella oneidensis MR-1 were determined at about 2 Å resolution under pressures ranging from 0.1 to 650 MPa using a diamond anvil cell (DAC). Although most of the protein cavities are monotonically compressed as the pressure increases, the volume of one particular cavity at the dimer interface increases at pressures over 340 MPa. In parallel with this volume increase, water penetration into the cavity could be observed at pressures over 410 MPa. In addition, the generation of a new cleft on the molecular surface accompanied by water penetration could also be observed at pressures over 580 MPa. These water-penetration phenomena are considered to be initial steps in the pressure-denaturation process of IPMDH.
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Affiliation(s)
- Takayuki Nagae
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Japan
| | | | - Leonard M. G. Chavas
- Structural Biology Research Center, Photon Factory, High Energy Research Organization (KEK), Japan
| | - Ken Niwa
- Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Japan
| | - Masashi Hasegawa
- Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Japan
| | - Chiaki Kato
- Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan
| | - Nobuhisa Watanabe
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Japan
- Synchrotron Radiation Research Center, Nagoya University, Japan
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30
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Collins MD, Kim CU, Gruner SM. High-pressure protein crystallography and NMR to explore protein conformations. Annu Rev Biophys 2011; 40:81-98. [PMID: 21275639 DOI: 10.1146/annurev-biophys-042910-155304] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High-pressure methods for solving protein structures by X-ray crystallography and NMR are maturing. These techniques are beginning to impact our understanding of thermodynamic and structural features that define not only the protein's native conformation, but also the higher free energy conformations. The ability of high-pressure methods to visualize these mostly unexplored conformations provides new insight into protein function and dynamics. In this review, we begin with a historical discussion of high-pressure structural studies, with an eye toward early results that paved the way to mapping the multiple conformations of proteins. This is followed by an examination of several recent studies that emphasize different strengths and uses of high-pressure structural studies, ranging from basic thermodynamics to the suggestion of high-pressure structural methods as a tool for protein engineering.
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Affiliation(s)
- Marcus D Collins
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA
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31
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Acharya H, Vembanur S, Jamadagni SN, Garde S. Mapping hydrophobicity at the nanoscale: applications to heterogeneous surfaces and proteins. Faraday Discuss 2010; 146:353-65; discussion 367-93, 395-401. [PMID: 21043432 DOI: 10.1039/b927019a] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Approaches to quantify wetting at the macroscale do not translate to the nanoscale, highlighting the need for new methods for characterizing hydrophobicity at the small scale. We use extensive molecular simulations to study the hydration of homo and heterogeneous self-assembled monolayers (SAMs) and of protein surfaces. For homogeneous SAMs, new pressure-dependent analysis shows that water displays higher compressibility and enhanced density fluctuations near hydrophobic surfaces, which are gradually quenched with increasing hydrophilicity, consistent with our previous studies. Heterogeneous surfaces show an interesting context dependence--adding a single -OH group in a CH3 terminated SAM has a more dramatic effect on water in the vicinity compared to that of a single CH3 group in an -OH background. For mixed -CH3/-OH SAMs, this asymmetry leads to a non-linear dependence of hydrophobicity on the surface concentration. We also present preliminary results to map hydrophobicity of protein surfaces by monitoring local density fluctuations and binding of probe hydrophobic solutes. These molecular measures account for the behavior of protein's hydration water, and present a more refined picture of its hydrophobicity map. At least for one protein, hydrophobin-II, we show that the hydrophobicity map is different from that suggested by a commonly used hydropathy scale.
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Affiliation(s)
- Hari Acharya
- The Howard P. Isermann Department of Chemical & Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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32
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Sarupria S, Ghosh T, García AE, Garde S. Studying pressure denaturation of a protein by molecular dynamics simulations. Proteins 2010; 78:1641-51. [PMID: 20146357 DOI: 10.1002/prot.22680] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Many globular proteins unfold when subjected to several kilobars of hydrostatic pressure. This "unfolding-up-on-squeezing" is counter-intuitive in that one expects mechanical compression of proteins with increasing pressure. Molecular simulations have the potential to provide fundamental understanding of pressure effects on proteins. However, the slow kinetics of unfolding, especially at high pressures, eliminates the possibility of its direct observation by molecular dynamics (MD) simulations. Motivated by experimental results-that pressure denatured states are water-swollen, and theoretical results-that water transfer into hydrophobic contacts becomes favorable with increasing pressure, we employ a water insertion method to generate unfolded states of the protein Staphylococcal Nuclease (Snase). Structural characteristics of these unfolded states-their water-swollen nature, retention of secondary structure, and overall compactness-mimic those observed in experiments. Using conformations of folded and unfolded states, we calculate their partial molar volumes in MD simulations and estimate the pressure-dependent free energy of unfolding. The volume of unfolding of Snase is negative (approximately -60 mL/mol at 1 bar) and is relatively insensitive to pressure, leading to its unfolding in the pressure range of 1500-2000 bars. Interestingly, once the protein is sufficiently water swollen, the partial molar volume of the protein appears to be insensitive to further conformational expansion or unfolding. Specifically, water-swollen structures with relatively low radii of gyration have partial molar volume that are similar to that of significantly more unfolded states. We find that the compressibility change on unfolding is negligible, consistent with experiments. We also analyze hydration shell fluctuations to comment on the hydration contributions to protein compressibility. Our study demonstrates the utility of molecular simulations in estimating volumetric properties and pressure stability of proteins, and can be potentially extended for applications to protein complexes and assemblies.
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Affiliation(s)
- Sapna Sarupria
- Howard P Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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33
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General Framework of Pressure Effects on Structures Formed by Entropically Driven Self-Assembly. ENTROPY 2010. [DOI: 10.3390/e12061632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Imai T, Sugita Y. Dynamic Correlation between Pressure-Induced Protein Structural Transition and Water Penetration. J Phys Chem B 2010; 114:2281-6. [DOI: 10.1021/jp909701j] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takashi Imai
- Computational Science Research Program and Advanced Science Institute, RIKEN, Wako, Saitama 351-0112, Japan
| | - Yuji Sugita
- Computational Science Research Program and Advanced Science Institute, RIKEN, Wako, Saitama 351-0112, Japan
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35
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Martínez L, Souza PCT, Garcia W, Batista FAH, Portugal RV, Nascimento AS, Nakahira M, Lima LMTR, Polikarpov I, Skaf MS. On the Denaturation Mechanisms of the Ligand Binding Domain of Thyroid Hormone Receptors. J Phys Chem B 2009; 114:1529-40. [DOI: 10.1021/jp911554p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Leandro Martínez
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Paulo C. T. Souza
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Wanius Garcia
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Fernanda A. H. Batista
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Rodrigo V. Portugal
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Alessandro S. Nascimento
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Marcel Nakahira
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Luis M. T. R. Lima
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Igor Polikarpov
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Munir S. Skaf
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
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Moghaddam S, Caliskan G, Chauhan S, Hyeon C, Briber RM, Thirumalai D, Woodson SA. Metal ion dependence of cooperative collapse transitions in RNA. J Mol Biol 2009; 393:753-64. [PMID: 19712681 PMCID: PMC2772878 DOI: 10.1016/j.jmb.2009.08.044] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/18/2009] [Accepted: 08/18/2009] [Indexed: 10/20/2022]
Abstract
Positively charged counterions drive RNA molecules into compact configurations that lead to their biologically active structures. To understand how the valence and size of the cations influences the collapse transition in RNA, small-angle X-ray scattering was used to follow the decrease in the radius of gyration (R(g)) of the Azoarcus and Tetrahymena ribozymes in different cations. Small, multivalent cations induced the collapse of both ribozymes more efficiently than did monovalent ions. Thus, the cooperativity of the collapse transition depends on the counterion charge density. Singular value decomposition of the scattering curves showed that folding of the smaller and more thermostable Azoarcus ribozyme is well described by two components, whereas collapse of the larger Tetrahymena ribozyme involves at least one intermediate. The ion-dependent persistence length, extracted from the distance distribution of the scattering vectors, shows that the Azoarcus ribozyme is less flexible at the midpoint of transition in low-charge-density ions than in high-charge-density ions. We conclude that the formation of sequence-specific tertiary interactions in the Azoarcus ribozyme overlaps with neutralization of the phosphate charge, while tertiary folding of the Tetrahymena ribozyme requires additional counterions. Thus, the stability of the RNA structure determines its sensitivity to the valence and size of the counterions.
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Affiliation(s)
- Sarvin Moghaddam
- Dept. of Materials Science and Engineering, University of Maryland, College Park, MD 20472
| | - Gokhan Caliskan
- T. C. Jenkins Dept. of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2685
| | - Seema Chauhan
- Dept. of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2685
| | - Changbong Hyeon
- Dept. of Chemistry, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - R. M. Briber
- Dept. of Materials Science and Engineering, University of Maryland, College Park, MD 20472
| | - D. Thirumalai
- Biophysics Program, Institute for Physical Sciences and Technology, University of Maryland, College Park, MD 20472 USA
| | - Sarah A. Woodson
- T. C. Jenkins Dept. of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2685
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37
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Aswal VK, Chodankar S, Kohlbrecher J, Vavrin R, Wagh AG. Small-angle neutron scattering study of protein unfolding and refolding. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:011924. [PMID: 19658746 DOI: 10.1103/physreve.80.011924] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 04/02/2009] [Indexed: 05/28/2023]
Abstract
Small-angle neutron scattering has been used to study protein unfolding and refolding in protein bovine serum albumin (BSA) due to perturbation in its native structure as induced by three different protein denaturating agents: urea, surfactant, and pressure. The BSA protein unfolds for urea concentrations greater than 4 M and is observed to be independent of the protein concentration. The addition of surfactant unfolds the protein by the formation of micellelike aggregates of surfactants along the unfolded polypeptide chains of the protein and depends on the ratio of surfactant to protein concentration. We make use of the dilution method to show the refolding of unfolded proteins in the presence of urea and surfactant. BSA does not show any protein unfolding up to the pressure of 450 MPa. The presence of urea and surfactant (for concentrations prior to inducing their own unfolding) has been used to examine pressure-induced unfolding of the protein at lower pressures. The protein unfolds at 200 MPa pressure in the presence of urea; however, no unfolding is observed with surfactant. The protein unfolding is shown to be reversible in all the above denaturating methods.
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Affiliation(s)
- V K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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38
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Krywka C, Sternemann C, Paulus M, Tolan M, Royer C, Winter R. Effect of Osmolytes on Pressure-Induced Unfolding of Proteins: A High-Pressure SAXS Study. Chemphyschem 2008; 9:2809-15. [DOI: 10.1002/cphc.200800522] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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39
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Harano Y, Yoshidome T, Kinoshita M. Molecular mechanism of pressure denaturation of proteins. J Chem Phys 2008; 129:145103. [DOI: 10.1063/1.2991176] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Ando N, Barstow B, Baase WA, Fields A, Matthews BW, Gruner SM. Structural and thermodynamic characterization of T4 lysozyme mutants and the contribution of internal cavities to pressure denaturation. Biochemistry 2008; 47:11097-109. [PMID: 18816066 DOI: 10.1021/bi801287m] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using small-angle X-ray scattering (SAXS) and tryptophan fluorescence spectroscopy, we have identified multiple compact denatured states of a series of T4 lysozyme mutants that are stabilized by high pressures. Recent studies imply that the mechanism of pressure denaturation is the penetration of water into the protein rather than the transfer of hydrophobic residues into water. To investigate water penetration and the volume change associated with pressure denaturation, we studied the solution behavior of four T4 lysozyme mutants having different cavity volumes at low and neutral pH up to a pressure of 400 MPa (0.1 MPa = 0.9869 atm). At low pH, L99A T4 lysozyme expanded from a compact folded state to a partially unfolded state with a corresponding change in radius of gyration from 17 to 32 A. The volume change upon denaturation correlated well with the total cavity volume, indicating that all of the molecule's major cavities are hydrated with pressure. As a direct comparison to high-pressure crystal structures of L99A T4 lysozyme solved at neutral pH [Collins, M. D., Hummer, G., Quillin, M. L., Matthews, B. W., and Gruner, S. M. (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 16668-16671], pressure denaturation of L99A and the structurally similar L99G/E108V mutant was studied at neutral pH. The pressure-denatured state at neutral pH is even more compact than at low pH, and the small volume changes associated with denaturation suggest that the preferential filling of large cavities is responsible for the compactness of the pressure-denatured state. These results confirm that pressure denaturation is characteristically distinct from thermal or chemical denaturation.
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Affiliation(s)
- Nozomi Ando
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
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41
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Kim YH, Stites WE. Effects of excluded volume upon protein stability in covalently cross-linked proteins with variable linker lengths. Biochemistry 2008; 47:8804-14. [PMID: 18656955 DOI: 10.1021/bi800297j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To explore the effects of molecular crowding and excluded volume upon protein stability, we used a series of cross-linking reagents with nine different single-cysteine mutants of staphylococcal nuclease to make covalently linked dimers. These cross-linkers ranged in length from 10.5 to 21.3 A, compelling separations which would normally be found only in the most concentrated protein solutions. The stabilities of the dimeric proteins and monomeric controls were determined by guanidine hydrochloride and thermal denaturation. Dimers with short linkers tend to exhibit pronounced three-state denaturation behavior, as opposed to the two-state behavior of the monomeric controls. Increasing linker length leads to less pronounced three-state behavior. The three-state behavior is interpreted in a three-state model where cross-linked native protein dimer, N-N, interconverts in a two-state transition with a dimer where one protein subunit is denatured, N-D. The remaining native protein in turn can denature in another two-state transition to a state, D-D, in which both tethered proteins are denatured. Three-state behavior is best explained by excluded volume effects in the denatured state. For many dimers, linkers longer than 17 A removed most three-state character. This sets a limit on the flexibility and size of the denatured state. Notably, in contradiction to theoretical predictions, these cross-linked dimers were not stabilized. The failure of these predictions is possibly due to neglect of the alteration in hydrophobic exposure that accompanies any significant reduction in the conformational space of the denatured state.
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Affiliation(s)
- Yun Ho Kim
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701-1021, USA
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42
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Djikaev YS, Ruckenstein E. Thermal denaturation of a native protein via spinodal decomposition in the framework of first-passage-time analysis. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:011909. [PMID: 18763984 DOI: 10.1103/physreve.78.011909] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Indexed: 05/26/2023]
Abstract
In this paper we present a kinetic model for the thermal unfolding of a native protein. Due to a sufficiently large temperature increase or decrease, the rate with which a cluster of native residues within a protein emits residues becomes larger than the rate of absorption of residues from the unfolded part of the protein in the whole range of cluster sizes up to the size of the whole protein. This leads to the unfolding of the protein in a barrierless way, i.e., as spinodal decomposition. Using the formalism of the first passage time analysis [previously applied also to the problem of protein folding via nucleation by the authors, J. Phys. Chem. B 111, 886 (2007); J. Chem. Phys. 126, 175103 (2007)], one can determine the temperature dependence of the rates of emission and absorption of residues by the cluster. Knowing these rates as functions of temperature and cluster size, one can find the threshold temperatures of cold and hot barrierless denaturation as well as the unfolding times at temperatures lower and higher, respectively, than those threshold values. For a numerical illustration, the method is applied to the thermal unfolding of a model protein consisting of 2500 residues.
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Affiliation(s)
- Y S Djikaev
- Department of Chemical and Biological Engineering, SUNY at Buffalo, Buffalo, New York 14260, USA.
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43
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Kangur L, Timpmann K, Freiberg A. Stability of Integral Membrane Proteins under High Hydrostatic Pressure: The LH2 and LH3 Antenna Pigment−Protein Complexes from Photosynthetic Bacteria. J Phys Chem B 2008; 112:7948-55. [DOI: 10.1021/jp801943w] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Liina Kangur
- Institute of Physics, University of Tartu, Riia 142, Tartu 51014, Estonia, and Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia
| | - Kõu Timpmann
- Institute of Physics, University of Tartu, Riia 142, Tartu 51014, Estonia, and Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia
| | - Arvi Freiberg
- Institute of Physics, University of Tartu, Riia 142, Tartu 51014, Estonia, and Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia
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44
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Chodankar S, Aswal VK, Kohlbrecher J, Vavrin R, Wagh AG. Structural evolution during protein denaturation as induced by different methods. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:031901. [PMID: 18517416 DOI: 10.1103/physreve.77.031901] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 11/19/2007] [Indexed: 05/26/2023]
Abstract
Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) have been used to study conformational changes in protein bovine serum albumin (BSA) due to perturbation in its native structure as induced by varying temperature and pressure, and in presence of protein denaturating agents urea and surfactant. BSA has prolate ellipsoidal shape at ambient temperature and we observe no effect of temperature on its structure up to a temperature of about 60 degrees C . At temperatures beyond 60 degrees C , protein denaturation leads to aggregation. The protein solution exhibits a fractal structure at temperatures above 64 degrees C , and its fractal dimension increases with temperature. This is an indication of aggregation followed by gelation that evolves with increasing temperature. It is known for some of the proteins (e.g., Staphylococcal Nuclease) that pressure of 200 MPa can unfold the protein, whereas BSA does not show any protein unfolding even up to the pressure of 450 MPa . In presence of urea, the BSA protein unfolds for urea concentrations greater than 4M and acquires a random coil configuration. We make use of the dilution method to show the reversibility of protein unfolding with urea. The addition of surfactant denaturates the protein by the formation of micellelike aggregates of surfactants along the unfolded polypeptide chains of the protein. We show such structure of the protein-surfactant complex can be stabilized at higher temperatures, which is not the case for pure protein.
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Affiliation(s)
- S Chodankar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085, India
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45
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Patel BA, Debenedetti PG, Stillinger FH, Rossky PJ. A water-explicit lattice model of heat-, cold-, and pressure-induced protein unfolding. Biophys J 2007; 93:4116-27. [PMID: 17766342 PMCID: PMC2098741 DOI: 10.1529/biophysj.107.108530] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigate the effect of temperature and pressure on polypeptide conformational stability using a two-dimensional square lattice model in which water is represented explicitly. The model captures many aspects of water thermodynamics, including the existence of density anomalies, and we consider here the simplest representation of a protein: a hydrophobic homopolymer. We show that an explicit treatment of hydrophobic hydration is sufficient to produce cold, pressure, and thermal denaturation. We investigate the effects of the enthalpic and entropic components of the water-protein interactions on the overall folding phase diagram, and show that even a schematic model such as the one we consider yields reasonable values for the temperature and pressure ranges within which highly compact homopolymer configurations are thermodynamically stable.
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Affiliation(s)
- Bryan A Patel
- Department of Chemical Engineering, Princeton University, Princeton, New Jersey, USA.
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46
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Oleinikova A, Smolin N, Brovchenko I. Origin of the dynamic transition upon pressurization of crystalline proteins. J Phys Chem B 2007; 110:19619-24. [PMID: 17004829 DOI: 10.1021/jp0629590] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We study the role of hydration water in the dynamic transition of low-hydrated proteins upon pressurization found recently (Meinhold, L.; Smith, J. C. Phys. Rev. E 2005, 72, 061908). Clustering and percolation of water in the hydration shells of protein molecules in crystalline Staphylococcal nuclease are analyzed at various pressures. The number of water molecules in the hydration shell increases and the hydrogen-bonded network of hydration water spans with increasing pressure. The dynamic transition of protein occurs when the spanning water network exists with the probability of about 50% and hydration water shows large density fluctuations. Formation of a spanning water network upon pressurization promotes protein dynamics as in the case of the dynamic transition with increasing hydration. Properties of hydration water in various thermodynamic states and their influence on biological function are discussed.
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Affiliation(s)
- Alla Oleinikova
- Department of Physical Chemistry, University of Dortmund, Otto-Hahn-Strasse 6, Dortmund D-44227, Germany.
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47
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Imai T, Ohyama S, Kovalenko A, Hirata F. Theoretical study of the partial molar volume change associated with the pressure-induced structural transition of ubiquitin. Protein Sci 2007; 16:1927-33. [PMID: 17660257 PMCID: PMC2206979 DOI: 10.1110/ps.072909007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The partial molar volume (PMV) change associated with the pressure-induced structural transition of ubiquitin is analyzed by the three-dimensional reference interaction site model (3D-RISM) theory of molecular solvation. The theory predicts that the PMV decreases upon the structural transition, which is consistent with the experimental observation. The volume decomposition analysis demonstrates that the PMV reduction is primarily caused by the decrease in the volume of structural voids in the protein, which is partially canceled by the volume expansion due to the hydration effects. It is found from further analysis that the PMV reduction is ascribed substantially to the penetration of water molecules into a specific part of the protein. Based on the thermodynamic relation, this result implies that the water penetration causes the pressure-induced structural transition. It supports the water penetration model of pressure denaturation of proteins proposed earlier.
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Affiliation(s)
- Takashi Imai
- Department of Bioscience and Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
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48
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Yamazaki T, Imai T, Hirata F, Kovalenko A. Theoretical study of the cosolvent effect on the partial molar volume change of staphylococcal nuclease associated with pressure denaturation. J Phys Chem B 2007; 111:1206-12. [PMID: 17266276 DOI: 10.1021/jp064615f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We explain the molecular mechanism of the effect of urea and glycerol cosolvents on the partial molar volume (PMV) change associated with the pressure denaturation of staphylococcal nuclease (SNase) protein recently observed in experiments. Native and denatured conformations of SNase are produced by using molecular dynamics simulations in water, and the PMV is obtained from the integral equation theory of molecular liquids called 3D-RISM, which is based on statistical mechanics. The PMV of the native SNase in water predicted by 3D-RISM theory is in good agreement with experiment. The PMV changes associated with pressure denaturation in water and in water-urea and water-glycerol mixtures are qualitatively reproduced. By analyzing the results obtained, we found two interesting cosolvent effects on the PMV: (1) both urea and glycerol cosolvents increase the PMVs of both native and denatured SNase compared to those in water and (2) both urea and glycerol cosolvents increase the PMV of denatured SNase more than that of native SNase. We also showed that these two observations can be explained in terms of the thermal volume, which is related to the packing effect of solvent molecules.
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Affiliation(s)
- Takeshi Yamazaki
- Department of Mechanical Engineering, University of Alberta, and National Institute for Nanotechnology, National Research Council of Canada, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
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49
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Olivares-Quiroz L, Garcia-Colin LS. Protein's native state stability in a chemically induced denaturation mechanism. J Theor Biol 2007; 246:214-24. [PMID: 17306831 DOI: 10.1016/j.jtbi.2006.12.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 12/06/2006] [Accepted: 12/12/2006] [Indexed: 11/23/2022]
Abstract
In this work, we present a generalization of Zwanzig's protein unfolding analysis [Zwanzig, R., 1997. Two-state models of protein folding kinetics. Proc. Natl Acad. Sci. USA 94, 148-150; Zwanzig, R., 1995. Simple model of protein folding kinetics. Proc. Natl Acad. Sci. USA 92, 9801], in order to calculate the free energy change Delta(N)(D)F between the protein's native state N and its unfolded state D in a chemically induced denaturation. This Extended Zwanzig Model (EZM) is both based on an equilibrium statistical mechanics approach and the inclusion of experimental denaturation curves. It enables us to construct a suitable partition function Z and to derive an analytical formula for Delta(N)(D)F in terms of the number K of residues of the macromolecule, the average number nu of accessible states for each single amino acid and the concentration C(1/2) where the midpoint of the N<==>D transition occurs. The results of the EZM for proteins where chemical denaturation follows a sigmoidal-type profile, as it occurs for the case of the T70N human variant of lysozyme (PDB code: T70N) [Esposito, G., et al., 2003. J. Biol. Chem. 278, 25910-25918], can be splitted into two lines. First, EZM shows that for sigmoidal denaturation profiles, the internal degrees of freedom of the chain play an outstanding role in the stability of the native state. On the other hand, that under certain conditions DeltaF can be written as a quadratic polynomial on concentration C(1/2), i.e., DeltaF approximately aC(1/2)(2)+bC(1/2)+c, where a,b,c are constant coefficients directly linked to protein's size K and the averaged number of non-native conformations nu. Such functional form for DeltaF has been widely known to fit experimental measures in chemically induced protein denaturation [Yagi, M., et al., 2003. J. Biol. Chem. 278, 47009-47015; Asgeirsson, B., Guojonsdottir, K., 2006. Biochim. Biophys. Acta 1764, 190-198; Sharma, S., et al., 2006. Protein Pept. Lett. 13(4), 323-329; Salem, M., et al., 2006. Biochim. Biophys. Acta 1764(5), 903-912] so EZM can shed some light into the physical meaning of the experimental values for the a,b,c coefficients.
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Affiliation(s)
- L Olivares-Quiroz
- Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Mexico DF 09340, Mexico.
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50
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Ado K, Taniguchi Y. Pressure effects on the structure and function of human thioredoxin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:813-21. [PMID: 17574940 DOI: 10.1016/j.bbapap.2007.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 03/13/2007] [Accepted: 03/14/2007] [Indexed: 12/15/2022]
Abstract
Thioredoxin is one of the major proteins that catalyze disulfide reduction and defines the thioredoxin superfamily bearing the CXXC structural motif. Human thioredoxin contains only 1 Trp residue proximal to the active site (WCGPC). We are interested in thioredoxin structure-function relationships, in particular, active site hydration and flexibility. Hence, in this study, we used hydrostatic pressure as a perturbation and monitored the conformational changes around the active site of thioredoxin by analyzing Trp fluorescence. The structure of thioredoxin was drastically altered by increasing pressure and did not completely refold after pressure release. The conformation in the active site vicinity was modified at low pressure (less than 100 MPa) and the Trp residue was completely exposed to aqueous medium at pressures above 350 MPa. Upon pressure release, thioredoxin showed no activity, although it folded 80% of the alpha-helical content relative to the native state. According to these results, pressure denaturation induces critical damage for the activity of thioredoxin, indicating extreme fragility of the active site with respect to pressure. This result is in contrast to the pressure effect on protein disulfide isomerase (PDI) which is organized by four thioredoxin-like domains including two WCGHC motifs.
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Affiliation(s)
- Kazuyoshi Ado
- Department of Applied Chemistry, College of Science and Engineering, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga 525-8577, Japan
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