1
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Hindson SA, Bunzel HA, Frank B, Svistunenko DA, Williams C, van der Kamp MW, Mulholland AJ, Pudney CR, Anderson JLR. Rigidifying a De Novo Enzyme Increases Activity and Induces a Negative Activation Heat Capacity. ACS Catal 2021; 11:11532-11541. [PMID: 34557328 PMCID: PMC8453482 DOI: 10.1021/acscatal.1c01776] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/29/2021] [Indexed: 12/22/2022]
Abstract
![]()
Conformational sampling
profoundly impacts the overall activity
and temperature dependence of enzymes. Peroxidases have emerged as
versatile platforms for high-value biocatalysis owing to their broad
palette of potential biotransformations. Here, we explore the role
of conformational sampling in mediating activity in the de
novo peroxidase C45. We demonstrate that 2,2,2-triflouoroethanol
(TFE) affects the equilibrium of enzyme conformational states, tending
toward a more globally rigid structure. This is correlated with increases
in both stability and activity. Notably, these effects are concomitant
with the emergence of curvature in the temperature-activity profile,
trading off activity gains at ambient temperature with losses at high
temperatures. We apply macromolecular rate theory (MMRT) to understand
enzyme temperature dependence data. These data point to an increase
in protein rigidity associated with a difference in the distribution
of protein dynamics between the ground and transition states. We compare
the thermodynamics of the de novo enzyme activity
to those of a natural peroxidase, horseradish peroxidase. We find
that the native enzyme resembles the rigidified de novo enzyme in terms of the thermodynamics of enzyme catalysis and the
putative distribution of protein dynamics between the ground and transition
states. The addition of TFE apparently causes C45 to behave more like
the natural enzyme. Our data suggest robust, generic strategies for
improving biocatalytic activity by manipulating protein rigidity;
for functional de novo protein catalysts in particular,
this can provide more enzyme-like catalysts without further rational
engineering, computational redesign, or directed evolution.
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Affiliation(s)
- Sarah A. Hindson
- Department of Biology and Biochemistry, Centre for Sustainable Chemical Technology, University of Bath, Bath BA2 7AY, U.K
| | - H. Adrian Bunzel
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, U.K
- Centre for Computational Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Bettina Frank
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, U.K
- Bristol Centre for Functional Nanomaterials, School of Physics, University of Bristol, Bristol BS8 1TL, U.K
| | | | | | | | | | - Christopher R. Pudney
- Department of Biology and Biochemistry, Centre for Sustainable Chemical Technology, University of Bath, Bath BA2 7AY, U.K
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2
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Gerringer ME, Yancey PH, Tikhonova OV, Vavilov NE, Zgoda VG, Davydov DR. Pressure tolerance of deep-sea enzymes can be evolved through increasing volume changes in protein transitions: a study with lactate dehydrogenases from abyssal and hadal fishes. FEBS J 2020; 287:5394-5410. [PMID: 32250538 PMCID: PMC7818408 DOI: 10.1111/febs.15317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 03/15/2020] [Accepted: 03/27/2020] [Indexed: 11/28/2022]
Abstract
We explore the principles of pressure tolerance in enzymes of deep-sea fishes using lactate dehydrogenases (LDH) as a case study. We compared the effects of pressure on the activities of LDH from hadal snailfishes Notoliparis kermadecensis and Pseudoliparis swirei with those from a shallow-adapted Liparis florae and an abyssal grenadier Coryphaenoides armatus. We then quantified the LDH content in muscle homogenates using mass-spectrometric determination of the LDH-specific conserved peptide LNLVQR. Existing theory suggests that adaptation to high pressure requires a decrease in volume changes in enzymatic catalysis. Accordingly, evolved pressure tolerance must be accompanied with an important reduction in the volume change associated with pressure-promoted alteration of enzymatic activity ( Δ V PP ∘ ). Our results suggest an important revision to this paradigm. Here, we describe an opposite effect of pressure adaptation-a substantial increase in the absolute value of Δ V PP ∘ in deep-living species compared to shallow-water counterparts. With this change, the enzyme activities in abyssal and hadal species do not substantially decrease their activity with pressure increasing up to 1-2 kbar, well beyond full-ocean depth pressures. In contrast, the activity of the enzyme from the tidepool snailfish, L. florae, decreases nearly linearly from 1 to 2500 bar. The increased tolerance of LDH activity to pressure comes at the expense of decreased catalytic efficiency, which is compensated with increased enzyme contents in high-pressure-adapted species. The newly discovered strategy is presumably used when the enzyme mechanism involves the formation of potentially unstable excited transient states associated with substantial changes in enzyme-solvent interactions.
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3
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Phillips RS, Craig S, Kovalevsky A, Gerlits O, Weiss K, Iorgu AI, Heyes DJ, Hay S. Pressure and Temperature Effects on the Formation of Aminoacrylate Intermediates of Tyrosine Phenol-lyase Demonstrate Reaction Dynamics. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert S. Phillips
- Department of Chemistry, University of Georgia, Athens, Georgia 30602 United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Steven Craig
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6475, United States
| | - Oksana Gerlits
- Tennessee Wesleyan University, Athens, Tennessee 37303, United States
| | - Kevin Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6475, United States
| | - Andreea I. Iorgu
- Manchester Institute of Biotechnology and Department of Chemistry, The University of Manchester, Manchester M17DN, U.K
| | - Derren J. Heyes
- Manchester Institute of Biotechnology and Department of Chemistry, The University of Manchester, Manchester M17DN, U.K
| | - Sam Hay
- Manchester Institute of Biotechnology and Department of Chemistry, The University of Manchester, Manchester M17DN, U.K
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4
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Stiller JB, Kerns SJ, Hoemberger M, Cho YJ, Otten R, Hagan MF, Kern D. Probing the Transition State in Enzyme Catalysis by High-Pressure NMR Dynamics. Nat Catal 2019; 2:726-734. [PMID: 32159076 DOI: 10.1038/s41929-019-0307-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein conformational changes are frequently essential for enzyme catalysis, and in several cases, shown to be the limiting factor for overall catalytic speed. However, a structural understanding of corresponding transition states, needed to rationalize the kinetics, remains obscure due to their fleeting nature. Here, we determine the transition-state ensemble of the rate-limiting conformational transition in the enzyme adenylate kinase, by a synergistic approach between experimental high-pressure NMR relaxation during catalysis and molecular dynamics simulations. By comparing homologous kinases evolved under ambient or high pressure in the deep-sea, we detail transition state ensembles that differ in solvation as directly measured by the pressure dependence of catalysis. Capturing transition-state ensembles begins to complete the catalytic energy landscape that is generally characterized by structures of all intermediates and frequencies of transitions among them.
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Affiliation(s)
- John B Stiller
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
| | - S Jordan Kerns
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Marc Hoemberger
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Young-Jin Cho
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States.,Present addresses: S.J.K. 27 Drydock Ave, Boston MA 02110 , M.H. 225 Binney St, Cambridge, MA 02142, Y.J.C. 733 Concord Ave Cambridge, MA 02138
| | - Renee Otten
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
| | - Michael F Hagan
- Department of Physics, Brandeis University, Waltham, Massachusetts 02452, United States
| | - Dorothee Kern
- Department of Biochemistry and Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02452, United States
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5
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Elucidation of pressure-induced lid movement and catalysis behavior of Rhizopus chinensis lipase. Int J Biol Macromol 2017; 103:360-365. [DOI: 10.1016/j.ijbiomac.2017.04.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 12/19/2022]
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6
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Chen G, Du H, Jiang B, Miao M, Feng B. Activity of Candida rugosa lipase for synthesis of hexyl octoate under high hydrostatic pressure and the mechanism of this reaction. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2017.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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7
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Decaneto E, Suladze S, Rosin C, Havenith M, Lubitz W, Winter R. Pressure and Temperature Effects on the Activity and Structure of the Catalytic Domain of Human MT1-MMP. Biophys J 2016; 109:2371-81. [PMID: 26636948 DOI: 10.1016/j.bpj.2015.10.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/12/2015] [Accepted: 10/19/2015] [Indexed: 11/19/2022] Open
Abstract
Membrane type 1-matrix metalloproteinase (MT1-MMP or MMP-14) is a zinc-transmembrane metalloprotease involved in the degradation of extracellular matrix and tumor invasion. While changes in solvation of MT1-MMP have been recently studied, little is known about the structural and energetic changes associated with MT1-MMP while interacting with substrates. Steady-state kinetic and thermodynamic data (including activation energies and activation volumes) were measured over a wide range of temperatures and pressures by means of a stopped-flow fluorescence technique. Complementary temperature- and pressure-dependent Fourier-transform infrared measurements provided corresponding structural information of the protein. MT1-MMP is stable and active over a wide range of temperatures (10-55 °C). A small conformational change was detected at 37 °C, which is responsible for the change in activity observed at the same temperature. Pressure decreases the enzymatic activity until complete inactivation occurs at 2 kbar. The inactivation is associated with changes in the rate-limiting step of the reaction caused by additional hydration of the active site upon compression and/or minor conformational changes in the active site region. Based on these data, an energy and volume diagram could be established for the various steps of the enzymatic reaction.
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Affiliation(s)
- Elena Decaneto
- Max Planck Institute for Chemical Energy Conversion, Mülheim a. d. Ruhr, Germany; Department of Physical Chemistry II, Ruhr-University Bochum, Bochum, Germany
| | - Saba Suladze
- Department of Chemistry and Chemical Biology, Physical Chemistry, Technische Universität Dortmund, Dortmund, Germany
| | - Christopher Rosin
- Department of Chemistry and Chemical Biology, Physical Chemistry, Technische Universität Dortmund, Dortmund, Germany
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr-University Bochum, Bochum, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Mülheim a. d. Ruhr, Germany
| | - Roland Winter
- Department of Chemistry and Chemical Biology, Physical Chemistry, Technische Universität Dortmund, Dortmund, Germany.
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8
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Suladze S, Cinar S, Sperlich B, Winter R. Pressure Modulation of the Enzymatic Activity of Phospholipase A2, A Putative Membrane-Associated Pressure Sensor. J Am Chem Soc 2015; 137:12588-96. [DOI: 10.1021/jacs.5b07009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Saba Suladze
- Department of Chemistry and
Chemical Biology, Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 6, D-44221 Dortmund, Germany
| | - Suleyman Cinar
- Department of Chemistry and
Chemical Biology, Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 6, D-44221 Dortmund, Germany
| | - Benjamin Sperlich
- Department of Chemistry and
Chemical Biology, Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 6, D-44221 Dortmund, Germany
| | - Roland Winter
- Department of Chemistry and
Chemical Biology, Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 6, D-44221 Dortmund, Germany
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9
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Hoeven R, Heyes DJ, Hay S, Scrutton NS. Does the pressure dependence of kinetic isotope effects report usefully on dynamics in enzyme H-transfer reactions? FEBS J 2015; 282:3243-55. [PMID: 25581554 PMCID: PMC4949571 DOI: 10.1111/febs.13193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/15/2014] [Accepted: 01/08/2015] [Indexed: 11/30/2022]
Abstract
The temperature dependence of kinetic isotope effects (KIEs) has emerged as the main experimental probe of enzymatic H-transfer by quantum tunnelling. Implicit in the interpretation is a presumed role for dynamic coupling of H-transfer chemistry to the protein environment, the so-called 'promoting motions/vibrations hypothesis'. This idea remains contentious, and others have questioned the importance and/or existence of promoting motions/vibrations. New experimental methods of addressing this problem are emerging, including use of mass-modulated enzymes and time-resolved spectroscopy. The pressure dependence of KIEs has been considered as a potential probe of quantum tunnelling reactions, because semi-classical KIEs, which are defined by differences in zero-point vibrational energy, are relatively insensitive to kbar changes in pressure. Reported combined pressure and temperature (p-T) dependence studies of H-transfer reactions are, however, limited. Here, we extend and review the available p-T studies that have utilized well-defined experimental systems in which quantum mechanical tunnelling is established. These include flavoproteins, quinoproteins, light-activated enzymes and chemical model systems. We show that there is no clear general trend between the p-T dependencies of the KIEs in these systems. Given the complex nature of p-T studies, we conclude that computational simulations using determined (e.g. X-ray) structures are also needed alongside experimental measurements of reaction rates/KIEs to guide the interpretation of p-T effects. In providing new insight into H-transfer/environmental coupling, combined approaches that unite both atomistic understanding with experimental rate measurements will require careful evaluation on a case-by-case basis. Although individually informative, we conclude that p-T studies do not provide the more generalized insight that has come from studies of the temperature dependence of KIEs.
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Affiliation(s)
- Robin Hoeven
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Derren J Heyes
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
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10
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Kuroi K, Okajima K, Ikeuchi M, Tokutomi S, Kamiyama T, Terazima M. Pressure-Sensitive Reaction Yield of the TePixD Blue-Light Sensor Protein. J Phys Chem B 2015; 119:2897-907. [DOI: 10.1021/jp511946u] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kunisato Kuroi
- Department of Chemistry, Graduate School
of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Koji Okajima
- Department of Life Sciences (Biology),
Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan
- Department
of Biological Science, Graduate School of Science, Osaka Prefecture University, Sakai,
Osaka 599-8531, Japan
| | - Masahiko Ikeuchi
- Department of Life Sciences (Biology),
Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan
| | - Satoru Tokutomi
- Department
of Biological Science, Graduate School of Science, Osaka Prefecture University, Sakai,
Osaka 599-8531, Japan
| | - Tadashi Kamiyama
- Department of Chemistry, School of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Masahide Terazima
- Department of Chemistry, Graduate School
of Science, Kyoto University, Kyoto 606-8502, Japan
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11
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Chakraborty S, Kaushik N, Rao PS, Mishra HN. High-Pressure Inactivation of Enzymes: A Review on Its Recent Applications on Fruit Purees and Juices. Compr Rev Food Sci Food Saf 2014; 13:578-596. [PMID: 33412700 DOI: 10.1111/1541-4337.12071] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 03/10/2014] [Indexed: 11/29/2022]
Abstract
In the last 2 decades high-pressure processing (HPP) has established itself as one of the most suitable nonthermal technologies applied to fruit products for the extension of shelf-life. Several oxidative and pectic enzymes are responsible for deterioration in color, flavor, and texture in fruit purees and juices (FP&J). The effect of HPP on the activities of polyphenoloxidase, peroxidase, β-glucosidase, pectinmethylesterase, polygalacturonase, lipoxygenase, amylase, and hydroperoxide lyase specific to FP&J have been studied by several researchers. In most of the cases, partial inactivation of the target enzymes was possible under the experimental domain, although their pressure sensitivity largely depended on the origin and their microenvironmental condition. The variable sensitivity of different enzymes also reflects on their kinetics. Several empirical models have been established to describe the kinetics of an enzyme specific to a FP&J. The scientific literature in the last decade illustrating the effects of HPP on enzymes in FP&J, enzymatic action on those products, mechanism of enzyme inactivation during high pressure, their inactivation kinetics, and several intrinsic and extrinsic factors influencing the efficacy of HPP is critically reviewed in this article. In addition, process optimization of HPP targeting specific enzymes is of great interest from an industrial approach. This review will give a fair idea about the target enzymes specific to FP&J and the optimum conditions needed to achieve sufficient inactivation during HPP treatment.
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Affiliation(s)
- Snehasis Chakraborty
- Agricultural and Food Engineering Dept, Indian Inst. of Technology, Kharagpur, 721302, India
| | - Neelima Kaushik
- Agricultural and Food Engineering Dept, Indian Inst. of Technology, Kharagpur, 721302, India
| | - P Srinivasa Rao
- Agricultural and Food Engineering Dept, Indian Inst. of Technology, Kharagpur, 721302, India
| | - H N Mishra
- Agricultural and Food Engineering Dept, Indian Inst. of Technology, Kharagpur, 721302, India
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12
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Davydov DR, Sineva EV, Davydova NY, Bartlett DH, Halpert JR. CYP261 enzymes from deep sea bacteria: a clue to conformational heterogeneity in cytochromes P450. Biotechnol Appl Biochem 2013; 60:30-40. [PMID: 23586990 DOI: 10.1002/bab.1083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 12/14/2012] [Indexed: 11/12/2022]
Abstract
We have explored the adaptation of the cytochromes P450 (P450) of deep-sea bacteria to high hydrostatic pressures. Strict conservation of the protein fold and functional importance of protein-bound water make P450 a unique subject for the studies of high-pressure adaptation. Earlier, we expressed and purified a fatty-acid binding P450 from the deep-sea bacteria Photobacterium profundum SS9 (CYP261C1). Here, we report purification and initial characterization of its mesophilic ortholog from the shallow-water P. profundum 3TCK (CYP261C2), as well as another piezophilic enzyme, CYP261D1, from deep-sea Moritella sp. PE36. Comparison of the three enzymes revealed a striking peculiarity of the piezophilic enzymes. Both CYP261C1 and CYP261D1 possess an apparent pressure-induced conformational toggle actuated at the pressures commensurate with the physiological pressure of habitation of the host bacteria. Furthermore, in contrast to CYP261C2, the piezophilic CYP261 enzymes may be chromatographically separated into two fractions with different properties, and different thermodynamic parameters of spin equilibrium in particular. According to our concept, the changes in the energy landscape that evolved in pressure-tolerant enzymes must stabilize the less-hydrated, closed conformers, which may be transient in the catalytic mechanisms of nonpiezophilic enzymes. The studies of enzymes of piezophiles should help unravel the mechanisms that control water access during the catalytic cycle.
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Affiliation(s)
- Dmitri R Davydov
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA.
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13
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Phillips RS, Wang AK, Marchal S, Lange R. Effects of Pressure and Osmolytes on the Allosteric Equilibria of Salmonella typhimurium Tryptophan Synthase. Biochemistry 2012; 51:9354-63. [DOI: 10.1021/bi301002q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert S. Phillips
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United
States
| | - Alexandre Kim Wang
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Stephane Marchal
- Inserm U710, Montpellier, F-34095 France, Université de Montpellier 2, Montpellier, F-34095 France, and EPHE, Paris, F-75007 France
| | - Reinhard Lange
- Inserm U710, Montpellier, F-34095 France, Université de Montpellier 2, Montpellier, F-34095 France, and EPHE, Paris, F-75007 France
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14
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Temperature- and pressure-dependent stopped-flow kinetic studies of jack bean urease. Implications for the catalytic mechanism. J Biol Inorg Chem 2012; 17:1123-34. [PMID: 22890689 PMCID: PMC3442171 DOI: 10.1007/s00775-012-0926-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/14/2012] [Indexed: 12/03/2022]
Abstract
Abstract Urease, a Ni-containing metalloenzyme, features an activity that has profound medical and agricultural implications. The mechanism of this activity, however, has not been as yet thoroughly established. Accordingly, to improve its understanding, in this study we analyzed the steady-state kinetic parameters of the enzyme (jack bean), KM and kcat, measured at different temperatures and pressures. Such an analysis is useful as it provides information on the molecular nature of the intermediate and transition states of the catalytic reaction. We measured the parameters in a noninteracting buffer using a stopped-flow technique in the temperature range 15–35 °C and in the pressure range 5–132 MPa, the pressure-dependent measurements being the first of their kind performed for urease. While temperature enhanced the activity of urease, pressure inhibited the enzyme; the inhibition was biphasic. Analyzing KM provided the characteristics of the formation of the ES complex, and analyzing kcat, the characteristics of the activation of ES. From the temperature-dependent measurements, the energetic parameters were derived, i.e. thermodynamic ΔHo and ΔSo for ES formation, and kinetic ΔH≠ and ΔS≠ for ES activation, while from the pressure-dependent measurements, the binding ΔVb and activation \documentclass[12pt]{minimal}
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\begin{document}$$ \Updelta V_{\rm cat}^{ \ne } $$\end{document} volumes were determined. The thermodynamic and activation parameters obtained are discussed in terms of the current proposals for the mechanism of the urease reaction, and they are found to support the mechanism proposed by Benini et al. (Structure 7:205–216; 1999), in which the Ni–Ni bridging hydroxide—not the terminal hydroxide—is the nucleophile in the catalytic reaction. Graphical abstract ![]()
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15
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Giel-Pietraszuk M, Barciszewski J. Hydrostatic and osmotic pressure study of the RNA hydration. Mol Biol Rep 2012; 39:6309-18. [PMID: 22314910 PMCID: PMC3310992 DOI: 10.1007/s11033-012-1452-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 01/23/2012] [Indexed: 11/17/2022]
Abstract
The tertiary structure of nucleic acids results from an equilibrium between electrostatic interactions of phosphates, stacking interactions of bases, hydrogen bonds between polar atoms and water molecules. Water interactions with ribonucleic acid play a key role in its structure formation, stabilization and dynamics. We used high hydrostatic pressure and osmotic pressure to analyze changes in RNA hydration. We analyzed the lead catalyzed hydrolysis of tRNAPhe from S. cerevisiae as well as hydrolytic activity of leadzyme. Pb(II) induced hydrolysis of the single phosphodiester bond in tRNAPhe is accompanied by release of 98 water molecules, while other molecule, leadzyme releases 86.
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Affiliation(s)
- Małgorzata Giel-Pietraszuk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
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16
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Sanfeld A, Sefiane K, Steinchen A. Reactions of dipolar bio-molecules in nano-capsules--example of folding-unfolding process. Adv Colloid Interface Sci 2011; 169:26-39. [PMID: 21867984 DOI: 10.1016/j.cis.2011.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 07/22/2011] [Accepted: 07/24/2011] [Indexed: 11/29/2022]
Abstract
The confinement of chemical reactions in nano-capsules can lead to a dramatic effect on the equilibrium constant of these latter. Indeed, capillary effects due to the curvature and surface energy of nano-capsules can alter in a noticeable way the evolution of reactions occurring within. Nano-encapsulation of bio-materials has attracted lately wide interest from the scientific community because of the great potential of its applications in biomedical areas and targeted therapies. The present paper focuses one's attention on alterations of conformation mechanisms due to extremely confining and interacting solvated dipolar macromolecules at their isoelectric point. As a specific example studied here, the folding-unfolding reaction of proteins (particularly RNase A and creatine kinase CK) is drastically changed when encapsulated in solid inorganic hollow nano-capsules. The effects demonstrated in this work can be extended to a wide variety of nano-encapsulation situations. The design and sizing of nano-capsules can even make use of the effects shown in the present study to achieve better and more effective encapsulation.
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Affiliation(s)
- A Sanfeld
- ISM2-AD2M, UMR 6263, Universitė Paul Cezanne, Bd Escadrille Normandie Niemen, 13397, Marseille Cedex 20, France
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Rosenbaum E, Gabel F, Durá MA, Finet S, Cléry-Barraud C, Masson P, Franzetti B. Effects of hydrostatic pressure on the quaternary structure and enzymatic activity of a large peptidase complex from Pyrococcus horikoshii. Arch Biochem Biophys 2011; 517:104-10. [PMID: 21896270 DOI: 10.1016/j.abb.2011.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 07/31/2011] [Indexed: 10/17/2022]
Abstract
While molecular adaptation to high temperature has been extensively studied, the effect of hydrostatic pressure on protein structure and enzymatic activity is still poorly understood. We have studied the influence of pressure on both the quaternary structure and enzymatic activity of the dodecameric TET3 peptidase from Pyrococcus horikoshii. Small angle X-ray scattering (SAXS) revealed a high robustness of the oligomer under high pressure of up to 300 MPa at 25°C as well as at 90°C. The enzymatic activity of TET3 was enhanced by pressure up to 180 MPa. From the pressure behavior of the different rate-constants we have determined the volume changes associated with substrate binding and catalysis. Based on these results we propose that a change in the rate-limiting step occurs around 180 MPa.
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Affiliation(s)
- Eva Rosenbaum
- Group Extremophiles and Large Molecular Assemblies (ELMA), CEA, Institut de Biologie Structurale, Grenoble, France
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18
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Steinchen A, Sefiane K, Sanfeld A. Nano-encapsulation as high pressure devices for folding–unfolding proteins. J Colloid Interface Sci 2011; 355:509-11. [DOI: 10.1016/j.jcis.2010.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 11/25/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
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19
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Stawoska I, Gawęda S, Bielak-Lakomska M, Brindell M, Lewiński K, Laidler P, Stochel G. Mechanistic studies of the hydrolysis of p-nitrophenyl sulfate catalyzed by arylsulfatase from Helix pomatia. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.500377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Iwona Stawoska
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
| | - Sylwia Gawęda
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
| | - Magdalena Bielak-Lakomska
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
| | - Małgorzata Brindell
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
| | - Krzysztof Lewiński
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
| | - Piotr Laidler
- b Chair of Medical Biochemistry , Jagiellonian University, Medical College , Kopernika 7, 31-034 Kraków, Poland
| | - Grażyna Stochel
- a Department of Inorganic Chemistry, Faculty of Chemistry , Jagiellonian University , Ingardena 3, 30-060 Kraków, Poland
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20
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Integrative analytical approach by capillary electrophoresis and kinetics under high pressure optimized for deciphering intrinsic and extrinsic cofactors that modulate activity and stability of human paraoxonase (PON1). J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:1346-55. [DOI: 10.1016/j.jchromb.2009.11.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/21/2022]
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21
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22
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Osváth S, Quynh LM, Smeller L. Thermodynamics and kinetics of the pressure unfolding of phosphoglycerate kinase. Biochemistry 2009; 48:10146-50. [PMID: 19775155 DOI: 10.1021/bi900922f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Due to the relationship between compressibility and volume fluctuations, high-pressure studies provide vital insight into protein dynamics and function. Most high-pressure experiments were performed on small and fast folding proteins or model peptides. Here we show that a detailed kinetic study is necessary to extract reliable information from the high-pressure-induced structural conversion of large, slowly folding proteins. The pressure-jump unfolding kinetics of yeast phosphoglycerate kinase was recorded at pressures between 50 and 150 MPa. The time dependence of the conformational state of the protein was followed by tryptophan fluorescence measurements from 30 s to 2 h. The observed changes were described by a three-state model, and the volume change and the activation volume as well as the midpoint pressure of the transitions between the folded, intermediate, and unfolded states were determined. An interesting feature of the pressure unfolding of phosphoglycerate kinase was that the unfolding process speeds up with increasing pressure, which is the consequence of negative activation volumes for the folded --> intermediate, intermediate --> unfolded, and unfolded --> intermediate transitions.
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Affiliation(s)
- Szabolcs Osváth
- Department of Biophysics and Radiation Biology, Semmelweis University, Tuzolto u. 37-47, Budapest, H-1094 Hungary
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23
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Exploring the structural and functional stabilities of different paraoxonase-1 formulations through electrophoretic mobilities and enzyme activity parameters under hydrostatic pressure. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:680-8. [DOI: 10.1016/j.bbapap.2009.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 01/15/2009] [Accepted: 01/20/2009] [Indexed: 11/23/2022]
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24
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Hay S, Pudney CR, McGrory TA, Pang J, Sutcliffe MJ, Scrutton NS. Barrier compression enhances an enzymatic hydrogen-transfer reaction. Angew Chem Int Ed Engl 2009; 48:1452-4. [PMID: 19145622 DOI: 10.1002/anie.200805502] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Putting the squeeze on: Hydrostatic pressure causes a shortening of the charge-transfer bond in the binary complex of morphinone reductase and NADH(4) (see diagram). Molecular dynamics simulations suggest that pressure reduces the average reaction barrier width by restricting the conformational space available to the flavin mononucleotide and NADH within the active site. The apparent rate of catalysis increases with pressure.
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Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester, UK
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Hay S, Pudney C, McGrory T, Pang J, Sutcliffe M, Scrutton N. Barrier Compression Enhances an Enzymatic Hydrogen‐Transfer Reaction. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200805502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐8918
| | - Christopher R. Pudney
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐8918
| | - Tom A. McGrory
- Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐5201
| | - Jiayun Pang
- Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐5201
| | - Michael J. Sutcliffe
- Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐5201
| | - Nigel S. Scrutton
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐306‐8918
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26
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Hay S, Scrutton NS. Incorporation of hydrostatic pressure into models of hydrogen tunneling highlights a role for pressure-modulated promoting vibrations. Biochemistry 2008; 47:9880-7. [PMID: 18717597 DOI: 10.1021/bi8005972] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrostatic pressure offers an alternative to temperature as an experimental probe of hydrogen-transfer reactions. H tunneling reactions have been shown to exhibit kinetic isotope effects (KIEs) that are sensitive to pressure, and environmentally coupled H tunneling reactions, those reactions in which H transfer is coupled to atomic fluctuations (a promoting vibration) along the reaction coordinate, often have quite temperature-dependent KIEs. We present here a theoretical treatment of the combined effect of temperature and pressure on environmentally coupled H tunneling reactions. We develop a generalized expression for the KIE, which can be used as a simple fitting function for combined experimental temperature- and pressure-dependent KIE data sets. With this expression, we are able to extract information about the pressure dependence of both the apparent tunneling distance and the frequency of the promoting vibration. The KIE expression is tested on two data sets {the reduction of chloranil by leuco crystal violet [Isaacs, N. S., Javaid, K., and Rannala, E. (1998) J. Chem. Soc., Perkin Trans. 2, 709-711] and the reduction of morphinone reductase by NADH [Hay, S., Sutcliffe, M. J., and Scrutton, N. S. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 507-512]} and suggests that hydrostatic pressure is a sensitive probe of nuclear quantum mechanical effects in H-transfer reactions.
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Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
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27
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Salvay AG, Santamaria M, le Maire M, Ebel C. Analytical ultracentrifugation sedimentation velocity for the characterization of detergent-solubilized membrane proteins Ca++-ATPase and ExbB. J Biol Phys 2008; 33:399-419. [PMID: 19669527 DOI: 10.1007/s10867-008-9058-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 01/28/2008] [Indexed: 10/22/2022] Open
Abstract
We have investigated the potential of new methods of analysis of sedimentation velocity (SV) analytical ultracentrifugation (AUC) for the characterization of detergent-solubilized membrane proteins. We analyze the membrane proteins Ca(++)-ATPase and ExbB solubilized with DDM (dodecyl-beta-D: -maltoside). SV is extremely well suited for characterizing sample heterogeneity. DDM micelles (s(20w) = 3.1 S) and complexes (Ca(++)-ATPase: s(20w) = 7.3 S; ExbB: s(20w) = 4 S) are easily distinguished. Using different detergent and protein concentrations, SV does not detect any evidence of self-association for the two proteins. An estimate of bound detergent of 0.9 g/g for Ca(++)-ATPase and 1.5 g/g for ExbB is obtained from the combined analysis of SV profiles obtained using absorbance and interference optics. Combining s(20w) with values of the hydrodynamic radius, R(s) = 5.5 nm for Ca(++)-ATPase or R(s) = 3.4 nm for ExbB, allows the determination of buoyant molar masses, M(b). In view of their M(b) and composition, Ca(++)-ATPase and ExbB are monomers in our experimental conditions. We conclude that one of the main advantages of SV versus other techniques is the possibility to ascertain the homogeneity of the samples and to focus on a given complex even in the presence of other impurities or aggregates. The relative rapidity of SV measurements also allows experiments on unstable samples.
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Affiliation(s)
- Andrés G Salvay
- CNRS, IBS, Laboratoire de Biophysique Moléculaire, Grenoble 38027, France
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28
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Ohmae E, Tatsuta M, Abe F, Kato C, Tanaka N, Kunugi S, Gekko K. Effects of pressure on enzyme function of Escherichia coli dihydrofolate reductase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1115-21. [PMID: 18472025 DOI: 10.1016/j.bbapap.2008.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 11/26/2022]
Abstract
To elucidate the effects of pressure on the function of Escherichia coli dihydrofolate reductase (DHFR), the enzyme activity and the dissociation constants of substrates and cofactors were measured at pressures up to 250 MPa at 25 degrees C and pH 7.0. The enzyme activity decreased with increasing pressure, accompanying the activation volume of 7.8 ml mol(-1). The values of the Michaelis constant (K(m)) for dihydrofolate and NADPH were slightly higher at 200 MPa than at atmospheric pressure. The hydride-transfer step was insensitive to pressure, as monitored by the effects of the deuterium isotope of NADPH on the reaction velocity. The dissociation constants of substrates and cofactors increased with pressure, producing volume reductions from 6.5 ml mol(-1) (tetrahydrofolate) to 33.5 ml mol(-1) (NADPH). However, the changes in Gibbs free energy with dissociation of many ligands showed different pressure dependences below and above 50 MPa, suggesting conformational changes of the enzyme at high pressure. The enzyme function at high pressure is discussed based on the volume levels of the intermediates and the candidates for the rate-limiting process.
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Affiliation(s)
- Eiji Ohmae
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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29
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Buckow R, Weiss U, Heinz V, Knorr D. Stability and catalytic activity of alpha-amylase from barley malt at different pressure-temperature conditions. Biotechnol Bioeng 2007; 97:1-11. [PMID: 17013936 DOI: 10.1002/bit.21209] [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: 11/08/2022]
Abstract
The impact of high hydrostatic pressure and temperature on the stability and catalytic activity of alpha-amylase from barley malt has been investigated. Inactivation experiments with alpha-amylase in the presence and absence of calcium ions have been carried out under combined pressure-temperature treatments in the range of 0.1-800 MPa and 30-75 degrees C. A stabilizing effect of Ca(2+) ions on the enzyme was found at all pressure-temperature combinations investigated. Kinetic analysis showed deviations of simple first-order reactions which were attributed to the presence of isoenzyme fractions. Polynomial models were used to describe the pressure-temperature dependence of the inactivation rate constants. Derived from that, pressure-temperature isokinetic diagrams were constructed, indicating synergistic and antagonistic effects of pressure and temperature on the inactivation of alpha-amylase. Pressure up to 200 MPa significantly stabilized the enzyme against temperature-induced inactivation. On the other hand, pressure also hampers the catalytic activity of alpha-amylase and a progressive deceleration of the conversion rate was detected at all temperatures investigated. However, for the overall reaction of blocked p-nitrophenyl maltoheptaoside cleavage and simultaneous occurring enzyme inactivation in ACES buffer (0.1 M, pH 5.6, 3.8 mM CaCl(2)), a maximum of substrate cleavage was identified at 152 MPa and 64 degrees C, yielding approximately 25% higher substrate conversion after 30 min, as compared to the maximum at ambient pressure and 59 degrees C.
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Affiliation(s)
- Roman Buckow
- Department of Food Biotechnology and Food Process Engineering, Berlin University of Technology, Koenigin-Luise-Str. 22, D-14195 Berlin, Germany
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30
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Knorr D, Heinz V, Buckow R. High pressure application for food biopolymers. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:619-31. [PMID: 16540383 DOI: 10.1016/j.bbapap.2006.01.017] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 01/23/2006] [Accepted: 01/23/2006] [Indexed: 11/18/2022]
Abstract
High hydrostatic pressure constitutes an efficient physical tool to modify food biopolymers, such as proteins or starches. This review presents data on the effects of high hydrostatic pressure in combination with temperature on protein stability, enzymatic activity and starch gelatinization. Attention is given to the protein thermodynamics in response to combined pressure and temperature treatments specifically on the pressure-temperature-isokineticity phase diagrams of selected enzymes, prions and starches relevant in food processing and biotechnology.
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Affiliation(s)
- Dietrich Knorr
- Department of Food Biotechnology and Food Process Engineering, Berlin Technical University, Königin-Luise-Str. 22, D-14195 Berlin, Germany.
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31
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Gorren ACF, Marchal S, Sørlie M, Andersson KK, Lange R, Mayer B. High-pressure studies of the reaction mechanism of nitric-oxide synthase. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1764:578-85. [PMID: 16376159 DOI: 10.1016/j.bbapap.2005.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 11/02/2005] [Indexed: 10/25/2022]
Abstract
Nitric-oxide synthase (NOS) generates nitric oxide from l-arginine in two reaction cycles with N(omega)-hydroxy-l-arginine as an obligate intermediate. Although much progress has been made in recent years in the elucidation of the reaction mechanism of NOS, many questions remain to be answered. The use of low temperature has been instrumental in the revelation of the mechanism of NO synthesis, particularly regarding the role of the cofactor 5,6,7,8-tetrahydrobopterin (BH4). High-pressure studies may be expected to be similarly useful, but have been very few so far. In this short review, we depict the present state of knowledge about the reaction mechanism of NO synthesis, and the role(s) BH4 plays in it. This exposition is followed by a summary of the results obtained thus far in high-pressure studies and of the conclusions that can be drawn from them.
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Affiliation(s)
- Antonius C F Gorren
- Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria.
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