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Gorokhov VV, Korvatovsky BN, Knox PP, Grishanova NP, Goryachev SN, Pashchenko VZ, Rubin AB. Temperature Dependence of Tryptophan Fluorescence Lifetime as an Indicator of Its Microenvironment Dynamics. DOKL BIOCHEM BIOPHYS 2021; 498:170-176. [PMID: 34189644 DOI: 10.1134/s1607672921030030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/29/2021] [Accepted: 02/05/2021] [Indexed: 11/23/2022]
Abstract
The spectral-kinetic characteristics of the fluorescence of the tryptophan molecule in an aqueous solution and in the composition of a protein (albumin) were studied in the temperature range from -170 to 25°C. To explain the observed changes in the spectra and the tryptophan fluorescence lifetime with temperature, a model of transitions between the excited and ground states involving a charge-transfer state was used, which takes into account the nonlinear nature of the dynamics of these transitions. In these processes, an important role is played by the interaction of tryptophan molecules with its microenvironment, as well as rearrangements in the system of hydrogen bonds of the water-protein matrix surrounding the tryptophan molecule.
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Affiliation(s)
| | | | - P P Knox
- Moscow State University, Moscow, Russia
| | | | | | | | - A B Rubin
- Moscow State University, Moscow, Russia
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2
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Paschenko VZ, Gorokhov VV, Korvatovsky BN, Knox PP, Grishanova NP, Goryachev SN. A Study of the Temperature Dependence of Tryptophan Fluorescence Lifetime in the Range of –170 to +20°С in Various Solvents. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921030143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kumaran R, Gayathri S, Augustine Arul Prasad T, Dhenadhayalan N, Keerthiga R, Sureka S, Jeevitha K, Karthick P. Fluorescence and quantum mechanical approach on the interaction of amides and their role on the stability and coexistence of the rotamer conformations of L-tryptophan in aqueous solution. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 243:118791. [PMID: 32810781 DOI: 10.1016/j.saa.2020.118791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Photophysical investigation on the fluorescence decay characteristics of L-tryptophan and a derivative N-acetyl-L-tryptophanamide (NATA) with alkyl amides were carried out in water. L-tryptophan exists in the zwitterionic form and exhibits a biexponential lifetime which is correlated to the existence of rotamer structures. Addition of formamide (F) and dimethylformamide (DMF) results in a decrease in the fluorescence lifetime and its proportion of the most stable structure of L-tryptophan wherein acetamide (ACM) results in an increase of the same. Interestingly, all the amides result in the formation of the lifetime of the rotamer whose lifetime doesn't exist initially and the lifetime and its distribution increases irrespective of the nature of amide. The interaction between L-tryptophan and amide is attributed to hydrogen-bonding such that these interactions influence the relative proportion of the existence of individual rotamers in the presence of amides.Strikingly, in the case of NATA that does not exhibit rotamer structures; the fluorescence lifetime is quenched in the presence of F, whereas ACM and DMF result in a larger fold of enhancement resulting in two different lifetimes. The variation in the fluorescence lifetime and amplitude of the various conformers of L-tryptophan and of NATA is completely governed by the concentration of the amides in solution such that the microenvironment surrounding the fluorophores are completely reorganised. The hydrogen-bonding functional groups in amides that are responsible for the coexistence of rotamers are elucidated and well supported by quantum mechanical (QM) studies. Time-correlated single-photon counting(TCSPC) technique is used as a probe as well as marker in establishing the variation in the lifetime properties of L-tryptophan and NATA with non-fluorescent hydrogen-bonding solutes in water which promotes this as fascinating field of research in the context of fluorescence properties of a complicated amino acid-like tryptophan.
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Affiliation(s)
- Rajendran Kumaran
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India.
| | - Somasundaram Gayathri
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
| | - Thomas Augustine Arul Prasad
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
| | | | - Ravichandran Keerthiga
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
| | - Suresh Sureka
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
| | - Kumar Jeevitha
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
| | - Pargunan Karthick
- Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous) (Affiliated to University of Madras), 833, Gokul Bagh, E.V.R.Periyar Road, Arumbakkam, Chennai 600106, Tamil Nadu, India
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Knox PP, Gorokhov VV, Korvatovsky BN, Grishanova NP, Goryachev SN, Paschenko VZ. Specific features of the temperature dependence of tryptophan fluorescence lifetime in the temperature range of −170–20 °C. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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5
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Knox PP, Gorokhov VV, Korvatovskiy BN, Lukashev EP, Goryachev SN, Paschenko VZ, Rubin AB. The effect of light and temperature on the dynamic state of Rhodobacter sphaeroides reaction centers proteins determined from changes in tryptophan fluorescence lifetime and P +Q A- recombination kinetics. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 180:140-148. [PMID: 29413697 DOI: 10.1016/j.jphotobiol.2018.01.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/22/2018] [Accepted: 01/29/2018] [Indexed: 11/26/2022]
Abstract
The temperature dependencies of the rate of dark recombination of separated charges between the photoactive bacteriochlorophyll and the primary quinone acceptor (QA) in photosynthetic reaction centers (RCs) of the purple bacteria Rhodobacter sphaeroides (Rb. sphaeroides) were investigated. Measurements were performed in water-glycerol and trehalose environments after freezing to -180 °C in the dark and under actinic light with subsequent heating. Simultaneously, the RC tryptophanyl fluorescence lifetime in the spectral range between 323 and 348 nm was measured under these conditions. A correlation was found between the temperature dependencies of the functional and dynamic parameters of RCs in different solvent mixtures. For the first time, differences in the average fluorescence lifetime of tryptophanyl residues were measured between RCs frozen in the dark and in the actinic light. The obtained results can be explained by the RC transitions between different conformational states and the dynamic processes in the structure of the hydrogen bonds of RCs. We assumed that RCs exist in two main microconformations - "fast" and "slow", which are characterized by different rates of P+ and QA- recombination reactions. The "fast" conformation is induced in frozen RCs in the dark, while the "slow" conformation of RC occurs when the RC preparation is frozen under actinic light. An explanation of the temperature dependencies of tryptophan fluorescence lifetimes in RC proteins was made under the assumption that temperature changes affect mainly the electron transfer from the indole ring of the tryptophan molecule to the nearest amide or carboxyl groups.
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Affiliation(s)
- Peter P Knox
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vladimir V Gorokhov
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Boris N Korvatovskiy
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Eugene P Lukashev
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Sergey N Goryachev
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vladimir Z Paschenko
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Andrew B Rubin
- Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
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6
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Gorokhov VV, Knox PP, Korvatovskiy BN, Seifullina NK, Goryachev SN, Paschenko VZ. Temperature Dependence of Tryptophan Fluorescence Lifetime in Aqueous Glycerol and Trehalose Solutions. BIOCHEMISTRY (MOSCOW) 2018; 82:1269-1275. [PMID: 29223153 DOI: 10.1134/s0006297917110049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The temperature dependences of tryptophan fluorescence decay kinetics in aqueous glycerol and 1 M trehalose solutions were examined. The fluorescence decay kinetics were recorded in the spectral region of 292.5-417.5 nm with nanosecond time resolution. The kinetics curves were approximated by the sum of three exponential terms, and the spectral distribution (DAS) of these components was determined. An antisymbatic course of fluorescence decay times of two (fast and medium) components in the temperature range from -60 to +10°C was observed. The third (slow) component showed only slight temperature dependence. The antisymbatic behavior of fluorescence lifetimes of the fast and medium components was explained on the assumption that some of the excited tryptophan molecules are transferred from a short-wavelength B-form with short fluorescence lifetime to a long-wavelength R-form with an intermediate fluorescence lifetime. This transfer occurred in the indicated temperature range.
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Affiliation(s)
- V V Gorokhov
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia.
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7
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Knox PP, Lukashev EP, Korvatovskii BN, Gorokhov VV, Grishanova NP, Seyfullina NK, Paschenko VZ, Rubin AB. A comparison of the temperature dependence of charge recombination in the ion-radical pair P870+QA - and tryptophan fluorescence in the photosynthetic reaction centers of Rhodobacter sphaeroides. Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s0006350916060191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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8
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Meyer V, Swanson MA, Clouston LJ, Boratyński PJ, Stein RA, Mchaourab HS, Rajca A, Eaton SS, Eaton GR. Room-temperature distance measurements of immobilized spin-labeled protein by DEER/PELDOR. Biophys J 2016; 108:1213-9. [PMID: 25762332 DOI: 10.1016/j.bpj.2015.01.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/17/2014] [Accepted: 01/14/2015] [Indexed: 11/18/2022] Open
Abstract
Nitroxide spin labels are used for double electron-electron resonance (DEER) measurements of distances between sites in biomolecules. Rotation of gem-dimethyls in commonly used nitroxides causes spin echo dephasing times (Tm) to be too short to perform DEER measurements at temperatures between ∼80 and 295 K, even in immobilized samples. A spirocyclohexyl spin label has been prepared that has longer Tm between 80 and 295 K in immobilized samples than conventional labels. Two of the spirocyclohexyl labels were attached to sites on T4 lysozyme introduced by site-directed spin labeling. Interspin distances up to ∼4 nm were measured by DEER at temperatures up to 160 K in water/glycerol glasses. In a glassy trehalose matrix the Tm for the doubly labeled T4 lysozyme was long enough to measure an interspin distance of 3.2 nm at 295 K, which could not be measured for the same protein labeled with the conventional 1-oxyl-2,2,5,5-tetramethyl-3-pyrroline-3-(methyl)methanethio-sulfonate label.
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Affiliation(s)
- Virginia Meyer
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Michael A Swanson
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Laura J Clouston
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska
| | | | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska
| | - Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado
| | - Gareth R Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado.
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Draganski AR, Corradini MG, Ludescher RD. Revisiting time-resolved protein phosphorescence. APPLIED SPECTROSCOPY 2015; 69:1074-1081. [PMID: 26253845 DOI: 10.1366/14-07799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Analysis of time-resolved phosphorescence data from proteins presents certain problems. Care must be taken in establishing that the analysis is not confounded in the early part of the decay by other emitting species. These species may include tyrosine, impurities found in the solvent, or impurities bound to the protein. In this paper, analysis of the phosphorescence of simple mixtures of tryptophan, tyrosine, and tryptophan + tyrosine in glycerol-water solvent has demonstrated the necessity of accounting for tyrosine emission in the analysis of protein phosphorescence. The tyrosine emission is especially strong at cold temperatures and becomes negligible above approximately 185 K in this solvent. Two fitting procedures have been developed to describe the bimodal emission that results from a single-tryptophan protein that contains a significant number of tyrosine residues. The methods utilize either a maximum entropy method-derived lifetime distribution or the stretched exponential function. In both cases some prior information regarding the expected decay characteristics of the tryptophan residue is applied to guide the separation of the tryptophan component from the tyrosine component. This prior information is obtained by comparing the tail of the protein decay to decays of free-tryptophan in solvent at a variety of temperatures until a match is found having close overlap on a log-intensity decay plot.
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Affiliation(s)
- Andrew R Draganski
- Rutgers University, Department of Food Science, 65 Dudley Road, New Brunswick, NJ 08901 USA
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10
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Chauhan S, Kumar K. Effect of glycine on aqueous solution behavior of saccharides at different temperatures: Volumetric and ultrasonic studies. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2014.03.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Zelent B, Buettger C, Grimsby J, Sarabu R, Vanderkooi JM, Wand AJ, Matschinsky FM. Thermal stability of glucokinase (GK) as influenced by the substrate glucose, an allosteric glucokinase activator drug (GKA) and the osmolytes glycerol and urea. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:769-84. [PMID: 22446163 DOI: 10.1016/j.bbapap.2012.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/15/2012] [Accepted: 03/05/2012] [Indexed: 11/27/2022]
Abstract
We investigated how glycerol, urea, glucose and a GKA influence kinetics and stability of wild-type and mutant GK. Glycerol and glucose stabilized GK additively. Glycerol barely affected the TF spectra of all GKs but decreased k(cat), glucose S(0.5) and K(D) values and ATP K(M) while leaving cooperativity unchanged. Glycerol sensitized all GKs to GKA as shown by TF. Glucose increased TF of GKs without influence of glycerol on the effect. Glycerol and GKA affected kinetics and binding additively. The activation energies for thermal denaturation of GK were a function of glucose with K(D)s of 3 and 1mM without and with glycerol, respectively. High urea denatured wild type GK reversibly at 20 and 60°C and urea treatment of irreversibly heat denatured GK allowed refolding as demonstrated by TF including glucose response. We concluded: Glycerol stabilizes GK indirectly without changing the folding structure of the apoenzyme, by restructuring the surface water of the protein, whereas glucose stabilizes GK directly by binding to its substrate site and inducing a compact conformation. Glucose or glycerol (alone or combined) is unable to prevent irreversible heat denaturation above 40°C. However, urea denatures GK reversibly even at 60°C by binding to the protein backbone and directly interacting with hydrophobic side chains. It prevents irreversible aggregation allowing complete refolding when urea is removed. This study establishes the foundation for exploring numerous instability mutants among the more than 600 variant GKs causing diabetes in animals and humans.
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Affiliation(s)
- B Zelent
- Department of Biochemistry and Biophysics and Diabetes Research Center, University of Pennsylvania, Philadelphia, PA 19104, USA
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Bräm O, Oskouei AA, Tortschanoff A, van Mourik F, Madrid M, Echave J, Cannizzo A, Chergui M. Relaxation dynamics of tryptophan in water: A UV fluorescence up-conversion and molecular dynamics study. J Phys Chem A 2010; 114:9034-42. [PMID: 20698563 DOI: 10.1021/jp101778u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report on an ultrafast experimental and simulations study of the early relaxation events of photoexcited tryptophan in water. Experimentally, we used fluorescence up-conversion in both polychromatic and single wavelength detection modes in the 300-480 nm range with polarization dependence. We report on the time evolution of the Stokes shift, bandwidth, and anisotropy from tens of femtoseconds to picoseconds. These observables contain signatures of the simultaneous occurrence of intramolecular and solvent-molecule interactions, which we disentangle with the help of nonequilibrium molecular dynamics simulations. We also observe a breakdown of the linear response approximation to describe our results.
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Affiliation(s)
- O Bräm
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, SB, Switzerland
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Paz-Alfaro KJ, Ruiz-Granados YG, Uribe-Carvajal S, Sampedro JG. Trehalose-mediated thermal stabilization of glucose oxidase from Aspergillus niger. J Biotechnol 2009; 141:130-6. [PMID: 19433216 DOI: 10.1016/j.jbiotec.2009.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 03/11/2009] [Accepted: 03/16/2009] [Indexed: 01/08/2023]
Abstract
Thermal inactivation and enzyme kinetics of glucose oxidase (a FAD dependent enzyme) were studied in the absence and presence of trehalose. The inactivation rate constant decreased by up to 50% at temperatures between 50 and 70 degrees C in the presence of 0.6M trehalose; as a consequence the glucose oxidase half-life increased. Intrinsic fluorescence spectra showed a maximum center of spectral mass (CSM) red shift of 6.5nm. Therefore, major structural changes seem to be related to glucose oxidase thermal inactivation. Trehalose decreased the rate constant for unfolding as monitored by CSM red shift kinetics indicating that this disaccharide favors the most compact folded state. The E(a) for unfolding was increased from 204 to 221kJ mol(-1). It is proposed that FAD dissociation is preceded by the exposition of hydrophobic regions, while the presence of trehalose was able to hinder the release of FAD. Enzyme kinetics analysis showed that trehalose does not affect V(max) but instead decreases K(m); as a result enzyme efficiency was increased. The stabilizing effect of trehalose in a cofactor-dependent enzyme has not been tested to date. In addition, glucose oxidase has an enormous commercial importance and therefore, the use of trehalose to stabilize glucose oxidase in its multiple applications seems to be promising.
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Affiliation(s)
- Karina J Paz-Alfaro
- Area Académica de Nutrición, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Hidalgo, Mexico
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Abstract
This chapter reviews basic concepts of nonlinear fluorescence upconversion, a technique whose temporal resolution is essentially limited only by the pulse width of the ultrafast laser. Design aspects for upconversion spectrophotofluorometers are discussed, and a recently developed system is described. We discuss applications in biophysics, particularly the measurement of time-resolved fluorescence spectra of proteins (with subpicosecond time resolution). Application of this technique to biophysical problems such as dynamics of tryptophan, peptides, proteins, and nucleic acids is reviewed.
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Affiliation(s)
- Jianhua Xu
- Laboratory of Molecular Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1412, USA
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15
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Dashnau J, Vanderkooi J. Computational Approaches to Investigate How Biological Macromolecules Can Be Protected in Extreme Conditions. J Food Sci 2007; 72:R001-10. [DOI: 10.1111/j.1750-3841.2006.00242.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Zelent B, Troxler T, Vanderkooi JM. Temperature dependence for fluorescence of beta-NADH in glycerol/water solution and in trehalose/sucrose glass. J Fluoresc 2006; 17:37-42. [PMID: 17171438 DOI: 10.1007/s10895-006-0146-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 10/13/2006] [Indexed: 11/25/2022]
Abstract
Fluorescence imaging of cells and tissue can be used to evaluate beta-NADH redox and location. At low temperature, beta-NADH fluorescence intensity increases and therefore sensitivity of imaging increases. In this paper, the temperature dependence of fluorescence was evaluated for beta-NADH in glycerol/water solution and in trehalose/sucrose glass. The average fluorescence lifetime for NADH in glycerol/water is 0.66 ns, compared with 5.3 ns in trehalose/ sucrose at 20 degrees C. Emission spectra were recorded from 290 to 12 K. The fluorescence of beta-NADH in glycerol/water increases approximately 16 fold and the emission shifts about 35 nm to the blue as temperature decreases. Much smaller change is seen for fluorescence of beta-NADH in sugar glass. Below 77 K, the beta-NADH spectral features did not change significantly with temperature change, and so no increase in sensitivity is obtained by going to very low temperatures. It is suggested that the sensitivity of beta-NADH fluorescence is related to water relaxation around the excited state molecule. Differences in water in various tissues may contribute to beta-NADH fluorescence changes when cells are altered.
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Affiliation(s)
- Bogumil Zelent
- Department of Biochemistry and Biophysics, School of Medicine, Philadelphia, PA 19104, USA
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17
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Navati MS, Friedman JM. Sugar-derived glasses support thermal and photo-initiated electron transfer processes over macroscopic distances. J Biol Chem 2006; 281:36021-8. [PMID: 17005567 DOI: 10.1074/jbc.m606866200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trehalose-derived glasses are shown to support long range electron transfer reactions between spatially well separated donors and protein acceptors. The results indicate that these matrices can be used not only to greatly stabilize protein structures but also to facilitate both thermal and photo-initiated hemeprotein reduction over large macroscopic distances. To date the promise of exciting new protein-based technologies that can harness the exceptional tunability of protein functionality has been significantly thwarted by both intrinsic instability and stringent solvent/environment requirements for the expression of functional properties. The presented results raise the prospect of overcoming these limitations with respect to incorporating redox active proteins into solid state devices such as tunable batteries, switches, and solar cells. The findings also have implications for formulations intended to enhance long term storage of biomaterials, new protein-based synthetic strategies, and biophysical studies of functional intermediates trapped under nonequilibrium conditions. In addition, the study shows that certain sugars such as glucose or tagatose, when added to redox-inactive glassy matrices, can be used as a source of thermal electrons that can be harvested by suitable redox active proteins, raising the prospect of using common sugars as an electron source in solid state thermal fuel cells.
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Affiliation(s)
- Mahantesh S Navati
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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18
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Vanderkooi JM, Dashnau JL, Zelent B. Temperature excursion infrared (TEIR) spectroscopy used to study hydrogen bonding between water and biomolecules. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1749:214-33. [PMID: 15927875 DOI: 10.1016/j.bbapap.2005.03.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 02/15/2005] [Accepted: 03/09/2005] [Indexed: 11/22/2022]
Abstract
Water is a highly polar molecule that is capable of making four H-bonding linkages. Stability and specificity of folding of water-soluble protein macromolecules are determined by the interplay between water and functional groups of the protein. Yet, under some conditions, water can be replaced with sugar or other polar protic molecules with retention of protein structure. Infrared (IR) spectroscopy allows one to probe groups on the protein that interact with solvent, whether the solvent is water, sugar or glycerol. The basis of the measurement is that IR spectral lines of functional groups involved in H-bonding show characteristic spectral shifts with temperature excursion, reflecting the dipolar nature of the group and its ability to H-bond. For groups involved in H-bonding to water, the stretching mode absorption bands shift to lower frequency, whereas bending mode absorption bands shift to higher frequency as temperature decreases. The results indicate increasing H-bonding and decreasing entropy occurring as a function of temperature, even at cryogenic temperatures. The frequencies of the amide group modes are temperature dependent, showing that as temperature decreases, the amide group H-bonds to water strengthen. These results are relevant to protein stability as a function of temperature. The influence of solvent relaxation is demonstrated for tryptophan fluorescence over the same temperature range where the solvent was examined by infrared spectroscopy.
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Affiliation(s)
- Jane M Vanderkooi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, 19104-6059, USA.
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