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Monti M, Biancorosso L, Coccia E. Time-Resolved Circular Dichroism in Molecules: Experimental and Theoretical Advances. Molecules 2024; 29:4049. [PMID: 39274897 PMCID: PMC11396666 DOI: 10.3390/molecules29174049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/16/2024] Open
Abstract
Following changes in chirality can give access to relevant information on the function or reactivity of molecular systems. Time-resolved circular dichroism (TRCD) spectroscopy proves to be a valid tool to achieve this goal. Depending on the class of molecules, different temporal ranges, spanning from seconds to femtoseconds, need to be investigated to observe such chiroptical changes. Therefore, over the years, several approaches have been adopted to cover the timescale of interest, especially based on pump-probe schemes. Moreover, various theoretical approaches have been proposed to simulate and explain TRCD spectra, including linear and non-linear response methods as well as non-adiabatic molecular dynamics. In this review, an overview on both experimental and theoretical advances in the TRCD field is provided, together with selected applications. A discussion on future theoretical developments for TRCD is also given.
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Affiliation(s)
- Marta Monti
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Leonardo Biancorosso
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Emanuele Coccia
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
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Clinger JA, Chen E, Kliger DS, Phillips GN. Pump-Probe Circular Dichroism Spectroscopy of Cyanobacteriochrome TePixJ Yields: Insights into Its Photoconversion. J Phys Chem B 2021; 125:202-210. [PMID: 33355472 DOI: 10.1021/acs.jpcb.0c04822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bilin-containing photoreceptor TePixJ, a member of the cyanobacteriochrome (CBCR) family of phytochromes, switches between blue-light-absorbing and green-light-absorbing states in order to drive phototaxis in Thermosynechococcus elongatus. Its photoswitching process involves the formation of a thioether linkage between the C10 carbon of phycoviolobilin and the sidechain of Cys494 during the change in state from green-absorbing to blue-absorbing forms. Complex changes in the binding pocket propagate the signal to other domains for downstream signaling. Here, we report time-resolved circular dichroism experiments in addition to pump-probe absorption measurements for interpretation of the biophysical mechanism of the green-to-blue photoconversion process of this receptor.
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Affiliation(s)
- Jonathan A Clinger
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
| | - Eefei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - David S Kliger
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - George N Phillips
- Department of Biosciences, Rice University, Houston, Texas 77005, United States.,Department of Chemistry, Rice University, Houston, Texas 77005, United States
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Chen E, Esquerra RM, Meléndez PA, Chandrasekaran SS, Kliger DS. Microviscosity in E. coli Cells from Time-Resolved Linear Dichroism Measurements. J Phys Chem B 2018; 122:11381-11389. [PMID: 30118225 DOI: 10.1021/acs.jpcb.8b07362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A protein's folding or function depends on its mobility through the viscous environment that is defined by the presence of macromolecules throughout the cell. The relevant parameter for this mobility is microviscosity-the viscosity on a time and distance scale that is important for protein folding/function movements. A quasi-null, ultrasensitive time-resolved linear dichroism (TRLD) spectroscopy is proving to be a useful tool for measurements of viscosity on this scale, with previous in vitro studies reporting on the microviscosities of crowded environments mimicked by high concentrations of different macromolecules. This study reports the microviscosity experienced by myoglobin in the E. coli cell's heterogeneous cytoplasm by using TRLD to measure rotational diffusion times. The results show that photolyzed deoxyMb ensembles randomize through environment-dependent rotational diffusion with a lifetime of 34 ± 6 ns. This value corresponds to a microviscosity of 2.82 ± 0.42 cP, which is consistent with previous reports of cytoplasmic viscosity in E. coli. The results of these TRLD studies in E. coli (1) provide a measurement of myoglobin mobility in the cytoplasm, (2) taken together with in vitro TRLD studies yield new insights into the nature of the cytoplasmic environment in cells, and (3) demonstrate the feasibility of TRLD as a probe of intracellular viscosity.
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Affiliation(s)
- Eefei Chen
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Raymond M Esquerra
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - Philipp A Meléndez
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - Sita S Chandrasekaran
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - David S Kliger
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
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Biophysical Methods to Investigate Intrinsically Disordered Proteins: Avoiding an “Elephant and Blind Men” Situation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 870:215-60. [DOI: 10.1007/978-3-319-20164-1_7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kliger DS, Chen E, Goldbeck RA. Probing kinetic mechanisms of protein function and folding with time-resolved natural and magnetic chiroptical spectroscopies. Int J Mol Sci 2012; 13:683-697. [PMID: 22312279 PMCID: PMC3269713 DOI: 10.3390/ijms13010683] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 01/05/2012] [Accepted: 01/05/2012] [Indexed: 11/16/2022] Open
Abstract
Recent and ongoing developments in time-resolved spectroscopy have made it possible to monitor circular dichroism, magnetic circular dichroism, optical rotatory dispersion, and magnetic optical rotatory dispersion with nanosecond time resolution. These techniques have been applied to determine structural changes associated with the function of several proteins as well as to determine the nature of early events in protein folding. These studies have required new approaches in triggering protein reactions as well as the development of time-resolved techniques for polarization spectroscopies with sufficient time resolution and sensitivity to probe protein structural changes.
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Affiliation(s)
- David S Kliger
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Eefei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Robert A Goldbeck
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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Chen E, Kliger DS. Deconstructing time-resolved optical rotatory dispersion kinetic measurements of cytochrome c folding: from molten globule to the native state. Methods Mol Biol 2012; 895:405-419. [PMID: 22760330 DOI: 10.1007/978-1-61779-927-3_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The far-UV time-resolved optical rotatory dispersion (TRORD) technique has contributed significantly to our understanding of nanosecond secondary structure kinetics in protein folding and function reactions. For reduced cytochrome c, protein folding kinetics have been probed largely from the unfolded to the native state. Here we provide details about sample preparation and the TRORD apparatus and measurements for studying folding from a partly unfolded state to the native secondary structure conformation of reduced cytochrome c.
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Affiliation(s)
- Eefei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.
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Chen E, Goldbeck RA, Kliger DS. Nanosecond time-resolved polarization spectroscopies: tools for probing protein reaction mechanisms. Methods 2010; 52:3-11. [PMID: 20438842 PMCID: PMC2934884 DOI: 10.1016/j.ymeth.2010.04.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 11/25/2022] Open
Abstract
Polarization methods, introduced in the 1800s, offered one of the earliest ways to examine protein structure. Since then, many other structure-sensitive probes have been developed, but circular dichroism (CD) remains a powerful technique because of its versatility and the specificity of protein structural information that can be explored. With improvements in time resolution, from millisecond to picosecond CD measurements, it has proven to be an important tool for studying the mechanism of folding and function in many biomolecules. For example, nanosecond time-resolved CD (TRCD) studies of the sub-microsecond events of reduced cytochrome c folding have provided direct experimental evidence of kinetic heterogeneity, which is an inherent property of the diffusional nature of early folding dynamics on the energy landscape. In addition, TRCD has been applied to the study of many biochemical processes, such as ligand rebinding in hemoglobin and myoglobin and signaling state formation in photoactive yellow protein and prototropin 1 LOV2. The basic approach to TRCD has also been extended to include a repertoire of nanosecond polarization spectroscopies: optical rotatory dispersion (ORD), magnetic CD and ORD, and linear dichroism. This article will discuss the details of the polarization methods used in this laboratory, as well as the coupling of time-resolved ORD with the temperature-jump trigger so that protein folding can be studied in a larger number of proteins.
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Affiliation(s)
- Eefei Chen
- Department of Chemistry & Biochemistry University of California Santa Cruz Santa Cruz, California 95064
| | - Robert A. Goldbeck
- Department of Chemistry & Biochemistry University of California Santa Cruz Santa Cruz, California 95064
| | - David S. Kliger
- Department of Chemistry & Biochemistry University of California Santa Cruz Santa Cruz, California 95064
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Hache F. Application of time-resolved circular dichroism to the study of conformational changes in photochemical and photobiological processes. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dartigalongue T, Niezborala C, Hache F. Subpicosecond UV spectroscopy of carbonmonoxy-myoglobin: absorption and circular dichroism studies. Phys Chem Chem Phys 2007; 9:1611-5. [PMID: 17429554 DOI: 10.1039/b616173a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A thorough absorption and circular dichroism study is performed in carbonmonoxy-myoglobin with a sub-picosecond visible pump, ultraviolet probe experiment. Differential absorption in the 220-360 nm range shows that the time-resolved response mainly comes from the heme and that aromatic amino acids do not contribute significantly. Time-resolved CD at 260 nm shows no dynamics and confirms this result. On the contrary, a strong CD dynamics is observed at 230 nm. This signal could originate from transient deformation of the alpha-helices in the protein.
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Affiliation(s)
- Thibault Dartigalongue
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, 91128 Palaiseau cedex, France
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Kliger DS, Chen E, Goldbeck RA. Kinetic and Spectroscopic Analysis of Early Events in Protein Folding. Methods Enzymol 2004; 380:308-27. [PMID: 15051343 DOI: 10.1016/s0076-6879(04)80014-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- David S Kliger
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064, USA
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Enhanced geminate ligand rebinding upon photo-dissociation of silica gel-embedded myoglobin–CO. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)01027-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Floyd JS, Haralampus-Grynaviski N, Ye T, Zheng B, Simon JD, Edington MD. Time-Resolved Spectroscopic Studies of Radiationless Decay Processes in Photoexcited Hemocyanins. J Phys Chem B 2001. [DOI: 10.1021/jp003123e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- James S. Floyd
- Department of Chemistry, Duke University, Durham, North Carolina 27708
| | | | - Tong Ye
- Department of Chemistry, Duke University, Durham, North Carolina 27708
| | - Bo Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708
| | - John D. Simon
- Department of Chemistry, Duke University, Durham, North Carolina 27708
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Esquerra RM, Goldbeck RA, Kim-Shapiro DB, Kliger DS. Spectroscopic evidence for nanosecond protein relaxation after photodissociation of myoglobin-CO. Biochemistry 1998; 37:17527-36. [PMID: 9860868 DOI: 10.1021/bi9814437] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanosecond time-resolved absorption and magnetic optical rotatory dispersion (MORD) measurements of photolyzed myoglobin-CO visible bands (500-650 nm) are presented. These measurements reveal a 400 ns process, spectrally distinct from ligand recombination, that accounts for 7% of the observed spectral evolution in the visible absorption bands and 4% in the MORD. The time-resolved MORD, more sensitive to heme coordination geometry than absorption, suggests that this process is most likely associated with protein relaxation on the distal side of the heme pocket, perhaps accompanying rehydration of the deoxymyoglobin photoproduct or accommodation of protein side chains to ligand escape.
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Affiliation(s)
- R M Esquerra
- Department of Chemistry and Biochemistry, University of California at Santa Cruz 95064, USA
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Esquerra RM, Goldbeck RA, Kim-Shapiro DB, Kliger DS. Fast Time-Resolved Magnetic Optical Rotatory Dispersion Measurements. 2. Confirmation of Mueller Analysis and Application to Myoglobin Ligand Photolysis. J Phys Chem A 1998. [DOI: 10.1021/jp981694p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Raymond M. Esquerra
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, California 95064
| | - Robert A. Goldbeck
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, California 95064
| | - Daniel B. Kim-Shapiro
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, California 95064
| | - David. S. Kliger
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, California 95064
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Chen E, Wood MJ, Fink AL, Kliger DS. Time-resolved circular dichroism studies of protein folding intermediates of cytochrome c. Biochemistry 1998; 37:5589-98. [PMID: 9548944 DOI: 10.1021/bi972369f] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The circular dichroism spectra of cytochrome c (cytc) in 4.6 M guanidine hydrochloride (pH 6.5) indicate that the secondary structure in reduced cytc is near-native, whereas in the CO-bound species (COCytc) it is substantially unfolded. Photolysis of COCytc should thus induce large changes in the secondary structure, which can be probed with time-resolved circular dichroism (TRCD) spectroscopy in the far-UV region. Time-resolved absorption (TROA) and TRCD methods were used to study the photolysis reaction of COCytc in efforts to identify structural intermediates in cytc folding on time scales from nanoseconds to seconds. TROA data from the Soret region, similar to previous studies, showed four intermediates with lifetimes of 2, 50, 225, and 880 micros. The 2-micros process is proposed to involve Fe(II)-Met80 coordination. Approximately 7% of the native CD signal was observed in the TRCD signal at 220 nm within 500 ns, with no significant additional secondary structure formation observed. Further folding after 2 micros may be inhibited by ligation of His26/His33 with Fe(II), which is suggested to be associated with the 50-micros phase. The two slowest components, tau = 225 and 880 micros, are attributed to CO rebinding on the basis of mixed-gas experiments. CO rebinding is expected to compete with protein folding and favor the unfolded state. However, when the two CO rebinding lifetimes are extended into milliseconds by reducing the CO concentration, there is still no significant increase in CD signal at 220 nm.
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Affiliation(s)
- E Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064, USA
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Abstract
The addition of circular or, more generally, elliptical polarization state detection to fast optical absorption spectroscopy can increase the amount of electronic and nuclear conformational information obtained about transient molecular species. To accomplish this, fast circular dichroism methods have emerged over the past decade that overcome the millisecond limit on time resolution associated with conventional modulation techniques and enable structural studies of excited states and kinetic intermediates. This article reviews techniques for time-resolved natural and magnetic circular dichroism spectroscopy covering the picosecond to millisecond time regimes and their applications, with particular emphasis on quasi-null ellipsometric techniques for nanosecond multichannel measurements of circular dichroism. Closely related quasi-null polarimetric techniques for nanosecond optical rotatory dispersion and linear dichroism measurements are also discussed.
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Affiliation(s)
- R A Goldbeck
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064-1077, USA.
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Chen E, Goldbeck RA, Kliger DS. Nanosecond time-resolved spectroscopy of biomolecular processes. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 1997; 26:327-55. [PMID: 9241422 DOI: 10.1146/annurev.biophys.26.1.327] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Over the past two decades, nanosecond absorption and vibrational spectroscopies have developed into powerful tools for monitoring the secondary, tertiary, and quaternary structural relaxations of biological macromolecules under near-physiological conditions of solvent and temperature. Observed through such methods, the dynamic response of a biomolecule to photoinitiated excursions from equilibrium can reveal valuable information about the structure-function relationship, information beyond that obtained from the static structures provided by X-ray crystallography, nuclear magnetic resonance spectroscopy, and other steady-state methods. Most recently, the development of ultra-sensitive polarization techniques for absorption spectroscopy has greatly enhanced the amount of time-resolved structural information that can be obtained from the broadened electronic spectra of biomolecules. This review examines nanosecond absorption, vibrational, and polarized absorption methods, and their applications to protein function and folding, emphasizing the complementary nature of information obtained from electronic and vibrational spectra measured on the nanosecond time scale.
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Affiliation(s)
- E Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064, USA
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