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Zielinski KA, Katz AM, Calvey GD, Pabit SA, Milano SK, Aplin C, San Emeterio J, Cerione RA, Pollack L. Chaotic advection mixer for capturing transient states of diverse biological macromolecular systems with time-resolved small-angle X-ray scattering. IUCRJ 2023; 10:363-375. [PMID: 37144817 PMCID: PMC10161774 DOI: 10.1107/s2052252523003482] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/17/2023] [Indexed: 05/06/2023]
Abstract
Advances in time-resolved structural techniques, mainly in macromolecular crystallography and small-angle X-ray scattering (SAXS), allow for a detailed view of the dynamics of biological macromolecules and reactions between binding partners. Of particular promise, are mix-and-inject techniques, which offer a wide range of experimental possibility as microfluidic mixers are used to rapidly combine two species just prior to data collection. Most mix-and-inject approaches rely on diffusive mixers, which have been effectively used within crystallography and SAXS for a variety of systems, but their success is dependent on a specific set of conditions to facilitate fast diffusion for mixing. The use of a new chaotic advection mixer designed for microfluidic applications helps to further broaden the types of systems compatible with time-resolved mixing experiments. The chaotic advection mixer can create ultra-thin, alternating layers of liquid, enabling faster diffusion so that even more slowly diffusing molecules, like proteins or nucleic acids, can achieve fast mixing on timescales relevant to biological reactions. This mixer was first used in UV-vis absorbance and SAXS experiments with systems of a variety of molecular weights, and thus diffusion speeds. Careful effort was also dedicated to making a loop-loading sample-delivery system that consumes as little sample as possible, enabling the study of precious, laboratory-purified samples. The combination of the versatile mixer with low sample consumption opens the door to many new applications for mix-and-inject studies.
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Affiliation(s)
- Kara A. Zielinski
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
| | - Andrea M. Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
| | - George D. Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
| | - Suzette A. Pabit
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
| | - Shawn K. Milano
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York USA
| | - Cody Aplin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York USA
| | - Josue San Emeterio
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
| | - Richard A. Cerione
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York USA
- Department of Molecular Medicine, Cornell University, Ithaca, New York USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York USA
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Calvey GD, Katz AM, Zielinski KA, Dzikovski B, Pollack L. Characterizing Enzyme Reactions in Microcrystals for Effective Mix-and-Inject Experiments using X-ray Free-Electron Lasers. Anal Chem 2020; 92:13864-13870. [PMID: 32955854 PMCID: PMC8367009 DOI: 10.1021/acs.analchem.0c02569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mix-and-inject serial crystallography is an emerging technique that utilizes X-ray free-electron lasers (XFELs) and microcrystalline samples to capture atomically detailed snapshots of biomolecules as they function. Early experiments have yielded exciting results; however, there are limited options to characterize reactions in crystallo in advance of the beamtime. Complementary measurements are needed to identify the best conditions and timescales for observing structural intermediates. Here, we describe the interface of XFEL compatible mixing injectors with rapid freeze-quenching and X-band EPR spectroscopy, permitting characterization of reactions in crystals under the same conditions as an XFEL experiment. We demonstrate this technology by tracking the reaction of azide with microcrystalline myoglobin, using only a fraction of the sample required for a mix-and-inject experiment. This spectroscopic method enables optimization of sample and mixer conditions to maximize the populations of intermediate states, eliminating the guesswork of current mix-and-inject experiments.
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Affiliation(s)
- George D Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - Andrea M Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - Kara A Zielinski
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
| | - Boris Dzikovski
- Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York 14853, United States
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
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Panarelli EG, van der Meer H, Gast P, Groenen EJJ. Effective coupling of rapid freeze-quench to high-frequency electron paramagnetic resonance. PLoS One 2020; 15:e0232555. [PMID: 32392255 PMCID: PMC7213726 DOI: 10.1371/journal.pone.0232555] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/16/2020] [Indexed: 11/18/2022] Open
Abstract
We report an easy, efficient and reproducible way to prepare Rapid-Freeze-Quench samples in sub-millimeter capillaries and load these into the probe head of a 275 GHz Electron Paramagnetic Resonance spectrometer. Kinetic data obtained for the binding reaction of azide to myoglobin demonstrate the feasibility of the method for high-frequency EPR. Experiments on the same samples at 9.5 GHz show that only a single series of Rapid-Freeze-Quench samples is required for studies at multiple microwave frequencies.
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Affiliation(s)
- E Gabriele Panarelli
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Harmen van der Meer
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Peter Gast
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Edgar J J Groenen
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
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Panarelli EG, Gast P, Groenen EJJ. Temperature-cycle electron paramagnetic resonance. Phys Chem Chem Phys 2020; 22:9487-9493. [PMID: 32314999 DOI: 10.1039/d0cp00664e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We report on a novel approach to the study of rates and short-lived intermediates of (bio)chemical reactions that involve paramagnetic species. Temperature-cycle Electron Paramagnetic Resonance (EPR) concerns the repeated heating of a reaction mixture in the cavity of an EPR spectrometer by pulsed irradiation with a near-infrared diode laser combined with intermittent characterization of the sample by 275 GHz EPR at a lower temperature at which the reaction does not proceed. The new technique is demonstrated for the reduction of TEMPOL with sodium dithionite in aqueous solution down to the sub-second time scale. We show that a single sample suffices to obtain a complete kinetic trace. Variation of the length and power of the laser pulse offers great flexibility as regards the time scale of the experiment and the temperature at which the reaction can be studied. For water/glycerol mixtures we introduce a simple way to obtain and load an unreacted sample into the spectrometer at low temperature.
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Affiliation(s)
- E Gabriele Panarelli
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands.
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Cai Z, Xiao D, Do LH. Cooperative Heterobimetallic Catalysts in Coordination Insertion Polymerization. COMMENT INORG CHEM 2019. [DOI: 10.1080/02603594.2019.1570165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Zhongzheng Cai
- Department of Chemistry, University of Houston, Houston, Texas, USA
| | - Dawei Xiao
- Department of Chemistry, University of Houston, Houston, Texas, USA
| | - Loi H. Do
- Department of Chemistry, University of Houston, Houston, Texas, USA
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Raper AT, Reed AJ, Suo Z. Kinetic Mechanism of DNA Polymerases: Contributions of Conformational Dynamics and a Third Divalent Metal Ion. Chem Rev 2018; 118:6000-6025. [DOI: 10.1021/acs.chemrev.7b00685] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Austin T. Raper
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Andrew J. Reed
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
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Collauto A, DeBerg HA, Kaufmann R, Zagotta WN, Stoll S, Goldfarb D. Rates and equilibrium constants of the ligand-induced conformational transition of an HCN ion channel protein domain determined by DEER spectroscopy. Phys Chem Chem Phys 2018; 19:15324-15334. [PMID: 28569901 DOI: 10.1039/c7cp01925d] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ligand binding can induce significant conformational changes in proteins. The mechanism of this process couples equilibria associated with the ligand binding event and the conformational change. Here we show that by combining the application of W-band double electron-electron resonance (DEER) spectroscopy with microfluidic rapid freeze quench (μRFQ) it is possible to resolve these processes and obtain both equilibrium constants and reaction rates. We studied the conformational transition of the nitroxide labeled, isolated carboxy-terminal cyclic-nucleotide binding domain (CNBD) of the HCN2 ion channel upon binding of the ligand 3',5'-cyclic adenosine monophosphate (cAMP). Using model-based global analysis, the time-resolved data of the μRFQ DEER experiments directly provide fractional populations of the open and closed conformations as a function of time. We modeled the ligand-induced conformational change in the protein using a four-state model: apo/open (AO), apo/closed (AC), bound/open (BO), bound/closed (BC). These species interconvert according to AC + L ⇌ AO + L ⇌ BO ⇌ BC. By analyzing the concentration dependence of the relative contributions of the closed and open conformations at equilibrium, we estimated the equilibrium constants for the two conformational equilibria and the open-state ligand dissociation constant. Analysis of the time-resolved μRFQ DEER data gave estimates for the intrinsic rates of ligand binding and unbinding as well as the rates of the conformational change. This demonstrates that DEER can quantitatively resolve both the thermodynamics and the kinetics of ligand binding and the associated conformational change.
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Affiliation(s)
- Alberto Collauto
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, 76100, Israel.
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