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Schönherr R, Boger J, Lahey-Rudolph JM, Harms M, Kaiser J, Nachtschatt S, Wobbe M, Duden R, König P, Bourenkov G, Schneider TR, Redecke L. A streamlined approach to structure elucidation using in cellulo crystallized recombinant proteins, InCellCryst. Nat Commun 2024; 15:1709. [PMID: 38402242 PMCID: PMC10894269 DOI: 10.1038/s41467-024-45985-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 02/02/2024] [Indexed: 02/26/2024] Open
Abstract
With the advent of serial X-ray crystallography on microfocus beamlines at free-electron laser and synchrotron facilities, the demand for protein microcrystals has significantly risen in recent years. However, by in vitro crystallization extensive efforts are usually required to purify proteins and produce sufficiently homogeneous microcrystals. Here, we present InCellCryst, an advanced pipeline for producing homogeneous microcrystals directly within living insect cells. Our baculovirus-based cloning system enables the production of crystals from completely native proteins as well as the screening of different cellular compartments to maximize chances for protein crystallization. By optimizing cloning procedures, recombinant virus production, crystallization and crystal detection, X-ray diffraction data can be collected 24 days after the start of target gene cloning. Furthermore, improved strategies for serial synchrotron diffraction data collection directly from crystals within living cells abolish the need to purify the recombinant protein or the associated microcrystals.
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Affiliation(s)
- Robert Schönherr
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany
| | - Juliane Boger
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany
| | - J Mia Lahey-Rudolph
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany
- Center for Free-Electron Laser Science (CFEL), Hamburg, Germany
- X-ray technology lab, TH Lübeck - University of Applied Sciences Lübeck, Lübeck, Germany
| | - Mareike Harms
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany
| | | | | | - Marla Wobbe
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany
| | - Rainer Duden
- Institute of Biology, University of Lübeck, Lübeck, Germany
| | - Peter König
- Institute of Anatomy, University of Lübeck, Lübeck, Germany
- Airway Research Center North (ARCN), University of Lübeck, German Center for Lung Research (DZL), Lübeck, Germany
| | - Gleb Bourenkov
- European Molecular Biology Laboratory, Hamburg Unit c/o Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Thomas R Schneider
- European Molecular Biology Laboratory, Hamburg Unit c/o Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Lars Redecke
- Institute of Biochemistry, University of Lübeck, Lübeck, Germany.
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
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2
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Dow XY, Dettmar CM, DeWalt EL, Newman JA, Dow AR, Roy-Chowdhury S, Coe JD, Kupitz C, Fromme P, Simpson GJ. Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals. Acta Crystallogr D Struct Biol 2016; 72:849-59. [PMID: 27377382 PMCID: PMC4932918 DOI: 10.1107/s205979831600841x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/24/2016] [Indexed: 11/10/2022] Open
Abstract
Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3 nanoparticles ranging from 200 to ∼500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.
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Affiliation(s)
- Ximeng Y. Dow
- Chemistry Department, Purdue University, West Lafayette, IN 47907, USA
| | | | - Emma L. DeWalt
- Chemistry Department, Purdue University, West Lafayette, IN 47907, USA
| | - Justin A. Newman
- Chemistry Department, Purdue University, West Lafayette, IN 47907, USA
| | - Alexander R. Dow
- Chemistry Department, Purdue University, West Lafayette, IN 47907, USA
| | - Shatabdi Roy-Chowdhury
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ 85287-7401, USA
| | - Jesse D. Coe
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ 85287-7401, USA
| | - Christopher Kupitz
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Petra Fromme
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Garth J. Simpson
- Chemistry Department, Purdue University, West Lafayette, IN 47907, USA
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3
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Jakobi AJ, Passon DM, Knoops K, Stellato F, Liang M, White TA, Seine T, Messerschmidt M, Chapman HN, Wilmanns M. In cellulo serial crystallography of alcohol oxidase crystals inside yeast cells. IUCRJ 2016; 3:88-95. [PMID: 27006771 PMCID: PMC4775156 DOI: 10.1107/s2052252515022927] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
The possibility of using femtosecond pulses from an X-ray free-electron laser to collect diffraction data from protein crystals formed in their native cellular organelle has been explored. X-ray diffraction of submicrometre-sized alcohol oxidase crystals formed in peroxisomes within cells of genetically modified variants of the methylotrophic yeast Hansenula polymorpha is reported and characterized. The observations are supported by synchrotron radiation-based powder diffraction data and electron microscopy. Based on these findings, the concept of in cellulo serial crystallography on protein targets imported into yeast peroxisomes without the need for protein purification as a requirement for subsequent crystallization is outlined.
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Affiliation(s)
- Arjen J. Jakobi
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, 22607 Hamburg, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Daniel M. Passon
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, 22607 Hamburg, Germany
| | - Kèvin Knoops
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Francesco Stellato
- Center for Free-Electron Laser Science, Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Mengning Liang
- Center for Free-Electron Laser Science, Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Thomas A. White
- Center for Free-Electron Laser Science, Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Thomas Seine
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, 22607 Hamburg, Germany
- Center for Free-Electron Laser Science, Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Marc Messerschmidt
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Henry N. Chapman
- Center for Free-Electron Laser Science, Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
- Center for Ultrafast Imaging, Luruper Chaussee 149, 22607 Hamburg, Germany
| | - Matthias Wilmanns
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory (EMBL), Notkestrasse 85, 22607 Hamburg, Germany
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
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4
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Macias-Romero C, Didier MEP, Jourdain P, Marquet P, Magistretti P, Tarun OB, Zubkovs V, Radenovic A, Roke S. High throughput second harmonic imaging for label-free biological applications. OPTICS EXPRESS 2014; 22:31102-31112. [PMID: 25607059 DOI: 10.1364/oe.22.031102] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Second harmonic generation (SHG) is inherently sensitive to the absence of spatial centrosymmetry, which can render it intrinsically sensitive to interfacial processes, chemical changes and electrochemical responses. Here, we seek to improve the imaging throughput of SHG microscopy by using a wide-field imaging scheme in combination with a medium-range repetition rate amplified near infrared femtosecond laser source and gated detection. The imaging throughput of this configuration is tested by measuring the optical image contrast for different image acquisition times of BaTiO₃ nanoparticles in two different wide-field setups and one commercial point-scanning configuration. We find that the second harmonic imaging throughput is improved by 2-3 orders of magnitude compared to point-scan imaging. Capitalizing on this result, we perform low fluence imaging of (parts of) living mammalian neurons in culture.
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5
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Cohen M, Varki A. Modulation of glycan recognition by clustered saccharide patches. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 308:75-125. [PMID: 24411170 DOI: 10.1016/b978-0-12-800097-7.00003-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
All cells in nature are covered with a dense and complex array of glycan chains. Specific recognition and binding of glycans is a critical aspect of cellular interactions, both within and between species. Glycan-protein interactions tend to be of low affinity but high specificity, typically utilizing multivalency to generate the affinity required for biologically relevant binding. This review focuses on a higher level of glycan organization, the formation of clustered saccharide patches (CSPs), which can constitute unique ligands for highly specific interactions. Due to technical challenges, this aspect of glycan recognition remains poorly understood. We present a wealth of evidence for CSPs-mediated interactions, and discuss recent advances in experimental tools that are beginning to provide new insights into the composition and organization of CSPs. The examples presented here are likely the tip of the iceberg, and much further work is needed to elucidate fully this higher level of glycan organization.
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Affiliation(s)
- Miriam Cohen
- Department Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, USA.
| | - Ajit Varki
- Department of Medicine, University of California, San Diego, California, USA; Department Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, USA.
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6
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Kissick DJ, Dettmar CM, Becker M, Mulichak AM, Cherezov V, Ginell SL, Battaile KP, Keefe LJ, Fischetti RF, Simpson GJ. Towards protein-crystal centering using second-harmonic generation (SHG) microscopy. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:843-51. [PMID: 23633594 PMCID: PMC3640472 DOI: 10.1107/s0907444913002746] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 01/28/2013] [Indexed: 11/10/2022]
Abstract
The potential of second-harmonic generation (SHG) microscopy for automated crystal centering to guide synchrotron X-ray diffraction of protein crystals was explored. These studies included (i) comparison of microcrystal positions in cryoloops as determined by SHG imaging and by X-ray diffraction rastering and (ii) X-ray structure determinations of selected proteins to investigate the potential for laser-induced damage from SHG imaging. In studies using β2 adrenergic receptor membrane-protein crystals prepared in lipidic mesophase, the crystal locations identified by SHG images obtained in transmission mode were found to correlate well with the crystal locations identified by raster scanning using an X-ray minibeam. SHG imaging was found to provide about 2 µm spatial resolution and shorter image-acquisition times. The general insensitivity of SHG images to optical scatter enabled the reliable identification of microcrystals within opaque cryocooled lipidic mesophases that were not identified by conventional bright-field imaging. The potential impact of extended exposure of protein crystals to five times a typical imaging dose from an ultrafast laser source was also assessed. Measurements of myoglobin and thaumatin crystals resulted in no statistically significant differences between structures obtained from diffraction data acquired from exposed and unexposed regions of single crystals. Practical constraints for integrating SHG imaging into an active beamline for routine automated crystal centering are discussed.
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Affiliation(s)
- David J. Kissick
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | | | - Michael Becker
- GM/CA-CAT at the APS, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Anne M. Mulichak
- IMCA-CAT, Hauptman–Woodward Medical Research Institute, Argonne, IL 60439, USA
| | | | - Stephan L. Ginell
- SBC-CAT at the APS, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Kevin P. Battaile
- IMCA-CAT, Hauptman–Woodward Medical Research Institute, Argonne, IL 60439, USA
| | - Lisa J. Keefe
- IMCA-CAT, Hauptman–Woodward Medical Research Institute, Argonne, IL 60439, USA
| | - Robert F. Fischetti
- GM/CA-CAT at the APS, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Garth J. Simpson
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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7
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Garz A, Sandmann M, Rading M, Ramm S, Menzel R, Steup M. Cell-to-cell diversity in a synchronized Chlamydomonas culture as revealed by single-cell analyses. Biophys J 2013; 103:1078-86. [PMID: 23009858 DOI: 10.1016/j.bpj.2012.07.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/08/2012] [Accepted: 07/05/2012] [Indexed: 11/25/2022] Open
Abstract
In a synchronized photoautotrophic culture of Chlamydomonas reinhardtii, cell size, cell number, and the averaged starch content were determined throughout the light-dark cycle. For single-cell analyses, the relative cellular starch was quantified by measuring the second harmonic generation (SHG). In destained cells, amylopectin essentially represents the only biophotonic structure. As revealed by various validation procedures, SHG signal intensities are a reliable relative measure of the cellular starch content. During photosynthesis-driven starch biosynthesis, synchronized Chlamydomonas cells possess an unexpected cell-to-cell diversity both in size and starch content, but the starch-related heterogeneity largely exceeds that of size. The cellular volume, starch content, and amount of starch/cell volume obey lognormal distributions. Starch degradation was initiated by inhibiting the photosynthetic electron transport in illuminated cells or by darkening. Under both conditions, the averaged rate of starch degradation is almost constant, but it is higher in illuminated than in darkened cells. At the single-cell level, rates of starch degradation largely differ but are unrelated to the initial cellular starch content. A rate equation describing the cellular starch degradation is presented. SHG-based three-dimensional reconstructions of Chlamydomonas cells containing starch granules are shown.
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Affiliation(s)
- Andreas Garz
- Institute of Physics and Astronomy, Department of Photonics, University of Potsdam, Potsdam-Golm, Germany
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8
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Haupert LM, DeWalt EL, Simpson GJ. Modeling the SHG activities of diverse protein crystals. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1513-21. [PMID: 23090400 DOI: 10.1107/s0907444912037638] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 08/31/2012] [Indexed: 11/10/2022]
Abstract
A symmetry-additive ab initio model for second-harmonic generation (SHG) activity of protein crystals was applied to assess the likely protein-crystal coverage of SHG microscopy. Calculations were performed for 250 proteins in nine point-group symmetries: a total of 2250 crystals. The model suggests that the crystal symmetry and the limit of detection of the instrument are expected to be the strongest predictors of coverage of the factors considered, which also included secondary-structural content and protein size. Much of the diversity in SHG activity is expected to arise primarily from the variability in the intrinsic protein response as well as the orientation within the crystal lattice. Two or more orders-of-magnitude variation in intensity are expected even within protein crystals of the same symmetry. SHG measurements of tetragonal lysozyme crystals confirmed detection, from which a protein coverage of ~84% was estimated based on the proportion of proteins calculated to produce SHG responses greater than that of tetragonal lysozyme. Good agreement was observed between the measured and calculated ratios of the SHG intensity from lysozyme in tetragonal and monoclinic lattices.
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Affiliation(s)
- Levi M Haupert
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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9
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Spence JCH, Weierstall U, Chapman HN. X-ray lasers for structural and dynamic biology. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:102601. [PMID: 22975810 DOI: 10.1088/0034-4885/75/10/102601] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Research opportunities and techniques are reviewed for the application of hard x-ray pulsed free-electron lasers (XFEL) to structural biology. These include the imaging of protein nanocrystals, single particles such as viruses, pump--probe experiments for time-resolved nanocrystallography, and snapshot wide-angle x-ray scattering (WAXS) from molecules in solution. The use of femtosecond exposure times, rather than freezing of samples, as a means of minimizing radiation damage is shown to open up new opportunities for the molecular imaging of biochemical reactions at room temperature in solution. This is possible using a 'diffract-and-destroy' mode in which the incident pulse terminates before radiation damage begins. Methods for delivering hundreds of hydrated bioparticles per second (in random orientations) to a pulsed x-ray beam are described. New data analysis approaches are outlined for the correlated fluctuations in fast WAXS, for protein nanocrystals just a few molecules on a side, and for the continuous x-ray scattering from a single virus. Methods for determining the orientation of a molecule from its diffraction pattern are reviewed. Methods for the preparation of protein nanocrystals are also reviewed. New opportunities for solving the phase problem for XFEL data are outlined. A summary of the latest results is given, which now extend to atomic resolution for nanocrystals. Possibilities for time-resolved chemistry using fast WAXS (solution scattering) from mixtures is reviewed, toward the general goal of making molecular movies of biochemical processes.
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Affiliation(s)
- J C H Spence
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA.
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10
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Probing the early temporal and spatial interaction of the Sindbis virus capsid and E2 proteins with reverse genetics. J Virol 2012; 86:12372-83. [PMID: 22951842 DOI: 10.1128/jvi.01220-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A 7-Å cryoelectron microscopy-based reconstruction of Sindbis virus (SINV) was recently generated. Fitting the crystal structure of the SINV capsid protein (Cp) into the density map revealed that the F2-G2 loop of the Cp was shifted away from cytoplasmic domain of E2 (cdE2) in the 7-Å reconstruction relative to its position in the Cp crystal structure. Furthermore, the reconstruction demonstrated that residue E395 in region I of the cytoplasmic domain of the E2 envelope protein (cdE2-RI) and K252 of Cp, part of the Cp F2-G2 loop, formed a putative salt bridge in the virion. We generated amino acid substitutions at residues K250 and K252 of the SINV Cp and explored the resulting phenotypes. In the context of cells infected with wild-type or mutant virus, reversing the charge of these two residues resulted in the appearance of Cp aggregates around cytopathic vacuole type I (CPV-I) structures, the absence of nucleocapsid (NC) formation, and a lack of virus particle release in the infected mammalian cell. However, expressing the same Cp mutants in the cell without the envelope proteins or expressing and purifying the mutants from an Escherichia coli expression system and assembling in vitro yielded NC assembly in all cases. In addition, second-site mutations within cdE2 restored NC assembly but not release of infectious particles. Our data suggest an early temporal and spatial interaction between cdE2-RI and the Cp F2-G2 loop that, when ablated, leads to the absence of NC assembly. This interaction also appears to be important for budding of virus particles.
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11
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Ubarretxena-Belandia I, Stokes DL. Membrane protein structure determination by electron crystallography. Curr Opin Struct Biol 2012; 22:520-8. [PMID: 22572457 DOI: 10.1016/j.sbi.2012.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 12/25/2022]
Abstract
During the past year, electron crystallography of membrane proteins has provided structural insights into the mechanism of several different transporters and into their interactions with lipid molecules within the bilayer. From a technical perspective there have been important advances in high-throughput screening of crystallization trials and in automated imaging of membrane crystals with the electron microscope. There have also been key developments in software, and in molecular replacement and phase extension methods designed to facilitate the process of structure determination.
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Affiliation(s)
- Iban Ubarretxena-Belandia
- Department of Structural and Chemical Biology, Mt. Sinai School of Medicine, New York, NY 10029, United States
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12
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Fromme P, Spence JCH. Femtosecond nanocrystallography using X-ray lasers for membrane protein structure determination. Curr Opin Struct Biol 2011; 21:509-16. [PMID: 21752635 DOI: 10.1016/j.sbi.2011.06.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022]
Abstract
The invention of free electron X-ray lasers has opened a new era for membrane protein structure determination with the recent first proof-of-principle of the new concept of femtosecond nanocrystallography. Structure determination is based on thousands of diffraction snapshots that are collected on a fully hydrated stream of nanocrystals. This review provides a summary of the method and describes how femtosecond X-ray crystallography overcomes the radiation-damage problem in X-ray crystallography, avoids the need for growth and freezing of large single crystals while offering a new method for direct digital phase determination by making use of the fully coherent nature of the X-ray beam. We briefly review the possibilities for time-resolved crystallography, and the potential for making 'molecular movies' of membrane proteins at work.
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Affiliation(s)
- Petra Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA.
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13
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Madden JT, DeWalt EL, Simpson GJ. Two-photon excited UV fluorescence for protein crystal detection. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2011; 67:839-46. [PMID: 21931215 DOI: 10.1107/s0907444911028253] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 07/14/2011] [Indexed: 11/10/2022]
Abstract
Two-photon excited ultraviolet fluorescence (TPE-UVF) microscopy is explored for sensitive protein-crystal detection as a complement to second-order nonlinear optical imaging of chiral crystals (SONICC). Like conventional ultraviolet fluorescence (UVF), TPE-UVF generates image contrast based on the intrinsic fluorescence of aromatic residues, generally producing higher fluorescence emission within crystals than the mother liquor by nature of the higher local protein concentration. However, TPE-UVF has several advantages over conventional UVF, including (i) insensitivity to optical scattering, allowing imaging in turbid matrices, (ii) direct compatibility with conventional optical plates and windows by using visible light for excitation, (iii) elimination of potentially damaging out-of-plane UV excitation, (iv) improved signal to noise through background reduction from out-of-plane excitation and (v) relatively simple integration into instrumentation developed for SONICC.
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Affiliation(s)
- Jeremy T Madden
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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