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Kardoost A, Schönherr R, Deiter C, Redecke L, Lorenzen K, Schulz J, de Diego I. Convolutional neural network approach for the automated identification of in cellulo crystals. J Appl Crystallogr 2024; 57:266-275. [PMID: 38596734 PMCID: PMC11001417 DOI: 10.1107/s1600576724000682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 01/18/2024] [Indexed: 04/11/2024] Open
Abstract
In cellulo crystallization is a rare event in nature. Recent advances that have made use of heterologous overexpression can promote the intracellular formation of protein crystals, but new tools are required to detect and characterize these targets in the complex cell environment. The present work makes use of Mask R-CNN, a convolutional neural network (CNN)-based instance segmentation method, for the identification of either single or multi-shaped crystals growing in living insect cells, using conventional bright field images. The algorithm can be rapidly adapted to recognize different targets, with the aim of extracting relevant information to support a semi-automated screening pipeline, in order to aid the development of the intracellular protein crystallization approach.
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Affiliation(s)
- Amirhossein Kardoost
- Sample Environment and Characterization Group, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Schleswig-Holstein, Germany
| | - Robert Schönherr
- Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Schleswig-Holstein, Germany
| | - Carsten Deiter
- Sample Environment and Characterization Group, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Schleswig-Holstein, Germany
| | - Lars Redecke
- Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Schleswig-Holstein, Germany
- Deutsches Elektronen-Synchrotron DESY, Photon Science, Notkestrasse 85, 22607 Hamburg, Germany
| | - Kristina Lorenzen
- Sample Environment and Characterization Group, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Schleswig-Holstein, Germany
| | - Joachim Schulz
- Sample Environment and Characterization Group, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Schleswig-Holstein, Germany
| | - Iñaki de Diego
- Sample Environment and Characterization Group, European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Schleswig-Holstein, Germany
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Norton-Baker B, Mehrabi P, Boger J, Schönherr R, von Stetten D, Schikora H, Kwok AO, Martin RW, Miller RJD, Redecke L, Schulz EC. A simple vapor-diffusion method enables protein crystallization inside the HARE serial crystallography chip. Acta Crystallogr D Struct Biol 2021; 77:820-834. [PMID: 34076595 PMCID: PMC8171066 DOI: 10.1107/s2059798321003855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/10/2021] [Indexed: 11/12/2022] Open
Abstract
Fixed-target serial crystallography has become an important method for the study of protein structure and dynamics at synchrotrons and X-ray free-electron lasers. However, sample homogeneity, consumption and the physical stress on samples remain major challenges for these high-throughput experiments, which depend on high-quality protein microcrystals. The batch crystallization procedures that are typically applied require time- and sample-intensive screening and optimization. Here, a simple protein crystallization method inside the features of the HARE serial crystallography chips is reported that circumvents batch crystallization and allows the direct transfer of canonical vapor-diffusion conditions to in-chip crystallization. Based on conventional hanging-drop vapor-diffusion experiments, the crystallization solution is distributed into the wells of the HARE chip and equilibrated against a reservoir with mother liquor. Using this simple method, high-quality microcrystals were generated with sufficient density for the structure determination of four different proteins. A new protein variant was crystallized using the protein concentrations encountered during canonical crystallization experiments, enabling structure determination from ∼55 µg of protein. Additionally, structure determination from intracellular crystals grown in insect cells cultured directly in the features of the HARE chips is demonstrated. In cellulo crystallization represents a comparatively unexplored space in crystallization, especially for proteins that are resistant to crystallization using conventional techniques, and eliminates any need for laborious protein purification. This in-chip technique avoids harvesting the sensitive crystals or any further physical handling of the crystal-containing cells. These proof-of-principle experiments indicate the potential of this method to become a simple alternative to batch crystallization approaches and also as a convenient extension to canonical crystallization screens.
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Affiliation(s)
- Brenna Norton-Baker
- Department for Atomically Resolved Dynamics, Max-Planck-Institute for Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
| | - Pedram Mehrabi
- Department for Atomically Resolved Dynamics, Max-Planck-Institute for Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Hamburg Centre for Ultrafast Imaging, Universität Hamburg, HARBOR, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Juliane Boger
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Robert Schönherr
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Photon Science, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - David von Stetten
- European Molecular Biology Laboratory, Hamburg Unit c/o Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Hendrik Schikora
- Scientific Support Unit Machine Physics, Max-Planck-Institute for Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Ashley O. Kwok
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
| | - Rachel W. Martin
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | - R. J. Dwayne Miller
- Department of Physics, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
- Departments of Chemistry and Physics, University of Toronto, 80 St George Street, Toronto, ON M5S 3H6, Canada
| | - Lars Redecke
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Photon Science, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany
| | - Eike C. Schulz
- Department for Atomically Resolved Dynamics, Max-Planck-Institute for Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Hamburg Centre for Ultrafast Imaging, Universität Hamburg, HARBOR, Luruper Chaussee 149, 22761 Hamburg, Germany
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Bergfors T, Majumdar S. Screening cells for crystals: a synergistic approach. J Appl Crystallogr 2020; 53:1414-1415. [PMID: 33304219 PMCID: PMC7710486 DOI: 10.1107/s1600576720014971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lahey-Rudolph and co-workers [J. Appl. Cryst. (2020), 53, 1169–1180] have reported a rapid and sensitive method to screen for crystals in cellulo – a welcome addition to the structural biology toolbox.
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Affiliation(s)
- Terese Bergfors
- Department of Cell and Molecular Biology, Uppsala University, Sweden
| | - Soneya Majumdar
- Department of Cell and Molecular Biology, Uppsala University, Sweden
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Abstract
Protein crystallization in living cells has been observed surprisingly often as a native assembly process during the past decades, and emerging evidence indicates that this phenomenon is also accessible for recombinant proteins. But only recently the advent of high-brilliance synchrotron sources, X-ray free-electron lasers, and improved serial data collection strategies has allowed the use of these micrometer-sized crystals for structural biology. Thus, in cellulo crystallization could offer exciting new possibilities for proteins that do not crystallize applying conventional approaches. In this review, we comprehensively summarize the current knowledge of intracellular protein crystallization. This includes an overview of the cellular functions, the physical properties, and, if known, the mode of regulation of native in cellulo crystal formation, complemented with a discussion of the reported crystallization events of recombinant proteins and the current method developments to successfully collect X-ray diffraction data from in cellulo crystals. Although the intracellular protein self-assembly mechanisms are still poorly understood, regulatory differences between native in cellulo crystallization linked to a specific function and accidently crystallizing proteins, either disease associated or recombinantly introduced, become evident. These insights are important to systematically exploit living cells as protein crystallization chambers in the future.
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Affiliation(s)
- Robert Schönherr
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.,Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany
| | - Janine Mia Rudolph
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.,Center for Free-Electron Laser Science (CFEL), DESY, Notkestrasse 85, D-22607 Hamburg, Germany
| | - Lars Redecke
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.,Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany
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