1
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Keown JR, Crawshaw AD, Trincao J, Carrique L, Gildea RJ, Horrell S, Warren AJ, Axford D, Owen R, Evans G, Bézier A, Metcalf P, Grimes JM. Atomic structure of a nudivirus occlusion body protein determined from a 70-year-old crystal sample. Nat Commun 2023; 14:4160. [PMID: 37443157 PMCID: PMC10345106 DOI: 10.1038/s41467-023-39819-1] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Infectious protein crystals are an essential part of the viral lifecycle for double-stranded DNA Baculoviridae and double-stranded RNA cypoviruses. These viral protein crystals, termed occlusion bodies or polyhedra, are dense protein assemblies that form a crystalline array, encasing newly formed virions. Here, using X-ray crystallography we determine the structure of a polyhedrin from Nudiviridae. This double-stranded DNA virus family is a sister-group to the baculoviruses, whose members were thought to lack occlusion bodies. The 70-year-old sample contains a well-ordered lattice formed by a predominantly α-helical building block that assembles into a dense, highly interconnected protein crystal. The lattice is maintained by extensive hydrophobic and electrostatic interactions, disulfide bonds, and domain switching. The resulting lattice is resistant to most environmental stresses. Comparison of this structure to baculovirus or cypovirus polyhedra shows a distinct protein structure, crystal space group, and unit cell dimensions, however, all polyhedra utilise common principles of occlusion body assembly.
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Affiliation(s)
- Jeremy R Keown
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Adam D Crawshaw
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Jose Trincao
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Loïc Carrique
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Richard J Gildea
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Sam Horrell
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Anna J Warren
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Danny Axford
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Robin Owen
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Gwyndaf Evans
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
- Rosalind Franklin Institute, Harwell Campus, Didcot, UK
| | - Annie Bézier
- Institut de Recherche sur la Biologie de l'Insecte (IRBI), UMR7261 CNRS-Université de Tours, Tours, France
| | - Peter Metcalf
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Jonathan M Grimes
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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2
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Parkhurst JM, Crawshaw AD, Siebert CA, Dumoux M, Owen CD, Nunes P, Waterman D, Glen T, Stuart DI, Naismith JH, Evans G. Investigation of the milling characteristics of different focused-ion-beam sources assessed by three-dimensional electron diffraction from crystal lamellae. IUCrJ 2023; 10:270-287. [PMID: 36952226 PMCID: PMC10161776 DOI: 10.1107/s2052252523001902] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 03/01/2023] [Indexed: 05/06/2023]
Abstract
Three-dimensional electron diffraction (3DED) from nanocrystals of biological macromolecules requires the use of very small crystals. These are typically less than 300 nm-thick in the direction of the electron beam due to the strong interaction between electrons and matter. In recent years, focused-ion-beam (FIB) milling has been used in the preparation of thin samples for 3DED. These instruments typically use a gallium liquid metal ion source. Inductively coupled plasma (ICP) sources in principle offer faster milling rates. Little work has been done to quantify the damage these sources cause to delicate biological samples at cryogenic temperatures. Here, an analysis of the effect that milling with plasma FIB (pFIB) instrumentation has on lysozyme crystals is presented. This work evaluates both argon and xenon plasmas and compares them with crystals milled with a gallium source. A milling protocol was employed that utilizes an overtilt to produce wedge-shaped lamellae with a shallow thickness gradient which yielded very thin crystalline samples. 3DED data were then acquired and standard data-processing statistics were employed to assess the quality of the diffraction data. An upper bound to the depth of the pFIB-milling damage layer of between 42.5 and 50 nm is reported, corresponding to half the thickness of the thinnest lamellae that resulted in usable diffraction data. A lower bound of between 32.5 and 40 nm is also reported, based on a literature survey of the minimum amount of diffracting material required for 3DED.
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Affiliation(s)
- James M Parkhurst
- Rosalind Franklin Insititute, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QX, United Kingdom
| | - Adam D Crawshaw
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QS, United Kingdom
| | - C Alistair Siebert
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QS, United Kingdom
| | - Maud Dumoux
- Rosalind Franklin Insititute, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QX, United Kingdom
| | - C David Owen
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QS, United Kingdom
| | - Pedro Nunes
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QS, United Kingdom
| | - David Waterman
- Research Complex at Harwell, Harwell Science and Innovation Campus, Harwell, Oxford OX11 0FA, United Kingdom
| | - Thomas Glen
- Rosalind Franklin Insititute, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QX, United Kingdom
| | - David I Stuart
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QS, United Kingdom
| | - James H Naismith
- Rosalind Franklin Insititute, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QX, United Kingdom
| | - Gwyndaf Evans
- Rosalind Franklin Insititute, Harwell Science and Innovation Campus, Didcot, Oxford OX11 0QX, United Kingdom
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3
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Brewitz L, Dumjahn L, Zhao Y, Owen CD, Laidlaw SM, Malla TR, Nguyen D, Lukacik P, Salah E, Crawshaw AD, Warren AJ, Trincao J, Strain-Damerell C, Carroll MW, Walsh MA, Schofield CJ. Alkyne Derivatives of SARS-CoV-2 Main Protease Inhibitors Including Nirmatrelvir Inhibit by Reacting Covalently with the Nucleophilic Cysteine. J Med Chem 2023; 66:2663-2680. [PMID: 36757959 PMCID: PMC9924091 DOI: 10.1021/acs.jmedchem.2c01627] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Indexed: 02/10/2023]
Abstract
Nirmatrelvir (PF-07321332) is a nitrile-bearing small-molecule inhibitor that, in combination with ritonavir, is used to treat infections by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Nirmatrelvir interrupts the viral life cycle by inhibiting the SARS-CoV-2 main protease (Mpro), which is essential for processing viral polyproteins into functional nonstructural proteins. We report studies which reveal that derivatives of nirmatrelvir and other Mpro inhibitors with a nonactivated terminal alkyne group positioned similarly to the electrophilic nitrile of nirmatrelvir can efficiently inhibit isolated Mpro and SARS-CoV-2 replication in cells. Mass spectrometric and crystallographic evidence shows that the alkyne derivatives inhibit Mpro by apparent irreversible covalent reactions with the active site cysteine (Cys145), while the analogous nitriles react reversibly. The results highlight the potential for irreversible covalent inhibition of Mpro and other nucleophilic cysteine proteases by alkynes, which, in contrast to nitriles, can be functionalized at their terminal position to optimize inhibition and selectivity, as well as pharmacodynamic and pharmacokinetic properties.
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Affiliation(s)
- Lennart Brewitz
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Leo Dumjahn
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Yilin Zhao
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - C. David Owen
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Research
Complex at Harwell, Harwell Science and
Innovation Campus, Didcot OX11 0FA, United
Kingdom
| | - Stephen M. Laidlaw
- Wellcome
Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Tika R. Malla
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Dung Nguyen
- Wellcome
Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Petra Lukacik
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Research
Complex at Harwell, Harwell Science and
Innovation Campus, Didcot OX11 0FA, United
Kingdom
| | - Eidarus Salah
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Adam D. Crawshaw
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Anna J. Warren
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Jose Trincao
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Claire Strain-Damerell
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Research
Complex at Harwell, Harwell Science and
Innovation Campus, Didcot OX11 0FA, United
Kingdom
| | - Miles W. Carroll
- Wellcome
Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Martin A. Walsh
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Research
Complex at Harwell, Harwell Science and
Innovation Campus, Didcot OX11 0FA, United
Kingdom
| | - Christopher J. Schofield
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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4
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Crawshaw AD, Beale EV, Warren AJ, Stallwood A, Duller G, Trincao J, Evans G. A Sample Preparation Pipeline for Microcrystals at the VMXm Beamline. J Vis Exp 2021. [PMID: 34223830 DOI: 10.3791/62306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The mounting of microcrystals (<10 µm) for single crystal cryo-crystallography presents a non-trivial challenge. Improvements in data quality have been seen for microcrystals with the development of beamline optics, beam stability and variable beam size focusing from submicron to microns, such as at the VMXm beamline at Diamond Light Source1. Further improvements in data quality will be gained through improvements in sample environment and sample preparation. Microcrystals inherently generate weaker diffraction, therefore improving the signal-to-noise is key to collecting quality X-ray diffraction data and will predominantly come from reductions in background noise. Major sources of X-ray background noise in a diffraction experiment are from their interaction with the air path before and after the sample, excess crystallization solution surrounding the sample, the presence of crystalline ice and scatter from any other beamline instrumentation or X-ray windows. The VMXm beamline comprises instrumentation and a sample preparation protocol to reduce all these sources of noise. Firstly, an in-vacuum sample environment at VMXm removes the air path between X-ray source and sample. Next, sample preparation protocols for macromolecular crystallography at VMXm utilize a number of processes and tools adapted from cryoTEM. These include copper grids with holey carbon support films, automated blotting and plunge cooling robotics making use of liquid ethane. These tools enable the preparation of hundreds of microcrystals on a single cryoTEM grid with minimal surrounding liquid on a low-noise support. They also minimize the formation of crystalline ice from any remaining liquid surrounding the crystals. We present the process for preparing and assessing the quality of soluble protein microcrystals using visible light and scanning electron microscopy before mounting the samples on the VMXm beamline for X-ray diffraction experiments. We will also provide examples of good quality samples as well as those which require further optimization and strategies to do so.
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Affiliation(s)
- Adam D Crawshaw
- Diamond Light Source Ltd, Harwell Science and Innovation Campus;
| | - Emma V Beale
- Diamond Light Source Ltd, Harwell Science and Innovation Campus; Paul Scherrer Institut
| | - Anna J Warren
- Diamond Light Source Ltd, Harwell Science and Innovation Campus
| | - Andrew Stallwood
- Diamond Light Source Ltd, Harwell Science and Innovation Campus; Central Laser Facility, Science and Technologies Facilities Council, Harwell Science and Innovation Campus
| | - Graham Duller
- Diamond Light Source Ltd, Harwell Science and Innovation Campus
| | - Jose Trincao
- Diamond Light Source Ltd, Harwell Science and Innovation Campus
| | - Gwyndaf Evans
- Diamond Light Source Ltd, Harwell Science and Innovation Campus; Rosalind Franklin Institute, Harwell Science and Innovation Campus
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5
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Beale EV, Warren AJ, Trincão J, Beilsten-Edmands J, Crawshaw AD, Sutton G, Stuart D, Evans G. Scanning electron microscopy as a method for sample visualization in protein X-ray crystallography. IUCrJ 2020; 7:500-508. [PMID: 32431833 PMCID: PMC7201292 DOI: 10.1107/s2052252520003875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/16/2020] [Indexed: 05/24/2023]
Abstract
Developing methods to determine high-resolution structures from micrometre- or even submicrometre-sized protein crystals has become increasingly important in recent years. This applies to both large protein complexes and membrane proteins, where protein production and the subsequent growth of large homogeneous crystals is often challenging, and to samples which yield only micro- or nanocrystals such as amyloid or viral polyhedrin proteins. The versatile macromolecular crystallography microfocus (VMXm) beamline at Diamond Light Source specializes in X-ray diffraction measurements from micro- and nanocrystals. Because of the possibility of measuring data from crystalline samples that approach the resolution limit of visible-light microscopy, the beamline design includes a scanning electron microscope (SEM) to visualize, locate and accurately centre crystals for X-ray diffraction experiments. To ensure that scanning electron microscopy is an appropriate method for sample visualization, tests were carried out to assess the effect of SEM radiation on diffraction quality. Cytoplasmic polyhedrosis virus polyhedrin protein crystals cryocooled on electron-microscopy grids were exposed to SEM radiation before X-ray diffraction data were collected. After processing the data with DIALS, no statistically significant difference in data quality was found between datasets collected from crystals exposed and not exposed to SEM radiation. This study supports the use of an SEM as a tool for the visualization of protein crystals and as an integrated visualization tool on the VMXm beamline.
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Affiliation(s)
- Emma V. Beale
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Anna J. Warren
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - José Trincão
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - James Beilsten-Edmands
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Adam D. Crawshaw
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Geoff Sutton
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, Oxfordshire OX3 7BN, UK
| | - David Stuart
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, Oxfordshire OX3 7BN, UK
| | - Gwyndaf Evans
- Life Science, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
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6
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Crawshaw AD, Baslé A, Salgado PS. A practical overview of molecular replacement: Clostridioides difficile PilA1, a difficult case study. Acta Crystallogr D Struct Biol 2020; 76:261-271. [PMID: 32133990 PMCID: PMC7057214 DOI: 10.1107/s2059798320000467] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 10/25/2019] [Accepted: 01/14/2020] [Indexed: 12/02/2022] Open
Abstract
Many biologists are now routinely seeking to determine the three-dimensional structures of their proteins of choice, illustrating the importance of this knowledge, but also of the simplification and streamlining of structure-determination processes. Despite the fact that most software packages offer simple pipelines, for the non-expert navigating the outputs and understanding the key aspects can be daunting. Here, the structure determination of the type IV pili (TFP) protein PilA1 from Clostridioides difficile is used to illustrate the different steps involved, the key decision criteria and important considerations when using the most common pipelines and software. Molecular-replacement pipelines within CCP4i2 are presented to illustrate the more commonly used processes. Previous knowledge of the biology and structure of TFP pilins, particularly the presence of a long, N-terminal α-helix required for pilus formation, allowed informed decisions to be made during the structure-determination strategy. The PilA1 structure was finally successfully determined using ARCIMBOLDO and the ab initio MR strategy used is described.
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Affiliation(s)
- Adam D. Crawshaw
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, England
| | - Arnaud Baslé
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, England
| | - Paula S. Salgado
- Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, England
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7
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Storm SLS, Crawshaw AD, Devenish NE, Bolton R, Hall DR, Tews I, Evans G. Measuring energy-dependent photoelectron escape in microcrystals. IUCrJ 2020; 7:129-135. [PMID: 31949913 PMCID: PMC6949606 DOI: 10.1107/s2052252519016178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/02/2019] [Indexed: 05/22/2023]
Abstract
With the increasing trend of using microcrystals and intense microbeams at synchrotron X-ray beamlines, radiation damage becomes a more pressing problem. Theoretical calculations show that the photoelectrons that primarily cause damage can escape microcrystals. This effect would become more pronounced with decreasing crystal size as well as at higher energies. To prove this effect, data from cryocooled lysozyme crystals of dimensions 5 × 3 × 3 and 20 × 8 × 8 µm mounted on cryo-transmission electron microscopy (cryo-TEM) grids were collected at 13.5 and 20.1 keV using a PILATUS CdTe 2M detector, which has a similar quantum efficiency at both energies. Accurate absorbed doses were calculated through the direct measurement of individual crystal sizes using scanning electron microscopy after the experiment and characterization of the X-ray microbeam. The crystal lifetime was then quantified based on the D 1/2 metric. In this first systematic study, a longer crystal lifetime for smaller crystals was observed and crystal lifetime increased at higher X-ray energies, supporting the theoretical predictions of photoelectron escape. The use of detector technologies specifically optimized for data collection at energies above 20 keV allows the theoretically predicted photoelectron escape to be quantified and exploited, guiding future beamline-design choices.
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Affiliation(s)
- Selina L. S. Storm
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Adam D. Crawshaw
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Nicholas E. Devenish
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Rachel Bolton
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Biological Sciences, Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - David R. Hall
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Ivo Tews
- Biological Sciences, Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - Gwyndaf Evans
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
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8
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Serrano M, Crawshaw AD, Dembek M, Monteiro JM, Pereira FC, Pinho MG, Fairweather NF, Salgado PS, Henriques AO. The SpoIIQ-SpoIIIAH complex of Clostridium difficile controls forespore engulfment and late stages of gene expression and spore morphogenesis. Mol Microbiol 2016; 100:204-28. [PMID: 26690930 PMCID: PMC4982068 DOI: 10.1111/mmi.13311] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2015] [Indexed: 11/29/2022]
Abstract
Engulfment of the forespore by the mother cell is a universal feature of endosporulation. In Bacillus subtilis, the forespore protein SpoIIQ and the mother cell protein SpoIIIAH form a channel, essential for endosporulation, through which the developing spore is nurtured. The two proteins also form a backup system for engulfment. Unlike in B. subtilis, SpoIIQ of Clostridium difficile has intact LytM zinc‐binding motifs. We show that spoIIQ or spoIIIAH deletion mutants of C. difficile result in anomalous engulfment, and that disruption of the SpoIIQ LytM domain via a single amino acid substitution (H120S) impairs engulfment differently. SpoIIQ and SpoIIQH120S interact with SpoIIIAH throughout engulfment. SpoIIQ, but not SpoIIQH120S, binds Zn2+, and metal absence alters the SpoIIQ‐SpoIIIAH complex in vitro. Possibly, SpoIIQH120S supports normal engulfment in some cells but not a second function of the complex, required following engulfment completion. We show that cells of the spoIIQ or spoIIIAH mutants that complete engulfment are impaired in post‐engulfment, forespore and mother cell‐specific gene expression, suggesting a channel‐like function. Both engulfment and a channel‐like function may be ancestral functions of SpoIIQ‐SpoIIIAH while the requirement for engulfment was alleviated through the emergence of redundant mechanisms in B. subtilis and related organisms.
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Affiliation(s)
- Mónica Serrano
- Microbial Development, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, Avenida da República, 2780-157, Oeiras, Portugal
| | - Adam D Crawshaw
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Marcin Dembek
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - João M Monteiro
- Bacterial Cell Biology Laboratory, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, Avenida da República, 2780-157, Oeiras, Portugal
| | - Fátima C Pereira
- Microbial Development, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, Avenida da República, 2780-157, Oeiras, Portugal
| | - Mariana Gomes Pinho
- Bacterial Cell Biology Laboratory, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, Avenida da República, 2780-157, Oeiras, Portugal
| | - Neil F Fairweather
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Paula S Salgado
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Adriano O Henriques
- Microbial Development, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, Avenida da República, 2780-157, Oeiras, Portugal
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9
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Warren AJ, Crawshaw AD, Trincao J, Aller P, Alcock S, Nistea I, Salgado PS, Evans G. In vacuo X-ray data collection from graphene-wrapped protein crystals. ACTA ACUST UNITED AC 2015; 71:2079-88. [PMID: 26457431 PMCID: PMC4601369 DOI: 10.1107/s1399004715014194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [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] [Received: 02/20/2015] [Accepted: 07/27/2015] [Indexed: 11/11/2022]
Abstract
A method is reported for collecting room-temperature data from protein crystals under vacuum by protecting them with a thin graphene layer. The measurement of diffraction data from macromolecular crystal samples held in vacuo holds the promise of a very low X-ray background and zero absorption of incident and scattered beams, leading to better data and the potential for accessing very long X-ray wavelengths (>3 Å) for native sulfur phasing. Maintaining the hydration of protein crystals under vacuum is achieved by the use of liquid jets, as with serial data collection at free-electron lasers, or is side-stepped by cryocooling the samples, as implemented at new synchrotron beamlines. Graphene has been shown to protect crystals from dehydration by creating an extremely thin layer that is impermeable to any exchanges with the environment. Furthermore, owing to its hydrophobicity, most of the aqueous solution surrounding the crystal is excluded during sample preparation, thus eliminating most of the background caused by liquid. Here, it is shown that high-quality data can be recorded at room temperature from graphene-wrapped protein crystals in a rough vacuum. Furthermore, it was observed that graphene protects crystals exposed to different relative humidities and a chemically harsh environment.
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Affiliation(s)
- Anna J Warren
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Adam D Crawshaw
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, England
| | - Jose Trincao
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Pierre Aller
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Simon Alcock
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Ioana Nistea
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
| | - Paula S Salgado
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, England
| | - Gwyndaf Evans
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England
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Warren AJ, Crawshaw AD, Trincao J, Aller P, Alcock S, Nistea I, Evans G. In vacuoX-ray data collection from graphene-wrapped protein crystals. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315099787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Crawshaw AD, Serrano M, Stanley WA, Henriques AO, Salgado PS. A mother cell-to-forespore channel: current understanding and future challenges. FEMS Microbiol Lett 2014; 358:129-36. [PMID: 25105965 DOI: 10.1111/1574-6968.12554] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/18/2014] [Accepted: 07/28/2014] [Indexed: 11/30/2022] Open
Abstract
Formation of endospores allows some bacteria to survive extreme nutrient limitation. The resulting dormant cell, the spore, persists in the environment and is highly resistant to physical and chemical stresses. During spore formation, cells divide asymmetrically and the mother cell engulfs the developing spore, encasing it within a double membrane and isolating it from the medium. Communication between mother cell and isolated forespore involves a specialised connection system that allows nurturing of the forespore and continued macromolecular synthesis, required to finalise spore maturation. Here, we review current understanding of this feeding channel formed by a forespore protein, SpoIIQ, and a mother cell protein, SpoIIIAH, in the model organism Bacillus subtilis and the important human pathogen Clostridium difficile. We also analyse the presence of this channel across endospore-forming bacteria and highlight the main questions still remaining.
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Affiliation(s)
- Adam D Crawshaw
- Faculty of Medical Sciences, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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