1
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Lv JL, Lai WQ, Gong YQ, Zheng KY, Zhang XY, Lu ZP, Li MW, Wang XY, Dai LS. Bombyx mori voltage-dependent anion-selective channel induces programmed cell death to defend against Bombyx mori nucleopolyhedrovirus infection. PEST MANAGEMENT SCIENCE 2024; 80:3752-3762. [PMID: 38488318 DOI: 10.1002/ps.8082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 03/08/2024] [Accepted: 03/10/2024] [Indexed: 04/21/2024]
Abstract
BACKGROUND Voltage-dependent anion-selective channels (VDACs) serve as pore proteins within the mitochondrial membrane, aiding in the regulation of cell life and cell death. Although the occurrence of cell death is crucial for defense against virus infection, the function played by VDAC in Bombyx mori, in response to the influence of Bombyx mori nucleopolyhedrovirus (BmNPV), remains unclear. RESULTS BmVDAC was found to be relatively highly expressed both during embryonic development, and in the Malpighian tubule and midgut. Additionally, the expression levels of BmVDAC were found to be different among silkworm strains with varying levels of resistance to BmNPV, strongly suggesting a connection between BmVDAC and virus infection. To gain further insight into the function of BmVDAC in BmNPV, we employed RNA interference (RNAi) to silence and overexpress it by pIZT/V5-His-mCherry. The results revealed that BmVDAC is instrumental in developing the resistance of host cells to BmNPV infection in BmN cell-line cells, which was further validated as likely to be associated with initiating programmed cell death (PCD). Furthermore, we evaluated the function of BmVDAC in another insect, Spodoptera exigua. Knockdown of the BmVDAC homolog in S. exigua, SeVDAC, made the larvae more sensitive to BmNPV. CONCLUSION We have substantiated the pivotal role of BmVDAC in conferring resistance against BmNPV infection, primarily associated with the initiation of PCD. The findings of this study shine new light on the molecular mechanisms governing the silkworm's response to BmNPV infection, thereby supporting innovative approaches for pest biocontrol. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Jun-Li Lv
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Wen-Qing Lai
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Yu-Quan Gong
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Kai-Yi Zheng
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Xiao-Ying Zhang
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Zhan-Peng Lu
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Mu-Wang Li
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Scientific Research Center, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Xue-Yang Wang
- Jiangsu Key Laboratory of Sericultural and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Scientific Research Center, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Li-Shang Dai
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
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2
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Bardin AA, Haymaker A, Banihashemi F, Lin JYS, Martynowycz MW, Nannenga BL. Focused ion beam milling and MicroED structure determination of metal-organic framework crystals. Ultramicroscopy 2024; 257:113905. [PMID: 38086288 PMCID: PMC10843726 DOI: 10.1016/j.ultramic.2023.113905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/30/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
We report new advancements in the determination and high-resolution structural analysis of beam-sensitive metal organic frameworks (MOFs) using microcrystal electron diffraction (MicroED) coupled with focused ion beam milling at cryogenic temperatures (cryo-FIB). A microcrystal of the beam-sensitive MOF, ZIF-8, was ion-beam milled in a thin lamella approximately 150 nm thick. MicroED data were collected from this thin lamella using an energy filter and a direct electron detector operating in counting mode. Using this approach, we achieved a greatly improved resolution of 0.59 Å with a minimal total exposure of only 0.64 e-/A2. These innovations not only improve model statistics but also further demonstrate that ion-beam milling is compatible with beam-sensitive materials, augmenting the capabilities of electron diffraction in MOF research.
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Affiliation(s)
- Andrey A Bardin
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States; Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, United States
| | - Alison Haymaker
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States; Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, United States
| | - Fateme Banihashemi
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States
| | - Jerry Y S Lin
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States
| | - Michael W Martynowycz
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States.
| | - Brent L Nannenga
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States; Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, United States.
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3
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Haymaker A, Nannenga BL. Advances and applications of microcrystal electron diffraction (MicroED). Curr Opin Struct Biol 2024; 84:102741. [PMID: 38086321 PMCID: PMC10882645 DOI: 10.1016/j.sbi.2023.102741] [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: 01/01/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 02/08/2024]
Abstract
Microcrystal electron diffraction, commonly referred to as MicroED, has become a powerful tool for high-resolution structure determination. The method makes use of cryogenic transmission electron microscopes to collect electron diffraction data from crystals that are several orders of magnitude smaller than those used by other conventional diffraction techniques. MicroED has been used on a variety of samples including soluble proteins, membrane proteins, small organic molecules, and materials. Here we will review the MicroED method and highlight recent advancements to the methodology, as well as describe applications of MicroED within the fields of structural biology and chemical crystallography.
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Affiliation(s)
- Alison Haymaker
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Brent L Nannenga
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, USA.
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4
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Mayse LA, Movileanu L. Gating of β-Barrel Protein Pores, Porins, and Channels: An Old Problem with New Facets. Int J Mol Sci 2023; 24:12095. [PMID: 37569469 PMCID: PMC10418385 DOI: 10.3390/ijms241512095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
β barrels are ubiquitous proteins in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. These transmembrane proteins (TMPs) execute a wide variety of tasks. For example, they can serve as transporters, receptors, membrane-bound enzymes, as well as adhesion, structural, and signaling elements. In addition, multimeric β barrels are common structural scaffolds among many pore-forming toxins. Significant progress has been made in understanding the functional, structural, biochemical, and biophysical features of these robust and versatile proteins. One frequently encountered fundamental trait of all β barrels is their voltage-dependent gating. This process consists of reversible or permanent conformational transitions between a large-conductance, highly permeable open state and a low-conductance, solute-restrictive closed state. Several intrinsic molecular mechanisms and environmental factors modulate this universal property of β barrels. This review article outlines the typical signatures of voltage-dependent gating. Moreover, we discuss recent developments leading to a better qualitative understanding of the closure dynamics of these TMPs.
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Affiliation(s)
- Lauren A. Mayse
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
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5
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Shiriaeva A, Martynowycz MW, Nicolas WJ, Cherezov V, Gonen T. MicroED structure of the human vasopressin 1B receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.05.547888. [PMID: 37461729 PMCID: PMC10350018 DOI: 10.1101/2023.07.05.547888] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
The small size and flexibility of G protein-coupled receptors (GPCRs) have long posed a significant challenge to determining their structures for research and therapeutic applications. Single particle cryogenic electron microscopy (cryoEM) is often out of reach due to the small size of the receptor without a signaling partner. Crystallization of GPCRs in lipidic cubic phase (LCP) often results in crystals that may be too small and difficult to analyze using X-ray microcrystallography at synchrotron sources or even serial femtosecond crystallography at X-ray free electron lasers. Here, we determine the previously unknown structure of the human vasopressin 1B receptor (V1BR) using microcrystal electron diffraction (MicroED). To achieve this, we grew V1BR microcrystals in LCP and transferred the material directly onto electron microscopy grids. The protein was labeled with a fluorescent dye prior to crystallization to locate the microcrystals using cryogenic fluorescence microscopy, and then the surrounding material was removed using a plasma-focused ion beam to thin the sample to a thickness amenable to MicroED. MicroED data from 14 crystalline lamellae were used to determine the 3.2 Å structure of the receptor in the crystallographic space group P 1. These results demonstrate the use of MicroED to determine previously unknown GPCR structures that, despite significant effort, were not tractable by other methods.
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Affiliation(s)
- Anna Shiriaeva
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Michael W. Martynowycz
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
| | - William J. Nicolas
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
| | - Vadim Cherezov
- Bridge Institute, University of Southern California Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90007
- Department of Chemistry, University of Southern California, Los Angeles, CA 90007
| | - Tamir Gonen
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
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6
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Gillman C, Nicolas WJ, Martynowycz MW, Gonen T. Design and implementation of suspended drop crystallization. IUCRJ 2023; 10:430-436. [PMID: 37223996 PMCID: PMC10324482 DOI: 10.1107/s2052252523004141] [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: 03/29/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023]
Abstract
In this work, a novel crystal growth method termed suspended drop crystallization has been developed. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber designed in-house, allowing for vapor diffusion to occur from both sides of the drop. A UV-transparent window above and below the grid enables the monitoring of crystal growth via light, UV or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for X-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, crystals of the enzyme proteinase K were grown and its structure was determined by MicroED following focused ion beam/scanning electron microscopy milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress and/or subject to preferred orientation on electron microscopy grids.
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Affiliation(s)
- Cody Gillman
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - William J. Nicolas
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles, CA, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA USA
| | - Michael W. Martynowycz
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles, CA, USA
| | - Tamir Gonen
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA USA
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7
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Danelius E, Patel K, Gonzalez B, Gonen T. MicroED in drug discovery. Curr Opin Struct Biol 2023; 79:102549. [PMID: 36821888 PMCID: PMC10023408 DOI: 10.1016/j.sbi.2023.102549] [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: 10/27/2022] [Revised: 01/16/2023] [Accepted: 01/23/2023] [Indexed: 02/23/2023]
Abstract
The cryo-electron microscopy (cryo-EM) method microcrystal electron diffraction (MicroED) was initially described in 2013 and has recently gained attention as an emerging technique for research in drug discovery. As compared to other methods in structural biology, MicroED provides many advantages deriving from the use of nanocrystalline material for the investigations. Here, we review the recent advancements in the field of MicroED and show important examples of small molecule, peptide and protein structures that has contributed to the current development of this method as an important tool for drug discovery.
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Affiliation(s)
- Emma Danelius
- Department of Biological Chemistry, University of California Los Angeles, 615 Charles E.Young Drive South, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Khushboo Patel
- Department of Biological Chemistry, University of California Los Angeles, 615 Charles E.Young Drive South, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Brenda Gonzalez
- Department of Biological Chemistry, University of California Los Angeles, 615 Charles E.Young Drive South, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Tamir Gonen
- Department of Biological Chemistry, University of California Los Angeles, 615 Charles E.Young Drive South, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Physiology, University of California Los Angeles, 615 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
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8
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Gillman C, Nicolas WJ, Martynowycz MW, Gonen T. Design and implementation of suspended drop crystallization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534639. [PMID: 37034794 PMCID: PMC10081258 DOI: 10.1101/2023.03.28.534639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have developed a novel crystal growth method known as suspended drop crystallization. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber which we designed, allowing for vapor diffusion to occur from both sides of the drop. A UV transparent window above and below the grid enables the monitoring of crystal growth via light, UV, or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for x-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, we grew crystals of the enzyme proteinase K and determined its structure by MicroED following FIB/SEM milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress, and/or suffering from preferred orientation on EM grids.
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Affiliation(s)
- Cody Gillman
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - William J. Nicolas
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles CA, USA
- Howard Hughes Medical Institute, University of California, Los Angeles CA, USA
| | - Michael W. Martynowycz
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles CA, USA
| | - Tamir Gonen
- Departments of Biological Chemistry and Physiology, University of California, Los Angeles CA, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, University of California, Los Angeles CA, USA
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9
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Danelius E, Porter NJ, Unge J, Arnold FH, Gonen T. MicroED Structure of a Protoglobin Reactive Carbene Intermediate. J Am Chem Soc 2023; 145:7159-7165. [PMID: 36948184 PMCID: PMC10080679 DOI: 10.1021/jacs.2c12004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Microcrystal electron diffraction (MicroED) is an emerging technique that has shown great potential for describing new chemical and biological molecular structures. Several important structures of small molecules, natural products, and peptides have been determined using ab initio methods. However, only a couple of novel protein structures have thus far been derived by MicroED. Taking advantage of recent technological advances, including higher acceleration voltage and using a low-noise detector in counting mode, we have determined the first structure of an Aeropyrum pernix protoglobin (ApePgb) variant by MicroED using an AlphaFold2 model for phasing. The structure revealed that mutations introduced during directed evolution enhance carbene transfer activity by reorienting an α helix of ApePgb into a dynamic loop, making the catalytic active site more readily accessible. After exposing the tiny crystals to the substrate, we also trapped the reactive iron-carbenoid intermediate involved in this engineered ApePgb's new-to-nature activity, a challenging carbene transfer from a diazirine via a putative metallo-carbene. The bound structure discloses how an enlarged active site pocket stabilizes the carbene bound to the heme iron and, presumably, the transition state for the formation of this key intermediate. This work demonstrates that improved MicroED technology and the advancement in protein structure prediction now enable investigation of structures that was previously beyond reach.
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Affiliation(s)
- Emma Danelius
- Department of Biological Chemistry, University of California, Los Angeles, 615 Charles E. Young Drive South, Los Angeles, California 90095, United States
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Nicholas J Porter
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 210-41, Pasadena, California 91125, United States
| | - Johan Unge
- Department of Biological Chemistry, University of California, Los Angeles, 615 Charles E. Young Drive South, Los Angeles, California 90095, United States
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 210-41, Pasadena, California 91125, United States
| | - Tamir Gonen
- Department of Biological Chemistry, University of California, Los Angeles, 615 Charles E. Young Drive South, Los Angeles, California 90095, United States
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Physiology, University of California, Los Angeles, 615 Charles E. Young Drive South, Los Angeles, California 90095, United States
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10
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Martynowycz MW, Shiriaeva A, Clabbers MTB, Nicolas WJ, Weaver SJ, Hattne J, Gonen T. A robust approach for MicroED sample preparation of lipidic cubic phase embedded membrane protein crystals. Nat Commun 2023; 14:1086. [PMID: 36841804 PMCID: PMC9968316 DOI: 10.1038/s41467-023-36733-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 02/15/2023] [Indexed: 02/26/2023] Open
Abstract
Crystallizing G protein-coupled receptors (GPCRs) in lipidic cubic phase (LCP) often yields crystals suited for the cryogenic electron microscopy (cryoEM) method microcrystal electron diffraction (MicroED). However, sample preparation is challenging. Embedded crystals cannot be targeted topologically. Here, we use an integrated fluorescence light microscope (iFLM) inside of a focused ion beam and scanning electron microscope (FIB-SEM) to identify fluorescently labeled GPCR crystals. Crystals are targeted using the iFLM and LCP is milled using a plasma focused ion beam (pFIB). The optimal ion source for preparing biological lamellae is identified using standard crystals of proteinase K. Lamellae prepared using either argon or xenon produced the highest quality data and structures. MicroED data are collected from the milled lamellae and the structures are determined. This study outlines a robust approach to identify and mill membrane protein crystals for MicroED and demonstrates plasma ion-beam milling is a powerful tool for preparing biological lamellae.
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Affiliation(s)
- Michael W Martynowycz
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - Anna Shiriaeva
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - Max T B Clabbers
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - William J Nicolas
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - Sara J Weaver
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - Johan Hattne
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA. .,Department of Biological Chemistry, University of California, Los Angeles, CA, 90095, USA. .,Department of Physiology, University of California, Los Angeles, CA, 90095, USA.
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11
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Clabbers MT, Martynowycz MW, Hattne J, Gonen T. Hydrogens and hydrogen-bond networks in macromolecular MicroED data. J Struct Biol X 2022; 6:100078. [PMID: 36507068 PMCID: PMC9731847 DOI: 10.1016/j.yjsbx.2022.100078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
Microcrystal electron diffraction (MicroED) is a powerful technique utilizing electron cryo-microscopy (cryo-EM) for protein structure determination of crystalline samples too small for X-ray crystallography. Electrons interact with the electrostatic potential of the sample, which means that the scattered electrons carry information about the charged state of atoms and provide relatively stronger contrast for visualizing hydrogen atoms. Accurately identifying the positions of hydrogen atoms, and by extension the hydrogen bonding networks, is of importance for understanding protein structure and function, in particular for drug discovery. However, identification of individual hydrogen atom positions typically requires atomic resolution data, and has thus far remained elusive for macromolecular MicroED. Recently, we presented the ab initio structure of triclinic hen egg-white lysozyme at 0.87 Å resolution. The corresponding data were recorded under low exposure conditions using an electron-counting detector from thin crystalline lamellae. Here, using these subatomic resolution MicroED data, we identified over a third of all hydrogen atom positions based on strong difference peaks, and directly visualize hydrogen bonding interactions and the charged states of residues. Furthermore, we find that the hydrogen bond lengths are more accurately described by the inter-nuclei distances than the centers of mass of the corresponding electron clouds. We anticipate that MicroED, coupled with ongoing advances in data collection and refinement, can open further avenues for structural biology by uncovering the hydrogen atoms and hydrogen bonding interactions underlying protein structure and function.
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Affiliation(s)
- Max T.B. Clabbers
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States,Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, United States
| | - Michael W. Martynowycz
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States,Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, United States
| | - Johan Hattne
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States,Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, United States
| | - Tamir Gonen
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States,Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, United States,Department of Physiology, University of California, Los Angeles, CA 90095, United States,Corresponding author at: Department of Biological Chemistry, University of California, Los Angeles, CA 90095, United States.
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12
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Abstract
Electron crystallography has a storied history which rivals that of its more established X-ray-enabled counterpart. Recent advances in data collection and analysis have sparked a renaissance in the field, opening a new chapter for this venerable technique. Burgeoning interest in electron crystallography has spawned innovative methods described by various interchangeable labels (3D ED, MicroED, cRED, etc.). This Review covers concepts and findings relevant to the practicing crystallographer, with an emphasis on experiments aimed at using electron diffraction to elucidate the atomic structure of three-dimensional molecular crystals.
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Affiliation(s)
- Ambarneil Saha
- UCLA−DOE
Institute for Genomics and Proteomics, University
of California, Los Angeles, Los Angeles, California 90095, United States
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Shervin S. Nia
- UCLA−DOE
Institute for Genomics and Proteomics, University
of California, Los Angeles, Los Angeles, California 90095, United States
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - José A. Rodríguez
- UCLA−DOE
Institute for Genomics and Proteomics, University
of California, Los Angeles, Los Angeles, California 90095, United States
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los
Angeles, California 90095, United States
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13
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Piper SJ, Johnson RM, Wootten D, Sexton PM. Membranes under the Magnetic Lens: A Dive into the Diverse World of Membrane Protein Structures Using Cryo-EM. Chem Rev 2022; 122:13989-14017. [PMID: 35849490 PMCID: PMC9480104 DOI: 10.1021/acs.chemrev.1c00837] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Indexed: 11/29/2022]
Abstract
Membrane proteins are highly diverse in both structure and function and can, therefore, present different challenges for structure determination. They are biologically important for cells and organisms as gatekeepers for information and molecule transfer across membranes, but each class of membrane proteins can present unique obstacles to structure determination. Historically, many membrane protein structures have been investigated using highly engineered constructs or using larger fusion proteins to improve solubility and/or increase particle size. Other strategies included the deconstruction of the full-length protein to target smaller soluble domains. These manipulations were often required for crystal formation to support X-ray crystallography or to circumvent lower resolution due to high noise and dynamic motions of protein subdomains. However, recent revolutions in membrane protein biochemistry and cryo-electron microscopy now provide an opportunity to solve high resolution structures of both large, >1 megadalton (MDa), and small, <100 kDa (kDa), drug targets in near-native conditions, routinely reaching resolutions around or below 3 Å. This review provides insights into how the recent advances in membrane biology and biochemistry, as well as technical advances in cryo-electron microscopy, help us to solve structures of a large variety of membrane protein groups, from small receptors to large transporters and more complex machineries.
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Affiliation(s)
- Sarah J. Piper
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Rachel M. Johnson
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Denise Wootten
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Patrick M. Sexton
- Drug
Discovery Biology theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- ARC
Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute
of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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14
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Ngo VA, Queralt-Martín M, Khan F, Bergdoll L, Abramson J, Bezrukov SM, Rostovtseva TK, Hoogerheide DP, Noskov SY. The Single Residue K12 Governs the Exceptional Voltage Sensitivity of Mitochondrial Voltage-Dependent Anion Channel Gating. J Am Chem Soc 2022; 144:14564-14577. [PMID: 35925797 DOI: 10.1021/jacs.2c03316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The voltage-dependent anion channel (VDAC) is a β-barrel channel of the mitochondrial outer membrane (MOM) that passively transports ions, metabolites, polypeptides, and single-stranded DNA. VDAC responds to a transmembrane potential by "gating," i.e. transitioning to one of a variety of low-conducting states of unknown structure. The gated state results in nearly complete suppression of multivalent mitochondrial metabolite (such as ATP and ADP) transport, while enhancing calcium transport. Voltage gating is a universal property of β-barrel channels, but VDAC gating is anomalously sensitive to transmembrane potential. Here, we show that a single residue in the pore interior, K12, is responsible for most of VDAC's voltage sensitivity. Using the analysis of over 40 μs of atomistic molecular dynamics (MD) simulations, we explore correlations between motions of charged residues inside the VDAC pore and geometric deformations of the β-barrel. Residue K12 is bistable; its motions between two widely separated positions along the pore axis enhance the fluctuations of the β-barrel and augment the likelihood of gating. Single channel electrophysiology of various K12 mutants reveals a dramatic reduction of the voltage-induced gating transitions. The crystal structure of the K12E mutant at a resolution of 2.6 Å indicates a similar architecture of the K12E mutant to the wild type; however, 60 μs of atomistic MD simulations using the K12E mutant show restricted motion of residue 12, due to enhanced connectivity with neighboring residues, and diminished amplitude of barrel motions. We conclude that β-barrel fluctuations, governed particularly by residue K12, drive VDAC gating transitions.
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Affiliation(s)
- Van A Ngo
- Center for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada.,Advanced Computing for Life Sciences and Engineering, Computing and Computational Sciences, National Center for Computational Sciences, Oak Ridge National Lab, Oak Ridge, Tennessee 37830, United States
| | - María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States.,Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071 Castellón, Spain
| | - Farha Khan
- Department of Physiology, University of California, Los Angeles, California 90095, United States
| | - Lucie Bergdoll
- LISM UMR 7255, CNRS and Aix-Marseille University, Marseille cedex 20, 13402, France
| | - Jeff Abramson
- Department of Physiology, University of California, Los Angeles, California 90095, United States
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sergei Yu Noskov
- Center for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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15
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Mechanisms of membrane protein crystallization in 'bicelles'. Sci Rep 2022; 12:11109. [PMID: 35773455 PMCID: PMC9246360 DOI: 10.1038/s41598-022-13945-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/31/2022] [Indexed: 12/14/2022] Open
Abstract
Despite remarkable progress, mainly due to the development of LCP and ‘bicelle’ crystallization, lack of structural information remains a bottleneck in membrane protein (MP) research. A major reason is the absence of complete understanding of the mechanism of crystallization. Here we present small-angle scattering studies of the evolution of the “bicelle” crystallization matrix in the course of MP crystal growth. Initially, the matrix corresponds to liquid-like bicelle state. However, after adding the precipitant, the crystallization matrix transforms to jelly-like state. The data suggest that this final phase is composed of interconnected ribbon-like bilayers, where crystals grow. A small amount of multilamellar phase appears, and its volume increases concomitantly with the volume of growing crystals. We suggest that the lamellar phase surrounds the crystals and is critical for crystal growth, which is also common for LCP crystallization. The study discloses mechanisms of “bicelle” MP crystallization and will support rational design of crystallization.
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16
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Clabbers MTB, Shiriaeva A, Gonen T. MicroED: conception, practice and future opportunities. IUCRJ 2022; 9:169-179. [PMID: 35371502 PMCID: PMC8895021 DOI: 10.1107/s2052252521013063] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
This article documents a keynote seminar presented at the IUCr Congress in Prague, 2021. The cryo-EM method microcrystal electron diffraction is described and put in the context of macromolecular electron crystallography from its origins in 2D crystals of membrane proteins to today's application to 3D crystals a millionth the size of that needed for X-ray crystallography. Milestones in method development and applications are described with an outlook to the future.
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Affiliation(s)
- Max T. B. Clabbers
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - Anna Shiriaeva
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - Tamir Gonen
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, USA
- Department of Physiology, University of California, Los Angeles, CA 90095, USA
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17
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Studying membrane proteins with MicroED. Biochem Soc Trans 2022; 50:231-239. [PMID: 35191473 PMCID: PMC9022970 DOI: 10.1042/bst20210911] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 12/27/2022]
Abstract
The structural investigation of biological macromolecules is indispensable in understanding the molecular mechanisms underlying diseases. Several structural biology techniques have been introduced to unravel the structural facets of biomolecules. Among these, the electron cryomicroscopy (cryo-EM) method microcrystal electron diffraction (MicroED) has produced atomic resolution structures of important biological and small molecules. Since its inception in 2013, MicroED established a demonstrated ability for solving structures of difficult samples using vanishingly small crystals. However, membrane proteins remain the next big frontier for MicroED. The intrinsic properties of membrane proteins necessitate improved sample handling and imaging techniques to be developed and optimized for MicroED. Here, we summarize the milestones of electron crystallography of two-dimensional crystals leading to MicroED of three-dimensional crystals. Then, we focus on four different membrane protein families and discuss representatives from each family solved by MicroED.
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18
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Najbauer EE, Tekwani Movellan K, Giller K, Benz R, Becker S, Griesinger C, Andreas LB. Structure and Gating Behavior of the Human Integral Membrane Protein VDAC1 in a Lipid Bilayer. J Am Chem Soc 2022; 144:2953-2967. [PMID: 35164499 PMCID: PMC8874904 DOI: 10.1021/jacs.1c09848] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
The voltage-dependent
anion channel (VDAC), the most abundant protein
in the outer mitochondrial membrane, is responsible for the transport
of all ions and metabolites into and out of mitochondria. Larger than
any of the β-barrel structures determined to date by magic-angle
spinning (MAS) NMR, but smaller than the size limit of cryo-electron
microscopy (cryo-EM), VDAC1’s 31 kDa size has long been a bottleneck
in determining its structure in a near-native lipid bilayer environment.
Using a single two-dimensional (2D) crystalline sample of human VDAC1
in lipids, we applied proton-detected fast magic-angle spinning NMR
spectroscopy to determine the arrangement of β strands. Combining
these data with long-range restraints from a spin-labeled sample,
chemical shift-based secondary structure prediction, and previous
MAS NMR and atomic force microscopy (AFM) data, we determined the
channel’s structure at a 2.2 Å root-mean-square deviation
(RMSD). The structure, a 19-stranded β-barrel, with an N-terminal
α-helix in the pore is in agreement with previous data in detergent,
which was questioned due to the potential for the detergent to perturb
the protein’s functional structure. Using a quintuple mutant
implementing the channel’s closed state, we found that dynamics
are a key element in the protein’s gating behavior, as channel
closure leads to the destabilization of not only the C-terminal barrel
residues but also the α2 helix. We showed that cholesterol,
previously shown to reduce the frequency of channel closure, stabilizes
the barrel relative to the N-terminal helix. Furthermore, we observed
channel closure through steric blockage by a drug shown to selectively
bind to the channel, the Bcl2-antisense oligonucleotide G3139.
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Affiliation(s)
- Eszter E Najbauer
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Kumar Tekwani Movellan
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Roland Benz
- Life Sciences and Chemistry, Jacobs University of Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
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19
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Preto J, Gorny H, Krimm I. A Deep Dive into VDAC1 Conformational Diversity Using All-Atom Simulations Provides New Insights into the Structural Origin of the Closed States. Int J Mol Sci 2022; 23:ijms23031175. [PMID: 35163095 PMCID: PMC8834982 DOI: 10.3390/ijms23031175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 01/14/2023] Open
Abstract
The voltage-dependent anion channel 1 (VDAC1) is a crucial mitochondrial transporter that controls the flow of ions and respiratory metabolites entering or exiting mitochondria. As a voltage-gated channel, VDAC1 can switch between a high-conducting “open” state and a low-conducting “closed” state emerging at high transmembrane (TM) potentials. Although cell homeostasis depends on channel gating to regulate the transport of ions and metabolites, structural hallmarks characterizing the closed states remain unknown. Here, we performed microsecond accelerated molecular dynamics to highlight a vast region of VDAC1 conformational landscape accessible at typical voltages known to promote closure. Conformers exhibiting durable subconducting properties inherent to closed states were identified. In all cases, the low conductance was due to the particular positioning of an unfolded part of the N-terminus, which obstructed the channel pore. While the N-terminal tail was found to be sensitive to voltage orientation, our models suggest that stable low-conducting states of VDAC1 predominantly take place from disordered events and do not result from the displacement of a voltage sensor or a significant change in the pore. In addition, our results were consistent with conductance jumps observed experimentally and corroborated a recent study describing entropy as a key factor for VDAC gating.
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20
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Gorelik TE, Tehrani KHME, Gruene T, Monecke T, Niessing D, Kaiser U, Blankenfeldt W, Müller R. Crystal structure of natural product argyrin-D determined by 3D electron diffraction. CrystEngComm 2022. [DOI: 10.1039/d2ce00707j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crystal structure of natural product argyrin D was determined from electron diffraction data.
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Affiliation(s)
- Tatiana E. Gorelik
- Electron Microscopy Group of Materials Science, Albert-Einstein-Allee 11, 89081 Ulm, Germany
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstraße 7, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University Campus, Saarbrucken, 66123, Germany
| | - Kamaleddin H. M. E. Tehrani
- Helmholtz Centre for Infection Research, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University Campus, Saarbrucken, 66123, Germany
| | - Tim Gruene
- Faculty of Chemistry, Department of Inorganic Chemistry, University of Vienna, AT-1090 Vienna, Austria
| | - Thomas Monecke
- Institute of Pharmaceutical Biotechnology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany
| | - Dierk Niessing
- Institute of Pharmaceutical Biotechnology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany
| | - Ute Kaiser
- Electron Microscopy Group of Materials Science, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Wulf Blankenfeldt
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstraße 7, Braunschweig, Germany
| | - Rolf Müller
- Helmholtz Centre for Infection Research, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University Campus, Saarbrucken, 66123, Germany
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21
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Martynowycz MW, Clabbers MTB, Hattne J, Gonen T. Ab initio phasing macromolecular structures using electron-counted MicroED data. Nat Methods 2022; 19:724-729. [PMID: 35637302 PMCID: PMC9184278 DOI: 10.1038/s41592-022-01485-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 04/07/2022] [Indexed: 12/31/2022]
Abstract
Structures of two globular proteins were determined ab initio using microcrystal electron diffraction (MicroED) data that were collected on a direct electron detector in counting mode. Microcrystals were identified using a scanning electron microscope (SEM) and thinned with a focused ion beam (FIB) to produce crystalline lamellae of ideal thickness. Continuous-rotation data were collected using an ultra-low exposure rate to enable electron counting in diffraction. For the first sample, triclinic lysozyme extending to a resolution of 0.87 Å, an ideal helical fragment of only three alanine residues provided initial phases. These phases were improved using density modification, allowing the entire atomic structure to be built automatically. A similar approach was successful on a second macromolecular sample, proteinase K, which is much larger and diffracted to a resolution of 1.5 Å. These results demonstrate that macromolecules can be determined to sub-ångström resolution by MicroED and that ab initio phasing can be successfully applied to counting data.
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Affiliation(s)
- Michael W. Martynowycz
- grid.19006.3e0000 0000 9632 6718Howard Hughes Medical Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Biological Chemistry, University of California, Los Angeles, CA USA
| | - Max T. B. Clabbers
- grid.19006.3e0000 0000 9632 6718Department of Biological Chemistry, University of California, Los Angeles, CA USA
| | - Johan Hattne
- grid.19006.3e0000 0000 9632 6718Howard Hughes Medical Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Biological Chemistry, University of California, Los Angeles, CA USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, USA. .,Department of Biological Chemistry, University of California, Los Angeles, CA, USA. .,Department of Physiology, University of California, Los Angeles, CA, USA.
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22
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Aljamal J. Effect of Lysine and Histidine Residues Modification on the Voltage Gating of the Mitochondrial Porin. JOURNAL OF BIOCHEMICAL TECHNOLOGY 2022. [DOI: 10.51847/dvlzksdsn8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Martynowycz MW, Clabbers MTB, Unge J, Hattne J, Gonen T. Benchmarking the ideal sample thickness in cryo-EM. Proc Natl Acad Sci U S A 2021; 118:e2108884118. [PMID: 34873060 PMCID: PMC8670461 DOI: 10.1073/pnas.2108884118] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 12/14/2022] Open
Abstract
The relationship between sample thickness and quality of data obtained is investigated by microcrystal electron diffraction (MicroED). Several electron microscopy (EM) grids containing proteinase K microcrystals of similar sizes from the same crystallization batch were prepared. Each grid was transferred into a focused ion beam and a scanning electron microscope in which the crystals were then systematically thinned into lamellae between 95- and 1,650-nm thick. MicroED data were collected at either 120-, 200-, or 300-kV accelerating voltages. Lamellae thicknesses were expressed in multiples of the corresponding inelastic mean free path to allow the results from different acceleration voltages to be compared. The quality of the data and subsequently determined structures were assessed using standard crystallographic measures. Structures were reliably determined with similar quality from crystalline lamellae up to twice the inelastic mean free path. Lower resolution diffraction was observed at three times the mean free path for all three accelerating voltages, but the data quality was insufficient to yield structures. Finally, no coherent diffraction was observed from lamellae thicker than four times the calculated inelastic mean free path. This study benchmarks the ideal specimen thickness with implications for all cryo-EM methods.
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Affiliation(s)
- Michael W Martynowycz
- HHMI, University of California, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Max T B Clabbers
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Johan Unge
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Johan Hattne
- HHMI, University of California, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Tamir Gonen
- HHMI, University of California, Los Angeles, CA 90095;
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
- Department of Physiology, University of California, Los Angeles, CA 90095
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24
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Clark LJ, Bu G, Nannenga BL, Gonen T. MicroED for the study of protein–ligand interactions and the potential for drug discovery. Nat Rev Chem 2021; 5:853-858. [PMID: 37117388 DOI: 10.1038/s41570-021-00332-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2021] [Indexed: 12/18/2022]
Abstract
Microcrystal electron diffraction (MicroED) is an electron cryo-microscopy (cryo-EM) technique used to determine molecular structures with crystals that are a millionth the size needed for traditional single-crystal X-ray crystallography. An exciting use of MicroED is in drug discovery and development, where it can be applied to the study of proteins and small molecule interactions, and for structure determination of natural products. The structures are then used for rational drug design and optimization. In this Perspective, we discuss the current applications of MicroED for structure determination of protein-ligand complexes and potential future applications in drug discovery.
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25
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Martynowycz MW, Gonen T. Protocol for the use of focused ion-beam milling to prepare crystalline lamellae for microcrystal electron diffraction (MicroED). STAR Protoc 2021; 2:100686. [PMID: 34382014 PMCID: PMC8339237 DOI: 10.1016/j.xpro.2021.100686] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We present an in-depth protocol to reproducibly prepare crystalline lamellae from protein crystals for subsequent microcrystal electron diffraction (MicroED) experiments. This protocol covers typical soluble proteins and membrane proteins embedded in dense media. Following these steps will allow the user to prepare crystalline lamellae for protein structure determination by MicroED. For complete details on the use and execution of this protocol, please refer to Martynowycz et al. (2019a, 2020a).
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Affiliation(s)
- Michael W. Martynowycz
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
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26
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Martynowycz MW, Shiriaeva A, Ge X, Hattne J, Nannenga BL, Cherezov V, Gonen T. MicroED structure of the human adenosine receptor determined from a single nanocrystal in LCP. Proc Natl Acad Sci U S A 2021; 118:e2106041118. [PMID: 34462357 PMCID: PMC8433539 DOI: 10.1073/pnas.2106041118] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs), or seven-transmembrane receptors, are a superfamily of membrane proteins that are critically important to physiological processes in the human body. Determining high-resolution structures of GPCRs without bound cognate signaling partners, such as a G protein, requires crystallization in lipidic cubic phase (LCP). GPCR crystals grown in LCP are often too small for traditional X-ray crystallography. These microcrystals are ideal for investigation by microcrystal electron diffraction (MicroED), but the gel-like nature of LCP makes traditional approaches to MicroED sample preparation insurmountable. Here, we show that the structure of a human A2A adenosine receptor can be determined by MicroED after converting the LCP into the sponge phase followed by focused ion-beam milling. We determined the structure of the A2A adenosine receptor to 2.8-Å resolution and resolved an antagonist in its orthosteric ligand-binding site, as well as four cholesterol molecules bound around the receptor. This study lays the groundwork for future structural studies of lipid-embedded membrane proteins by MicroED using single microcrystals that would be impossible with other crystallographic methods.
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Affiliation(s)
- Michael W Martynowycz
- HHMI, University of California, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Anna Shiriaeva
- Bridge Institute, University of Southern California Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90007
- Department of Chemistry, University of Southern California, Los Angeles, CA 90007
| | - Xuanrui Ge
- Bridge Institute, University of Southern California Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90007
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90007
| | - Johan Hattne
- HHMI, University of California, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
| | - Brent L Nannenga
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287
- Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Vadim Cherezov
- Bridge Institute, University of Southern California Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90007;
- Department of Chemistry, University of Southern California, Los Angeles, CA 90007
| | - Tamir Gonen
- HHMI, University of California, Los Angeles, CA 90095;
- Department of Biological Chemistry, University of California, Los Angeles, CA 90095
- Department of Physiology, University of California, Los Angeles, CA 90095
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Clabbers MTB, Holmes S, Muusse TW, Vajjhala PR, Thygesen SJ, Malde AK, Hunter DJB, Croll TI, Flueckiger L, Nanson JD, Rahaman MH, Aquila A, Hunter MS, Liang M, Yoon CH, Zhao J, Zatsepin NA, Abbey B, Sierecki E, Gambin Y, Stacey KJ, Darmanin C, Kobe B, Xu H, Ve T. MyD88 TIR domain higher-order assembly interactions revealed by microcrystal electron diffraction and serial femtosecond crystallography. Nat Commun 2021; 12:2578. [PMID: 33972532 PMCID: PMC8110528 DOI: 10.1038/s41467-021-22590-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/18/2021] [Indexed: 02/03/2023] Open
Abstract
MyD88 and MAL are Toll-like receptor (TLR) adaptors that signal to induce pro-inflammatory cytokine production. We previously observed that the TIR domain of MAL (MALTIR) forms filaments in vitro and induces formation of crystalline higher-order assemblies of the MyD88 TIR domain (MyD88TIR). These crystals are too small for conventional X-ray crystallography, but are ideally suited to structure determination by microcrystal electron diffraction (MicroED) and serial femtosecond crystallography (SFX). Here, we present MicroED and SFX structures of the MyD88TIR assembly, which reveal a two-stranded higher-order assembly arrangement of TIR domains analogous to that seen previously for MALTIR. We demonstrate via mutagenesis that the MyD88TIR assembly interfaces are critical for TLR4 signaling in vivo, and we show that MAL promotes unidirectional assembly of MyD88TIR. Collectively, our studies provide structural and mechanistic insight into TLR signal transduction and allow a direct comparison of the MicroED and SFX techniques.
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Affiliation(s)
- Max T B Clabbers
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Susannah Holmes
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Timothy W Muusse
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Parimala R Vajjhala
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Sara J Thygesen
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Alpeshkumar K Malde
- Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Dominic J B Hunter
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Kensington, New South Wales, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Tristan I Croll
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Leonie Flueckiger
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Md Habibur Rahaman
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Andrew Aquila
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Mark S Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Mengning Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Chun Hong Yoon
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Jingjing Zhao
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
| | - Nadia A Zatsepin
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Brian Abbey
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Emma Sierecki
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Kensington, New South Wales, Australia
| | - Yann Gambin
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Kensington, New South Wales, Australia
| | - Katryn J Stacey
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Connie Darmanin
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
| | - Hongyi Xu
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Southport, Queensland, Australia.
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Martynowycz MW, Gonen T. Microcrystal Electron Diffraction of Small Molecules. J Vis Exp 2021:10.3791/62313. [PMID: 33779618 PMCID: PMC9974888 DOI: 10.3791/62313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
A detailed protocol for preparing small molecule samples for microcrystal electron diffraction (MicroED) experiments is described. MicroED has been developed to solve structures of proteins and small molecules using standard electron cryo-microscopy (cryo-EM) equipment. In this way, small molecules, peptides, soluble proteins, and membrane proteins have recently been determined to high resolutions. Protocols are presented here for preparing grids of small-molecule pharmaceuticals using the drug carbamazepine as an example. Protocols for screening and collecting data are presented. Additional steps in the overall process, such as data integration, structure determination, and refinement are presented elsewhere. The time required to prepare the small-molecule grids is estimated to be less than 30 min.
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Affiliation(s)
- Michael W. Martynowycz
- Howard Hughes Medical Institute, University of California Los Angeles,Department of Biological Chemistry, University of California Los Angeles
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California Los Angeles; Department of Biological Chemistry, University of California Los Angeles; Department of Physiology, University of California Los Angeles;
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29
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Clabbers MTB, Xu H. Macromolecular crystallography using microcrystal electron diffraction. Acta Crystallogr D Struct Biol 2021; 77:313-324. [PMID: 33645535 PMCID: PMC7919406 DOI: 10.1107/s2059798320016368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/16/2020] [Indexed: 11/10/2022] Open
Abstract
Microcrystal electron diffraction (MicroED) has recently emerged as a promising method for macromolecular structure determination in structural biology. Since the first protein structure was determined in 2013, the method has been evolving rapidly. Several protein structures have been determined and various studies indicate that MicroED is capable of (i) revealing atomic structures with charges, (ii) solving new protein structures by molecular replacement, (iii) visualizing ligand-binding interactions and (iv) determining membrane-protein structures from microcrystals embedded in lipidic mesophases. However, further development and optimization is required to make MicroED experiments more accurate and more accessible to the structural biology community. Here, we provide an overview of the current status of the field, and highlight the ongoing development, to provide an indication of where the field may be going in the coming years. We anticipate that MicroED will become a robust method for macromolecular structure determination, complementing existing methods in structural biology.
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Affiliation(s)
- Max T. B. Clabbers
- Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden
| | - Hongyi Xu
- Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden
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30
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Abstract
Microcrystal electron diffraction (MicroED) enables atomic resolution structures to be determined from vanishingly small crystals. Soluble proteins typically grow crystals that are tens to hundreds of microns in size for X-ray crystallography. But membrane protein crystals often grow crystals that are too small for X-ray diffraction and yet too large for MicroED. These crystals are often formed in thick, viscous media that challenge traditional cryoEM grid preparation. Here, we describe two approaches for preparing membrane protein crystals for MicroED data collection: application of a crystal slurry directly to EM grids, and focused ion beam milling in a Scanning Electron Microscope (FIB-SEM). We summarize the case of preparing an ion channel, NaK, and the workflow of focused ion-beam milling. By milling away the excess media and crystalline material, crystals of any size may be prepared for MicroED. Finally, an energy filter may be used to help minimize inelastic scattering leading to lower noise on recorded images.
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Affiliation(s)
- Michael W. Martynowycz
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA.,Department of Physiology, University of California Los Angeles, Los Angeles, CA, USA.,Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Tamir Gonen
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA. .,Department of Physiology, University of California Los Angeles, Los Angeles, CA, USA. .,Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA.
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