1
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Zhao Q, Hong X, Wang Y, Zhang S, Ding Z, Meng X, Song Q, Hong Q, Jiang W, Shi X, Cai T, Cong Y. An immobilized antibody-based affinity grid strategy for on-grid purification of target proteins enables high-resolution cryo-EM. Commun Biol 2024; 7:715. [PMID: 38858498 PMCID: PMC11164986 DOI: 10.1038/s42003-024-06406-z] [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: 01/17/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024] Open
Abstract
In cryo-electron microscopy (cryo-EM), sample preparation poses a critical bottleneck, particularly for rare or fragile macromolecular assemblies and those suffering from denaturation and particle orientation distribution issues related to air-water interface. In this study, we develop and characterize an immobilized antibody-based affinity grid (IAAG) strategy based on the high-affinity PA tag/NZ-1 antibody epitope tag system. We employ Pyr-NHS as a linker to immobilize NZ-1 Fab on the graphene oxide or carbon-covered grid surface. Our results demonstrate that the IAAG grid effectively enriches PA-tagged target proteins and overcomes preferred orientation issues. Furthermore, we demonstrate the utility of our IAAG strategy for on-grid purification of low-abundance target complexes from cell lysates, enabling atomic resolution cryo-EM. This approach greatly streamlines the purification process, reduces the need for large quantities of biological samples, and addresses common challenges encountered in cryo-EM sample preparation. Collectively, our IAAG strategy provides an efficient and robust means for combined sample purification and vitrification, feasible for high-resolution cryo-EM. This approach holds potential for broader applicability in both cryo-EM and cryo-electron tomography (cryo-ET).
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Affiliation(s)
- Qiaoyu Zhao
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Xiaoyu Hong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Yanxing Wang
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Shaoning Zhang
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Zhanyu Ding
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Xueming Meng
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Qianqian Song
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Qin Hong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Wanying Jiang
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Xiangyi Shi
- Shanghai Nanoport, Thermo Fisher Scientific, Shanghai, China
| | - Tianxun Cai
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Yao Cong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China.
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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2
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Cho US. The Core Complex of Yeast COMPASS and Human Mixed-Lineage Leukemia (MLL), Structure, Function, and Recognition of the Nucleosome. Subcell Biochem 2024; 104:101-117. [PMID: 38963485 DOI: 10.1007/978-3-031-58843-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Yeast COMPASS (complex of proteins associated with Set1) and human MLL (mixed-lineage leukemia) complexes are histone H3 lysine 4 methyltransferases with critical roles in gene regulation and embryonic development. Both complexes share a conserved C-terminal SET domain, responsible for catalyzing histone H3 K4 methylation on nucleosomes. Notably, their catalytic activity toward nucleosomes is enhanced and optimized with assembly of auxiliary subunits. In this review, we aim to illustrate the recent X-ray and cryo-EM structures of yeast COMPASS and human MLL1 core complexes bound to either unmodified nucleosome core particle (NCP) or H2B mono-ubiquitinated NCP (H2Bub.NCP). We further delineate how each auxiliary component of the complex contributes to the NCP and ubiquitin recognition to maximize the methyltransferase activity.
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Affiliation(s)
- Uhn-Soo Cho
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.
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3
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Yu Y, Wang S, Wang Z, Gao R, Lee J. Arabidopsis thaliana: a powerful model organism to explore histone modifications and their upstream regulations. Epigenetics 2023; 18:2211362. [PMID: 37196184 DOI: 10.1080/15592294.2023.2211362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 04/07/2023] [Accepted: 04/28/2023] [Indexed: 05/19/2023] Open
Abstract
Histones are subjected to extensive covalent modifications that affect inter-nucleosomal interactions as well as alter chromatin structure and DNA accessibility. Through switching the corresponding histone modifications, the level of transcription and diverse downstream biological processes can be regulated. Although animal systems are widely used in studying histone modifications, the signalling processes that occur outside the nucleus prior to histone modifications have not been well understood due to the limitations including non viable mutants, partial lethality, and infertility of survivors. Here, we review the benefits of using Arabidopsis thaliana as the model organism to study histone modifications and their upstream regulations. Similarities among histones and key histone modifiers such as the Polycomb group (PcG) and Trithorax group (TrxG) in Drosophila, Human, and Arabidopsis are examined. Furthermore, prolonged cold-induced vernalization system has been well-studied and revealed the relationship between the controllable environment input (duration of vernalization), its chromatin modifications of FLOWERING LOCUS C (FLC), following gene expression, and the corresponding phenotypes. Such evidence suggests that research on Arabidopsis can bring insights into incomplete signalling pathways outside of the histone box, which can be achieved through viable reverse genetic screenings based on the phenotypes instead of direct monitoring of histone modifications among individual mutants. The potential upstream regulators in Arabidopsis can provide cues or directions for animal research based on the similarities between them.
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Affiliation(s)
- Yang Yu
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Sihan Wang
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Ziqin Wang
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Renwei Gao
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Joohyun Lee
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
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4
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Deshpande N, Bryk M. Diverse and dynamic forms of gene regulation by the S. cerevisiae histone methyltransferase Set1. Curr Genet 2023; 69:91-114. [PMID: 37000206 DOI: 10.1007/s00294-023-01265-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 03/11/2023] [Accepted: 03/14/2023] [Indexed: 04/01/2023]
Abstract
Gene transcription is an essential and highly regulated process. In eukaryotic cells, the structural organization of nucleosomes with DNA wrapped around histone proteins impedes transcription. Chromatin remodelers, transcription factors, co-activators, and histone-modifying enzymes work together to make DNA accessible to RNA polymerase. Histone lysine methylation can positively or negatively regulate gene transcription. Methylation of histone 3 lysine 4 by SET-domain-containing proteins is evolutionarily conserved from yeast to humans. In higher eukaryotes, mutations in SET-domain proteins are associated with defects in the development and segmentation of embryos, skeletal and muscle development, and diseases, including several leukemias. Since histone methyltransferases are evolutionarily conserved, the mechanisms of gene regulation mediated by these enzymes are also conserved. Budding yeast Saccharomyces cerevisiae is an excellent model system to study the impact of histone 3 lysine 4 (H3K4) methylation on eukaryotic gene regulation. Unlike larger eukaryotes, yeast cells have only one enzyme that catalyzes H3K4 methylation, Set1. In this review, we summarize current knowledge about the impact of Set1-catalyzed H3K4 methylation on gene transcription in S. cerevisiae. We describe the COMPASS complex, factors that influence H3K4 methylation, and the roles of Set1 in gene silencing at telomeres and heterochromatin, as well as repression and activation at euchromatic loci. We also discuss proteins that "read" H3K4 methyl marks to regulate transcription and summarize alternate functions for Set1 beyond H3K4 methylation.
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Affiliation(s)
- Neha Deshpande
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Mary Bryk
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
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5
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Pan X, Hao L, Yang C, Lin H, Wu D, Chen X, Zhang M, Ma D, Wang Y, Fu W, Yao Y, Wang S, Zhuang Z. SWD1 epigenetically chords fungal morphogenesis, aflatoxin biosynthesis, metabolism, and virulence of Aspergillus flavus. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131542. [PMID: 37172387 DOI: 10.1016/j.jhazmat.2023.131542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/17/2023] [Accepted: 04/28/2023] [Indexed: 05/14/2023]
Abstract
As the main producer of aflatoxins, Aspergillus flavus is also one of the most important causes of invasive and non-invasive aspergillosis. Therefore, it is crucial to unravel the regulatory mechanisms of growth, metabolism, and pathogenicity of A. flavus. SWD1 is highly conserved across species for maintaining COMPASS methyltransferase activity, but the bio-function of SWD1 in A. flavus has not been explored. Through genetic analysis, this study revealed that SWD1 is involved in fungal morphogenesis and AFB1 biosynthesis by regulating the orthodox pathways through H3K4me1-3. Stresses sensitivity and crop models analysis revealed that SWD1 is a key regulator for the resistance of A. flavus to adapt to extreme adverse environments and to colonize crop kernels. It also revealed that the WD40 domain and 25 aa highly conserved sequence are indispensable for SWD1 in the regulation of mycotoxin bio-synthesis and fungal virulence. Metabolomic analysis inferred that SWD1 is crucial for the biosynthesis of numerous primary and secondary metabolites, regulates biological functions by reshaping the whole metabolic process, and may inhibit fungal virulence by inducing the apoptosis of mycelia through the inducer sphingosine. This study elucidates the epigenetic mechanism of SWD1 in regulating fungal pathogenicity and mycotoxin biosynthesis, and provides a potential novel target for controlling the virulence of A. flavus.
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Affiliation(s)
- Xiaohua Pan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Key Laboratory of Propagated Sensation along Meridian, Fujian Academy of Chinese Medical Sciences, Fuzhou 350003, China
| | - Ling Hao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chi Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Institute of Edible Mushroom, Fujian Academy of Agricultural Sciences, Fuzhou 350014, China
| | - Hong Lin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dandan Wu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xuan Chen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mengjuan Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dongmei Ma
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yu Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wangzhuo Fu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yanfang Yao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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6
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Zhao G, Wang J, Chen X, Sha H, Liu X, Han Y, Qiu G, Zhang F, Fang J. OsASHL1 and OsASHL2, two members of the COMPASS-like complex, control floral transition and plant development in rice. J Genet Genomics 2022; 49:870-880. [DOI: 10.1016/j.jgg.2022.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/14/2022] [Accepted: 02/20/2022] [Indexed: 11/26/2022]
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7
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Deshpande N, Jordan R, Henderson Pozzi M, Bryk M. Histone 3 lysine 4 monomethylation supports activation of transcription in S. cerevisiae during nutrient stress. Curr Genet 2022; 68:181-194. [PMID: 35041077 PMCID: PMC8976815 DOI: 10.1007/s00294-022-01226-2] [Citation(s) in RCA: 6] [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] [Received: 06/15/2021] [Revised: 12/17/2021] [Accepted: 12/31/2021] [Indexed: 12/11/2022]
Abstract
Mono-methylation of the fourth lysine on the N-terminal tail of histone H3 was found to support the induction of RNA polymerase II transcription in S. cerevisiae during nutrient stress. In S. cerevisiae, the mono-, di- and tri-methylation of lysine 4 on histone H3 (H3K4) is catalyzed by the protein methyltransferase, Set1. The three distinct methyl marks on H3K4 act in discrete ways to regulate transcription. Nucleosomes enriched with tri-methylated H3K4 are usually associated with active transcription whereas di-methylated H3K4 is associated with gene repression. Mono-methylated H3K4 has been shown to repress gene expression in S. cerevisiae and is detected at enhancers and promoters in eukaryotes. S. cerevisiae set1Δ mutants unable to methylate H3K4 exhibit growth defects during histidine starvation. The growth defects are rescued by either a wild-type allele of SET1 or partial-function alleles of set1, including a mutant that predominantly generates H3K4me1 and not H3K4me3. Rescue of the growth defect is associated with induction of the HIS3 gene. Growth defects observed when set1Δ cultures were starved for isoleucine and valine were also rescued by wild-type SET1 or partial-function set1 alleles. The results show that H3K4me1, in the absence of H3K4me3, supports transcription of the HIS3 gene and expression of one or more of the genes required for biosynthesis of isoleucine and valine during nutrient stress. Set1-like methyltransferases are evolutionarily conserved, and research has linked their functions to developmental gene regulation and several cancers in higher eukaryotes. Identification of mechanisms of H3K4me1-mediated activation of transcription in budding yeast will provide insight into gene regulation in all eukaryotes.
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Affiliation(s)
- Neha Deshpande
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Rachel Jordan
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
- iBio, 8800 HSC Blvd, Bryan, TX, 77807, USA
| | - Michelle Henderson Pozzi
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Mary Bryk
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA.
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8
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Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM. Proc Natl Acad Sci U S A 2021; 118:2021180118. [PMID: 34871179 DOI: 10.1073/pnas.2021180118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The radial spoke (RS) heads of motile cilia and flagella contact projections of the central pair (CP) apparatus to coordinate motility, but the morphology is distinct for protozoa and metazoa. Here we show the murine RS head is compositionally distinct from that of Chlamydomonas Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a and Rsph10b, whose orthologs exist in the protozoan RS head. We resolve its cryo-electron microscopy (cryo-EM) structure at 3.2-Å resolution. Our atomic model further reveals a twofold symmetric brake pad-shaped structure, in which Rsph4a and Rsph9 form a compact body extended laterally with two long arms of twisted Rsph1 β-sheets and potentially connected dorsally via Rsph3b to the RS stalk. Furthermore, our modeling suggests that the core complex contacts the periodic CP projections either rigidly through its tooth-shaped Rsph4a regions or elastically through both arms for optimized RS-CP interactions and mechanosignal transduction.
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9
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McCafferty CL, Verbeke EJ, Marcotte EM, Taylor DW. Structural Biology in the Multi-Omics Era. J Chem Inf Model 2020; 60:2424-2429. [PMID: 32129623 PMCID: PMC7254829 DOI: 10.1021/acs.jcim.9b01164] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Rapid developments in cryogenic electron microscopy have opened new avenues to probe the structures of protein assemblies in their near native states. Recent studies have begun applying single -particle analysis to heterogeneous mixtures, revealing the potential of structural-omics approaches that combine the power of mass spectrometry and electron microscopy. Here we highlight advances and challenges in sample preparation, data processing, and molecular modeling for handling increasingly complex mixtures. Such advances will help structural-omics methods extend to cellular-level models of structural biology.
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Affiliation(s)
- Caitlyn L. McCafferty
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
| | - Eric J. Verbeke
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
| | - Edward M. Marcotte
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
- Institute
for Cellular and Molecular Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Systems and Synthetic Biology, University
of Texas at Austin, Austin, Texas 78712, United States
| | - David W. Taylor
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
- Institute
for Cellular and Molecular Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Systems and Synthetic Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- LIVESTRONG
Cancer Institutes, Dell Medical School, Austin, Texas 78712, United States
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10
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The Set1 N-terminal domain and Swd2 interact with RNA polymerase II CTD to recruit COMPASS. Nat Commun 2020; 11:2181. [PMID: 32358498 PMCID: PMC7195483 DOI: 10.1038/s41467-020-16082-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/14/2020] [Indexed: 12/24/2022] Open
Abstract
Methylation of histone H3 lysine 4 (H3K4) by Set1/COMPASS occurs co-transcriptionally, and is important for gene regulation. Set1/COMPASS associates with the RNA polymerase II C-terminal domain (CTD) to establish proper levels and distribution of H3K4 methylations. However, details of CTD association remain unclear. Here we report that the Set1 N-terminal region and the COMPASS subunit Swd2, which interact with each other, are both needed for efficient CTD binding in Saccharomyces cerevisiae. Moreover, a single point mutation in Swd2 that affects its interaction with Set1 also impairs COMPASS recruitment to chromatin and H3K4 methylation. A CTD interaction domain (CID) from the protein Nrd1 can partially substitute for the Set1 N-terminal region to restore CTD interactions and histone methylation. However, even when Set1/COMPASS is recruited via the Nrd1 CID, histone H2B ubiquitylation is still required for efficient H3K4 methylation, indicating that H2Bub acts after the initial recruitment of COMPASS to chromatin.
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11
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Casañal A, Shakeel S, Passmore LA. Interpretation of medium resolution cryoEM maps of multi-protein complexes. Curr Opin Struct Biol 2019; 58:166-174. [PMID: 31362190 PMCID: PMC6863432 DOI: 10.1016/j.sbi.2019.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/14/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022]
Abstract
CryoEM maps at medium (3.5–6 Å) resolution can be challenging to interpret. Integration of multiple methods can inform cryoEM studies. Mass spectrometry and biochemistry facilitate map interpretation and model building.
Electron cryo-microscopy (cryoEM) is used to determine structures of biological molecules, including multi-protein complexes. Maps at better than 3.0 Å resolution are relatively straightforward to interpret since atomic models of proteins and nucleic acids can be built directly. Still, these resolutions are often difficult to achieve, and map quality frequently varies within a structure. This results in data that are challenging to interpret, especially when crystal structures or suitable homology models are not available. Recent advances in mass spectrometry techniques, computational methods and model building tools facilitate subunit/domain fitting into maps, elucidation of protein contacts, and de novo generation of atomic models. Here, we review techniques for map interpretation and provide examples from recent studies of multi-protein complexes.
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Affiliation(s)
- Ana Casañal
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
| | - Shabih Shakeel
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Lori A Passmore
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
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12
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Brown ZP, Takagi J. Advances in domain and subunit localization technology for electron microscopy. Biophys Rev 2019; 11:149-155. [PMID: 30834502 DOI: 10.1007/s12551-019-00513-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 02/20/2019] [Indexed: 12/26/2022] Open
Abstract
The award of the 2017 Nobel Prize in chemistry, 'for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution', was recognition that this method, and electron microscopy more generally, represent powerful techniques in the scientific armamentarium for atomic level structural assessment. Technical advances in equipment, software, and sample preparation, have allowed for high-resolution structural determination of a range of complex biological machinery such that the position of individual atoms within these mega-structures can be determined. However, not all targets are amenable to attaining such high-resolution structures and some may only be resolved at so-called intermediate resolutions. In these cases, other tools are needed to correctly characterize the domain or subunit orientation and architecture. In this review, we will outline various methods that can provide additional information to help understand the macro-level organization of proteins/biomolecular complexes when high-resolution structural description is not available. In particular, we will discuss the recent development and use of a novel protein purification approach, known as the the PA tag/NZ-1 antibody system, which provides numberous beneficial properties, when used in electron microscopy experimentation.
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Affiliation(s)
- Zuben P Brown
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Osaka, Japan
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