1
|
Ishida H, Matsumoto A, Tanaka H, Okuda A, Morishima K, Wade PA, Kurumizaka H, Sugiyama M, Kono H. Structural and Dynamic Changes of Nucleosome upon GATA3 Binding. J Mol Biol 2023; 435:168308. [PMID: 37805066 PMCID: PMC10843466 DOI: 10.1016/j.jmb.2023.168308] [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: 08/03/2023] [Revised: 09/30/2023] [Accepted: 10/03/2023] [Indexed: 10/09/2023]
Abstract
Pioneer factors, which can directly bind to nucleosomes, have been considered to change chromatin conformations. However, the binding impact on the nucleosome is little known. Here, we show how the pioneer factor GATA3 binds to nucleosomal DNA and affects the conformation and dynamics of nucleosomes by using a combination of SAXS, molecular modeling, and molecular dynamics simulations. Our structural models, consistent with the SAXS data, indicate that only one of the two DNA binding domains, N- and C-fingers, of GATA3 binds to an end of the DNA in solution. Our MD simulations further showed that the other unbound end of the DNA increases the fluctuation and enhances the DNA dissociation from the histone core when the N-finger binds to a DNA end, a site near the entry or exit of the nucleosome. However, this was not true for the binding of the C-finger that binds to a location about 15 base pairs distant from the DNA end. In this case, DNA dissociation occurred on the bound end. Taken together, we suggest that the N-finger and C-finger bindings of GATA3 commonly enhance DNA dissociation at one of the two DNA ends (the bound end for the C-finger binding and the unbound end for the N-finger binding), leading to triggering a conformational change in the chromatin.
Collapse
Affiliation(s)
- Hisashi Ishida
- Institute for Quantum Life Science, Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba city, Chiba 263-8555, Japan
| | - Atsushi Matsumoto
- Institute for Quantum Life Science, Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba city, Chiba 263-8555, Japan
| | - Hiroki Tanaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan; Present address: Department of Structural Virology, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Aya Okuda
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka, 590-0494, Japan
| | - Ken Morishima
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka, 590-0494, Japan
| | - Paul A Wade
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC 27709, USA
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Masaaki Sugiyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-1010 Asashironishi, Kumatori, Sennan-gun, Osaka, 590-0494, Japan
| | - Hidetoshi Kono
- Institute for Quantum Life Science, Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba city, Chiba 263-8555, Japan; Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
| |
Collapse
|
2
|
Richardson JS, Williams CJ, Chen VB, Prisant MG, Richardson DC. The bad and the good of trends in model building and refinement for sparse-data regions: pernicious forms of overfitting versus good new tools and predictions. Acta Crystallogr D Struct Biol 2023; 79:1071-1078. [PMID: 37921807 PMCID: PMC10833350 DOI: 10.1107/s2059798323008847] [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: 05/10/2023] [Accepted: 10/09/2023] [Indexed: 11/04/2023] Open
Abstract
Model building and refinement, and the validation of their correctness, are very effective and reliable at local resolutions better than about 2.5 Å for both crystallography and cryo-EM. However, at local resolutions worse than 2.5 Å both the procedures and their validation break down and do not ensure reliably correct models. This is because in the broad density at lower resolution, critical features such as protein backbone carbonyl O atoms are not just less accurate but are not seen at all, and so peptide orientations are frequently wrongly fitted by 90-180°. This puts both backbone and side chains into the wrong local energy minimum, and they are then worsened rather than improved by further refinement into a valid but incorrect rotamer or Ramachandran region. On the positive side, new tools are being developed to locate this type of pernicious error in PDB depositions, such as CaBLAM, EMRinger, Pperp diagnosis of ribose puckers, and peptide flips in PDB-REDO, while interactive modeling in Coot or ISOLDE can help to fix many of them. Another positive trend is that artificial intelligence predictions such as those made by AlphaFold2 contribute additional evidence from large multiple sequence alignments, and in high-confidence parts they provide quite good starting models for loops, termini or whole domains with otherwise ambiguous density.
Collapse
Affiliation(s)
- Jane S. Richardson
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | | | - Vincent B. Chen
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Michael G. Prisant
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - David C. Richardson
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| |
Collapse
|
3
|
McRae EKS, Rasmussen HØ, Liu J, Bøggild A, Nguyen MTA, Sampedro Vallina N, Boesen T, Pedersen JS, Ren G, Geary C, Andersen ES. Structure, folding and flexibility of co-transcriptional RNA origami. NATURE NANOTECHNOLOGY 2023; 18:808-817. [PMID: 36849548 PMCID: PMC10566746 DOI: 10.1038/s41565-023-01321-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
RNA origami is a method for designing RNA nanostructures that can self-assemble through co-transcriptional folding with applications in nanomedicine and synthetic biology. However, to advance the method further, an improved understanding of RNA structural properties and folding principles is required. Here we use cryogenic electron microscopy to study RNA origami sheets and bundles at sub-nanometre resolution revealing structural parameters of kissing-loop and crossover motifs, which are used to improve designs. In RNA bundle designs, we discover a kinetic folding trap that forms during folding and is only released after 10 h. Exploration of the conformational landscape of several RNA designs reveal the flexibility of helices and structural motifs. Finally, sheets and bundles are combined to construct a multidomain satellite shape, which is characterized by individual-particle cryo-electron tomography to reveal the domain flexibility. Together, the study provides a structural basis for future improvements to the design cycle of genetically encoded RNA nanodevices.
Collapse
Affiliation(s)
- Ewan K S McRae
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Helena Østergaard Rasmussen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Andreas Bøggild
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Michael T A Nguyen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | | | - Thomas Boesen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Cody Geary
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Ebbe Sloth Andersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
| |
Collapse
|
4
|
Sampedro Vallina N, McRae EKS, Geary C, Andersen ES. An RNA Paranemic Crossover Triangle as A 3D Module for Cotranscriptional Nanoassembly. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2204651. [PMID: 36526605 DOI: 10.1002/smll.202204651] [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: 07/29/2022] [Revised: 11/15/2022] [Indexed: 05/28/2023]
Abstract
RNA nanotechnology takes advantage of structural modularity to build self-assembling nano-architectures with applications in medicine and synthetic biology. The use of paranemic motifs, that form without unfolding existing secondary structure, allows for the creation of RNA nanostructures that are compatible with cotranscriptional folding in vitro and in vivo. In previous work, kissing-loop (KL) motifs have been widely used to design RNA nanostructures that fold cotranscriptionally. However, the paranemic crossover (PX) motif has not yet been explored for cotranscriptional RNA origami architectures and information about the structural geometry of the motif is unknown. Here, a six base pair-wide paranemic RNA interaction that arranges double helices in a perpendicular manner is introduced, allowing for the generation of a new and versatile building block: the paranemic-crossover triangle (PXT). The PXT is self-assembled by cotranscriptional folding and characterized by cryogenic electron microscopy, revealing for the first time an RNA PX interaction in high structural detail. The PXT is used as a building block for the construction of multimers that form filaments and rings and a duplicated PXT motif is used as a building block to self-assemble cubic structures, demonstrating the PXT as a rigid self-folding domain for the development of wireframe RNA origami architectures.
Collapse
Affiliation(s)
- Néstor Sampedro Vallina
- Interdisciplinary Nanoscience Center (iNANO); Gustav Wieds Vej 14, Aarhus University, Aarhus, DK-8000, Denmark
| | - Ewan K S McRae
- Interdisciplinary Nanoscience Center (iNANO); Gustav Wieds Vej 14, Aarhus University, Aarhus, DK-8000, Denmark
| | - Cody Geary
- Interdisciplinary Nanoscience Center (iNANO); Gustav Wieds Vej 14, Aarhus University, Aarhus, DK-8000, Denmark
| | - Ebbe Sloth Andersen
- Interdisciplinary Nanoscience Center (iNANO); Gustav Wieds Vej 14, Aarhus University, Aarhus, DK-8000, Denmark
| |
Collapse
|
5
|
Joseph AP, Malhotra S, Burnley T, Winn MD. Overview and applications of map and model validation tools in the CCP-EM software suite. Faraday Discuss 2022; 240:196-209. [PMID: 35916020 PMCID: PMC9642004 DOI: 10.1039/d2fd00103a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cryogenic electron microscopy (cryo-EM) has recently been established as a powerful technique for solving macromolecular structures. Although the best resolutions achievable are improving, a significant majority of data are still resolved at resolutions worse than 3 Å, where it is non-trivial to build or fit atomic models. The map reconstructions and atomic models derived from the maps are also prone to errors accumulated through the different stages of data processing. Here, we highlight the need to evaluate both model geometry and fit to data at different resolutions. Assessment of cryo-EM structures from SARS-CoV-2 highlights a bias towards optimising the model geometry to agree with the most common conformations, compared to the agreement with data. We present the CoVal web service which provides multiple validation metrics to reflect the quality of atomic models derived from cryo-EM data of structures from SARS-CoV-2. We demonstrate that further refinement can lead to improvement of the agreement with data without the loss of geometric quality. We also discuss the recent CCP-EM developments aimed at addressing some of the current shortcomings.
Collapse
Affiliation(s)
- Agnel Praveen Joseph
- Scientific Computing Department, Science and Technology Facilities CouncilDidcot OX11 0FAUK
| | - Sony Malhotra
- Scientific Computing Department, Science and Technology Facilities CouncilDidcot OX11 0FAUK
| | - Tom Burnley
- Scientific Computing Department, Science and Technology Facilities CouncilDidcot OX11 0FAUK
| | - Martyn D. Winn
- Scientific Computing Department, Science and Technology Facilities CouncilDidcot OX11 0FAUK
| |
Collapse
|
6
|
Chojnowski G. Sequence-assignment validation in cryo-EM models with checkMySequence. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:806-816. [PMID: 35775980 PMCID: PMC9248842 DOI: 10.1107/s2059798322005009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/10/2022] [Indexed: 01/18/2023]
Abstract
A new method, checkMySequence, for the fast and automated detection of register errors in protein models built into cryo-EM reconstructions is presented. The availability of new artificial intelligence-based protein-structure-prediction tools has radically changed the way that cryo-EM maps are interpreted, but it has not eliminated the challenges of map interpretation faced by a microscopist. Models will continue to be locally rebuilt and refined using interactive tools. This inevitably results in occasional errors, among which register shifts remain one of the most difficult to identify and correct. Here, checkMySequence, a fast, fully automated and parameter-free method for detecting register shifts in protein models built into cryo-EM maps, is introduced. It is shown that the method can assist model building in cases where poorer map resolution hinders visual interpretation. It is also shown that checkMySequence could have helped to avoid a widely discussed sequence-register error in a model of SARS-CoV-2 RNA-dependent RNA polymerase that was originally detected thanks to a visual residue-by-residue inspection by members of the structural biology community. The software is freely available at https://gitlab.com/gchojnowski/checkmysequence.
Collapse
|
7
|
Joseph AP, Olek M, Malhotra S, Zhang P, Cowtan K, Burnley T, Winn MD. Atomic model validation using the CCP-EM software suite. Acta Crystallogr D Struct Biol 2022; 78:152-161. [PMID: 35102881 PMCID: PMC8805302 DOI: 10.1107/s205979832101278x] [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: 06/29/2021] [Accepted: 12/01/2021] [Indexed: 12/02/2022] Open
Abstract
Recently, there has been a dramatic improvement in the quality and quantity of data derived using cryogenic electron microscopy (cryo-EM). This is also associated with a large increase in the number of atomic models built. Although the best resolutions that are achievable are improving, often the local resolution is variable, and a significant majority of data are still resolved at resolutions worse than 3 Å. Model building and refinement is often challenging at these resolutions, and hence atomic model validation becomes even more crucial to identify less reliable regions of the model. Here, a graphical user interface for atomic model validation, implemented in the CCP-EM software suite, is presented. It is aimed to develop this into a platform where users can access multiple complementary validation metrics that work across a range of resolutions and obtain a summary of evaluations. Based on the validation estimates from atomic models associated with cryo-EM structures from SARS-CoV-2, it was observed that models typically favor adopting the most common conformations over fitting the observations when compared with the model agreement with data. At low resolutions, the stereochemical quality may be favored over data fit, but care should be taken to ensure that the model agrees with the data in terms of resolvable features. It is demonstrated that further re-refinement can lead to improvement of the agreement with data without the loss of geometric quality. This also highlights the need for improved resolution-dependent weight optimization in model refinement and an effective test for overfitting that would help to guide the refinement process.
Collapse
Affiliation(s)
- Agnel Praveen Joseph
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Mateusz Olek
- Department of Chemistry, University of York, York, United Kingdom
- Electron BioImaging Center, Diamond Light Source, Rutherford Appleton Laboratory, Didcot, United Kingdom
| | - Sony Malhotra
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Peijun Zhang
- Electron BioImaging Center, Diamond Light Source, Rutherford Appleton Laboratory, Didcot, United Kingdom
| | - Kevin Cowtan
- Department of Chemistry, University of York, York, United Kingdom
| | - Tom Burnley
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Martyn D. Winn
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| |
Collapse
|
8
|
Liebschner D, Afonine PV, Moriarty NW, Poon BK, Chen VB, Adams PD. CERES: a cryo-EM re-refinement system for continuous improvement of deposited models. Acta Crystallogr D Struct Biol 2021; 77:48-61. [PMID: 33404525 PMCID: PMC7787109 DOI: 10.1107/s2059798320015879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/03/2020] [Indexed: 11/10/2022] Open
Abstract
The field of electron cryomicroscopy (cryo-EM) has advanced quickly in recent years as the result of numerous technological and methodological developments. This has led to an increase in the number of atomic structures determined using this method. Recently, several tools for the analysis of cryo-EM data and models have been developed within the Phenix software package, such as phenix.real_space_refine for the refinement of atomic models against real-space maps. Also, new validation metrics have been developed for low-resolution cryo-EM models. To understand the quality of deposited cryo-EM structures and how they might be improved, models deposited in the Protein Data Bank that have map resolutions of better than 5 Å were automatically re-refined using current versions of Phenix tools. The results are available on a publicly accessible web page (https://cci.lbl.gov/ceres). The implementation of a Cryo-EM Re-refinement System (CERES) for the improvement of models deposited in the wwPDB, and the results of the re-refinements, are described. Based on these results, contents are proposed for a `cryo-EM Table 1', which summarizes experimental details and validation metrics in a similar way to `Table 1' in crystallography. The consistent use of robust metrics for the evaluation of cryo-EM models and data should accompany every structure deposition and be reported in scientific publications.
Collapse
Affiliation(s)
- Dorothee Liebschner
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Pavel V. Afonine
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Nigel W. Moriarty
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Billy K. Poon
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Vincent B. Chen
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Paul D. Adams
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, USA
| |
Collapse
|
9
|
Watson ZL, Ward FR, Méheust R, Ad O, Schepartz A, Banfield JF, Cate JH. Structure of the bacterial ribosome at 2 Å resolution. eLife 2020; 9:60482. [PMID: 32924932 DOI: 10.1101/2020.06.26.174334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/11/2020] [Indexed: 05/24/2023] Open
Abstract
Using cryo-electron microscopy (cryo-EM), we determined the structure of the Escherichia coli 70S ribosome with a global resolution of 2.0 Å. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and models of the bacterial ribosome presented here now allow a deeper phylogenetic analysis of ribosomal components including structural conservation to the level of solvation. The high quality of the maps should enable future structural analyses of the chemical basis for translation and aid the development of robust tools for cryo-EM structure modeling and refinement.
Collapse
Affiliation(s)
- Zoe L Watson
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Fred R Ward
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Raphaël Méheust
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States
- Earth and Planetary Science, University of California, Berkeley, Berkeley, United States
| | - Omer Ad
- Department of Chemistry, Yale University, New Haven, United States
| | - Alanna Schepartz
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States
- Earth and Planetary Science, University of California, Berkeley, Berkeley, United States
- Environmental Science, Policy and Management, University of California Berkeley, Berkeley, United States
| | - Jamie Hd Cate
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| |
Collapse
|
10
|
Watson ZL, Ward FR, Méheust R, Ad O, Schepartz A, Banfield JF, Cate JHD. Structure of the bacterial ribosome at 2 Å resolution. eLife 2020; 9:e60482. [PMID: 32924932 PMCID: PMC7550191 DOI: 10.7554/elife.60482] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022] Open
Abstract
Using cryo-electron microscopy (cryo-EM), we determined the structure of the Escherichia coli 70S ribosome with a global resolution of 2.0 Å. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and models of the bacterial ribosome presented here now allow a deeper phylogenetic analysis of ribosomal components including structural conservation to the level of solvation. The high quality of the maps should enable future structural analyses of the chemical basis for translation and aid the development of robust tools for cryo-EM structure modeling and refinement.
Collapse
Affiliation(s)
- Zoe L Watson
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Fred R Ward
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Raphaël Méheust
- Innovative Genomics Institute, University of California, BerkeleyBerkeleyUnited States
- Earth and Planetary Science, University of California, BerkeleyBerkeleyUnited States
| | - Omer Ad
- Department of Chemistry, Yale UniversityNew HavenUnited States
| | - Alanna Schepartz
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, BerkeleyBerkeleyUnited States
- Earth and Planetary Science, University of California, BerkeleyBerkeleyUnited States
- Environmental Science, Policy and Management, University of California BerkeleyBerkeleyUnited States
| | - Jamie HD Cate
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| |
Collapse
|
11
|
A Global Ramachandran Score Identifies Protein Structures with Unlikely Stereochemistry. Structure 2020; 28:1249-1258.e2. [PMID: 32857966 DOI: 10.1016/j.str.2020.08.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/23/2020] [Accepted: 08/07/2020] [Indexed: 12/18/2022]
Abstract
Ramachandran plots report the distribution of the (ϕ, ψ) torsion angles of the protein backbone and are one of the best quality metrics of experimental structure models. Typically, validation software reports the number of residues belonging to "outlier," "allowed," and "favored" regions. While "zero unexplained outliers" can be considered the current "gold standard," this can be misleading if deviations from expected distributions are not considered. We revisited the Ramachandran Z score (Rama-Z), a quality metric introduced more than two decades ago but underutilized. We describe a reimplementation of the Rama-Z score in the Computational Crystallography Toolbox along with an algorithm to estimate its uncertainty for individual models; final implementations are available in Phenix and PDB-REDO. We discuss the interpretation of the Rama-Z score and advocate including it in the validation reports provided by the Protein Data Bank. We also advocate reporting it alongside the outlier/allowed/favored counts in structural publications.
Collapse
|
12
|
Prisant MG, Williams CJ, Chen VB, Richardson JS, Richardson DC. New tools in MolProbity validation: CaBLAM for CryoEM backbone, UnDowser to rethink "waters," and NGL Viewer to recapture online 3D graphics. Protein Sci 2020; 29:315-329. [PMID: 31724275 PMCID: PMC6933861 DOI: 10.1002/pro.3786] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/17/2022]
Abstract
The MolProbity web service provides macromolecular model validation to help correct local errors, for the structural biology community worldwide. Here we highlight new validation features, and also describe how we are fighting back against outside developments which compromise that mission. Our new tool called UnDowser analyzes the properties and context of clashing HOH "waters" to diagnose what they might actually represent; a dozen distinct scenarios are illustrated and described. We now treat alternate conformations more thoroughly, and switching to the Neo4j database (graphical rather than relational) enables cleaner, more comprehensive, and much larger reference datasets. A problematic outside change is that refinement software now increasingly restrains traditional validation criteria (geometry, clashes, rotamers, and even Ramachandran) in order to supplement the sparser experimental data at 3-4 Å resolutions typical of modern cryoEM. But unfortunately the broad density allows model optimization without fixing underlying problems, which means these structures often score much better on validation than they really are. CaBLAM, our tool designed for evaluating peptide orientations at lower resolutions, was described in the previous Tools issue, and here we demonstrate its effectiveness in diagnosing local errors even when other validation outliers have been artificially removed. Sophisticated hacking of the MolProbity server has required continual monitoring and various security measures short of restricting user access. The deprecation of Java applets now prevents KiNG interactive online display of outliers on the 3D model during a MolProbity run, but that important functionality has now been recaptured with a modified version of the Javascript NGL Viewer.
Collapse
Affiliation(s)
- Michael G. Prisant
- Department of BiochemistryDuke University Medical CenterDurhamNorth Carolina
| | | | - Vincent B. Chen
- Department of BiochemistryDuke University Medical CenterDurhamNorth Carolina
| | - Jane S. Richardson
- Department of BiochemistryDuke University Medical CenterDurhamNorth Carolina
| | - David C. Richardson
- Department of BiochemistryDuke University Medical CenterDurhamNorth Carolina
| |
Collapse
|
13
|
Moriarty NW, Janowski PA, Swails JM, Nguyen H, Richardson JS, Case DA, Adams PD. Improved chemistry restraints for crystallographic refinement by integrating the Amber force field into Phenix. Acta Crystallogr D Struct Biol 2020; 76:51-62. [PMID: 31909743 PMCID: PMC6939439 DOI: 10.1107/s2059798319015134] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/08/2019] [Indexed: 02/01/2023] Open
Abstract
The refinement of biomolecular crystallographic models relies on geometric restraints to help to address the paucity of experimental data typical in these experiments. Limitations in these restraints can degrade the quality of the resulting atomic models. Here, an integration of the full all-atom Amber molecular-dynamics force field into Phenix crystallographic refinement is presented, which enables more complete modeling of biomolecular chemistry. The advantages of the force field include a carefully derived set of torsion-angle potentials, an extensive and flexible set of atom types, Lennard-Jones treatment of nonbonded interactions and a full treatment of crystalline electrostatics. The new combined method was tested against conventional geometry restraints for over 22 000 protein structures. Structures refined with the new method show substantially improved model quality. On average, Ramachandran and rotamer scores are somewhat better, clashscores and MolProbity scores are significantly improved, and the modeling of electrostatics leads to structures that exhibit more, and more correct, hydrogen bonds than those refined using traditional geometry restraints. In general it is found that model improvements are greatest at lower resolutions, prompting plans to add the Amber target function to real-space refinement for use in electron cryo-microscopy. This work opens the door to the future development of more advanced applications such as Amber-based ensemble refinement, quantum-mechanical representation of active sites and improved geometric restraints for simulated annealing.
Collapse
Affiliation(s)
- Nigel W. Moriarty
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235, USA
| | - Pawel A. Janowski
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Jason M. Swails
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Hai Nguyen
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | | | - David A. Case
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Paul D. Adams
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235, USA
- Department of Bioengineering, University of California at Berkeley, Berkeley, CA 94720, USA
| |
Collapse
|
14
|
Liebschner D, Afonine PV, Baker ML, Bunkóczi G, Chen VB, Croll TI, Hintze B, Hung LW, Jain S, McCoy AJ, Moriarty NW, Oeffner RD, Poon BK, Prisant MG, Read RJ, Richardson JS, Richardson DC, Sammito MD, Sobolev OV, Stockwell DH, Terwilliger TC, Urzhumtsev AG, Videau LL, Williams CJ, Adams PD. Macromolecular structure determination using X-rays, neutrons and electrons: recent developments in Phenix. Acta Crystallogr D Struct Biol 2019; 75:861-877. [PMID: 31588918 PMCID: PMC6778852 DOI: 10.1107/s2059798319011471] [Citation(s) in RCA: 3465] [Impact Index Per Article: 693.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 08/15/2019] [Indexed: 12/16/2022] Open
Abstract
Diffraction (X-ray, neutron and electron) and electron cryo-microscopy are powerful methods to determine three-dimensional macromolecular structures, which are required to understand biological processes and to develop new therapeutics against diseases. The overall structure-solution workflow is similar for these techniques, but nuances exist because the properties of the reduced experimental data are different. Software tools for structure determination should therefore be tailored for each method. Phenix is a comprehensive software package for macromolecular structure determination that handles data from any of these techniques. Tasks performed with Phenix include data-quality assessment, map improvement, model building, the validation/rebuilding/refinement cycle and deposition. Each tool caters to the type of experimental data. The design of Phenix emphasizes the automation of procedures, where possible, to minimize repetitive and time-consuming manual tasks, while default parameters are chosen to encourage best practice. A graphical user interface provides access to many command-line features of Phenix and streamlines the transition between programs, project tracking and re-running of previous tasks.
Collapse
Affiliation(s)
- Dorothee Liebschner
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Pavel V. Afonine
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matthew L. Baker
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gábor Bunkóczi
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Vincent B. Chen
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Tristan I. Croll
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Bradley Hintze
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Li-Wei Hung
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Swati Jain
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Airlie J. McCoy
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Nigel W. Moriarty
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Robert D. Oeffner
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Billy K. Poon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Randy J. Read
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | | | | | - Massimo D. Sammito
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Oleg V. Sobolev
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Duncan H. Stockwell
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Thomas C. Terwilliger
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Alexandre G. Urzhumtsev
- Centre for Integrative Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS–INSERM–UdS, 67404 Illkirch, France
- Faculté des Sciences et Technologies, Université de Lorraine, BP 239, 54506 Vandoeuvre-lès-Nancy, France
| | | | | | - Paul D. Adams
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, USA
| |
Collapse
|
15
|
Igaev M, Kutzner C, Bock LV, Vaiana AC, Grubmüller H. Automated cryo-EM structure refinement using correlation-driven molecular dynamics. eLife 2019; 8:e43542. [PMID: 30829573 PMCID: PMC6424565 DOI: 10.7554/elife.43542] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 03/03/2019] [Indexed: 12/22/2022] Open
Abstract
We present a correlation-driven molecular dynamics (CDMD) method for automated refinement of atomistic models into cryo-electron microscopy (cryo-EM) maps at resolutions ranging from near-atomic to subnanometer. It utilizes a chemically accurate force field and thermodynamic sampling to improve the real-space correlation between the modeled structure and the cryo-EM map. Our framework employs a gradual increase in resolution and map-model agreement as well as simulated annealing, and allows fully automated refinement without manual intervention or any additional rotamer- and backbone-specific restraints. Using multiple challenging systems covering a wide range of map resolutions, system sizes, starting model geometries and distances from the target state, we assess the quality of generated models in terms of both model accuracy and potential of overfitting. To provide an objective comparison, we apply several well-established methods across all examples and demonstrate that CDMD performs best in most cases.
Collapse
Affiliation(s)
- Maxim Igaev
- Department of Theoretical and Computational BiophysicsMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Carsten Kutzner
- Department of Theoretical and Computational BiophysicsMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Lars V Bock
- Department of Theoretical and Computational BiophysicsMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Andrea C Vaiana
- Department of Theoretical and Computational BiophysicsMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Helmut Grubmüller
- Department of Theoretical and Computational BiophysicsMax Planck Institute for Biophysical ChemistryGöttingenGermany
| |
Collapse
|
16
|
Affiliation(s)
- Catherine L Lawson
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ 08854, USA.
| | - Wah Chiu
- Division of Cryo-EM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA; Department of Bioengineering, Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|