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Mohammed ASA, Soloviov D, Jeffries CM. Perspectives on solution-based small angle X-ray scattering for protein and biological macromolecule structural biology. Phys Chem Chem Phys 2024. [PMID: 39323216 DOI: 10.1039/d4cp02001d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Small-angle X-ray scattering (SAXS) is used to extract structural information from a wide variety of non-crystalline samples in different fields (e.g., materials science, physics, chemistry, and biology). This review provides an overview of SAXS as applied to structural biology, specifically for proteins and other biomacromolecules in solution with an emphasis on extracting key structural parameters and the interpretation of SAXS data using a diverse array of techniques. These techniques cover aspects of building and assessing models to describe data measured from monodispersed and ideal dilute samples through to more complicated structurally polydisperse systems. Ab initio modelling, rigid body modelling as well as normal-mode analysis, molecular dynamics, mixed component and structural ensemble modelling are discussed. Dealing with polydispersity both physically in terms of component separation as well as approaching the analysis and modelling of data of mixtures and evolving systems are described, including methods for data decomposition such as single value decomposition/principle component analysis and evolving factor analysis. This review aims to highlight that solution SAXS, with the cohort of developments in data analysis and modelling, is well positioned to build upon the traditional 'single particle view' foundation of structural biology to take the field into new areas for interpreting the structures of proteins and biomacromolecules as population-states and dynamic structural systems.
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Affiliation(s)
- Ahmed S A Mohammed
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, co/DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
- Physics Department, Faculty of Science, Fayoum University, 63514 Fayoum, Egypt
- Department of Biomedical Physics, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Dmytro Soloviov
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, co/DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
| | - Cy M Jeffries
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, co/DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
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Agarwal V, McShan AC. The power and pitfalls of AlphaFold2 for structure prediction beyond rigid globular proteins. Nat Chem Biol 2024; 20:950-959. [PMID: 38907110 DOI: 10.1038/s41589-024-01638-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 04/29/2024] [Indexed: 06/23/2024]
Abstract
Artificial intelligence-driven advances in protein structure prediction in recent years have raised the question: has the protein structure-prediction problem been solved? Here, with a focus on nonglobular proteins, we highlight the many strengths and potential weaknesses of DeepMind's AlphaFold2 in the context of its biological and therapeutic applications. We summarize the subtleties associated with evaluation of AlphaFold2 model quality and reliability using the predicted local distance difference test (pLDDT) and predicted aligned error (PAE) values. We highlight various classes of proteins that AlphaFold2 can be applied to and the caveats involved. Concrete examples of how AlphaFold2 models can be integrated with experimental data in the form of small-angle X-ray scattering (SAXS), solution NMR, cryo-electron microscopy (cryo-EM) and X-ray diffraction are discussed. Finally, we highlight the need to move beyond structure prediction of rigid, static structural snapshots toward conformational ensembles and alternate biologically relevant states. The overarching theme is that careful consideration is due when using AlphaFold2-generated models to generate testable hypotheses and structural models, rather than treating predicted models as de facto ground truth structures.
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Affiliation(s)
- Vinayak Agarwal
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Andrew C McShan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
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Sülzen H, Volkov AN, Geens R, Zahedifard F, Stijlemans B, Zoltner M, Magez S, Sterckx YGJ, Zoll S. Beyond the VSG layer: Exploring the role of intrinsic disorder in the invariant surface glycoproteins of African trypanosomes. PLoS Pathog 2024; 20:e1012186. [PMID: 38648216 PMCID: PMC11065263 DOI: 10.1371/journal.ppat.1012186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 05/02/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024] Open
Abstract
In the bloodstream of mammalian hosts, African trypanosomes face the challenge of protecting their invariant surface receptors from immune detection. This crucial role is fulfilled by a dense, glycosylated protein layer composed of variant surface glycoproteins (VSGs), which undergo antigenic variation and provide a physical barrier that shields the underlying invariant surface glycoproteins (ISGs). The protective shield's limited permeability comes at the cost of restricted access to the extracellular host environment, raising questions regarding the specific function of the ISG repertoire. In this study, we employ an integrative structural biology approach to show that intrinsically disordered membrane-proximal regions are a common feature of members of the ISG super-family, conferring the ability to switch between compact and elongated conformers. While the folded, membrane-distal ectodomain is buried within the VSG layer for compact conformers, their elongated counterparts would enable the extension beyond it. This dynamic behavior enables ISGs to maintain a low immunogenic footprint while still allowing them to engage with the host environment when necessary. Our findings add further evidence to a dynamic molecular organization of trypanosome surface antigens wherein intrinsic disorder underpins the characteristics of a highly flexible ISG proteome to circumvent the constraints imposed by the VSG coat.
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Affiliation(s)
- Hagen Sülzen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Alexander N. Volkov
- VIB-VUB Center for Structural Biology, Flemish Institute of Biotechnology (VIB), Brussels, Belgium
- Jean Jeener NMR Centre, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Rob Geens
- VIB-VUB Center for Structural Biology, Flemish Institute of Biotechnology (VIB), Brussels, Belgium
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Center of Excellence, Department of Pharmaceutical Sciences, Universiteit of Antwerp, Wilrijk, Belgium
| | - Farnaz Zahedifard
- Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Benoit Stijlemans
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Myeloid Cell Immunology Laboratory, VIB Center for Inflammation Research, Brussels, Belgium
| | - Martin Zoltner
- Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Stefan Magez
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Gent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Incheon, South Korea
| | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Center of Excellence, Department of Pharmaceutical Sciences, Universiteit of Antwerp, Wilrijk, Belgium
| | - Sebastian Zoll
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
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Choudhury J, Yonezawa K, Anu A, Shimizu N, Chaudhuri B. SAXS/WAXS data of conformationally flexible ribose binding protein. Data Brief 2024; 52:109932. [PMID: 38178847 PMCID: PMC10764985 DOI: 10.1016/j.dib.2023.109932] [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: 11/01/2023] [Revised: 12/03/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Modern artificial intelligence-based protein structure prediction methods, such as Alphafold2, can predict structures of folded proteins with reasonable accuracy. However, Alphafold2 provides a static view of a protein, which does not show the conformational variability of the protein, domain movement in a multi-domain protein, or ligand-induced conformational changes it might undergo in solution. Small-angle X-ay scattering (SAXS) and wide-angle X-ray scattering (WAXS) are solution techniques that can aid in integrative modeling of conformationally flexible proteins, or in validating their predicted ensemble structures. While SAXS is sensitive to global structural features, WAXS can expand the scope of structural modeling by including information about local structural changes. We present SAXS and WAXS datasets obtained from conformationally flexible d-ribose binding protein (RBP) from Escherichia coli in the ribose bound and unbound forms. SAXS/WAXS datasets of RBP provided here may aid in method development efforts for more accurate prediction of structural ensembles of conformationally flexible proteins, and their conformational changes.
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Affiliation(s)
- Jagrity Choudhury
- GN Ramachandran Protein Center, CSIR Institute of Microbial Technology, Chandigarh 160036, India
| | - Kento Yonezawa
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Anu Anu
- GN Ramachandran Protein Center, CSIR Institute of Microbial Technology, Chandigarh 160036, India
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Nobutaka Shimizu
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Barnali Chaudhuri
- GN Ramachandran Protein Center, CSIR Institute of Microbial Technology, Chandigarh 160036, India
- Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
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Receveur-Bréchot V. AlphaFold, small-angle X-ray scattering and ensemble modelling: a winning combination for intrinsically disordered proteins. J Appl Crystallogr 2023; 56:1313-1314. [PMID: 37791368 PMCID: PMC10543683 DOI: 10.1107/s1600576723008403] [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] [Indexed: 10/05/2023] Open
Abstract
A recent article by Brookes, Rocco, Vachette & Trewhella [J. Appl. Cryst. (2023), 56, 910-926] on improving the accuracy of AlphaFold structural predictions for disordered proteins is discussed.
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Affiliation(s)
- Véronique Receveur-Bréchot
- CNRS, Aix Marseille Univ., BIP Bioénergétique et Ingénierie des Protéines, UMR7281, F-13402 Marseille, France
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