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Woods H, Leman JK, Meiler J. Modeling membrane geometries implicitly in Rosetta. Protein Sci 2024; 33:e4908. [PMID: 38358133 PMCID: PMC10868433 DOI: 10.1002/pro.4908] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 02/16/2024]
Abstract
Interactions between membrane proteins (MPs) and lipid bilayers are critical for many cellular functions. In the Rosetta molecular modeling suite, the implicit membrane energy function is based on a "slab" model, which represent the membrane as a flat bilayer. However, in nature membranes often have a curvature that is important for function and/or stability. Even more prevalent, in structural biology research MPs are reconstituted in model membrane systems such as micelles, bicelles, nanodiscs, or liposomes. Thus, we have modified the existing membrane energy potentials within the RosettaMP framework to allow users to model MPs in different membrane geometries. We show that these modifications can be utilized in core applications within Rosetta such as structure refinement, protein-protein docking, and protein design. For MP structures found in curved membranes, refining these structures in curved, implicit membranes produces higher quality models with structures closer to experimentally determined structures. For MP systems embedded in multiple membranes, representing both membranes results in more favorable scores compared to only representing one of the membranes. Modeling MPs in geometries mimicking the membrane model system used in structure determination can improve model quality and model discrimination.
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Affiliation(s)
- Hope Woods
- Center of Structural Biology, Vanderbilt UniversityNashvilleTennesseeUSA
- Chemical and Physical Biology ProgramVanderbilt UniversityNashvilleTennesseeUSA
| | | | - Jens Meiler
- Center of Structural Biology, Vanderbilt UniversityNashvilleTennesseeUSA
- Department of ChemistryVanderbilt UniversityNashvilleTennesseeUSA
- Institute for Drug Discovery, Leipzig University Medical SchoolLeipzigGermany
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2
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Grigas AT, Liu Z, Regan L, O'Hern CS. Core packing of well‐defined X‐ray and
NMR
structures is the same. Protein Sci 2022; 31:e4373. [PMID: 35900019 PMCID: PMC9277709 DOI: 10.1002/pro.4373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 05/06/2022] [Accepted: 06/02/2022] [Indexed: 11/10/2022]
Abstract
Numerous studies have investigated the differences and similarities between protein structures determined by solution NMR spectroscopy and those determined by X-ray crystallography. A fundamental question is whether any observed differences are due to differing methodologies or to differences in the behavior of proteins in solution versus in the crystalline state. Here, we compare the properties of the hydrophobic cores of high-resolution protein crystal structures and those in NMR structures, determined using increasing numbers and types of restraints. Prior studies have reported that many NMR structures have denser cores compared with those of high-resolution X-ray crystal structures. Our current work investigates this result in more detail and finds that these NMR structures tend to violate basic features of protein stereochemistry, such as small non-bonded atomic overlaps and few Ramachandran and sidechain dihedral angle outliers. We find that NMR structures solved with more restraints, and which do not significantly violate stereochemistry, have hydrophobic cores that have a similar size and packing fraction as their counterparts determined by X-ray crystallography at high resolution. These results lead us to conclude that, at least regarding the core packing properties, high-quality structures determined by NMR and X-ray crystallography are the same, and the differences reported earlier are most likely a consequence of methodology, rather than fundamental differences between the protein in the two different environments.
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Affiliation(s)
- Alex T. Grigas
- Graduate Program in Computational Biology and Bioinformatics Yale University New Haven Connecticut USA
- Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut USA
| | - Zhuoyi Liu
- Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut USA
- Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut USA
| | - Lynne Regan
- Institute of Quantitative Biology, Biochemistry and Biotechnology Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh Edinburgh UK
| | - Corey S. O'Hern
- Graduate Program in Computational Biology and Bioinformatics Yale University New Haven Connecticut USA
- Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut USA
- Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut USA
- Department of Physics Yale University New Haven Connecticut USA
- Department of Applied Physics Yale University New Haven Connecticut USA
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3
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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
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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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4
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Mei Z, Treado JD, Grigas AT, Levine ZA, Regan L, O'Hern CS. Analyses of protein cores reveal fundamental differences between solution and crystal structures. Proteins 2020; 88:1154-1161. [PMID: 32105366 PMCID: PMC7415476 DOI: 10.1002/prot.25884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/05/2020] [Accepted: 02/23/2020] [Indexed: 12/20/2022]
Abstract
There have been several studies suggesting that protein structures solved by NMR spectroscopy and X-ray crystallography show significant differences. To understand the origin of these differences, we assembled a database of high-quality protein structures solved by both methods. We also find significant differences between NMR and crystal structures-in the root-mean-square deviations of the C α atomic positions, identities of core amino acids, backbone, and side-chain dihedral angles, and packing fraction of core residues. In contrast to prior studies, we identify the physical basis for these differences by modeling protein cores as jammed packings of amino acid-shaped particles. We find that we can tune the jammed packing fraction by varying the degree of thermalization used to generate the packings. For an athermal protocol, we find that the average jammed packing fraction is identical to that observed in the cores of protein structures solved by X-ray crystallography. In contrast, highly thermalized packing-generation protocols yield jammed packing fractions that are even higher than those observed in NMR structures. These results indicate that thermalized systems can pack more densely than athermal systems, which suggests a physical basis for the structural differences between protein structures solved by NMR and X-ray crystallography.
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Affiliation(s)
- Zhe Mei
- Integrated Graduate Program in Physical & Engineering Biology, Yale University, New Haven, Connecticut
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - John D Treado
- Integrated Graduate Program in Physical & Engineering Biology, Yale University, New Haven, Connecticut
- Department of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut
| | - Alex T Grigas
- Integrated Graduate Program in Physical & Engineering Biology, Yale University, New Haven, Connecticut
- Graduate Program in Computational Biology & Bioinformatics, Yale University, New Haven, Connecticut
| | - Zachary A Levine
- Department of Pathology, Yale University, New Haven, Connecticut
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Lynne Regan
- Institute of Quantitative Biology, Biochemistry and Biotechnology, Center for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Corey S O'Hern
- Integrated Graduate Program in Physical & Engineering Biology, Yale University, New Haven, Connecticut
- Department of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut
- Department of Physics, Yale University, New Haven, Connecticut
- Department of Applied Physics, Yale University, New Haven, Connecticut
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5
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Hrmova M, Gilliham M. Plants fighting back: to transport or not to transport, this is a structural question. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:68-76. [PMID: 30138844 DOI: 10.1016/j.pbi.2018.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/06/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
Membrane-embedded transport proteins are fundamental to life; their co-ordinated action controls the movement and distribution of solutes into, around and out of cells for signalling, metabolism, nutrition, stress tolerance and development. Here we outline two case studies of transport systems that plants use to tolerate soil elemental toxicity, demonstrating how iterative studies of protein structure and function result in unparalleled insights into transport mechanics. Further, we propose that integrative platforms of biological, biochemical and biophysical tools can provide quantitative data on substrate specificity and transport rates, which are important in understanding transporter evolution and their roles in cell biology and whole plant physiology. Such knowledge equips biotechnologists and breeders with the power to deliver improvements in crop yields in sub-optimal soils.
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Affiliation(s)
- Maria Hrmova
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia; School of Life Sciences, Huaiyin Normal University, Huai'an 223300, China.
| | - Matthew Gilliham
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia; Australian Research Council Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Research Institute, Glen Osmond, South Australia 5064, Australia
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Koehler Leman J, Bonneau R. A Novel Domain Assembly Routine for Creating Full-Length Models of Membrane Proteins from Known Domain Structures. Biochemistry 2017; 57:1939-1944. [PMID: 29185719 DOI: 10.1021/acs.biochem.7b00995] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Membrane proteins composed of soluble and membrane domains are often studied one domain at a time. However, to understand the biological function of entire protein systems and their interactions with each other and drugs, knowledge of full-length structures or models is required. Although few computational methods exist that could potentially be used to model full-length constructs of membrane proteins, none of these methods are perfectly suited for the problem at hand. Existing methods require an interface or knowledge of the relative orientations of the domains or are not designed for domain assembly, and none of them are developed for membrane proteins. Here we describe the first domain assembly protocol specifically designed for membrane proteins that assembles intra- and extracellular soluble domains and the transmembrane domain into models of the full-length membrane protein. Our protocol does not require an interface between the domains and samples possible domain orientations based on backbone dihedrals in the flexible linker regions, created via fragment insertion, while keeping the transmembrane domain fixed in the membrane. For five examples tested, our method mp_domain_assembly, implemented in RosettaMP, samples domain orientations close to the known structure and is best used in conjunction with experimental data to reduce the conformational search space.
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Affiliation(s)
- Julia Koehler Leman
- Department of Biology and Center for Genomics and Systems Biology , New York University , New York , New York 10003 , United States.,Center for Computational Biology, Flatiron Institute , Simons Foundation , 162 Fifth Avenue , New York , New York 10010 , United States
| | - Richard Bonneau
- Center for Computational Biology, Flatiron Institute , Simons Foundation , 162 Fifth Avenue , New York , New York 10010 , United States.,Center for Data Science , New York University , New York , New York 10011 , United States
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