1
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Rat C, Heindl C, Neuweiler H. Domain swap facilitates structural transitions of spider silk protein C-terminal domains. Protein Sci 2023; 32:e4783. [PMID: 37712205 PMCID: PMC10578117 DOI: 10.1002/pro.4783] [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: 06/23/2023] [Revised: 08/25/2023] [Accepted: 09/12/2023] [Indexed: 09/16/2023]
Abstract
Domain swap is a mechanism of protein dimerization where the two interacting domains exchange parts of their structure. Web spiders make use of the process in the connection of C-terminal domains (CTDs) of spidroins, the soluble protein building blocks that form tough silk fibers. Besides providing connectivity and solubility, spidroin CTDs are responsible for inducing structural transitions during passage through an acidified assembly zone within spinning ducts. The underlying molecular mechanisms are elusive. Here, we studied the folding of five homologous spidroin CTDs from different spider species or glands. Four of these are domain-swapped dimers formed by five-helix bundles from spidroins of major and minor ampullate glands. The fifth is a dimer that lacks domain swap, formed by four-helix bundles from a spidroin of a flagelliform gland. Spidroins from this gland do not undergo structural transitions whereas the others do. We found a three-state mechanism of folding and dimerization that was conserved across homologues. In chemical denaturation experiments the native CTD dimer unfolded to a dimeric, partially structured intermediate, followed by full unfolding to denatured monomers. The energetics of the individual folding steps varied between homologues. Contrary to the common belief that domain swap stabilizes protein assemblies, the non-swapped homologue was most stable and folded four orders of magnitude faster than a swapped variant. Domain swap of spidroin CTDs induces an entropic penalty to the folding of peripheral helices, thus unfastening them for acid-induced unfolding within a spinning duct, which primes them for refolding into alternative structures during silk formation.
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Affiliation(s)
- Charlotte Rat
- Department of Biotechnology & BiophysicsJulius‐Maximilians‐University WürzburgWürzburgGermany
| | - Cedric Heindl
- Department of Biotechnology & BiophysicsJulius‐Maximilians‐University WürzburgWürzburgGermany
| | - Hannes Neuweiler
- Department of Biotechnology & BiophysicsJulius‐Maximilians‐University WürzburgWürzburgGermany
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2
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Gerlach P, Garland W, Lingaraju M, Salerno-Kochan A, Bonneau F, Basquin J, Jensen TH, Conti E. Structure and regulation of the nuclear exosome targeting complex guides RNA substrates to the exosome. Mol Cell 2022; 82:2505-2518.e7. [PMID: 35688157 PMCID: PMC9278407 DOI: 10.1016/j.molcel.2022.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/07/2022] [Accepted: 04/08/2022] [Indexed: 11/30/2022]
Abstract
In mammalian cells, spurious transcription results in a vast repertoire of unproductive non-coding RNAs, whose deleterious accumulation is prevented by rapid decay. The nuclear exosome targeting (NEXT) complex plays a central role in directing non-functional transcripts to exosome-mediated degradation, but the structural and molecular mechanisms remain enigmatic. Here, we elucidated the architecture of the human NEXT complex, showing that it exists as a dimer of MTR4-ZCCHC8-RBM7 heterotrimers. Dimerization preconfigures the major MTR4-binding region of ZCCHC8 and arranges the two MTR4 helicases opposite to each other, with each protomer able to function on many types of RNAs. In the inactive state of the complex, the 3′ end of an RNA substrate is enclosed in the MTR4 helicase channel by a ZCCHC8 C-terminal gatekeeping domain. The architecture of a NEXT-exosome assembly points to the molecular and regulatory mechanisms with which the NEXT complex guides RNA substrates to the exosome. NEXT homodimerizes through two intertwined ZCCHC8 subunits ZCCHC8 binds MTR4 with both constitutive and regulatory interactions Stable MTR4 arch interactions orient the two helicases in opposite directions Regulatory interactions at the MTR4 helicase domain guide RNA to the exosome
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Affiliation(s)
- Piotr Gerlach
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany.
| | - William Garland
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Mahesh Lingaraju
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Fabien Bonneau
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Jérôme Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany.
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3
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Garton M, MacKinnon SS, Malevanets A, Wodak SJ. Interplay of self-association and conformational flexibility in regulating protein function. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0190. [PMID: 29735742 DOI: 10.1098/rstb.2017.0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 12/18/2022] Open
Abstract
Many functional roles have been attributed to homodimers, the most common mode of protein self-association, notably in the regulation of enzymes, ion channels, transporters and transcription factors. Here we review findings that offer new insights into the different roles conformational flexibility plays in regulating homodimer function. Intertwined homodimers of two-domain proteins and their related family members display significant conformational flexibility, which translates into concerted motion between structural domains. This flexibility enables the corresponding proteins to regulate function across family members by modulating the spatial positions of key recognition surfaces of individual domains, to either maintain subunit interfaces, alter them or break them altogether, leading to a variety of functional consequences. Many proteins may exist as monomers but carry out their biological function as homodimers or higher-order oligomers. We present early evidence that in such systems homodimer formation primes the protein for its functional role. It does so by inducing elevated mobility in protein regions corresponding to the binding epitopes of functionally important ligands. In some systems this process acts as an allosteric response elicited by the self-association reaction itself. Our analysis furthermore suggests that the induced extra mobility likely facilitates ligand binding through the mechanism of conformational selection.This article is part of a discussion meeting issue 'Allostery and molecular machines'.
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Affiliation(s)
- Michael Garton
- Department of Molecular Genetics, University of Toronto, The Donnelly Centre, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Stephen S MacKinnon
- Cyclica Inc., 18 King Street East, Suite 810, Toronto, Ontario M5C 1C4, Canada
| | - Anatoly Malevanets
- Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| | - Shoshana J Wodak
- VIB Structural Biology research Centre, VUB, Building E Pleinlaan 2, 1050 Brussels, Belgium
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4
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Miller AF, Park JT, Ferguson KL, Pitsawong W, Bommarius AS. Informing Efforts to Develop Nitroreductase for Amine Production. Molecules 2018; 23:molecules23020211. [PMID: 29364838 PMCID: PMC6017928 DOI: 10.3390/molecules23020211] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/03/2018] [Accepted: 01/12/2018] [Indexed: 12/19/2022] Open
Abstract
Nitroreductases (NRs) hold promise for converting nitroaromatics to aromatic amines. Nitroaromatic reduction rate increases with Hammett substituent constant for NRs from two different subgroups, confirming substrate identity as a key determinant of reactivity. Amine yields were low, but compounds yielding amines tend to have a large π system and electron withdrawing substituents. Therefore, we also assessed the prospects of varying the enzyme. Several different subgroups of NRs include members able to produce aromatic amines. Comparison of four NR subgroups shows that they provide contrasting substrate binding cavities with distinct constraints on substrate position relative to the flavin. The unique architecture of the NR dimer produces an enormous contact area which we propose provides the stabilization needed to offset the costs of insertion of the active sites between the monomers. Thus, we propose that the functional diversity included in the NR superfamily stems from the chemical versatility of the flavin cofactor in conjunction with a structure that permits tremendous active site variability. These complementary properties make NRs exceptionally promising enzymes for development for biocatalysis in prodrug activation and conversion of nitroaromatics to valuable aromatic amines. We provide a framework for identifying NRs and substrates with the greatest potential to advance.
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Affiliation(s)
- Anne-Frances Miller
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
| | - Jonathan T Park
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
| | - Kyle L Ferguson
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
| | - Warintra Pitsawong
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
| | - Andreas S Bommarius
- School of Chemical and Biomolecular Engineering, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0100, USA.
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5
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Lensink MF, Velankar S, Baek M, Heo L, Seok C, Wodak SJ. The challenge of modeling protein assemblies: the CASP12-CAPRI experiment. Proteins 2017; 86 Suppl 1:257-273. [PMID: 29127686 DOI: 10.1002/prot.25419] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/31/2017] [Accepted: 11/07/2017] [Indexed: 12/18/2022]
Abstract
We present the quality assessment of 5613 models submitted by predictor groups from both CAPRI and CASP for the total of 15 most tractable targets from the second joint CASP-CAPRI protein assembly prediction experiment. These targets comprised 12 homo-oligomers and 3 hetero-complexes. The bulk of the analysis focuses on 10 targets (of CAPRI Round 37), which included all 3 hetero-complexes, and whose protein chains or the full assembly could be readily modeled from structural templates in the PDB. On average, 28 CAPRI groups and 10 CASP groups (including automatic servers), submitted models for each of these 10 targets. Additionally, about 16 groups participated in the CAPRI scoring experiments. A range of acceptable to high quality models were obtained for 6 of the 10 Round 37 targets, for which templates were available for the full assembly. Poorer results were achieved for the remaining targets due to the lower quality of the templates available for the full complex or the individual protein chains, highlighting the unmet challenge of modeling the structural adjustments of the protein components that occur upon binding or which must be accounted for in template-based modeling. On the other hand, our analysis indicated that residues in binding interfaces were correctly predicted in a sizable fraction of otherwise poorly modeled assemblies and this with higher accuracy than published methods that do not use information on the binding partner. Lastly, the strengths and weaknesses of the assessment methods are evaluated and improvements suggested.
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Affiliation(s)
- Marc F Lensink
- University Lille, CNRS UMR8576 UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Sameer Velankar
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Minkyung Baek
- Department of Chemistry, Seoul National University, Seoul, Korea
| | - Lim Heo
- Department of Chemistry, Seoul National University, Seoul, Korea
| | - Chaok Seok
- Department of Chemistry, Seoul National University, Seoul, Korea
| | - Shoshana J Wodak
- VIB Structural Biology Research Center, VUB, Pleinlaan 2, Brussels, Belgium
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6
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First model of dimeric LRRK2: the challenge of unrevealing the structure of a multidomain Parkinson's-associated protein. Biochem Soc Trans 2016; 44:1635-1641. [DOI: 10.1042/bst20160226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/30/2016] [Accepted: 10/04/2016] [Indexed: 01/10/2023]
Abstract
Mutations within the leucine-rich repeat kinase 2 (LRRK2) gene represent the most common cause of Mendelian forms of Parkinson's disease, among autosomal dominant cases. Its gene product, LRRK2, is a large multidomain protein that belongs to the Roco protein family exhibiting GTPase and kinase activity, with the latter activity increased by pathogenic mutations. To allow rational drug design against LRRK2 and to understand the cross-regulation of the G- and the kinase domain at a molecular level, it is key to solve the three-dimensional structure of the protein. We review here our recent successful approach to build the first structural model of dimeric LRRK2 by an integrative modeling approach.
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7
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Huang J, Wu C, Liu D, Yang X, Wu R, Zhang J, Ma C, He H. C-terminal domains of bacterial proteases: structure, function and the biotechnological applications. J Appl Microbiol 2016; 122:12-22. [DOI: 10.1111/jam.13317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/21/2016] [Accepted: 10/03/2016] [Indexed: 12/28/2022]
Affiliation(s)
- J. Huang
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - C. Wu
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - D. Liu
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - X. Yang
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - R. Wu
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - J. Zhang
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - C. Ma
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
| | - H. He
- State Key Laboratory of Medical Genetics; School of Life Sciences; Central South University; Changsha China
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8
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Baiesi M, Orlandini E, Trovato A, Seno F. Linking in domain-swapped protein dimers. Sci Rep 2016; 6:33872. [PMID: 27659606 PMCID: PMC5034241 DOI: 10.1038/srep33872] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/05/2016] [Indexed: 11/24/2022] Open
Abstract
The presence of knots has been observed in a small fraction of single-domain proteins and related to their thermodynamic and kinetic properties. The exchanging of identical structural elements, typical of domain-swapped proteins, makes such dimers suitable candidates to validate the possibility that mutual entanglement between chains may play a similar role for protein complexes. We suggest that such entanglement is captured by the linking number. This represents, for two closed curves, the number of times that each curve winds around the other. We show that closing the curves is not necessary, as a novel parameter G', termed Gaussian entanglement, is strongly correlated with the linking number. Based on 110 non redundant domain-swapped dimers, our analysis evidences a high fraction of chains with a significant intertwining, that is with |G'| > 1. We report that Nature promotes configurations with negative mutual entanglement and surprisingly, it seems to suppress intertwining in long protein dimers. Supported by numerical simulations of dimer dissociation, our results provide a novel topology-based classification of protein-swapped dimers together with some preliminary evidence of its impact on their physical and biological properties.
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Affiliation(s)
- Marco Baiesi
- Department of Physics and Astronomy, University of Padova, Padova, Italy
- INFN-Sezione di Padova, Padova, Italy
| | - Enzo Orlandini
- Department of Physics and Astronomy, University of Padova, Padova, Italy
- INFN-Sezione di Padova, Padova, Italy
| | - Antonio Trovato
- Department of Physics and Astronomy, University of Padova, Padova, Italy
- CNISM-Unità di Padova, Padova, Italy
| | - Flavio Seno
- Department of Physics and Astronomy, University of Padova, Padova, Italy
- CNISM-Unità di Padova, Padova, Italy
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9
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Guaitoli G, Raimondi F, Gilsbach BK, Gómez-Llorente Y, Deyaert E, Renzi F, Li X, Schaffner A, Jagtap PKA, Boldt K, von Zweydorf F, Gotthardt K, Lorimer DD, Yue Z, Burgin A, Janjic N, Sattler M, Versées W, Ueffing M, Ubarretxena-Belandia I, Kortholt A, Gloeckner CJ. Structural model of the dimeric Parkinson's protein LRRK2 reveals a compact architecture involving distant interdomain contacts. Proc Natl Acad Sci U S A 2016; 113:E4357-66. [PMID: 27357661 PMCID: PMC4968714 DOI: 10.1073/pnas.1523708113] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leucine-rich repeat kinase 2 (LRRK2) is a large, multidomain protein containing two catalytic domains: a Ras of complex proteins (Roc) G-domain and a kinase domain. Mutations associated with familial and sporadic Parkinson's disease (PD) have been identified in both catalytic domains, as well as in several of its multiple putative regulatory domains. Several of these mutations have been linked to increased kinase activity. Despite the role of LRRK2 in the pathogenesis of PD, little is known about its overall architecture and how PD-linked mutations alter its function and enzymatic activities. Here, we have modeled the 3D structure of dimeric, full-length LRRK2 by combining domain-based homology models with multiple experimental constraints provided by chemical cross-linking combined with mass spectrometry, negative-stain EM, and small-angle X-ray scattering. Our model reveals dimeric LRRK2 has a compact overall architecture with a tight, multidomain organization. Close contacts between the N-terminal ankyrin and C-terminal WD40 domains, and their proximity-together with the LRR domain-to the kinase domain suggest an intramolecular mechanism for LRRK2 kinase activity regulation. Overall, our studies provide, to our knowledge, the first structural framework for understanding the role of the different domains of full-length LRRK2 in the pathogenesis of PD.
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Affiliation(s)
- Giambattista Guaitoli
- German Center for Neurodegenerative Diseases, 72076 Tübingen, Germany; Center for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany
| | - Francesco Raimondi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy; Cell Networks, University of Heidelberg, 69120 Heidelberg, Germany
| | - Bernd K Gilsbach
- German Center for Neurodegenerative Diseases, 72076 Tübingen, Germany; Department of Cell Biochemistry, University of Groningen, Groningen 9747 AG, The Netherlands; Structural Biology Group, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Yacob Gómez-Llorente
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Egon Deyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Vlaams Instituut voor Biotechnologie, Structural Biology Research Center, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Fabiana Renzi
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Xianting Li
- Departments of Neurology and Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Adam Schaffner
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029; Departments of Neurology and Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Pravin Kumar Ankush Jagtap
- Center for Integrated Protein Science Munich at Department of Chemistry, Technische Universität München, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Karsten Boldt
- Center for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany
| | - Felix von Zweydorf
- German Center for Neurodegenerative Diseases, 72076 Tübingen, Germany; Center for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany
| | - Katja Gotthardt
- Structural Biology Group, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | | | - Zhenyu Yue
- Departments of Neurology and Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | | | | | - Michael Sattler
- Center for Integrated Protein Science Munich at Department of Chemistry, Technische Universität München, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Wim Versées
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Vlaams Instituut voor Biotechnologie, Structural Biology Research Center, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Marius Ueffing
- Center for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany
| | - Iban Ubarretxena-Belandia
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029;
| | - Arjan Kortholt
- Department of Cell Biochemistry, University of Groningen, Groningen 9747 AG, The Netherlands;
| | - Christian Johannes Gloeckner
- German Center for Neurodegenerative Diseases, 72076 Tübingen, Germany; Center for Ophthalmology, Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany;
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10
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Woodard JC, Dunatunga S, Shakhnovich EI. A Simple Model of Protein Domain Swapping in Crowded Cellular Environments. Biophys J 2016; 110:2367-2376. [PMID: 27276255 DOI: 10.1016/j.bpj.2016.04.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/07/2016] [Accepted: 04/20/2016] [Indexed: 11/25/2022] Open
Abstract
Domain swapping in proteins is an important mechanism of functional and structural innovation. However, despite its ubiquity and importance, the physical mechanisms that lead to domain swapping are poorly understood. Here, we present a simple two-dimensional coarse-grained model of protein domain swapping in the cytoplasm. In our model, two-domain proteins partially unfold and diffuse in continuous space. Monte Carlo multiprotein simulations of the model reveal that domain swapping occurs at intermediate temperatures, whereas folded dimers and folded monomers prevail at low temperatures, and partially unfolded monomers predominate at high temperatures. We use a simplified amino acid alphabet consisting of four residue types, and find that the oligomeric state at a given temperature depends on the sequence of the protein. We also show that hinge strain between domains can promote domain swapping, consistent with experimental observations for real proteins. Domain swapping depends nonmonotonically on the protein concentration, with domain-swapped dimers occurring at intermediate concentrations and nonspecific interactions between partially unfolded proteins occurring at high concentrations. For folded proteins, we recover the result obtained in three-dimensional lattice simulations, i.e., that functional dimerization is most prevalent at intermediate temperatures and nonspecific interactions increase at low temperatures.
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Affiliation(s)
- Jaie C Woodard
- Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Sachith Dunatunga
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts.
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11
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Smaldone G, Vigorita M, Ruggiero A, Balasco N, Dattelbaum JD, D'Auria S, Del Vecchio P, Graziano G, Vitagliano L. Proline 235 plays a key role in the regulation of the oligomeric states of Thermotoga maritima Arginine Binding Protein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:814-24. [PMID: 27087545 DOI: 10.1016/j.bbapap.2016.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 10/22/2022]
Abstract
The Arginine Binding Protein isolated from Thermotoga maritima (TmArgBP) is a protein endowed with several peculiar properties. We have previously shown that TmArgBP dimerization is a consequence of the swapping of the C-terminal helix. Here we explored the structural determinants of TmArgBP domain swapping and oligomerization. In particular, we report a mutational analysis of the residue Pro235, which is located in the hinge region of the swapping dimer. This residue was either replaced with a Gly-Lys dipeptide (TmArgBP(P235GK)) or a Gly residue (TmArgBP(P235G)). Different forms of these mutants were generated and extensively characterized using biophysical techniques. For both TmArgBP(P235GK) and TmArgBP(P235G) mutants, the occurrence of multiple oligomerization states (monomers, dimers and trimers) was detected. The formation of well-folded monomeric forms for these mutants indicates that the dimerization through C-terminal domain swapping observed in wild-type TmArgBP is driven by conformational restraints imposed by the presence of Pro235 in the hinge region. Molecular dynamics studies corroborate this observation by showing that Gly235 assumes conformational states forbidden for Pro residues in the TmArgBP(P235G) monomer. Unexpectedly, the trimeric forms present: (a) peculiar circular dichroism spectra, (b) a great susceptibility to heating, and (c) the ability to bind the Thioflavin T dye. The present findings clearly demonstrate that single-point mutations have an important impact on the TmArgBP oligomerization process. In a wider context, they also indicate that proteins endowed with an intrinsic propensity to swap have an easy access to states with altered structural and, possibly, functional properties.
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Affiliation(s)
| | - Marilisa Vigorita
- Department of Sciences and Technologies, Università del Sannio, Via Port'arsa 11, Benevento 82100, Italy
| | - Alessia Ruggiero
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Nicole Balasco
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy; DiSTABiF, Second University of Naples, Caserta 81100, Italy
| | | | - Sabato D'Auria
- Institute of Food Science, CNR, Via Roma, 64, Avellino, Italy
| | - Pompea Del Vecchio
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 80126 Napoli, Italy
| | - Giuseppe Graziano
- Department of Sciences and Technologies, Università del Sannio, Via Port'arsa 11, Benevento 82100, Italy
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy.
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12
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Crystallographic studies on protein misfolding: Domain swapping and amyloid formation in the SH3 domain. Arch Biochem Biophys 2016; 602:116-126. [PMID: 26924596 DOI: 10.1016/j.abb.2016.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 12/18/2022]
Abstract
Oligomerization by 3D domain swapping is found in a variety of proteins of diverse size, fold and function. In the early 1960s this phenomenon was postulated for the oligomers of ribonuclease A, but it was not until the 1990s that X-ray diffraction provided the first experimental evidence of this special manner of oligomerization. Nowadays, structural information has allowed the identification of these swapped oligomers in over one hundred proteins. Although the functional relevance of this phenomenon is not clear, this alternative folding of protomers into intertwined oligomers has been related to amyloid formation. Studies on proteins that develop 3D domain swapping might provide some clues on the early stages of amyloid formation. The SH3 domain is a small modular domain that has been used as a model to study the basis of protein folding. Among SH3 domains, the c-Src-SH3 domain emerges as a helpful model to study 3D domain swapping and amyloid formation.
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Wodak SJ, Malevanets A, MacKinnon SS. The Landscape of Intertwined Associations in Homooligomeric Proteins. Biophys J 2015; 109:1087-100. [PMID: 26340815 DOI: 10.1016/j.bpj.2015.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/06/2015] [Accepted: 08/03/2015] [Indexed: 01/22/2023] Open
Abstract
We present an overview of the full repertoire of intertwined associations in homooligomeric proteins. This overview summarizes recent findings on the different categories of intertwined associations in known protein structures, their assembly modes, the properties of their interfaces, and their structural plasticity. Furthermore, the current body of knowledge on the so-called three-dimensional domain-swapped systems is reexamined in the context of the wider landscape of intertwined homooligomers, with a particular focus on the mechanistic aspects that underpin intertwined self-association processes in proteins. Insights gained from this integrated overview into the physical and biological roles of intertwining are highlighted.
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Affiliation(s)
- Shoshana J Wodak
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; VIB Structural Biology Research Center, Brussels, Belgium.
| | | | - Stephen S MacKinnon
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Cyclica, Inc., Toronto, Ontario, Canada
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