1
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Niemyska W, Mukherjee S, Gren BA, Niewieczerzal S, Bujnicki JM, Sulkowska JI. Discovery of a trefoil knot in the RydC RNA: Challenging previous notions of RNA topology. J Mol Biol 2024; 436:168455. [PMID: 38272438 DOI: 10.1016/j.jmb.2024.168455] [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: 10/17/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
Knots are very common in polymers, including DNA and protein molecules. Yet, no genuine knot has been identified in natural RNA molecules to date. Upon re-examining experimentally determined RNA 3D structures, we discovered a trefoil knot 31, the most basic non-trivial knot, in the RydC RNA. This knotted RNA is a member of a small family of short bacterial RNAs, whose secondary structure is characterized by an H-type pseudoknot. Molecular dynamics simulations suggest a folding pathway of the RydC RNA that starts with a native twisted loop. Based on sequence analyses and computational RNA 3D structure predictions, we postulate that this trefoil knot is a conserved feature of all RydC-related RNAs. The first discovery of a knot in a natural RNA molecule introduces a novel perspective on RNA 3D structure formation and on fundamental research on the relationship between function and spatial structure of biopolymers.
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Affiliation(s)
- Wanda Niemyska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland; Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland.
| | - Sunandan Mukherjee
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, 02-109 Warsaw, Poland
| | - Bartosz A Gren
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Szymon Niewieczerzal
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, 02-109 Warsaw, Poland.
| | - Joanna I Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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2
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Gao M, Huang Y. Molecular dynamics simulations revealed topological frustration in the binding-wrapping process of eIF4G with eIF4E. Phys Chem Chem Phys 2024; 26:2073-2081. [PMID: 38131207 DOI: 10.1039/d3cp04899c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Interaction between the cap-binding protein eIF4E and the scaffolding protein eIF4G is essential for the cap-dependent translation initiation in eukaryotes. In the Saccharomyces cerevisiae eIF4G/eIF4E complex, the intrinsically disordered eIF4E-binding domain of eIF4G folds into a bracelet-like structure upon binding to eIF4E. Aiming to unveil the molecular mechanism underlying the binding-wrapping process of eIF4G with eIF4E, we performed extensive coarse-grained molecular dynamics simulations and transition path analysis in this work. The major transition pathway revealed from our simulations showed that docking of the eIF4E-binding motif of eIF4G to the folded core of eIF4E initiates the binding process and then the disordered eIF4G wraps around the N-terminal tail of eIF4E. Additionally, we identified a minor transition pathway which indicates the involvement of topological frustration in the binding process. By manipulating the interaction strength of the wrapping contacts and the latching contacts, we further dissected factors affecting the formation of topological frustration and the binding transition kinetics. Our findings provide new clues for experimental studies on the binding mechanism of eIF4G to eIF4E in the future and exemplify the involvement of topological frustration in the binding process of intrinsically disordered proteins.
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Affiliation(s)
- Meng Gao
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China.
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei University of Technology, Wuhan 430068, China
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China
| | - Yongqi Huang
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China.
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei University of Technology, Wuhan 430068, China
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China
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3
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Mainan A, Roy S. Dynamic Counterion Condensation Model Decodes Functional Dynamics of RNA Pseudoknot in SARS-CoV-2: Control of Ion-Mediated Pierced Lasso Topology. J Phys Chem Lett 2023; 14:10402-10411. [PMID: 37955626 DOI: 10.1021/acs.jpclett.3c02755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
The programmed frameshifting stimulatory element, a promising drug target for COVID-19 treatment, involves a RNA pseudoknot (PK) structure. This RNA PK facilitates frameshifting, enabling RNA viruses to translate multiple proteins from a single mRNA, which is a key strategy for their rapid evolution. Overcoming the challenges of capturing large-scale structural changes of RNA under the influence of a dynamic counterion environment (K+ and Mg2+), the study extended the applications of a newly developed dynamic counterion condensation (DCC) model. DCC simulations reveal potential folding pathways of this RNA PK, supported by the experimental findings obtained using optical tweezers. The study elucidates the pivotal role of Mg2+ ions in crafting a lasso-like RNA topology, a novel RNA motif that governs dynamic transitions between the ring-opened and ring-closed states of the RNA. The pierced lasso component guided by Mg2+-mediated interactions orchestrates inward and outward motion fine-tuning tension on the slippery segment, a critical factor for optimizing frameshifting efficiency.
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Affiliation(s)
- Avijit Mainan
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
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4
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Halder R, Nissley DA, Sitarik I, Jiang Y, Rao Y, Vu QV, Li MS, Pritchard J, O'Brien EP. How soluble misfolded proteins bypass chaperones at the molecular level. Nat Commun 2023; 14:3689. [PMID: 37344452 DOI: 10.1038/s41467-023-38962-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/24/2023] [Indexed: 06/23/2023] Open
Abstract
Subpopulations of soluble, misfolded proteins can bypass chaperones within cells. The extent of this phenomenon and how it happens at the molecular level are unknown. Through a meta-analysis of the experimental literature we find that in all quantitative protein refolding studies there is always a subpopulation of soluble but misfolded protein that does not fold in the presence of one or more chaperones, and can take days or longer to do so. Thus, some misfolded subpopulations commonly bypass chaperones. Using multi-scale simulation models we observe that the misfolded structures that bypass various chaperones can do so because their structures are highly native like, leading to a situation where chaperones do not distinguish between the folded and near-native-misfolded states. More broadly, these results provide a mechanism by which long-time scale changes in protein structure and function can persist in cells because some misfolded states can bypass components of the proteostasis machinery.
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Affiliation(s)
- Ritaban Halder
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel A Nissley
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Statistics, University of Oxford, Oxford, OX1 3LB, UK
| | - Ian Sitarik
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yiyun Rao
- Molecular, Cellular and Integrative Biosciences Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - Quyen V Vu
- Institute of Physics, Polish Academy of Sciences; Al. Lotnikow 32/46, 02-668, Warsaw, Poland
| | - Mai Suan Li
- Institute of Physics, Polish Academy of Sciences; Al. Lotnikow 32/46, 02-668, Warsaw, Poland
- Institute for Computational Sciences and Technology; Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City, Vietnam
| | - Justin Pritchard
- Department of Biomedical Engineering, Pennsylvania State University, State College, PA, 16802, USA
- Huck Institute for the Life Sciences, Pennsylvania State University, State College, PA, 16802, USA
| | - Edward P O'Brien
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA.
- Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
- Institute for Computational and Data Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
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5
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Yu J, Zhang ZW, Yang HY, Liu CJ, Lu WC. Study of fusion peptide release for the spike protein of SARS-CoV-2. RSC Adv 2023; 13:16970-16983. [PMID: 37288377 PMCID: PMC10242618 DOI: 10.1039/d3ra01764h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/11/2023] [Indexed: 06/09/2023] Open
Abstract
The spike protein of SARS-CoV-2 can recognize the ACE2 membrane protein on the host cell and plays a key role in the membrane fusion process between the virus envelope and the host cell membrane. However, to date, the mechanism for the spike protein recognizing host cells and initiating membrane fusion remains unknown. In this study, based on the general assumption that all three S1/S2 junctions of the spike protein are cleaved, structures with different forms of S1 subunit stripping and S2' site cleavage were constructed. Then, the minimum requirement for the release of the fusion peptide was studied by all-atom structure-based MD simulations. The results from simulations showed that stripping an S1 subunit from the A-, B- or C-chain of the spike protein and cleaving the specific S2' site on the B-chain (C-chain or A-chain) may result in the release of the fusion peptide, suggesting that the requirement for the release of FP may be more relaxed than previously expected.
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Affiliation(s)
- Jie Yu
- College of Physics, Qingdao University Qingdao 266071 Shandong P. R. China
| | - Zhi-Wei Zhang
- College of Physics, Qingdao University Qingdao 266071 Shandong P. R. China
| | - Han-Yu Yang
- College of Physics, Qingdao University Qingdao 266071 Shandong P. R. China
| | - Chong-Jin Liu
- College of Physics, Qingdao University Qingdao 266071 Shandong P. R. China
| | - Wen-Cai Lu
- College of Physics, Qingdao University Qingdao 266071 Shandong P. R. China
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6
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Mouro PR, Sanches MN, Leite VBP, Chahine J. Exploring the Folding Mechanism of Dimeric Superoxide Dismutase. J Phys Chem B 2023; 127:1338-1349. [PMID: 36716437 DOI: 10.1021/acs.jpcb.2c08877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Cu/Zn Human Superoxide Dismutase (SOD1) is a dimeric metalloenzyme whose genetic mutations are directly related to amyotrophic lateral sclerosis (ALS), so understanding its folding mechanism is of fundamental importance. Currently, the SOD1 dimer formation is studied via molecular dynamics simulations using a simplified structure-based model and an all-atom model. Results from the simplified model reveal a mechanism dependent on distances between monomers, which are limited by constraints to mimic concentration dependence. The stability of intermediates (during the int state) is significantly affected by this distance, as well as by the presence of two folded monomers prior to dimer formation. The kinetics of interface formation are also highly dependent on the separation distance. The folding temperature of the dimer is about 4.2% higher than that of the monomer, a value not too different from experimental data. All-atom simulations on the apo dimer give binding free energy between monomers similar to experimental values. An intermediate state is evident for the apo form at a separation distance between monomers slightly larger than the native distance which has little formed interface between monomers. We have shown that this intermediate is stabilized by non-native intra- and intercontacts.
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Affiliation(s)
- Paulo R Mouro
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto15054-000, Brazil
| | - Murilo N Sanches
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto15054-000, Brazil
| | - Vitor B P Leite
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto15054-000, Brazil
| | - Jorge Chahine
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto15054-000, Brazil
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7
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Anderson DM, Jayanthi LP, Gosavi S, Meiering EM. Engineering the kinetic stability of a β-trefoil protein by tuning its topological complexity. Front Mol Biosci 2023; 10:1021733. [PMID: 36845544 PMCID: PMC9945329 DOI: 10.3389/fmolb.2023.1021733] [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: 08/17/2022] [Accepted: 01/02/2023] [Indexed: 02/11/2023] Open
Abstract
Kinetic stability, defined as the rate of protein unfolding, is central to determining the functional lifetime of proteins, both in nature and in wide-ranging medical and biotechnological applications. Further, high kinetic stability is generally correlated with high resistance against chemical and thermal denaturation, as well as proteolytic degradation. Despite its significance, specific mechanisms governing kinetic stability remain largely unknown, and few studies address the rational design of kinetic stability. Here, we describe a method for designing protein kinetic stability that uses protein long-range order, absolute contact order, and simulated free energy barriers of unfolding to quantitatively analyze and predict unfolding kinetics. We analyze two β-trefoil proteins: hisactophilin, a quasi-three-fold symmetric natural protein with moderate stability, and ThreeFoil, a designed three-fold symmetric protein with extremely high kinetic stability. The quantitative analysis identifies marked differences in long-range interactions across the protein hydrophobic cores that partially account for the differences in kinetic stability. Swapping the core interactions of ThreeFoil into hisactophilin increases kinetic stability with close agreement between predicted and experimentally measured unfolding rates. These results demonstrate the predictive power of readily applied measures of protein topology for altering kinetic stability and recommend core engineering as a tractable target for rationally designing kinetic stability that may be widely applicable.
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Affiliation(s)
| | - Lakshmi P. Jayanthi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Elizabeth M. Meiering
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada,*Correspondence: Elizabeth M. Meiering,
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8
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Banerjee A, Gosavi S. Potential Self-Peptide Inhibitors of the SARS-CoV-2 Main Protease. J Phys Chem B 2023; 127:855-865. [PMID: 36689738 PMCID: PMC9883841 DOI: 10.1021/acs.jpcb.2c05917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 11/23/2022] [Indexed: 01/24/2023]
Abstract
The SARS-CoV-2 main protease (Mpro) plays an essential role in viral replication, cleaving viral polyproteins into functional proteins. This makes Mpro an important drug target. Mpro consists of an N-terminal catalytic domain and a C-terminal α-helical domain (MproC). Previous studies have shown that peptides derived from a given protein sequence (self-peptides) can affect the folding and, in turn, the function of that protein. Since the SARS-CoV-1 MproC is known to stabilize its Mpro and regulate its function, we hypothesized that SARS-CoV-2 MproC-derived self-peptides may modulate the folding and the function of SARS-CoV-2 Mpro. To test this, we studied the folding of MproC in the presence of various self-peptides using coarse-grained structure-based models and molecular dynamics simulations. In these simulations of MproC and one self-peptide, we found that two self-peptides, the α1-helix and the loop between α4 and α5 (loop4), could replace the equivalent native sequences in the MproC structure. Replacement of either sequence in full-length Mpro should, in principle, be able to perturb Mpro function albeit through different mechanisms. Some general principles for the rational design of self-peptide inhibitors emerge: The simulations show that prefolded self-peptides are more likely to replace native sequences than those which do not possess structure. Additionally, the α1-helix self-peptide is kinetically stable and once inserted rarely exchanges with the native α1-helix, while the loop4 self-peptide is easily replaced by the native loop4, making it less useful for modulating function. In summary, a prefolded α1-derived peptide should be able to inhibit SARS-CoV-2 Mpro function.
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Affiliation(s)
- Arkadeep Banerjee
- Simons Centre for the Study
of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Shachi Gosavi
- Simons Centre for the Study
of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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9
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Dias RVR, Ferreira CTA, Jennings PA, Whitford PC, Oliveira LCD. Csk αC Helix: A Computational Analysis of an Essential Region for Conformational Transitions. J Phys Chem B 2022; 126:10587-10596. [PMID: 36512419 DOI: 10.1021/acs.jpcb.2c05408] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Conformational changes are an essential feature for the function of some dynamic proteins. Understanding the mechanism of such motions may allow us to identify important properties, which may be directly related to the regulatory function of a protein. Also, this knowledge may be employed for a rational design of drugs that can shift the balance between active and inactive conformations, as well as affect the kinetics of the activation process. Here, the conformational changes in carboxyl-terminal Src kinase, the major catalytic repressor to the Src family of kinases, was investigated, and it was proposed as a functionally related hypothesis. A Cα Structure-Based Model (Cα-SBM) was applied to provide a description of the overall conformational landscape and further analysis complemented by detailed molecular dynamics simulations. As a first approach to Cα-SBM simulations, reversible transitions between active (closed) and inactive (open) forms were modeled as fluctuations between these two energetic basins. It was found that, in addition to the interdomain Carboxyl-terminal SRC Kinase (Csk) correlated motions, a conformational change in the αC helix is required for a complete conformational transition. The result reveals this as an important region of transition control and domain coordination. Restrictions in the αC helix region of the Csk protein were performed, and the analyses showed a direct correlation with the global conformational changes, with this location being propitious for future studies of ligands. Also, the Src Homology 3 (SH3) and SH3 plus Src Homology 2 (SH2) domains were excluded for a direct comparison with experimental results previously published. Simulations where the SH3 was deleted presented a reduction of the transitions during the simulations, while the SH3-SH2 deletion vanishes the Csk transitions, corroborating the experimental results mentioned and linking the conformational changes with the catalytic functionality of Csk. The study was complemented by the introduction of a known kinase inhibitor close to the Csk αC helix region where its consequences for the kinetic behavior and domain displacement of Csk were verified through detailed molecular dynamics. The findings describe the mechanisms involving the Csk αC helix for the transitions and also support the dynamic correlation between SH3 and SH2 domains against the Csk lobes and how local energetic restrictions or interactions in the Csk αC helix can play an important role for long-range motions. The results also allow speculation if the Csk activity is restricted to one specific conformation or a consequence of a state transition, this point being a target for future studies. However, the αC helix is revealed as a potential region for rational drug design.
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Affiliation(s)
- Raphael Vinicius Rodrigues Dias
- São Paulo State University (Unesp), Department of Physics, Institute of Biosciences, Humanities and Exact Sciences, Rua Cristóvão Colombo, 2265, São José do Rio Preto, São Paulo15054-000, Brazil
| | - Carolina Tatiani Alves Ferreira
- São Paulo State University (Unesp), Department of Physics, Institute of Biosciences, Humanities and Exact Sciences, Rua Cristóvão Colombo, 2265, São José do Rio Preto, São Paulo15054-000, Brazil
| | - Patricia Ann Jennings
- University of California, San Diego, 9500 Gilman Drive, Natural Science Building #3110, La Jolla, California92093, United States
| | - Paul Charles Whitford
- Northeastern University, Department of Physics and Center for Theoretical Biological Physics, 360 Huntington Avenue, Boston, Massachusetts02115, United States
| | - Leandro Cristante de Oliveira
- São Paulo State University (Unesp), Department of Physics, Institute of Biosciences, Humanities and Exact Sciences, Rua Cristóvão Colombo, 2265, São José do Rio Preto, São Paulo15054-000, Brazil
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10
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Dahlstrom TJ, Capraro DT, Jennings PA, Finke JM. Knotting Optimization and Folding Pathways of a Go-Model with a Deep Knot. J Phys Chem B 2022; 126:10221-10236. [PMID: 36424347 DOI: 10.1021/acs.jpcb.2c05588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Formation of protein knots is an intriguing offshoot of the protein folding problem. Since experimental resolution on knot formation is limited, theoretical methods currently provide the most detailed insights into the knotting process. While suitable for shallow knots, molecular dynamics simulations have faced challenges capturing the formation of deep knots in proteins such as the minimally tied trefoil α/β methyltransferase from Thermotoga maritima (MTTTM). To improve the efficiency of MTTTM knotting in Cα Go-model simulations, mutant variants of the MTTTM Go-model were investigated. Through a structure-based analysis of knotted and unknotted states, four residues (K71, R72, E75, V76) were identified to increase the knotting efficiency from 2% to 83% when their contact energies were doubled and dihedral strength around the knot loop increased. The key features of this model are (i) a C-terminal slipknot intermediate that threads the knot in a highly unstructured intermediate, (ii) the inability to knot in native-like intermediate states, and (iii) a minor population in a long-lived trap that cannot knot. Examination of residue 71-76 contacts provides a small set of potential mutants that can directly test the model's validity. In addition, the knotting optimization process developed here has broad applicability in generating knotting-efficient models of other knotted proteins.
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Affiliation(s)
- Thomas J Dahlstrom
- Division of Sciences and Mathematics, Interdisciplinary Arts and Sciences, University of Washington Tacoma, Tacoma, Washington98402, United States
| | - Dominique T Capraro
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California92093, United States
| | - Particia A Jennings
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California92093, United States
| | - John M Finke
- Division of Sciences and Mathematics, Interdisciplinary Arts and Sciences, University of Washington Tacoma, Tacoma, Washington98402, United States
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11
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Nissley DA, Jiang Y, Trovato F, Sitarik I, Narayan KB, To P, Xia Y, Fried SD, O'Brien EP. Universal protein misfolding intermediates can bypass the proteostasis network and remain soluble and less functional. Nat Commun 2022; 13:3081. [PMID: 35654797 PMCID: PMC9163053 DOI: 10.1038/s41467-022-30548-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 05/05/2022] [Indexed: 01/12/2023] Open
Abstract
Some misfolded protein conformations can bypass proteostasis machinery and remain soluble in vivo. This is an unexpected observation, as cellular quality control mechanisms should remove misfolded proteins. Three questions, then, are: how do long-lived, soluble, misfolded proteins bypass proteostasis? How widespread are such misfolded states? And how long do they persist? We address these questions using coarse-grain molecular dynamics simulations of the synthesis, termination, and post-translational dynamics of a representative set of cytosolic E. coli proteins. We predict that half of proteins exhibit misfolded subpopulations that bypass molecular chaperones, avoid aggregation, and will not be rapidly degraded, with some misfolded states persisting for months or longer. The surface properties of these misfolded states are native-like, suggesting they will remain soluble, while self-entanglements make them long-lived kinetic traps. In terms of function, we predict that one-third of proteins can misfold into soluble less-functional states. For the heavily entangled protein glycerol-3-phosphate dehydrogenase, limited-proteolysis mass spectrometry experiments interrogating misfolded conformations of the protein are consistent with the structural changes predicted by our simulations. These results therefore provide an explanation for how proteins can misfold into soluble conformations with reduced functionality that can bypass proteostasis, and indicate, unexpectedly, this may be a wide-spread phenomenon.
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Affiliation(s)
- Daniel A Nissley
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Fabio Trovato
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Ian Sitarik
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Karthik B Narayan
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Philip To
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Yingzi Xia
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Stephen D Fried
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
- Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Edward P O'Brien
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA.
- Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
- Institute for Computational and Data Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
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12
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Chu X, Suo Z, Wang J. Investigating the Conformational Dynamics of a Y-Family DNA Polymerase during Its Folding and Binding to DNA and a Nucleotide. JACS AU 2022; 2:341-356. [PMID: 35252985 PMCID: PMC8889613 DOI: 10.1021/jacsau.1c00368] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Indexed: 06/14/2023]
Abstract
During DNA polymerization, the Y-family DNA polymerases are capable of bypassing various DNA damage, which can stall the replication fork progression. It has been well acknowledged that the structures of the Y-family DNA polymerases have been naturally evolved to undertake this vital task. However, the mechanisms of how these proteins utilize their unique structural and conformational dynamical features to perform the translesion DNA synthesis are less understood. Here, we developed structure-based models to study the precatalytic DNA polymerization process, including DNA and nucleotide binding to DPO4, a paradigmatic Y-family polymerase from Sulfolobus solfataricus. We studied the interplay between the folding and the conformational dynamics of DPO4 and found that DPO4 undergoes first unraveling (unfolding) and then folding for accomplishing the functional "open-to-closed" conformational transition. DNA binding dynamically modulates the conformational equilibrium in DPO4 during the stepwise binding through different types of interactions, leading to different conformational distributions of DPO4 at different DNA binding stages. We observed that nucleotide binding induces modulation of a few contacts surrounding the active site of the DPO4-DNA complex associated with a high free energy barrier. Our simulation results resonate with the experimental evidence that the conformational change at the active site led by nucleotide is the rate-limiting step of nucleotide incorporation. In combination with localized frustration analyses, we underlined the importance of DPO4 conformational dynamics and fluctuations in facilitating DNA and nucleotide binding. Our findings offer mechanistic insights into the processes of DPO4 conformational dynamics associated with the substrate binding and contribute to the understanding of the "structure-dynamics-function" relationship in the Y-family DNA polymerases.
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Affiliation(s)
- Xiakun Chu
- Department
of Chemistry, State University of New York
at Stony Brook, Stony
Brook, New York 11794, United States
| | - Zucai Suo
- Department
of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, United States
| | - Jin Wang
- Department
of Chemistry, State University of New York
at Stony Brook, Stony
Brook, New York 11794, United States
- Department
of Physics and Astronomy, State University
of New York at Stony Brook, Stony Brook, New York 11794, United States
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13
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Gao M, Li P, Su Z, Huang Y. Topological frustration leading to backtracking in a coupled folding-binding process. Phys Chem Chem Phys 2022; 24:2630-2637. [PMID: 35029261 DOI: 10.1039/d1cp04927e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intrinsically disordered proteins (IDPs) are abundant in all species. Their discovery challenges the traditional "sequence-structure-function" paradigm of protein science because IDPs play important roles in various biological processes without preformed folded structures. Bioinformatic analysis reveals that the intrinsically conformational disorder of IDPs as well as their conformational transition upon binding to their targets is encoded by their amino acid sequences. The rRNase domain of colicin E3 and the immunity protein Im3 are a pair of proteins involved in bacterial survival. While the N-terminal segment and the central segment of E3 make comparable intermolecular contacts with Im3 in the bound state, binding of E3 with Im3 is dominantly triggered by the central segment of E3. In this work, to further investigate the binding mechanism of disordered E3 with Im3, we performed systematic free energy and transition path analysis through coarse-grained molecular dynamics simulations. We observed backtracking of the N-terminal segment of E3 in the binding process, whose occurrence depends on salt concentration. Conformational analysis revealed that initial binding of the N-terminal segment of E3 to Im3 usually leads to misorientation of a central hairpin of E3 on Im3, which generates topological frustration and results in backtracking of the N-terminal segment. Our results not only provide deeper mechanistic insights into the coupled folding-binding process of the E3/Im3 complex, but also suggest that topological frustration could be present in the coupled folding-binding process of IDPs and play an important role in regulating the binding transition pathways.
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Affiliation(s)
- Meng Gao
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China.
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Department of Biological Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Ping Li
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China.
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Department of Biological Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Zhengding Su
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China.
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Department of Biological Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Yongqi Huang
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan 430068, China.
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Department of Biological Engineering, Hubei University of Technology, Wuhan 430068, China
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14
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Contessoto VG, de Oliveira VM, Leite VBP. Coarse-Grained Simulations of Protein Folding: Bridging Theory and Experiments. Methods Mol Biol 2022; 2376:303-315. [PMID: 34845616 DOI: 10.1007/978-1-0716-1716-8_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Computational coarse-grained models play a fundamental role as a research tool in protein folding, and they are important in bridging theory and experiments. Folding mechanisms are generally discussed using the energy landscape framework, which is well mapped within a class of simplified structure-based models. In this chapter, simplified computer models are discussed with special focus on structure-based ones.
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Affiliation(s)
| | - Vinícius M de Oliveira
- Brazilian Biosciences National Laboratory, LNBio/CNPEM, Campinas, SP, Brazil
- São Paulo State University, IBILCE/UNESP, São José do Rio Preto, SP, Brazil
| | - Vitor B P Leite
- São Paulo State University, IBILCE/UNESP, São José do Rio Preto, SP, Brazil.
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15
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Contessoto VG, Ferreira PHB, Chahine J, Leite VBP, Oliveira RJ. Small Neutral Crowding Solute Effects on Protein Folding Thermodynamic Stability and Kinetics. J Phys Chem B 2021; 125:11673-11686. [PMID: 34644091 DOI: 10.1021/acs.jpcb.1c07663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular crowding is a ubiquitous phenomenon in biological systems, with significant consequences on protein folding and stability. Small compounds, such as the osmolyte trimethylamine N-oxide (TMAO), can also present similar effects. To analyze the effects arising from these solute-like molecules, we performed a series of crowded coarse-grained folding simulations. Two well-known proteins were chosen, CI2 and SH3, modeled by the alpha-carbon-structure-based model. In the simulations, the crowding molecules were represented by low-sized neutral atom beads in different concentrations. The results show that a low level of the volume fraction occupied by neutral agents can change protein stability and folding kinetics for the two systems. However, the kinetics were shown to be unaffected in their respective folding temperatures. The faster kinetics correlates with changes in the folding route for systems at the same temperature, where non-native contacts were shown to be relevant. The transition states of the two systems with and without crowders are similar. In the case of SH3, there are differences in the structuring of two strands, which may be associated with the increase in its folding rate, in addition to the destabilization of the denatured ensemble. The present study also detected a crossover in the thermodynamic stability behavior, previously observed experimentally and theoretically. As the temperature increases, crowders change from destabilizing to stabilizing agents.
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Affiliation(s)
- Vinícius G Contessoto
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences, São Paulo State University, São José do Rio Preto 15054-000, Brazil
| | - Paulo H B Ferreira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba 38064-200, Brazil
| | - Jorge Chahine
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences, São Paulo State University, São José do Rio Preto 15054-000, Brazil
| | - Vitor B P Leite
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences, São Paulo State University, São José do Rio Preto 15054-000, Brazil
| | - Ronaldo J Oliveira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba 38064-200, Brazil
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16
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Dodero-Rojas E, Onuchic JN, Whitford PC. Sterically confined rearrangements of SARS-CoV-2 Spike protein control cell invasion. eLife 2021; 10:70362. [PMID: 34463614 PMCID: PMC8456623 DOI: 10.7554/elife.70362] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/06/2021] [Indexed: 12/13/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious, and transmission involves a series of processes that may be targeted by vaccines and therapeutics. During transmission, host cell invasion is controlled by a large-scale (200–300 Å) conformational change of the Spike protein. This conformational rearrangement leads to membrane fusion, which creates transmembrane pores through which the viral genome is passed to the host. During Spike-protein-mediated fusion, the fusion peptides must be released from the core of the protein and associate with the host membrane. While infection relies on this transition between the prefusion and postfusion conformations, there has yet to be a biophysical characterization reported for this rearrangement. That is, structures are available for the endpoints, though the intermediate conformational processes have not been described. Interestingly, the Spike protein possesses many post-translational modifications, in the form of branched glycans that flank the surface of the assembly. With the current lack of data on the pre-to-post transition, the precise role of glycans during cell invasion has also remained unclear. To provide an initial mechanistic description of the pre-to-post rearrangement, an all-atom model with simplified energetics was used to perform thousands of simulations in which the protein transitions between the prefusion and postfusion conformations. These simulations indicate that the steric composition of the glycans can induce a pause during the Spike protein conformational change. We additionally show that this glycan-induced delay provides a critical opportunity for the fusion peptides to capture the host cell. In contrast, in the absence of glycans, the viral particle would likely fail to enter the host. This analysis reveals how the glycosylation state can regulate infectivity, while providing a much-needed structural framework for studying the dynamics of this pervasive pathogen.
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Affiliation(s)
- Esteban Dodero-Rojas
- Center for Theoretical Biological Physics, Rice University, Houston, United States
| | - Jose N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, United States.,Department of Physics and Astronomy, Rice University, Houston, United States.,Department of Chemistry, Rice University, Houston, United States.,Department of Biosciences, Rice University, Houston, United States
| | - Paul Charles Whitford
- Center for Theoretical Biological Physics, Northeastern University, Boston, United States.,Department of Physics, Northeastern University, Boston, United States
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17
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Especial JNC, Faísca PFN. A Specific Set of Heterogeneous Native Interactions Yields Efficient Knotting in Protein Folding. J Phys Chem B 2021; 125:7359-7367. [PMID: 34197706 DOI: 10.1021/acs.jpcb.1c03127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Native interactions are crucial for folding, and non-native interactions appear to be critical for efficiently knotting proteins. Therefore, it is important to understand both their roles in the folding of knotted proteins. It has been proposed that non-native interactions drive the correct order of contact formation, which is essential to avoid backtracking and efficiently self-tie. In this study, we ask if non-native interactions are strictly necessary to tangle a protein or if the correct order of contact formation can be assured by a specific set of native, but otherwise heterogeneous (i.e., having distinct energies), interactions. In order to address this problem, we conducted extensive Monte Carlo simulations of lattice models of protein-like sequences designed to fold into a preselected knotted conformation embedding a trefoil knot. We were able to identify a specific set of heterogeneous native interactions that drives efficient knotting and is able to fold the protein when combined with the remaining native interactions modeled as homogeneous. This specific set of heterogeneous native interactions is strictly enough to efficiently self-tie. A distinctive feature of these native interactions is that they do not backtrack because their energies ensure the correct order of contact formation. Furthermore, they stabilize a knotted intermediate state, which is en route to the native structure. Our results thus show that-at least in the context of the adopted model-non-native interactions are not necessary to knot a protein. However, when they are taken into account in protein energetics, it is possible to find specific, nonlocal non-native interactions that operate as a scaffold that assists the knotting step.
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Affiliation(s)
- João N C Especial
- Departamento de Física, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal.,BioISI-Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal
| | - Patrícia F N Faísca
- Departamento de Física, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal.,BioISI-Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal
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18
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Municio C, Criado G. Therapies Targeting Trained Immune Cells in Inflammatory and Autoimmune Diseases. Front Immunol 2021; 11:631743. [PMID: 33569065 PMCID: PMC7868395 DOI: 10.3389/fimmu.2020.631743] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
The concept of trained immunity has recently emerged as a mechanism contributing to several immune mediated inflammatory conditions. Trained immunity is defined by the immunological memory developed in innate immune cells after a primary non-specific stimulus that, in turn, promotes a heightened inflammatory response upon a secondary challenge. The most characteristic changes associated to this process involve the rewiring of cell metabolism and epigenetic reprogramming. Under physiological conditions, the role of trained immune cells ensures a prompt response. This action is limited by effective resolution of inflammation and tissue repair in order to restore homeostasis. However, unrestrained activation of innate immune cells contributes to the development of chronic inflammation and tissue destruction through the secretion of inflammatory cytokines, proteases and growth factors. Therefore, interventions aimed at reversing the changes induced by trained immunity provide potential therapeutic approaches to treat inflammatory and autoimmune diseases like rheumatoid arthritis (RA). We review cellular approaches that target metabolism and the epigenetic reprogramming of dendritic cells, macrophages, natural killer cells, and other trained cells in the context of autoimmune inflammatory diseases.
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Affiliation(s)
- Cristina Municio
- Grupo de Enfermedades Inflamatorias y Autoinmunes, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Gabriel Criado
- Grupo de Enfermedades Inflamatorias y Autoinmunes, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
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19
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Terse VL, Gosavi S. The Molecular Mechanism of Domain Swapping of the C-Terminal Domain of the SARS-Coronavirus Main Protease. Biophys J 2020; 120:504-516. [PMID: 33359834 PMCID: PMC7837137 DOI: 10.1016/j.bpj.2020.11.2277] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/09/2020] [Accepted: 11/24/2020] [Indexed: 11/25/2022] Open
Abstract
In three-dimensional domain swapping, two protein monomers exchange a part of their structures to form an intertwined homodimer, whose subunits resemble the monomer. Several viral proteins domain swap to increase their structural complexity or functional avidity. The main protease (Mpro) of the severe acute respiratory syndrome (SARS) coronavirus proteolyzes viral polyproteins and has been a target for anti-SARS drug design. Domain swapping in the α-helical C-terminal domain of Mpro (MproC) locks Mpro into a hyperactive octameric form that is hypothesized to promote the early stages of viral replication. However, in the absence of a complete molecular understanding of the mechanism of domain swapping, investigations into the biological relevance of this octameric Mpro have stalled. Isolated MproC can exist as a monomer or a domain-swapped dimer. Here, we investigate the mechanism of domain swapping of MproC using coarse-grained structure-based models and molecular dynamics simulations. Our simulations recapitulate several experimental features of MproC folding. Further, we find that a contact between a tryptophan in the MproC domain-swapping hinge and an arginine elsewhere forms early during folding, modulates the folding route, and promotes domain swapping to the native structure. An examination of the sequence and the structure of the tryptophan containing hinge loop shows that it has a propensity to form multiple secondary structures and contacts, indicating that it could be stabilized into either the monomer- or dimer-promoting conformations by mutations or ligand binding. Finally, because all residues in the tryptophan loop are identical in SARS-CoV and SARS-CoV-2, mutations that modulate domain swapping may provide insights into the role of octameric Mpro in the early-stage viral replication of both viruses.
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Affiliation(s)
- Vishram L Terse
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
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20
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Simulations of Phage T7 Capsid Expansion Reveal the Role of Molecular Sterics on Dynamics. Viruses 2020; 12:v12111273. [PMID: 33171826 PMCID: PMC7695174 DOI: 10.3390/v12111273] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 12/30/2022] Open
Abstract
Molecular dynamics techniques provide numerous strategies for investigating biomolecular energetics, though quantitative analysis is often only accessible for relatively small (frequently monomeric) systems. To address this limit, we use simulations in combination with a simplified energetic model to study complex rearrangements in a large assembly. We use cryo-EM reconstructions to simulate the DNA packaging-associated 3 nm expansion of the protein shell of an initially assembled phage T7 capsid (called procapsid or capsid I). This is accompanied by a disorder-order transition and expansion-associated externalization displacement of the 420 N-terminal tails of the shell proteins. For the simulations, we use an all-atom structure-based model (1.07 million atoms), which is specifically designed to probe the influence of molecular sterics on dynamics. We find that the rate at which the N-terminal tails undergo translocation depends heavily on their position within hexons and pentons. Specifically, trans-shell displacements of the hexon E subunits are the most frequent and hexon A subunits are the least frequent. The simulations also implicate numerous tail translocation intermediates during tail translocation that involve topological traps, as well as sterically induced barriers. The presented study establishes a foundation for understanding the precise relationship between molecular structure and phage maturation.
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21
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Chu X, Suo Z, Wang J. Investigating the trade-off between folding and function in a multidomain Y-family DNA polymerase. eLife 2020; 9:60434. [PMID: 33079059 PMCID: PMC7641590 DOI: 10.7554/elife.60434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/16/2020] [Indexed: 01/01/2023] Open
Abstract
The way in which multidomain proteins fold has been a puzzling question for decades. Until now, the mechanisms and functions of domain interactions involved in multidomain protein folding have been obscure. Here, we develop structure-based models to investigate the folding and DNA-binding processes of the multidomain Y-family DNA polymerase IV (DPO4). We uncover shifts in the folding mechanism among ordered domain-wise folding, backtracking folding, and cooperative folding, modulated by interdomain interactions. These lead to ‘U-shaped’ DPO4 folding kinetics. We characterize the effects of interdomain flexibility on the promotion of DPO4–DNA (un)binding, which probably contributes to the ability of DPO4 to bypass DNA lesions, which is a known biological role of Y-family polymerases. We suggest that the native topology of DPO4 leads to a trade-off between fast, stable folding and tight functional DNA binding. Our approach provides an effective way to quantitatively correlate the roles of protein interactions in conformational dynamics at the multidomain level.
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Affiliation(s)
- Xiakun Chu
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
| | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, United States
| | - Jin Wang
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
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22
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Neelamraju S, Wales DJ, Gosavi S. Protein energy landscape exploration with structure-based models. Curr Opin Struct Biol 2020; 64:145-151. [DOI: 10.1016/j.sbi.2020.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/30/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022]
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23
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Piejko M, Niewieczerzal S, Sulkowska JI. The Folding of Knotted Proteins: Distinguishing the Distinct Behavior of Shallow and Deep Knots. Isr J Chem 2020. [DOI: 10.1002/ijch.202000036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Maciej Piejko
- Faculty of ChemistryUniversity of Warsaw Pasteura 1 Warsaw 02-093 Poland
- Centre of New TechnologiesUniversity of Warsaw Banacha 2c Warsaw 02-097 Poland
| | | | - Joanna I. Sulkowska
- Faculty of ChemistryUniversity of Warsaw Pasteura 1 Warsaw 02-093 Poland
- Centre of New TechnologiesUniversity of Warsaw Banacha 2c Warsaw 02-097 Poland
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24
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Chu X, Suo Z, Wang J. Confinement and Crowding Effects on Folding of a Multidomain Y-Family DNA Polymerase. J Chem Theory Comput 2020; 16:1319-1332. [PMID: 31972079 PMCID: PMC7258223 DOI: 10.1021/acs.jctc.9b01146] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Proteins in vivo endure highly various interactions from the luxuriant surrounding macromolecular cosolutes. Confinement and macromolecular crowding are the two major effects that should be considered while comparing the results of protein dynamics from in vitro to in vivo. However, efforts have been largely focused on single domain protein folding up to now, and the quantifications of the in vivo effects in terms of confinements and crowders on modulating the structure and dynamics as well as the physical understanding of the underlying mechanisms on multidomain protein folding are still challenging. Here we developed a topology-based model to investigate folding of a multidomain Y-family DNA polymerase (DPO4) within spherical confined space and in the presence of repulsive and attractive crowders. We uncovered that the entropic component of the thermodynamic driving force led by confinements and repulsive crowders increases the stability of folded states relative to the folding intermediates and unfolded states, while the enthalpic component of the thermodynamic driving force led by attractive crowders gives rise to the opposite effects with less stability. We found that the shapes of DPO4 conformations influenced by the confinements and the crowders are quite different even when only the entropic component of the thermodynamic driving force is considered. We uncovered that under all in vivo conditions, the folding cooperativity of DPO4 decreases compared to that in bulk. We showed that the loss of folding cooperativity can promote the sequential domain-wise folding, which was widely found in cotranslational multidomain protein folding, and effectively prohibit the backtracking led by topological frustrations during multidomain protein folding processes.
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Affiliation(s)
- Xiakun Chu
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794, United States
| | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, United States
| | - Jin Wang
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794, United States
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25
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Bigman LS, Levy Y. Proteins: molecules defined by their trade-offs. Curr Opin Struct Biol 2020; 60:50-56. [DOI: 10.1016/j.sbi.2019.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/07/2019] [Accepted: 11/11/2019] [Indexed: 12/30/2022]
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26
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Mouro PR, Povinelli APR, Leite VBP, Chahine J. Exploring Folding Aspects of Monomeric Superoxide Dismutase. J Phys Chem B 2020; 124:650-661. [DOI: 10.1021/acs.jpcb.9b09640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paulo R. Mouro
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto 15054-000, Brazil
| | - Ana P. R. Povinelli
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto 15054-000, Brazil
| | - Vitor B. P. Leite
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto 15054-000, Brazil
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Jorge Chahine
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto 15054-000, Brazil
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27
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Muttathukattil AN, Singh PC, Reddy G. Role of Disulfide Bonds and Topological Frustration in the Kinetic Partitioning of Lysozyme Folding Pathways. J Phys Chem B 2019; 123:3232-3241. [PMID: 30913878 DOI: 10.1021/acs.jpcb.9b00739] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Disulfide bonds in proteins can strongly influence the folding pathways by constraining the conformational space. Lysozyme has four disulfide bonds and is widely studied for its antibacterial properties. Experiments on lysozyme infer that the protein folds through a fast and a slow pathway. However, the reasons for the kinetic partitioning in the folding pathways are not completely clear. Using a coarse-grained protein model and simulations, we show that two out of the four disulfide bonds, which are present in the α-domain of lysozyme, are responsible for the slow folding pathway. In this pathway, a kinetically trapped intermediate state, which is close to the native state, is populated. In this state, the orientations of α-helices present in the α-domain are misaligned relative to each other. The protein in this state has to partially unfold by breaking down the interhelical contacts between the misaligned helices to fold to the native state. However, the topological constraints due to the two disulfide bonds present in the α-domain make the protein less flexible, and it is trapped in this conformation for hundreds of milliseconds. On disabling these disulfide bonds, we find that the kinetically trapped intermediate state and the slow folding pathway disappear. Simulations mimicking the folding of protein without disulfide bonds under oxidative conditions show that the native disulfide bonds are formed as the protein folds, indicating that folding guides the formation of disulfide bonds. The sequence of formation of the disulfide bonds is Cys64-Cys80 → Cys76-Cys94 → Cys30-Cys115 → Cys6-Cys127. Any disulfide bond that forms before its precursor in the sequence has to break and follow the sequence for the protein to fold. These results show that lysozyme also serves as a very good model system to probe the role of disulfide bonds and topological frustration in protein folding. The predictions from the simulations can be verified by single-molecule fluorescence resonance energy transfer or single-molecule pulling experiments, which can probe heterogeneity in the folding pathways.
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Affiliation(s)
- Aswathy N Muttathukattil
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bengaluru 560012 , Karnataka , India
| | - Prashant Chandra Singh
- School of Chemical Science , Indian Association for the Cultivation of Science , 2A & 2B, Raja S.C. Mullick Road , Jadavpur, Kolkata 700032 , India
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bengaluru 560012 , Karnataka , India
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28
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Neelamraju S, Gosavi S, Wales DJ. Energy Landscape of the Designed Protein Top7. J Phys Chem B 2018; 122:12282-12291. [DOI: 10.1021/acs.jpcb.8b08499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Sridhar Neelamraju
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
- University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - David J. Wales
- University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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29
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Terse VL, Gosavi S. The Sensitivity of Computational Protein Folding to Contact Map Perturbations: The Case of Ubiquitin Folding and Function. J Phys Chem B 2018; 122:11497-11507. [PMID: 30234303 DOI: 10.1021/acs.jpcb.8b07409] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ubiquitin is a small model protein, commonly used in protein folding experiments and simulations. We simulated ubiquitin using a well-tested structure-based model coarse-grained to a Cα level (Cα-SBM) and found that the simulated folding route did not agree with the experimentally observed one. Simulating the Cα-SBM with a cutoff contact map, instead of a screened contact map, switched the folding route with the new route matching the experimental route. Thus, the simulated folding of ubiquitin is sensitive to contact map definition. The screened contact map, which is used in folding simulations because it captures protein folding cooperativity, removes contacts in which the atoms in contact are occluded by a third atom and is less sensitive to the value of the cutoff distance in well-packed regions of the protein. In sparsely packed regions, the larger cutoff distance creates bridging contacts between atoms which are separated by voids. Such contacts do not seem to affect the folding of most proteins, including those of the ubiquitin fold. However, the surface of ubiquitin has several protruding functional side chains which naturally create bridging contacts. Together, our results show that subtle structural features of a protein that may not be apparent by mere observation can be identified by comparing folding simulations of SBMs in which these features are differently encoded. When such structural features are preserved for functional reasons, differences in computational folding can be leveraged to identify functional features. Notably, such features are accessible to a gradation of SBMs even in commonly studied proteins such as ubiquitin.
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Affiliation(s)
- Vishram L Terse
- Simons Centre for the Study of Living Machines , National Centre for Biological Sciences , Tata Institute of Fundamental Research, Bangalore 560065 , India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines , National Centre for Biological Sciences , Tata Institute of Fundamental Research, Bangalore 560065 , India
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Simulations Reveal Multiple Intermediates in the Unzipping Mechanism of Neuronal SNARE Complex. Biophys J 2018; 115:1470-1480. [PMID: 30268539 DOI: 10.1016/j.bpj.2018.08.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/26/2018] [Accepted: 08/16/2018] [Indexed: 11/22/2022] Open
Abstract
The assembling of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor protein complex is a fundamental step in neuronal exocytosis, and it has been extensively studied in the last two decades. Yet, many details of this process remain inaccessible with the current experimental space and time resolution. Here, we study the zipping mechanism of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex computationally by using a coarse-grained model. We explore the different pathways available and analyze their dependence on the computational model employed. We reveal and characterize multiple intermediate states, in agreement with previous experimental findings. We use our model to analyze the influence of single-residue mutations on the thermodynamics of the folding process.
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Abstract
Background Autoinflammatory diseases are distinct from autoimmune diseases. Whereas autoinflammatory diseases are due to dysfunctional T-cells and B-cells, autoinflammatory diseases are due to overproduction of macrophage cytokines particularly interleukin-1 beta (IL-1β). A causative role for IL-1 in autoinflammatory diseases is derived from clinical studies blocking the IL-1 receptor or neutralizing monoclonal antibodies or soluble receptors. Methods A review was performed of clinical trials in autoinflammatory diseases using the IL-1 receptor antagonist (anakinra), the soluble IL-1 receptor (rilonacept), antibodies to IL-1β (canakinumab, gevokizumab) and anti-IL-1α (xilonix). Findings Anakinra blocks the IL-1 Receptor type 1 (IL-1R1) and therefore blocks the activities of both IL-1α and IL-1β. Off-label use of anakinra is common for a broad spectrum of inflammatory diseases. Neutralization of IL-1β is used to treat hereditary autoinflammatory diseases but also atherosclerosis. Rilonacept reduces arterial wall inflammation in patients with chronic kidney disease. Neutralization of IL-1α has prolonged life in patients with advanced metastatic colorectal cancer. Compared to other cytokine blocking therapies, reducing the activities of IL-1 has an excellent safety record. Conclusions Blocking IL-1 therapies can be used to treat a wide-spectrum of acute and chronic inflammatory diseases.
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32
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Baweja L, Roche J. Pushing the Limits of Structure-Based Models: Prediction of Nonglobular Protein Folding and Fibrils Formation with Go-Model Simulations. J Phys Chem B 2018; 122:2525-2535. [DOI: 10.1021/acs.jpcb.7b12129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lokesh Baweja
- Department of Biochemistry, Molecular Biology and Biophysics, Iowa State University, Ames, Iowa 50011, United States
| | - Julien Roche
- Department of Biochemistry, Molecular Biology and Biophysics, Iowa State University, Ames, Iowa 50011, United States
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33
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Ren W, Li W, Wang J, Zhang J, Wang W. Consequences of Energetic Frustration on the Ligand-Coupled Folding/Dimerization Dynamics of Allosteric Protein S100A12. J Phys Chem B 2017; 121:9799-9806. [DOI: 10.1021/acs.jpcb.7b06919] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Weitong Ren
- National
Laboratory of Solid State Microstructure, Department of Physics, and
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wenfei Li
- National
Laboratory of Solid State Microstructure, Department of Physics, and
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jun Wang
- National
Laboratory of Solid State Microstructure, Department of Physics, and
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jian Zhang
- National
Laboratory of Solid State Microstructure, Department of Physics, and
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wei Wang
- National
Laboratory of Solid State Microstructure, Department of Physics, and
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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34
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Mouro PR, de Godoi Contessoto V, Chahine J, Junio de Oliveira R, Pereira Leite VB. Quantifying Nonnative Interactions in the Protein-Folding Free-Energy Landscape. Biophys J 2017; 111:287-293. [PMID: 27463131 DOI: 10.1016/j.bpj.2016.05.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 05/10/2016] [Accepted: 05/17/2016] [Indexed: 11/27/2022] Open
Abstract
Protein folding is a central problem in biological physics. Energetic roughness is an important aspect that controls protein-folding stability and kinetics. The roughness is associated with conflicting interactions in the protein and is also known as frustration. Recent studies indicate that an addition of a small amount of energetic frustration may enhance folding speed for certain proteins. In this study, we have investigated the conditions under which frustration increases the folding rate. We used a Cα structure-based model to simulate a group of proteins. We found that the free-energy barrier at the transition state (ΔF) correlates with nonnative-contact variation (ΔA), and the simulated proteins are clustered according to their fold motifs. These findings are corroborated by the Clementi-Plotkin analytical model. As a consequence, the optimum frustration regime for protein folding can be predicted analytically.
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Affiliation(s)
- Paulo Ricardo Mouro
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, São Paulo, Brazil
| | - Vinícius de Godoi Contessoto
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, São Paulo, Brazil
| | - Jorge Chahine
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, São Paulo, Brazil
| | - Ronaldo Junio de Oliveira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Vitor Barbanti Pereira Leite
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista, São José do Rio Preto, São Paulo, Brazil.
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35
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Niewieczerzal S, Sulkowska JI. Knotting and unknotting proteins in the chaperonin cage: Effects of the excluded volume. PLoS One 2017; 12:e0176744. [PMID: 28489858 PMCID: PMC5425179 DOI: 10.1371/journal.pone.0176744] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/14/2017] [Indexed: 11/18/2022] Open
Abstract
Molecular dynamics simulations are used to explore the effects of chaperonin-like cages on knotted proteins with very low sequence similarity, different depths of a knot but with a similar fold, and the same type of topology. The investigated proteins are VirC2, DndE and MJ0366 with two depths of a knot. A comprehensive picture how encapsulation influences folding rates is provided based on the analysis of different cage sizes and temperature conditions. Neither of these two effects with regard to knotted proteins has been studied by means of molecular dynamics simulations with coarse-grained structure-based models before. We show that encapsulation in a chaperonin is sufficient to self-tie and untie small knotted proteins (VirC2, DndE), for which the equilibrium process is not accessible in the bulk solvent. Furthermore, we find that encapsulation reduces backtracking that arises from the destabilisation of nucleation sites, smoothing the free energy landscape. However, this effect can also be coupled with temperature rise. Encapsulation facilitates knotting at the early stage of folding and can enhance an alternative folding route. Comparison to unknotted proteins with the same fold shows directly how encapsulation influences the free energy landscape. In addition, we find that as the size of the cage decreases, folding times increase almost exponentially in a certain range of cage sizes, in accordance with confinement theory and experimental data for unknotted proteins.
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Affiliation(s)
- Szymon Niewieczerzal
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Joanna I. Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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36
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Makhatadze GI. Linking computation and experiments to study the role of charge-charge interactions in protein folding and stability. Phys Biol 2017; 14:013002. [PMID: 28169222 DOI: 10.1088/1478-3975/14/1/013002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Over the past two decades there has been an increase in appreciation for the role of surface charge-charge interactions in protein folding and stability. The perception shifted from the belief that charge-charge interactions are not important for protein folding and stability to the near quantitative understanding of how these interactions shape the folding energy landscape. This led to the ability of computational approaches to rationally redesign surface charge-charge interactions to modulate thermodynamic properties of proteins. Here we summarize our progress in understanding the role of charge-charge interactions for protein stability using examples drawn from my own laboratory and touch upon unanswered questions.
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Affiliation(s)
- George I Makhatadze
- Center for Biotechnology and Interdisciplinary Studies, and Department of Biological Sciences, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 USA
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37
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Haglund E, Pilko A, Wollman R, Jennings PA, Onuchic JN. Pierced Lasso Topology Controls Function in Leptin. J Phys Chem B 2017; 121:706-718. [PMID: 28035835 DOI: 10.1021/acs.jpcb.6b11506] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein engineering is a powerful tool in drug design and therapeutics, where disulphide bridges are commonly introduced to stabilize proteins. However, these bonds also introduce covalent loops, which are often neglected. These loops may entrap the protein backbone on opposite sides, leading to a "knotted" topology, forming a so-called Pierced Lasso (PL). In this elegant system, the "knot" is held together with a single disulphide bridge where part of the polypeptide chain is threaded through. The size and position of these covalent loops can be manipulated through protein design in vitro, whereas nature uses polymorphism to switch the PL topology. The PL protein leptin shows genetic modification of an N-terminal residue, adding a third cysteine to the same sequence. In an effort to understand the mechanism of threading of these diverse topologies, we designed three loop variants to mimic the polymorphic sequence. This adds elegance to the system under study, as it allows the generation of three possible covalent loops; they are the original wild-type C-terminal loop protein, the fully circularized unthreaded protein, and the N-terminal loop protein, responsible for different lasso topologies. The size of the loop changes the threading mechanism from a slipknotting to a plugging mechanism, with increasing loop size. Interestingly, the ground state of the native protein structure is largely unaffected, but biological assays show that the activity is maximized by properly controlled dynamics in the threaded state. A threaded topology with proper conformational dynamics is important for receptor interaction and activation of the signaling pathways in vivo.
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Affiliation(s)
- Ellinor Haglund
- Center for Theoretical Biological Physics (CTBP) and Departments of Physics and Astronomy, Chemistry and Biosciences, Rice University , Houston, Texas, United States
| | - Anna Pilko
- Department of Chemistry and Biochemistry, The University of California, San Diego (UCSD) , La Jolla, California, United States
| | - Roy Wollman
- Department of Chemistry and Biochemistry, The University of California, San Diego (UCSD) , La Jolla, California, United States
| | - Patricia Ann Jennings
- Department of Chemistry and Biochemistry, The University of California, San Diego (UCSD) , La Jolla, California, United States
| | - José Nelson Onuchic
- Center for Theoretical Biological Physics (CTBP) and Departments of Physics and Astronomy, Chemistry and Biosciences, Rice University , Houston, Texas, United States
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38
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Seki K, Bagchi K, Bagchi B. Anomalous dimensionality dependence of diffusion in a rugged energy landscape: How pathological is one dimension? J Chem Phys 2016; 144:194106. [PMID: 27208935 DOI: 10.1063/1.4948936] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Diffusion in one dimensional rugged energy landscape (REL) is predicted to be pathologically different (from any higher dimension) with a much larger chance of encountering broken ergodicity [D. L. Stein and C. M. Newman, AIP Conf. Proc. 1479, 620 (2012)]. However, no quantitative study of this difference has been reported, despite the prevalence of multidimensional physical models in the literature (like a high dimensional funnel guiding protein folding/unfolding). Paradoxically, some theoretical studies of these phenomena still employ a one dimensional diffusion description for analytical tractability. We explore the dimensionality dependent diffusion on REL by carrying out an effective medium approximation based analytical calculations and compare them with the available computer simulation results. We find that at an intermediate level of ruggedness (assumed to have a Gaussian distribution), where diffusion is well-defined, the value of the effective diffusion coefficient depends on dimensionality and changes (increases) by several factors (∼5-10) in going from 1d to 2d. In contrast, the changes in subsequent transitions (like 2d to 3d and 3d to 4d and so on) are far more modest, of the order of 10-20% only. When ruggedness is given by random traps with an exponential distribution of barrier heights, the mean square displacement (MSD) is sub-diffusive (a well-known result), but the growth of MSD is described by different exponents in one and higher dimensions. The reason for such strong ruggedness induced retardation in the case of one dimensional REL is discussed. We also discuss the special limiting case of infinite dimension (d = ∞) where the effective medium approximation becomes exact and where theoretical results become simple. We discuss, for the first time, the role of spatial correlation in the landscape on diffusion of a random walker.
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Affiliation(s)
- Kazuhiko Seki
- Nanomaterials Research Institute (NMRI), National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba 305-8565, Japan
| | - Kaushik Bagchi
- Department of Mathematics, Ohio State University, Columbus, Ohio 43201, USA and Chitrakut Annexe, 4th Main Road, Malleswaram, Bangalore 560012, India
| | - Biman Bagchi
- Institute of Molecular Science, Okazaki, Aichi 444, Japan and Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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39
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Faraj SE, González-Lebrero RM, Roman EA, Santos J. Human Frataxin Folds Via an Intermediate State. Role of the C-Terminal Region. Sci Rep 2016; 6:20782. [PMID: 26856628 PMCID: PMC4746760 DOI: 10.1038/srep20782] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/12/2016] [Indexed: 11/30/2022] Open
Abstract
The aim of this study is to investigate the folding reaction of human frataxin, whose deficiency causes the neurodegenerative disease Friedreich's Ataxia (FRDA). The characterization of different conformational states would provide knowledge about how frataxin can be stabilized without altering its functionality. Wild-type human frataxin and a set of mutants, including two highly destabilized FRDA-associated variants were studied by urea-induced folding/unfolding in a rapid mixing device and followed by circular dichroism. The analysis clearly indicates the existence of an intermediate state (I) in the folding route with significant secondary structure content but relatively low compactness, compared with the native ensemble. However, at high NaCl concentrations I-state gains substantial compaction, and the unfolding barrier is strongly affected, revealing the importance of electrostatics in the folding mechanism. The role of the C-terminal region (CTR), the key determinant of frataxin stability, was also studied. Simulations consistently with experiments revealed that this stretch is essentially unstructured, in the most compact transition state ensemble (TSE2). The complete truncation of the CTR drastically destabilizes the native state without altering TSE2. Results presented here shed light on the folding mechanism of frataxin, opening the possibility of mutating it to generate hyperstable variants without altering their folding kinetics.
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Affiliation(s)
- Santiago E. Faraj
- Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Junín 956, 1113AAD, Buenos Aires, Argentina
| | - Rodolfo M. González-Lebrero
- Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Junín 956, 1113AAD, Buenos Aires, Argentina
| | - Ernesto A. Roman
- Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Junín 956, 1113AAD, Buenos Aires, Argentina
| | - Javier Santos
- Instituto de Química y Físico-Química Biológicas, Universidad de Buenos Aires, Junín 956, 1113AAD, Buenos Aires, Argentina
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40
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Using the folding landscapes of proteins to understand protein function. Curr Opin Struct Biol 2016; 36:67-74. [PMID: 26812092 DOI: 10.1016/j.sbi.2016.01.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/31/2015] [Accepted: 01/06/2016] [Indexed: 11/20/2022]
Abstract
Proteins fold on a biologically-relevant timescale because of a funnel-shaped energy landscape. This landscape is sculpted through evolution by selecting amino-acid sequences that stabilize native interactions while suppressing stable non-native interactions that occur during folding. However, there is strong evolutionary selection for functional residues and these cannot be chosen to optimize folding. Their presence impacts the folding energy landscape in a variety of ways. Here, we survey the effects of functional residues on folding by providing several examples. We then review how such effects can be detected computationally and be used as assays for protein function. Overall, an understanding of how functional residues modulate folding should provide insights into the design of natural proteins and their homeostasis.
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41
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Baruah A, Biswas P. Globular–disorder transition in proteins: a compromise between hydrophobic and electrostatic interactions? Phys Chem Chem Phys 2016; 18:23207-14. [DOI: 10.1039/c6cp03185d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protein disorder, like protein folding, satisfies the principle of minimal frustration.
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42
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Xia X, Longo LM, Sutherland MA, Blaber M. Evolution of a protein folding nucleus. Protein Sci 2015; 25:1227-40. [PMID: 26610273 DOI: 10.1002/pro.2848] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/10/2015] [Indexed: 12/22/2022]
Abstract
The folding nucleus (FN) is a cryptic element within protein primary structure that enables an efficient folding pathway and is the postulated heritable element in the evolution of protein architecture; however, almost nothing is known regarding how the FN structurally changes as complex protein architecture evolves from simpler peptide motifs. We report characterization of the FN of a designed purely symmetric β-trefoil protein by ϕ-value analysis. We compare the structure and folding properties of key foldable intermediates along the evolutionary trajectory of the β-trefoil. The results show structural acquisition of the FN during gene fusion events, incorporating novel turn structure created by gene fusion. Furthermore, the FN is adjusted by circular permutation in response to destabilizing functional mutation. FN plasticity by way of circular permutation is made possible by the intrinsic C3 cyclic symmetry of the β-trefoil architecture, identifying a possible selective advantage that helps explain the prevalence of cyclic structural symmetry in the proteome.
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Affiliation(s)
- Xue Xia
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, 32306-4300
| | - Liam M Longo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, 32306-4300.,Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Mason A Sutherland
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, 32306-4300
| | - Michael Blaber
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, 32306-4300
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43
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Designed protein reveals structural determinants of extreme kinetic stability. Proc Natl Acad Sci U S A 2015; 112:14605-10. [PMID: 26554002 DOI: 10.1073/pnas.1510748112] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The design of stable, functional proteins is difficult. Improved design requires a deeper knowledge of the molecular basis for design outcomes and properties. We previously used a bioinformatics and energy function method to design a symmetric superfold protein composed of repeating structural elements with multivalent carbohydrate-binding function, called ThreeFoil. This and similar methods have produced a notably high yield of stable proteins. Using a battery of experimental and computational analyses we show that despite its small size and lack of disulfide bonds, ThreeFoil has remarkably high kinetic stability and its folding is specifically chaperoned by carbohydrate binding. It is also extremely stable against thermal and chemical denaturation and proteolytic degradation. We demonstrate that the kinetic stability can be predicted and modeled using absolute contact order (ACO) and long-range order (LRO), as well as coarse-grained simulations; the stability arises from a topology that includes many long-range contacts which create a large and highly cooperative energy barrier for unfolding and folding. Extensive data from proteomic screens and other experiments reveal that a high ACO/LRO is a general feature of proteins with strong resistances to denaturation and degradation. These results provide tractable approaches for predicting resistance and designing proteins with sufficient topological complexity and long-range interactions to accommodate destabilizing functional features as well as withstand chemical and proteolytic challenge.
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44
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MD Simulations of tRNA and Aminoacyl-tRNA Synthetases: Dynamics, Folding, Binding, and Allostery. Int J Mol Sci 2015; 16:15872-902. [PMID: 26184179 PMCID: PMC4519929 DOI: 10.3390/ijms160715872] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 07/07/2015] [Accepted: 07/08/2015] [Indexed: 12/21/2022] Open
Abstract
While tRNA and aminoacyl-tRNA synthetases are classes of biomolecules that have been extensively studied for decades, the finer details of how they carry out their fundamental biological functions in protein synthesis remain a challenge. Recent molecular dynamics (MD) simulations are verifying experimental observations and providing new insight that cannot be addressed from experiments alone. Throughout the review, we briefly discuss important historical events to provide a context for how far the field has progressed over the past few decades. We then review the background of tRNA molecules, aminoacyl-tRNA synthetases, and current state of the art MD simulation techniques for those who may be unfamiliar with any of those fields. Recent MD simulations of tRNA dynamics and folding and of aminoacyl-tRNA synthetase dynamics and mechanistic characterizations are discussed. We highlight the recent successes and discuss how important questions can be addressed using current MD simulations techniques. We also outline several natural next steps for computational studies of AARS:tRNA complexes.
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45
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Giri Rao VVH, Gosavi S. Structural Perturbations Present in the Folding Cores of Interleukin-33 and Interleukin-1β Correlate to Differences in Their Function. J Phys Chem B 2015; 119:11203-14. [DOI: 10.1021/acs.jpcb.5b03111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- V. V. Hemanth Giri Rao
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Shachi Gosavi
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
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46
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Chen T, Chan HS. Native contact density and nonnative hydrophobic effects in the folding of bacterial immunity proteins. PLoS Comput Biol 2015; 11:e1004260. [PMID: 26016652 PMCID: PMC4446218 DOI: 10.1371/journal.pcbi.1004260] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 03/29/2015] [Indexed: 11/18/2022] Open
Abstract
The bacterial colicin-immunity proteins Im7 and Im9 fold by different mechanisms. Experimentally, at pH 7.0 and 10°C, Im7 folds in a three-state manner via an intermediate but Im9 folding is two-state-like. Accordingly, Im7 exhibits a chevron rollover, whereas the chevron arm for Im9 folding is linear. Here we address the biophysical basis of their different behaviors by using native-centric models with and without additional transferrable, sequence-dependent energies. The Im7 chevron rollover is not captured by either a pure native-centric model or a model augmented by nonnative hydrophobic interactions with a uniform strength irrespective of residue type. By contrast, a more realistic nonnative interaction scheme that accounts for the difference in hydrophobicity among residues leads simultaneously to a chevron rollover for Im7 and an essentially linear folding chevron arm for Im9. Hydrophobic residues identified by published experiments to be involved in nonnative interactions during Im7 folding are found to participate in the strongest nonnative contacts in this model. Thus our observations support the experimental perspective that the Im7 folding intermediate is largely underpinned by nonnative interactions involving large hydrophobics. Our simulation suggests further that nonnative effects in Im7 are facilitated by a lower local native contact density relative to that of Im9. In a one-dimensional diffusion picture of Im7 folding with a coordinate- and stability-dependent diffusion coefficient, a significant chevron rollover is consistent with a diffusion coefficient that depends strongly on native stability at the conformational position of the folding intermediate. In order to fold correctly, a globular protein must avoid being trapped in wrong, i.e., nonnative conformations. Thus a biophysical account of how attractive nonnative interactions are bypassed by some amino acid sequences but not others is key to deciphering protein structure and function. We examine two closely related bacterial immunity proteins, Im7 and Im9, that are experimentally known to fold very differently: Whereas Im9 folds directly, Im7 folds through a mispacked conformational intermediate. A simple model we developed accounts for their intriguingly different folding kinetics in terms of a balance between the density of native-promoting contacts and the hydrophobicity of local amino acid sequences. This emergent principle is extensible to other biomolecular recognition processes.
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Affiliation(s)
- Tao Chen
- Departments of Biochemistry, of Molecular Genetics, and of Physics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Hue Sun Chan
- Departments of Biochemistry, of Molecular Genetics, and of Physics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- * E-mail:
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47
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Vazquez DS, Sánchez IE, Garrote A, Sica MP, Santos J. The E. coli thioredoxin folding mechanism: The key role of the C-terminal helix. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:127-37. [DOI: 10.1016/j.bbapap.2014.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 10/23/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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48
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Tripathi S, Wang Q, Zhang P, Hoffman L, Waxham MN, Cheung MS. Conformational frustration in calmodulin-target recognition. J Mol Recognit 2015; 28:74-86. [PMID: 25622562 DOI: 10.1002/jmr.2413] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 11/10/2022]
Abstract
Calmodulin (CaM) is a primary calcium (Ca(2+) )-signaling protein that specifically recognizes and activates highly diverse target proteins. We explored the molecular basis of target recognition of CaM with peptides representing the CaM-binding domains from two Ca(2+) -CaM-dependent kinases, CaMKI and CaMKII, by employing experimentally constrained molecular simulations. Detailed binding route analysis revealed that the two CaM target peptides, although similar in length and net charge, follow distinct routes that lead to a higher binding frustration in the CaM-CaMKII complex than in the CaM-CaMKI complex. We discovered that the molecular origin of the binding frustration is caused by intermolecular contacts formed with the C-domain of CaM that need to be broken before the formation of intermolecular contacts with the N-domain of CaM. We argue that the binding frustration is important for determining the kinetics of the recognition process of proteins involving large structural fluctuations.
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Affiliation(s)
- Swarnendu Tripathi
- Department of Physics, University of Houston, Houston, TX, 77204, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX, 77005, USA
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Modulation of folding energy landscape by charge-charge interactions: linking experiments with computational modeling. Proc Natl Acad Sci U S A 2015; 112:E259-66. [PMID: 25564663 DOI: 10.1073/pnas.1410424112] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The kinetics of folding-unfolding of a structurally diverse set of four proteins optimized for thermodynamic stability by rational redesign of surface charge-charge interactions is characterized experimentally. The folding rates are faster for designed variants compared with their wild-type proteins, whereas the unfolding rates are largely unaffected. A simple structure-based computational model, which incorporates the Debye-Hückel formalism for the electrostatics, was used and found to qualitatively recapitulate the experimental results. Analysis of the energy landscapes of the designed versus wild-type proteins indicates the differences in refolding rates may be correlated with the degree of frustration of their respective energy landscapes. Our simulations indicate that naturally occurring wild-type proteins have frustrated folding landscapes due to the surface electrostatics. Optimization of the surface electrostatics seems to remove some of that frustration, leading to enhanced formation of native-like contacts in the transition-state ensembles (TSE) and providing a less frustrated energy landscape between the unfolded and TS ensembles. Macroscopically, this results in faster folding rates. Furthermore, analyses of pairwise distances and radii of gyration suggest that the less frustrated energy landscapes for optimized variants are a result of more compact unfolded and TS ensembles. These findings from our modeling demonstrates that this simple model may be used to: (i) gain a detailed understanding of charge-charge interactions and their effects on modulating the energy landscape of protein folding and (ii) qualitatively predict the kinetic behavior of protein surface electrostatic interactions.
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50
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Whitford PC, Onuchic JN. What protein folding teaches us about biological function and molecular machines. Curr Opin Struct Biol 2015; 30:57-62. [PMID: 25559307 DOI: 10.1016/j.sbi.2014.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 01/15/2023]
Abstract
Protein folding was the first area of molecular biology for which a systematic statistical-mechanical analysis of dynamics was developed. As a result, folding is described as a process by which a disordered protein chain diffuses across a high-dimensional energy landscape and finally reaches the folded ensemble. Folding studies have produced countless theoretical concepts that are generalizable to other biomolecular processes, such as the functional dynamics of molecular assemblies. Common themes in folding and function include the dominant role of excluded volume, that a balance between energetic roughness and geometrical effects guides dynamics, and that folding/functional landscapes are relatively smooth. Here, we discuss how insights into protein folding have been applied to investigate the functional dynamics of biomolecular assemblies.
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Affiliation(s)
- Paul C Whitford
- Department of Physics, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, United States.
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77251, United States.
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