1
|
Al Masri C, Wan B, Yu J. Nonspecific vs. specific DNA binding free energetics of a transcription factor domain protein. Biophys J 2023; 122:4476-4487. [PMID: 37897044 PMCID: PMC10722393 DOI: 10.1016/j.bpj.2023.10.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 07/06/2023] [Accepted: 10/20/2023] [Indexed: 10/29/2023] Open
Abstract
Transcription factor (TF) proteins regulate gene expression by binding to specific sites on the genome. In the facilitated diffusion model, an optimized search process is achieved by the TF alternating between 3D diffusion in the bulk and 1D diffusion along DNA. While undergoing 1D diffusion, the protein can switch from a search mode for fast diffusion along nonspecific DNA to a recognition mode for stable binding to specific DNA. It was recently noticed that, for a small TF domain protein, reorientations on DNA happen between the nonspecific and specific DNA binding. We here conducted all-atom molecular dynamics simulations with steering forces to reveal the protein-DNA binding free energetics, confirming that the search and recognition modes are distinguished primarily by protein orientations on the DNA. As the binding free energy difference between the specific and nonspecific DNA system slightly deviates from that being estimated directly from dissociation constants on 15-bp DNA constructs, we hypothesize that the discrepancy can come from DNA sequences flanking the 6-bp central binding sites that impact on the dissociation kinetics measurements. The hypothesis is supported by a simplified spherical protein-DNA model along with stochastic simulations and kinetic modeling.
Collapse
Affiliation(s)
- Carmen Al Masri
- Department of Physics and Astronomy, University of California, Irvine, California
| | - Biao Wan
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China
| | - Jin Yu
- Department of Physics and Astronomy, University of California, Irvine, California; Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, California.
| |
Collapse
|
2
|
Hazra M, Levy Y. Cross-Talk of Cation-π Interactions with Electrostatic and Aromatic Interactions: A Salt-Dependent Trade-off in Biomolecular Condensates. J Phys Chem Lett 2023; 14:8460-8469. [PMID: 37721444 PMCID: PMC10544028 DOI: 10.1021/acs.jpclett.3c01642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Biomolecular condensates are essential for cellular functionality, yet the complex interplay among the diverse molecular interactions that mediate their formation remains poorly understood. Here, using coarse-grained molecular dynamics simulations, we address the contribution of cation-π interactions to the stability of condensates formed via liquid-liquid phase separation. We found greater stabilization of up to 80% via cation-π interactions in condensates formed from peptides with higher aromatic residue content or less charge clustering. The contribution of cation-π interactions to droplet stability increases with increasing ionic strength, suggesting a trade-off between cation-π and electrostatic interactions. Cation-π interactions, therefore, can compensate for reduced electrostatic interactions, such as occurs at higher salt concentrations and in sequences with less charged residue content or clustering. Designing condensates with desired biophysical characteristics therefore requires quantification not only of the individual interactions but also cross-talks involving charge-charge, π-π, and cation-π interactions.
Collapse
Affiliation(s)
- Milan
Kumar Hazra
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
| |
Collapse
|
3
|
Hazra MK, Gilron Y, Levy Y. Not Only Expansion: Proline Content and Density Also Induce Disordered Protein Conformation Compaction. J Mol Biol 2023; 435:168196. [PMID: 37442414 DOI: 10.1016/j.jmb.2023.168196] [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: 03/25/2023] [Revised: 06/28/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023]
Abstract
Intrinsically disordered proteins (IDPs) adopt a wide array of different conformations that can be constrained by the presence of proline residues, which are frequently found in IDPs. To assess the effects of proline, we designed a series of peptides that differ with respect to the number of prolines in the sequence and their organization. Using high-resolution atomistic molecular dynamics simulations, we found that accounting for whether the proline residues are clustered or isolated contributed significantly to explaining deviations in the experimentally-determined gyration radii of IDPs from the values expected based on the Flory scaling-law. By contrast, total proline content makes smaller contribution to explaining the effect of prolines on IDP conformation. Proline residues exhibit opposing effects depending on their organizational pattern in the IDP sequence. Clustered prolines (i.e., prolines with ≤2 intervening non-proline residues) result in expanded peptide conformations whereas isolated prolines (i.e., prolines with >2 intervening non-proline residues) impose compacted conformations. Clustered prolines were estimated to induce an expansion of ∼20% in IDP dimension (via formation of PPII structural elements) whereas isolated prolines were estimated to induce a compaction of ∼10% in IDP dimension (via the formation of backbone turns). This dual role of prolines provides a mechanism for conformational switching that does not rely on the kinetically much slower isomerization of cis proline to the trans form. Bioinformatic analysis demonstrates high populations of both isolated and clustered prolines and implementing them in coarse-grained molecular dynamics models illustrates that they improve the characterization of the conformational ensembles of IDPs.
Collapse
Affiliation(s)
- Milan Kumar Hazra
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yishai Gilron
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
4
|
Wang X, Bigman LS, Greenblatt HM, Yu B, Levy Y, Iwahara J. Negatively charged, intrinsically disordered regions can accelerate target search by DNA-binding proteins. Nucleic Acids Res 2023; 51:4701-4712. [PMID: 36774964 PMCID: PMC10250230 DOI: 10.1093/nar/gkad045] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/03/2023] [Accepted: 01/17/2023] [Indexed: 02/14/2023] Open
Abstract
In eukaryotes, many DNA/RNA-binding proteins possess intrinsically disordered regions (IDRs) with large negative charge, some of which involve a consecutive sequence of aspartate (D) or glutamate (E) residues. We refer to them as D/E repeats. The functional role of D/E repeats is not well understood, though some of them are known to cause autoinhibition through intramolecular electrostatic interaction with functional domains. In this work, we investigated the impacts of D/E repeats on the target DNA search kinetics for the high-mobility group box 1 (HMGB1) protein and the artificial protein constructs of the Antp homeodomain fused with D/E repeats of varied lengths. Our experimental data showed that D/E repeats of particular lengths can accelerate the target association in the overwhelming presence of non-functional high-affinity ligands ('decoys'). Our coarse-grained molecular dynamics (CGMD) simulations showed that the autoinhibited proteins can bind to DNA and transition into the uninhibited complex with DNA through an electrostatically driven induced-fit process. In conjunction with the CGMD simulations, our kinetic model can explain how D/E repeats can accelerate the target association process in the presence of decoys. This study illuminates an unprecedented role of the negatively charged IDRs in the target search process.
Collapse
Affiliation(s)
- Xi Wang
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| | - Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Binhan Yu
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Junji Iwahara
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| |
Collapse
|
5
|
Lüking M, Elf J, Levy Y. Conformational Change of Transcription Factors from Search to Specific Binding: A lac Repressor Case Study. J Phys Chem B 2022; 126:9971-9984. [PMID: 36416228 PMCID: PMC9743208 DOI: 10.1021/acs.jpcb.2c05006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In a process known as facilitated diffusion, DNA-binding proteins find their target sites by combining three-dimensional diffusion and one-dimensional scanning of the DNA. Following the trade-off between speed and stability, agile exploration of DNA requires loose binding, whereas, at the DNA target site, the searching protein needs to establish tight interactions with the DNA. To enable both efficient search and stable binding, DNA-binding proteins and DNA often switch conformations upon recognition. Here, we study the one-dimensional diffusion and DNA binding of the dimeric lac repressor (LacI), which was reported to adopt two different conformations when binding different conformations of DNA. Using coarse-grained molecular dynamic simulations, we studied the diffusion and the sequence-specific binding of these conformations of LacI, as well as their truncated or monomeric variants, with two DNA conformations: straight and bent. The simulations were compared to experimental observables. This study supports that linear diffusion along DNA combines tight rotation-coupled groove tracking and rotation-decoupled hopping, where the protein briefly dissociates and reassociates just a few base pairs away. Tight groove tracking is crucial for target-site recognition, while hopping speeds up the overall search process. We investigated the diffusion of different LacI conformations on DNA and show how the flexibility of LacI's hinge regions ensures agility on DNA as well as faithful groove tracking. If the hinge regions instead form α-helices at the protein-DNA interface, tight groove tracking is not possible. On the contrary, the helical hinge region is essential for tight binding to bent, specific DNA, for the formation of the specific complex. Based on our study of different encounter complexes, we argue that the conformational change in LacI and DNA bending are somewhat coupled. Our findings underline the importance of two distinct protein conformations for facilitated diffusion and specific binding, respectively.
Collapse
Affiliation(s)
- Malin Lüking
- Department
of Cell- and Molecular Biology-ICM, Uppsala
University, Uppsala, Uppsala County751 24, Sweden
| | - Johan Elf
- Department
of Cell- and Molecular Biology-ICM, Uppsala
University, Uppsala, Uppsala County751 24, Sweden
| | - Yaakov Levy
- Department
of Chemical and Structural Biology, Weizmann
Institute of Science, Rehovot, Central District76100, Israel,. Tel.: 972-8-9344587
| |
Collapse
|
6
|
Mondal A, Bhattacherjee A. Understanding protein diffusion on force-induced stretched DNA conformation. Front Mol Biosci 2022; 9:953689. [PMID: 36545509 PMCID: PMC9760818 DOI: 10.3389/fmolb.2022.953689] [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: 05/26/2022] [Accepted: 11/22/2022] [Indexed: 12/11/2022] Open
Abstract
DNA morphology is subjected to environmental conditions and is closely coupled with its function. For example, DNA experiences stretching forces during several biological processes, including transcription and genome transactions, that significantly alter its conformation from that of B-DNA. Indeed, a well-defined 1.5 times extended conformation of dsDNA, known as Σ-DNA, has been reported in DNA complexes with proteins such as Rad51 and RecA. A striking feature in Σ-DNA is that the nucleobases are partitioned into triplets of three locally stacked bases separated by an empty rise gap of ∼ 5 Å. The functional role of such a DNA base triplet was hypothesized to be coupled with the ease of recognition of DNA bases by DNA-binding proteins (DBPs) and the physical origin of three letters (codon/anti-codon) in the genetic code. However, the underlying mechanism of base-triplet formation and the ease of DNA base-pair recognition by DBPs remain elusive. To investigate, here, we study the diffusion of a protein on a force-induced stretched DNA using coarse-grained molecular dynamics simulations. Upon pulling at the 3' end of DNA by constant forces, DNA exhibits a conformational transition from B-DNA to a ladder-like S-DNA conformation via Σ-DNA intermediate. The resulting stretched DNA conformations exhibit non-uniform base-pair clusters such as doublets, triplets, and quadruplets, of which triplets are energetically more stable than others. We find that protein favors the triplet formation compared to its unbound form while interacting non-specifically along DNA, and the relative population of it governs the ruggedness of the protein-DNA binding energy landscape and enhances the efficiency of DNA base recognition. Furthermore, we analyze the translocation mechanism of a DBP under different force regimes and underscore the significance of triplet formation in regulating the facilitated diffusion of protein on DNA. Our study, thus, provides a plausible framework for understanding the structure-function relationship between triplet formation and base recognition by a DBP and helps to understand gene regulation in complex regulatory processes.
Collapse
|
7
|
Zhao W, Du H, Xia Y, Xie S, Huang YP, Xu T, Zhang J, Gao YQ, Wan X. Accelerating supramolecular aggregation by molecular sliding. Phys Chem Chem Phys 2022; 24:23840-23848. [PMID: 36165176 DOI: 10.1039/d2cp04064f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diffusion-based translocation along DNA or RNA molecules is essential for genome regulatory proteins to execute their biological functions. The reduced dimensionality of the searching process makes the proteins bind specific target sites at a "faster-than-diffusion-controlled rate". We herein report a photoresponsive slider-track diffusion system capable of self-assembly rate acceleration, which consists of (-)-camphorsulfonic acid, 4-(4'-n-octoxylphenylazo)benzenesulfonic acid, and isotactic poly(2-vinylpyridine). The protonated pyridine rings act as the footholds for anionic azo sliders to diffusively bind and slide along polycationic tracks via electrostatic interactions. Ultraviolet light triggers the trans to cis isomerization and aggregation of azo sliders, which can be monitored by multiple spectroscopic methods without labeling. The presence of vinyl polymer track increases the aggregation rate of cis azobenzene up to ∼20 times, depending on the stereoregularity of the polymer chain, the acid/base ratio and the addition of salt. This system has a feature of simplicity, monitorability, controllability, and could find applications in designing molecular machines with desired functionalities.
Collapse
Affiliation(s)
- Wenjing Zhao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Hongxu Du
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Yijie Xia
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Siyu Xie
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Yu-Peng Huang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Tieqi Xu
- State Key Laboratory of Fine Chemicals, College of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Jie Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Yi Qin Gao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| | - Xinhua Wan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| |
Collapse
|
8
|
Wang A, Levi M, Mohanty U, Whitford PC. Diffuse Ions Coordinate Dynamics in a Ribonucleoprotein Assembly. J Am Chem Soc 2022; 144:9510-9522. [PMID: 35593477 DOI: 10.1021/jacs.2c04082] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Proper ionic concentrations are required for the functional dynamics of RNA and ribonucleoprotein (RNP) assemblies. While experimental and computational techniques have provided many insights into the properties of chelated ions, less is known about the energetic contributions of diffuse ions to large-scale conformational rearrangements. To address this, we present a model that is designed to quantify the influence of diffuse monovalent and divalent ions on the dynamics of biomolecular assemblies. This model employs all-atom (non-H) resolution and explicit ions, where effective potentials account for hydration effects. We first show that the model accurately predicts the number of excess Mg2+ ions for prototypical RNA systems, at a level comparable to modern coarse-grained models. We then apply the model to a complete ribosome and show how the balance between diffuse Mg2+ and K+ ions can control the dynamics of tRNA molecules during translation. The model predicts differential effects of diffuse ions on the free-energy barrier associated with tRNA entry and the energy of tRNA binding to the ribosome. Together, this analysis reveals the direct impact of diffuse ions on the dynamics of an RNP assembly.
Collapse
Affiliation(s)
- Ailun Wang
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States.,Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Mariana Levi
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Udayan Mohanty
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Paul C Whitford
- Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.,Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| |
Collapse
|
9
|
Giri M, Gupta P, Maulik A, Gracias M, Singh M. Structure and DNA binding analysis of AT-rich interaction domain present in human BAF-B specific subunit BAF250b. Protein Sci 2022; 31:e4294. [PMID: 35481652 PMCID: PMC8994505 DOI: 10.1002/pro.4294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/21/2022] [Accepted: 02/28/2022] [Indexed: 11/06/2022]
Abstract
BAF250b and its paralog BAF250a are the DNA-binding central hub proteins present in BAF-B and BAF-A classes of SWI/SNF chromatin-remodeling complexes. BAF250b contains an AT-rich interaction domain (ARID) and C-terminal BAF250_C domain, and it is found mutated in several cancers. ARID is a conserved helix-turn-helix motif-containing DNA-binding domain present in several eukaryotic proteins. The ARID of BAF250b has been proposed to play roles in recruiting SWI/SNF to the target gene promoters for their activation. BAF250b ARID structures had been deposited in the protein data bank by a structural genomics consortium. However, it is not well-studied for its DNA-binding and solution dynamic properties. Here, we report complete backbone NMR resonance assignments of human BAF250b ARID. NMR chemical shifts and the backbone dynamics showed that the solution structure of the protein matched the reported crystal structures. The structure and chemical shift indexing revealed the presence of a short β-sheet in the DNA-binding region of BAF250b ARID that was absent in the structure of its paralog BAF250a ARID. NMR chemical shift perturbations identified DNA-binding residues and revealed the DNA-binding interface on BAF250b ARID. NMR data-driven HADDOCK models of BAF250b ARID - DNA complexes revealed its plausible mode of DNA-binding. Isothermal titration calorimetry experiments showed that BAF250b ARID interacts with DNA sequences with moderate affinities like BAF250a ARID. However, distinct thermodynamic signatures were observed for binding of BAF250a ARID and BAF250b ARID to AT-rich DNA sequence, suggesting that subtle sequence and structural differences in these two proteins influence their DNA-binding.
Collapse
Affiliation(s)
- Malyasree Giri
- Molecular Biophysics UnitIndian Institute of ScienceBengaluruIndia
| | - Parul Gupta
- Molecular Biophysics UnitIndian Institute of ScienceBengaluruIndia
| | - Aditi Maulik
- Molecular Biophysics UnitIndian Institute of ScienceBengaluruIndia
| | - Magaly Gracias
- Molecular Biophysics UnitIndian Institute of ScienceBengaluruIndia
| | - Mahavir Singh
- Molecular Biophysics UnitIndian Institute of ScienceBengaluruIndia
| |
Collapse
|
10
|
de Oliveira VM, Dias MMG, Avelino TM, Videira NB, da Silva FB, Doratioto TR, Whitford PC, Leite VBP, Figueira ACM. pH and the Breast Cancer Recurrent Mutation D538G Affect the Process of Activation of Estrogen Receptor α. Biochemistry 2022; 61:455-463. [PMID: 35238537 DOI: 10.1021/acs.biochem.1c00806] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Estrogen receptor α (ERα) is a regulatory protein that can access a set of distinct structural configurations. ERα undergoes extensive remodeling as it interacts with different agonists and antagonists, as well as transcription activation and repression factors. Moreover, breast cancer tumors resistant to hormone therapy have been associated with the imbalance between the active and inactive ERα states. Cancer-activating mutations in ERα play a crucial role in this imbalance and can promote the progression of cancer. However, the rate of this progression can also be increased by dysregulated pH in the tumor microenvironment. Many molecular aspects of the process of activation of ERα that can be affected by these pH changes and mutations are still unclear. Thus, we applied computational and experimental techniques to explore the activation process dynamics of ER for environments with different pHs and in the presence of one of the most recurrent cancer-activating mutations, D538G. Our results indicated that the effect of the pH increase associated with the D538G mutation promoted a robust stabilization of the active state of ER. We were also able to determine the main protein regions that have the most potential to influence the activation process under different pH conditions, which may provide targets of future therapeutics for the treatment of hormone-resistant breast cancer tumors. Finally, the approach used here can be applied for proteins associated with the proliferation of other cancer types, which can also have their function affected by small pH changes.
Collapse
Affiliation(s)
- Vinícius M de Oliveira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| | - Marieli M G Dias
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| | - Thayná M Avelino
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| | - Natália B Videira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| | - Fernando B da Silva
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto 01140-070, SP, Brazil
| | - Tábata R Doratioto
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| | - Paul C Whitford
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Vitor B P Leite
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto 01140-070, SP, Brazil
| | - Ana Carolina M Figueira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM, Campinas 13083-970, SP, Brazil
| |
Collapse
|
11
|
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: 1] [Impact Index Per Article: 0.5] [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.
Collapse
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
| |
Collapse
|
12
|
Molecular Simulations of Intrinsically Disordered Proteins and Their Binding Mechanisms. Methods Mol Biol 2022; 2376:343-362. [PMID: 34845619 DOI: 10.1007/978-1-0716-1716-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intrinsically disordered proteins (IDPs) lack well-defined secondary or tertiary structures in solution but are found to be involved in a wide range of critical cellular processes that highlight their functional importance. IDPs usually undergo folding upon binding to their targets. Such binding coupled to folding behavior has widened our perspective on the protein structure-dynamics-function paradigm in molecular biology. However, characterizing the folding upon binding mechanism of IDPs experimentally remains quite challenging. Molecular simulations emerge as a potentially powerful tool that offers information complementary to experiments. Here we present a general computational framework for the molecular simulations of IDP folding upon binding processes that combines all-atom molecular dynamics (MD) and coarse-grained simulations. The classical all-atom molecular dynamics approach using GPU acceleration allows the researcher to explore the properties of the IDP conformational ensemble, whereas coarse-grained structure-based models implemented with parameters carefully calibrated to available experimental measurements can be used to simulate the entire folding upon binding process. We also discuss a set of tools for the analysis of MD trajectories and describe the details of the computational protocol to follow so that it can be adapted by the user to study any IDP in isolation and in complex with partners.
Collapse
|
13
|
Bae S, Kim JS. Potential of Mean Force for DNA Wrapping Around a Cationic Nanoparticle. J Chem Theory Comput 2021; 17:7952-7961. [PMID: 34792353 DOI: 10.1021/acs.jctc.1c00797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sharp bending and wrapping of DNA around proteins and nanoparticles (NPs) has been of extensive research interest. Here, we present the potential of mean force (PMF) for wrapping a DNA double helix around a cationic NP using coarse-grained models of a double-stranded DNA and a cationic NP. Starting from a NP wrapped around by DNA, the PMF was calculated along the distance between the center of the NP and one end of the DNA molecule. A relationship between the distance and the extent of DNA wrapping is used to calculate the PMF as a function of DNA wrapping around a NP. In particular, the PMF was compared for two DNA sequences of (AT)25/(AT)25 and (AC)25/(GT)25, for which the persistence lengths are different by ∼10 nm. The simulation results provide solid evidence of the thermodynamic preference for complex formation of a cationic NP with more flexible DNA over the less flexible DNA. Furthermore, we estimated the elastic energy of DNA bending, which was in good order-of-magnitude agreement with the theoretical prediction of elastic rods. This work suggests that the variation of sequence-dependent DNA flexibility can be utilized in DNA nanotechnologies, in which the position and dynamics of NPs are regulated on large-scale DNA structures, or the structural transformation of DNA is triggered by the sequence-dependent binding of NPs.
Collapse
Affiliation(s)
- Sehui Bae
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jun Soo Kim
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| |
Collapse
|
14
|
Oliveira GM, Oravecz A, Kobi D, Maroquenne M, Bystricky K, Sexton T, Molina N. Precise measurements of chromatin diffusion dynamics by modeling using Gaussian processes. Nat Commun 2021; 12:6184. [PMID: 34702821 PMCID: PMC8548522 DOI: 10.1038/s41467-021-26466-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 10/07/2021] [Indexed: 11/08/2022] Open
Abstract
The spatiotemporal organization of chromatin influences many nuclear processes: from chromosome segregation to transcriptional regulation. To get a deeper understanding of these processes, it is essential to go beyond static viewpoints of chromosome structures, to accurately characterize chromatin's diffusion properties. We present GP-FBM: a computational framework based on Gaussian processes and fractional Brownian motion to extract diffusion properties from stochastic trajectories of labeled chromatin loci. GP-FBM uses higher-order temporal correlations present in the data, therefore, outperforming existing methods. Furthermore, GP-FBM allows to interpolate incomplete trajectories and account for substrate movement when two or more particles are present. Using our method, we show that average chromatin diffusion properties are surprisingly similar in interphase and mitosis in mouse embryonic stem cells. We observe surprising heterogeneity in local chromatin dynamics, correlating with potential regulatory activity. We also present GP-Tool, a user-friendly graphical interface to facilitate usage of GP-FBM by the research community.
Collapse
Affiliation(s)
- Guilherme M Oliveira
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France.
| | - Attila Oravecz
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France
| | - Dominique Kobi
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France
| | - Manon Maroquenne
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France
| | - Kerstin Bystricky
- Molecular Cellular and Developmental Biology unit (MCD), Centre de Biologie Integrative (CBI) UPS, CNRS, Toulouse, France
| | - Tom Sexton
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France.
| | - Nacho Molina
- Institute of Genetics and Molecular and Cellular Biology (IGBMC) CNRS UMR7104, INSERM U1258, University of Strasbourg, Illkirch, France.
| |
Collapse
|
15
|
Liu W, Li J, Xu Y, Yin D, Zhu X, Fu H, Su X, Guo X. Complete Mapping of DNA‐Protein Interactions at the Single‐Molecule Level. ADVANCED SCIENCE 2021; 8:2101383. [PMCID: PMC8655176 DOI: 10.1002/advs.202101383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
DNA–protein interaction plays an essential role in the storage, expression, and regulation of genetic information. A 1D/3D facilitated diffusion mechanism has been proposed to explain the extraordinarily rapid rate of DNA‐binding protein (DBP) searching for cognate sequence along DNA and further studied by single‐molecule experiments. However, direct observation of the detailed chronological protein searching image is still a formidable challenge. Here, for the first time, a single‐molecule electrical monitoring technique is utilized to realize label‐free detection of the DBP–DNA interaction process based on high‐gain silicon nanowire field‐effect transistors (SiNW FETs). The whole binding process of WRKY domain and DNA has been visualized with high sensitivity and single‐base resolution. Impressively, the swinging of hydrogen bonds between amino acid residues and bases in DNA induce the dynamic collective motion of DBP–DNA. This in situ, label‐free electrical detection platform provides a practical experimental methodology for dynamic studies of various biomolecules.
Collapse
Affiliation(s)
- Wenzhe Liu
- State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesBeijing National Laboratory for Molecular SciencesNational Biomedical Imaging CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P. R. China
| | - Jie Li
- State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesBeijing National Laboratory for Molecular SciencesNational Biomedical Imaging CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P. R. China
- Shenzhen Bay LaboratoryShenzhen518132P. R. China
| | - Yongping Xu
- State Key Laboratory of Protein and Plant Gene ResearchBiomedical Pioneering Innovation Center (BIOPIC)Peking UniversityBeijing100871P. R. China
| | - Dongbao Yin
- State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesBeijing National Laboratory for Molecular SciencesNational Biomedical Imaging CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P. R. China
| | - Xin Zhu
- Center of Single‐Molecule SciencesFrontiers Science Center for New Organic MatterInstitute of Modern OpticsCollege of Electronic Information and Optical EngineeringNankai University38 Tongyan Road, Jinnan DistrictTianjin300350P. R. China
| | - Huanyan Fu
- Center of Single‐Molecule SciencesFrontiers Science Center for New Organic MatterInstitute of Modern OpticsCollege of Electronic Information and Optical EngineeringNankai University38 Tongyan Road, Jinnan DistrictTianjin300350P. R. China
| | - Xiaodong Su
- State Key Laboratory of Protein and Plant Gene ResearchBiomedical Pioneering Innovation Center (BIOPIC)Peking UniversityBeijing100871P. R. China
| | - Xuefeng Guo
- State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesBeijing National Laboratory for Molecular SciencesNational Biomedical Imaging CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P. R. China
- Center of Single‐Molecule SciencesFrontiers Science Center for New Organic MatterInstitute of Modern OpticsCollege of Electronic Information and Optical EngineeringNankai University38 Tongyan Road, Jinnan DistrictTianjin300350P. R. China
| |
Collapse
|
16
|
Lin SN, Dame RT, Wuite GJL. Direct visualization of the effect of DNA structure and ionic conditions on HU-DNA interactions. Sci Rep 2021; 11:18492. [PMID: 34531428 PMCID: PMC8446073 DOI: 10.1038/s41598-021-97763-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 08/04/2021] [Indexed: 11/17/2022] Open
Abstract
Architectural DNA–binding proteins are involved in many important DNA transactions by virtue of their ability to change DNA conformation. Histone-like protein from E. coli strain U93, HU, is one of the most studied bacterial architectural DNA–binding proteins. Nevertheless, there is still a limited understanding of how the interactions between HU and DNA are affected by ionic conditions and the structure of DNA. Here, using optical tweezers in combination with fluorescent confocal imaging, we investigated how ionic conditions affect the interaction between HU and DNA. We directly visualized the binding and the diffusion of fluorescently labelled HU dimers on DNA. HU binds with high affinity and exhibits low mobility on the DNA in the absence of Mg2+; it moves 30-times faster and stays shorter on the DNA with 8 mM Mg2+ in solution. Additionally, we investigated the effect of DNA tension on HU–DNA complexes. On the one hand, our studies show that binding of HU enhances DNA helix stability. On the other hand, we note that the binding affinity of HU for DNA in the presence of Mg2+ increases at tensions above 50 pN, which we attribute to force-induced structural changes in the DNA. The observation that HU diffuses faster along DNA in presence of Mg2+ compared to without Mg2+ suggests that the free energy barrier for rotational diffusion along DNA is reduced, which can be interpreted in terms of reduced electrostatic interaction between HU and DNA, possibly coinciding with reduced DNA bending.
Collapse
Affiliation(s)
- Szu-Ning Lin
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.,Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Remus T Dame
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands. .,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands.
| | - Gijs J L Wuite
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands. .,LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| |
Collapse
|
17
|
Bae S, Oh I, Yoo J, Kim JS. Effect of DNA Flexibility on Complex Formation of a Cationic Nanoparticle with Double-Stranded DNA. ACS OMEGA 2021; 6:18728-18736. [PMID: 34337212 PMCID: PMC8319935 DOI: 10.1021/acsomega.1c01709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
We present extensive molecular dynamics simulations of a cationic nanoparticle and a double-stranded DNA molecule to discuss the effect of DNA flexibility on the complex formation of a cationic nanoparticle with double-stranded DNA. Martini coarse-grained models were employed to describe double-stranded DNA molecules with two different flexibilities and cationic nanoparticles with three different electric charges. As the electric charge of a cationic nanoparticle increases, the degree of DNA bending increases, eventually leading to the wrapping of DNA around the nanoparticle at high electric charges. However, a small increase in the persistence length of DNA by 10 nm requires a cationic nanoparticle with a markedly increased electric charge to bend and wrap DNA around. Thus, a more flexible DNA molecule bends and wraps around a cationic nanoparticle with an intermediate electric charge, whereas a less flexible DNA molecule binds to a nanoparticle with the same electric charge without notable bending. This work provides solid evidence that a small difference in DNA flexibility (as small as 10 nm in persistence length) has a substantial influence on the complex formation of DNA with proteins from a biological perspective and suggests that the variation of sequence-dependent DNA flexibility can be utilized in DNA nanotechnology as a new tool to manipulate the structure of DNA molecules mediated by nanoparticle binding.
Collapse
Affiliation(s)
- Sehui Bae
- Department
of Chemistry and Nanoscience, Ewha Womans
University, Seoul 03760, Republic of Korea
| | - Inrok Oh
- LG
Chem Ltd., LG Science Park, Seoul 07796, Republic of Korea
| | - Jejoong Yoo
- Department
of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jun Soo Kim
- Department
of Chemistry and Nanoscience, Ewha Womans
University, Seoul 03760, Republic of Korea
| |
Collapse
|
18
|
Characterization of caspase-7 interaction with RNA. Biochem J 2021; 478:2681-2696. [PMID: 34156061 DOI: 10.1042/bcj20210366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022]
Abstract
Apoptosis is a regulated form of cell death essential to the removal of unwanted cells. At its core, a family of cysteine peptidases named caspases cleave key proteins allowing cell death to occur. To do so, each caspase catalytic pocket recognizes preferred amino acid sequences resulting in proteolysis, but some also use exosites to select and cleave important proteins efficaciously. Such exosites have been found in a few caspases, notably caspase-7 that has a lysine patch (K38KKK) that binds RNA, which acts as a bridge to RNA-binding proteins favoring proximity between the peptidase and its substrates resulting in swifter cleavage. Although caspase-7 interaction with RNA has been identified, in-depth characterization of this interaction is lacking. In this study, using in vitro cleavage assays, we determine that RNA concentration and length affect the cleavage of RNA-binding proteins. Additionally, using binding assays and RNA sequencing, we found that caspase-7 binds RNA molecules regardless of their type, sequence, or structure. Moreover, we demonstrate that the N-terminal peptide of caspase-7 reduces the affinity of the peptidase for RNA, which translates into slower cleavages of RNA-binding proteins. Finally, employing engineered heterodimers, we show that a caspase-7 dimer can use both exosites simultaneously to increase its affinity to RNA because a heterodimer with only one exosite has reduced affinity for RNA and cleavage efficacy. These findings shed light on a mechanism that furthers substrate recognition by caspases and provides potential insight into its regulation during apoptosis.
Collapse
|
19
|
Wang X, Greenblatt HM, Bigman LS, Yu B, Pletka CC, Levy Y, Iwahara J. Dynamic Autoinhibition of the HMGB1 Protein via Electrostatic Fuzzy Interactions of Intrinsically Disordered Regions. J Mol Biol 2021; 433:167122. [PMID: 34181980 DOI: 10.1016/j.jmb.2021.167122] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/03/2021] [Accepted: 06/22/2021] [Indexed: 10/21/2022]
Abstract
Highly negatively charged segments containing only aspartate or glutamate residues ("D/E repeats") are found in many eukaryotic proteins. For example, the C-terminal 30 residues of the HMGB1 protein are entirely D/E repeats. Using nuclear magnetic resonance (NMR), fluorescence, and computational approaches, we investigated how the D/E repeats causes the autoinhibition of HMGB1 against its specific binding to cisplatin-modified DNA. By varying ionic strength in a wide range (40-900 mM), we were able to shift the conformational equilibrium between the autoinhibited and uninhibited states toward either of them to the full extent. This allowed us to determine the macroscopic and microscopic equilibrium constants for the HMGB1 autoinhibition at various ionic strengths. At a macroscopic level, a model involving the autoinhibited and uninhibited states can explain the salt concentration-dependent binding affinity data. Our data at a microscopic level show that the D/E repeats and other parts of HMGB1 undergo electrostatic fuzzy interactions, each of which is weaker than expected from the macroscopic autoinhibitory effect. This discrepancy suggests that the multivalent nature of the fuzzy interactions enables strong autoinhibition at a macroscopic level despite the relatively weak intramolecular interaction at each site. Both experimental and computational data suggest that the D/E repeats interact preferentially with other intrinsically disordered regions (IDRs) of HMGB1. We also found that mutations mimicking post-translational modifications relevant to nuclear export of HMGB1 can moderately modulate DNA-binding affinity, possibly by impacting the autoinhibition. This study illuminates a functional role of the fuzzy interactions of D/E repeats.
Collapse
Affiliation(s)
- Xi Wang
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| | - Harry M Greenblatt
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Binhan Yu
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| | - Channing C Pletka
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Junji Iwahara
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-1068, USA.
| |
Collapse
|
20
|
Crocker K, London J, Medina A, Fishel R, Bundschuh R. Evolutionary advantage of a dissociative search mechanism in DNA mismatch repair. Phys Rev E 2021; 103:052404. [PMID: 34134264 DOI: 10.1103/physreve.103.052404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/08/2021] [Indexed: 01/10/2023]
Abstract
Protein complexes involved in DNA mismatch repair diffuse along dsDNA as sliding clamps in order to locate a hemimethylated incision site. They have been observed to use a dissociative mechanism, in which two proteins, while continuously remaining attached to the DNA, sometimes associate into a single complex sliding on the DNA and sometimes dissociate into two independently sliding proteins. Here, we study the probability that these complexes locate a given target site via a semi-analytic, Monte Carlo calculation that tracks the association and dissociation of the sliding complexes. We compare such probabilities to those obtained using a nondissociative diffusive scan in the space of physically realistic diffusion constants, hemimethylated site distances, and total search times to determine the regions in which dissociative searching is more or less efficient than nondissociative searching. We conclude that the dissociative search mechanism is advantageous in the majority of the physically realistic parameter space, suggesting that the dissociative search mechanism confers an evolutionary advantage.
Collapse
Affiliation(s)
- Kyle Crocker
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - James London
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Andrés Medina
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Richard Fishel
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ralf Bundschuh
- Department of Physics, Department of Chemistry and Biochemistry, Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
| |
Collapse
|
21
|
Singh RK, Mukherjee A. Molecular Mechanism of the Intercalation of the SOX-4 Protein into DNA Inducing Bends and Kinks. J Phys Chem B 2021; 125:3752-3762. [PMID: 33848164 DOI: 10.1021/acs.jpcb.0c11496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
DNA-protein interactions regulate several biophysical functions, yet the mechanism of only a few is investigated in molecular detail. An important example is the intercalation of transcription factor proteins into DNA that produce bent and kinked DNA. Here, we have studied the molecular mechanism of the intercalation of a transcription factor SOX4 into DNA with a goal to understand the sequence of molecular events that precede the bending and kinking of the DNA. Our long well-tempered metadynamics and molecular dynamics (MD) simulations show that the protein primarily binds to the backbone of DNA and rotates around it to form an intercalative native state. We show that although there are multiple pathways for intercalation, the deintercalation pathway matches with the most probable intercalation pathway. In both cases, bending and kinking happen simultaneously, driven by the onset of the intercalation of the amino acid.
Collapse
Affiliation(s)
- Reman Kumar Singh
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| |
Collapse
|
22
|
Bigman LS, Greenblatt HM, Levy Y. What Are the Molecular Requirements for Protein Sliding along DNA? J Phys Chem B 2021; 125:3119-3131. [PMID: 33754737 PMCID: PMC8041311 DOI: 10.1021/acs.jpcb.1c00757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
DNA-binding proteins rely on linear
diffusion along the longitudinal
DNA axis, supported by their nonspecific electrostatic affinity for
DNA, to search for their target recognition sites. One may therefore
expect that the ability to engage in linear diffusion along DNA is
universal to all DNA-binding proteins, with the detailed biophysical
characteristics of that diffusion differing between proteins depending
on their structures and functions. One key question is whether the
linear diffusion mechanism is defined by translation coupled with
rotation, a mechanism that is often termed sliding. We conduct coarse-grained
and atomistic molecular dynamics simulations to investigate the minimal
requirements for protein sliding along DNA. We show that coupling,
while widespread, is not universal. DNA-binding proteins that slide
along DNA transition to uncoupled translation–rotation (i.e.,
hopping) at higher salt concentrations. Furthermore, and consistently
with experimental reports, we find that the sliding mechanism is the
less dominant mechanism for some DNA-binding proteins, even at low
salt concentrations. In particular, the toroidal PCNA protein is shown
to follow the hopping rather than the sliding mechanism.
Collapse
Affiliation(s)
- Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
23
|
Chu WT, Wang J. Thermodynamic and sequential characteristics of phase separation and droplet formation for an intrinsically disordered region/protein ensemble. PLoS Comput Biol 2021; 17:e1008672. [PMID: 33684117 PMCID: PMC7939360 DOI: 10.1371/journal.pcbi.1008672] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/04/2021] [Indexed: 11/21/2022] Open
Abstract
Liquid–liquid phase separation (LLPS) of some IDPs/IDRs can lead to the formation of the membraneless organelles in vitro and in vivo, which are essential for many biological processes in the cell. Here we select three different IDR segments of chaperon Swc5 and develop a polymeric slab model at the residue-level. By performing the molecular dynamics simulations, LLPS can be observed at low temperatures even without charge interactions and disappear at high temperatures. Both the sequence length and the charge pattern of the Swc5 segments can influence the critical temperature of LLPS. The results suggest that the effects of the electrostatic interactions on the LLPS behaviors can change significantly with the ratios and distributions of the charged residues, especially the sequence charge decoration (SCD) values. In addition, three different forms of swc conformation can be distinguished on the phase diagram, which is different from the conventional behavior of the free IDP/IDR. Both the packed form (the condensed-phase) and the dispersed form (the dilute-phase) of swc chains are found to be coexisted when LLPS occurs. They change to the fully-spread form at high temperatures. These findings will be helpful for the investigation of the IDP/IDR ensemble behaviors as well as the fundamental mechanism of the LLPS process in bio-systems. The membraneless organelles caused by liquid–liquid phase separation (LLPS) of IDPs/IDRs are involved in a wide range of biological functions such as RNA processing, ribosome biogenesis, and sequestration of mRNA, proteins, and compacted chromatin. In this study, we focus on the histone H2A-H2B binding partner, Swc5 and investigate the effects of the temperature, sequence length and number of charged residues on the LLPS behaviors. Moreover, we proposed three forms of swc conformation in ensemble according to the phase diagram. These characteristics of conformational changes (from LLPS to no LLPS, from condensed-phase to dilute-phase) are observed in the swc chains with different sequence length and charge pattern, which may be the general property for the IDP/IDR ensembles.
Collapse
Affiliation(s)
- Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, People's Republic of China
| | - Jin Wang
- Department of Chemistry & Physics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
| |
Collapse
|
24
|
Hazra MK, Levy Y. Biophysics of Phase Separation of Disordered Proteins Is Governed by Balance between Short- And Long-Range Interactions. J Phys Chem B 2021; 125:2202-2211. [PMID: 33629837 PMCID: PMC8028311 DOI: 10.1021/acs.jpcb.0c09975] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Intrinsically disordered proteins
play a crucial role in cellular
phase separation, yet the diverse molecular forces driving phase separation
are not fully understood. It is of utmost importance to understand
how peptide sequence, and particularly the balance between the peptides’
short- and long-range interactions with other peptides, may affect
the stability, structure, and dynamics of liquid–liquid phase
separation in protein condensates. Here, using coarse-grained molecular
dynamics simulations, we studied the liquid properties of the condensate
in a series of polymers in which the ratio of short-range dispersion
interactions to long-range electrostatic interactions varied. As the
fraction of mutations that participate in short-range interactions
increases at the expense of long-range electrostatic interactions,
a significant decrease in the critical temperature of phase separation
is observed. Nevertheless, sequences with a high fraction of short-range
interactions exhibit stabilization, which suggests compensation for
the loss of long-range electrostatic interactions. Decreased condensate
stability is coupled with decreased translational diffusion of the
polymers in the condensate, which may result in the loss of liquid
characteristics in the presence of a high fraction of uncharged residues.
The effect of exchanging long-range electrostatic interactions for
short-range interactions can be explained by the kinetics of breaking
intermolecular contacts with neighboring polymers and the kinetics
of intramolecular fluctuations. While both time scales are coupled
and increase as electrostatic interactions are lost, for sequences
that are dominated by short-range interactions, the kinetics of intermolecular
contact breakage significantly slows down. Our study supports the
contention that different types of interactions can maintain protein
condensates, however, long-range electrostatic interactions enhance
its liquid-like behavior.
Collapse
Affiliation(s)
- Milan Kumar Hazra
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
25
|
Chu WT, Wang J. Influence of sequence length and charged residues on Swc5 binding with histone H2A-H2B. Proteins 2020; 89:512-520. [PMID: 33320380 DOI: 10.1002/prot.26035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/25/2020] [Accepted: 12/12/2020] [Indexed: 01/23/2023]
Abstract
SWR is a member of chromatin remodeler family and participates the replacement of histone H2A with H2A.Z. One of the SWR subunits, Swc5, has an intrinsically disordered region and binds to H2A-H2B dimer. Though the binding structure of Swc5 and H2A-H2B has been resolved recently, it is still challenging to investigate the binding mechanism as well as the role of the charge interactions between Swc5 and H2A-H2B. Here we developed a coarse-grained structure-based model and performed molecular dynamics simulations to investigate the binding processes of two Swc5 regions with different lengths (swc5-a and swc5-b) to H2A-H2B. The simulation results suggest a different role of electrostatic interactions between swc5-a/swc5-b and H2A-H2B on binding. The electrostatic interactions between swc5-a/swc5-b and H2A-H2B can not only accelerate the initial capture step of binding, but can also trap the swc5-a/swc5-b at the wrong binding site on H2A. Besides, the conserved DEF/Y-2 motif of Swc5 is important for the binding affinity and the recognition with H2A-H2B at the initial step. Both swc5-a and swc5-b undergo a structural shift before reaching the final bound state. This theoretical study provides important details and the underlying physical mechanisms of the binding processes of swc5-a/swc5-b and H2A-H2B.
Collapse
Affiliation(s)
- Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Jin Wang
- Department of Chemistry and Physics, State University of New York at Stony Brook, Stony Brook, New York, USA
| |
Collapse
|
26
|
Pal A, Greenblatt HM, Levy Y. Prerecognition Diffusion Mechanism of Human DNA Mismatch Repair Proteins along DNA: Msh2-Msh3 versus Msh2-Msh6. Biochemistry 2020; 59:4822-4832. [PMID: 33319999 PMCID: PMC7872316 DOI: 10.1021/acs.biochem.0c00669] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
DNA
mismatch repair (MMR) is an important postreplication process
that eliminates mispaired or unpaired nucleotides to ensure genomic
replication fidelity. In humans, Msh2-Msh6 and Msh2-Msh3 are the two
mismatch repair initiation factors that recognize DNA lesions. While
X-ray crystal structures exist for these proteins in complex with
DNA lesions, little is known about their structures during the initial
search along nonspecific double-stranded DNA, because they are short-lived
and difficult to determine experimentally. In this study, various
computational approaches were used to sidestep these difficulties.
All-atom and coarse-grained simulations based on the crystal structures
of Msh2-Msh3 and Msh2-Msh6 showed no translation along the DNA, suggesting
that the initial search conformation differs from the lesion-bound
crystal structure. We modeled probable search-mode structures of MSH
proteins and showed, using coarse-grained molecular dynamics simulations,
that they can perform rotation-coupled diffusion on DNA, which is
a suitable and efficient search mechanism for their function and one
predicted earlier by fluorescence resonance energy transfer and fluorescence
microscopy studies. This search mechanism is implemented by electrostatic
interactions among the mismatch-binding domain (MBD), the clamp domains,
and the DNA backbone. During simulations, their diffusion rate did
not change significantly with an increasing salt concentration, which
is consistent with observations from experimental studies. When the
gap between their DNA-binding clamps was increased, Msh2-Msh3 diffused
mostly via the clamp domains while Msh2-Msh6 still diffused using
the MBD, reproducing the experimentally measured lower diffusion coefficient
of Msh2-Msh6. Interestingly, Msh2-Msh3 was capable of dissociating
from the DNA, whereas Msh2-Msh6 always diffused on the DNA duplex.
This is consistent with the experimental observation that Msh2-Msh3,
unlike Msh2-Msh6, can overcome obstacles such as nucleosomes. Our
models provide a molecular picture of the different mismatch search
mechanisms undertaken by Msh2-Msh6 and Msh2-Msh3, despite the similarity
of their structures.
Collapse
Affiliation(s)
- Arumay Pal
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
27
|
Iwahara J, Kolomeisky AB. Discrete-state stochastic kinetic models for target DNA search by proteins: Theory and experimental applications. Biophys Chem 2020; 269:106521. [PMID: 33338872 PMCID: PMC7855466 DOI: 10.1016/j.bpc.2020.106521] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 12/15/2022]
Abstract
To perform their functions, transcription factors and DNA-repair/modifying enzymes randomly search DNA in order to locate their specific targets on DNA. Discrete-state stochastic kinetic models have been developed to explain how the efficiency of the search process is influenced by the molecular properties of proteins and DNA as well as by other factors such as molecular crowding. These theoretical models not only offer explanations on the relation of microscopic processes to macroscopic behavior of proteins, but also facilitate the analysis and interpretation of experimental data. In this review article, we provide an overview on discrete-state stochastic kinetic models and explain how these models can be applied to experimental investigations using stopped-flow, single-molecule, nuclear magnetic resonance (NMR), and other biophysical and biochemical methods.
Collapse
Affiliation(s)
- Junji Iwahara
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Anatoly B Kolomeisky
- Department of Chemistry, Department of Chemical and Biomolecular Engineering, Department of Physics and Astronomy and Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| |
Collapse
|
28
|
A steric gate controls P/E hybrid-state formation of tRNA on the ribosome. Nat Commun 2020; 11:5706. [PMID: 33177497 PMCID: PMC7658246 DOI: 10.1038/s41467-020-19450-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/15/2020] [Indexed: 12/19/2022] Open
Abstract
The ribosome is a biomolecular machine that undergoes multiple large-scale structural rearrangements during protein elongation. Here, we focus on a conformational rearrangement during translocation, known as P/E hybrid-state formation. Using a model that explicitly represents all non-hydrogen atoms, we simulated more than 120 spontaneous transitions, where the tRNA molecule is displaced between the P and E sites of the large subunit. In addition to predicting a free-energy landscape that is consistent with previous experimental observations, the simulations reveal how a six-residue gate-like region can limit P/E formation, where sub-angstrom structural perturbations lead to an order-of-magnitude change in kinetics. Thus, this precisely defined set of residues represents a novel target that may be used to control functional dynamics in bacterial ribosomes. This theoretical analysis establishes a direct relationship between ribosome structure and large-scale dynamics, and it suggests how next-generation experiments may precisely dissect the energetics of hybrid formation on the ribosome. The ribosome undergoes multiple large-scale structural rearrangements during protein elongation. Here the authors present an all-atom model of the ribosome to study the energetics of P/E hybrid-state formation, an early conformational rearrangement occurring during translocation.
Collapse
|
29
|
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.
Collapse
|
30
|
Does PCNA diffusion on DNA follow a rotation-coupled translation mechanism? Nat Commun 2020; 11:5000. [PMID: 33020481 PMCID: PMC7536400 DOI: 10.1038/s41467-020-18855-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/29/2020] [Indexed: 01/25/2023] Open
|
31
|
Dai L, Yu J. Inchworm stepping of Myc-Max heterodimer protein diffusion along DNA. Biochem Biophys Res Commun 2020; 533:97-103. [PMID: 32933752 DOI: 10.1016/j.bbrc.2020.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/02/2020] [Indexed: 02/07/2023]
Abstract
Oncogenic protein Myc serves as a transcription factor to control cell metabolisms. Myc dimerizes via leucine zipper with its associated partner protein Max to form a heterodimer structure, which then binds target DNA sequences to regulate gene transcription. The regulation depends on Myc-Max binding to DNA and searching for target sequences via diffusional motions along DNA. Here, we conduct structure-based molecular dynamics (MD) simulations to investigate the diffusion dynamics of the Myc-Max heterodimer along DNA. We found that the heterodimer protein slides on the DNA in a rotation-uncoupled manner in coarse-grained simulations, as its two helical DNA binding basic regions (BRs) alternate between open and closed conformations via inchworm stepping motions. In such motions, the two BRs of the heterodimer step across the DNA strand one by one, with step sizes reaching about half of a DNA helical pitch length. Atomic MD simulations of the Myc-Max heterodimer in complex with DNA have also been conducted. Hydrogen bond interactions are revealed between the two BRs and two complementary DNA strands, respectively. In the non-specific DNA binding, the BR from Myc shows an onset of stepping on one association DNA strand and starts detaching from the other strand. Overall, our simulation studies suggest that the inchworm stepping motions of the Myc-Max heterodimer can be achieved during the protein diffusion along DNA.
Collapse
Affiliation(s)
- Liqiang Dai
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA, 92697, USA.
| |
Collapse
|
32
|
Chen J, Qi Y, Duan Y, Duan M, Yang M. C1188D mutation abolishes specific recognition between MLL1-CXXC domain and CpG site by inducing conformational switch of flexible N-terminal. Proteins 2020; 88:1401-1412. [PMID: 32519403 DOI: 10.1002/prot.25960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/22/2020] [Accepted: 06/06/2020] [Indexed: 01/19/2023]
Abstract
Mixed lineage leukemia protein (MLL1 protein) recognizes the CpG site via its CXXC domain and is frequently associated with leukemia. The specific recognition is abolished by C1188D mutation, which also prevents MLL-related leukemia. In this paper, multiple molecular dynamic (MD) simulations were performed to investigate the mechanism of recognition and influences of C1188D mutation. Started from fully dissociated DNA and MLL1-CXXC domain, remarkably, the center of mass (COM) of MLL1-CXXC domain quickly concentrates on the vicinity of the CpG site in all 53 short MD simulations. Extended simulations of the wild type showed that the native complex formed in 500 ns among 4 of 53 simulations. In contrast, the C1188D mutant COM distributed broadly around the DNA and the native complex was not observed in any of the extended simulations. Simulations on the apo MLL1-CXXC domain further suggest that the wild type protein remained predominantly in an open form that closely resembles its structure in the native complex whereas C1188D mutant formed predominantly compact structures in which the N- terminal bends to D1188. This conformational switch hinders the formation of encounter complex, thus abolishes the recognition. Our study also provides clues to the study mechanism of recognition, by the CXXC domain from proteins like DNA methyltransferase and ten-eleven translocation enzymes.
Collapse
Affiliation(s)
- Jiawen Chen
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonances in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Yanping Qi
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonances in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.,College of Physical Science and Technology, Central China Normal University, Wuhan, China
| | - Yong Duan
- Department of Biomedical Engineering and UC Davis Genome Center, University of California at Davis, Davis, California, USA
| | - Mojie Duan
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonances in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonances in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
33
|
Bigman LS, Levy Y. Protein Diffusion on Charged Biopolymers: DNA versus Microtubule. Biophys J 2020; 118:3008-3018. [PMID: 32492371 DOI: 10.1016/j.bpj.2020.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/28/2020] [Accepted: 05/12/2020] [Indexed: 02/06/2023] Open
Abstract
Protein diffusion in lower-dimensional spaces is used for various cellular functions. For example, sliding on DNA is essential for proteins searching for their target sites, and protein diffusion on microtubules is important for proper cell division and neuronal development. On the one hand, these linear diffusion processes are mediated by long-range electrostatic interactions between positively charged proteins and negatively charged biopolymers and have similar characteristic diffusion coefficients. On the other hand, DNA and microtubules have different structural properties. Here, using computational approaches, we studied the mechanism of protein diffusion along DNA and microtubules by exploring the diffusion of both protein types on both biopolymers. We found that DNA-binding and microtubule-binding proteins can diffuse on each other's substrates; however, the adopted diffusion mechanism depends on the molecular properties of the diffusing proteins and the biopolymers. On the protein side, only DNA-binding proteins can perform rotation-coupled diffusion along DNA, with this being due to their higher net charge and its spatial organization at the DNA recognition helix. By contrast, the lower net charge on microtubule-binding proteins enables them to diffuse more quickly than DNA-binding proteins on both biopolymers. On the biopolymer side, microtubules possess intrinsically disordered, negatively charged C-terminal tails that interact with microtubule-binding proteins, thus supporting their diffusion. Thus, although both DNA-binding and microtubule-binding proteins can diffuse on the negatively charged biopolymers, the unique molecular features of the biopolymers and of their natural substrates are essential for function.
Collapse
Affiliation(s)
- Lavi S Bigman
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
34
|
Zhao Y, Cortes-Huerto R, Kremer K, Rudzinski JF. Investigating the Conformational Ensembles of Intrinsically Disordered Proteins with a Simple Physics-Based Model. J Phys Chem B 2020; 124:4097-4113. [PMID: 32345021 PMCID: PMC7246978 DOI: 10.1021/acs.jpcb.0c01949] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Intrinsically
disordered proteins (IDPs) play an important role
in an array of biological processes but present a number of fundamental
challenges for computational modeling. Recently, simple polymer models
have regained popularity for interpreting the experimental characterization
of IDPs. Homopolymer theory provides a strong foundation for understanding
generic features of phenomena ranging from single-chain conformational
dynamics to the properties of entangled polymer melts, but is difficult
to extend to the copolymer context. This challenge is magnified for
proteins due to the variety of competing interactions and large deviations
in side-chain properties. In this work, we apply a simple physics-based
coarse-grained model for describing largely disordered conformational
ensembles of peptides, based on the premise that sampling sterically
forbidden conformations can compromise the faithful description of
both static and dynamical properties. The Hamiltonian of the employed
model can be easily adjusted to investigate the impact of distinct
interactions and sequence specificity on the randomness of the resulting
conformational ensemble. In particular, starting with a bead–spring-like
model and then adding more detailed interactions one by one, we construct
a hierarchical set of models and perform a detailed comparison of
their properties. Our analysis clarifies the role of generic attractions,
electrostatics, and side-chain sterics, while providing a foundation
for developing efficient models for IDPs that retain an accurate description
of the hierarchy of conformational dynamics, which is nontrivially
influenced by interactions with surrounding proteins and solvent molecules.
Collapse
Affiliation(s)
- Yani Zhao
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | | | - Kurt Kremer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Joseph F Rudzinski
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| |
Collapse
|
35
|
Chu WT, Shammas SL, Wang J. Charge Interactions Modulate the Encounter Complex Ensemble of Two Differently Charged Disordered Protein Partners of KIX. J Chem Theory Comput 2020; 16:3856-3868. [PMID: 32325001 DOI: 10.1021/acs.jctc.9b01264] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Disordered proteins play important roles in cell signaling and are frequently involved in protein-protein interactions. They also have a larger proportion of charged and polar residues than their folded counterparts. Here, we developed a structure-based model and applied molecular dynamics simulations to examine the presence and importance of electrostatic interactions in the binding processes of two differently charged intrinsically disordered ligands of the KIX domain of CBP. We observed non-native opposite-charged contacts in the encounter complexes for both ligands with KIX, and this may be a general feature of coupled folding and binding reactions. The ensemble of successful encounter complexes is a diverse set of structures, and in the case of the highly charged ligand, this ensemble was found to be malleable with respect to ionic strength. There are only minor differences between encounter complex ensembles for successful and unsuccessful collisions with no key interactions that appear to make the process far more productive. The energy landscape at this early stage in the process does not appear highly funneled. Strikingly we observed many native interactions that appear to reduce chances of an encounter complex being productive. Instead it appears that collectively non-native electrostatic interactions in the encounter complex increase the likelihood of productivity by holding the proteins together long enough for folding to take place. This mechanism is more effective for the more highly charged ligand.
Collapse
Affiliation(s)
- Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P.R.China
| | - Sarah L Shammas
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Jin Wang
- Department of Chemistry & Physics, State University of New York at Stony Brook, Stony Brook, New York 11794, United States
| |
Collapse
|
36
|
Mondal K, Chaudhury S. Effect of DNA Conformation on the Protein Search for Targets on DNA: A Theoretical Perspective. J Phys Chem B 2020; 124:3518-3526. [PMID: 32268727 DOI: 10.1021/acs.jpcb.0c01996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein-DNA interactions are important for all biological processes and involve the process of proteins searching for and recognizing specific binding sites on the DNA. Many aspects of the mechanism of the protein search for targets on DNA are not well understood. One important problem is the effect of DNA conformation on the protein search dynamics. Using a theoretical method based on a discrete-state stochastic approach, we obtained an analytical description of the dynamic properties. We investigated a system with two DNA conformers. It was found that the average search time on one DNA conformer via 1D or 3D motions depended on the dynamics of the search process on the other DNA conformer.
Collapse
Affiliation(s)
- Kinjal Mondal
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Srabanti Chaudhury
- Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| |
Collapse
|
37
|
Tubulin tails and their modifications regulate protein diffusion on microtubules. Proc Natl Acad Sci U S A 2020; 117:8876-8883. [PMID: 32245812 DOI: 10.1073/pnas.1914772117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Microtubules (MTs) are essential components of the eukaryotic cytoskeleton that serve as "highways" for intracellular trafficking. In addition to the well-known active transport of cargo by motor proteins, many MT-binding proteins seem to adopt diffusional motility as a transportation mechanism. However, because of the limited spatial resolution of current experimental techniques, the detailed mechanism of protein diffusion has not been elucidated. In particular, the precise role of tubulin tails and tail modifications in the diffusion process is unclear. Here, using coarse-grained molecular dynamics simulations validated against atomistic simulations, we explore the molecular mechanism of protein diffusion along MTs. We found that electrostatic interactions play a central role in protein diffusion; the disordered tubulin tails enhance affinity but slow down diffusion, and diffusion occurs in discrete steps. While diffusion along wild-type MT is performed in steps of dimeric tubulin, the removal of the tails results in a step of monomeric tubulin. We found that the energy barrier for diffusion is larger when diffusion on MTs is mediated primarily by the MT tails rather than the MT body. In addition, globular proteins (EB1 and PRC1) diffuse more slowly than an intrinsically disordered protein (Tau) on MTs. Finally, we found that polyglutamylation and polyglycylation of tubulin tails lead to slower protein diffusion along MTs, although polyglycylation leads to faster diffusion across MT protofilaments. Taken together, our results explain experimentally observed data and shed light on the roles played by disordered tubulin tails and tail modifications in the molecular mechanism of protein diffusion along MTs.
Collapse
|
38
|
Mishra G, Bigman LS, Levy Y. ssDNA diffuses along replication protein A via a reptation mechanism. Nucleic Acids Res 2020; 48:1701-1714. [PMID: 31919510 PMCID: PMC7038930 DOI: 10.1093/nar/gkz1202] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/23/2019] [Accepted: 01/08/2020] [Indexed: 01/30/2023] Open
Abstract
Replication protein A (RPA) plays a critical role in all eukaryotic DNA processing involving single-stranded DNA (ssDNA). Contrary to the notion that RPA provides solely inert protection to transiently formed ssDNA, the RPA-ssDNA complex acts as a dynamic DNA processing unit. Here, we studied the diffusion of RPA along 60 nt ssDNA using a coarse-grained model in which the ssDNA-RPA interface was modeled by both aromatic and electrostatic interactions. Our study provides direct evidence of bulge formation during the diffusion of ssDNA along RPA. Bulges can form at a few sites along the interface and store 1-7 nt of ssDNA whose release, upon bulge dissolution, leads to propagation of ssDNA diffusion. These findings thus support the reptation mechanism, which involves bulge formation linked to the aromatic interactions, whose short range nature reduces cooperativity in ssDNA diffusion. Greater cooperativity and a larger diffusion coefficient for ssDNA diffusion along RPA are observed for RPA variants with weaker aromatic interactions and for interfaces homogenously stabilized by electrostatic interactions. ssDNA propagation in the latter instance is characterized by lower probabilities of bulge formation; thus, it may fit the sliding-without-bulge model better than the reptation model. Thus, the reptation mechanism allows ssDNA mobility despite the extensive and high affinity interface of RPA with ssDNA. The short-range aromatic interactions support bulge formation while the long-range electrostatic interactions support the release of the stored excess ssDNA in the bulge and thus the overall diffusion.
Collapse
Affiliation(s)
- Garima Mishra
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.,Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Lavi S Bigman
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
39
|
Dey P, Bhattacherjee A. Structural Basis of Enhanced Facilitated Diffusion of DNA-Binding Protein in Crowded Cellular Milieu. Biophys J 2020; 118:505-517. [PMID: 31862109 PMCID: PMC6976804 DOI: 10.1016/j.bpj.2019.11.3388] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/03/2019] [Accepted: 11/18/2019] [Indexed: 02/06/2023] Open
Abstract
Although the fast association between DNA-binding proteins (DBPs) and DNA is explained by a facilitated diffusion mechanism, in which DBPs adopt a weighted combination of three-dimensional diffusion and one-dimensional (1D) sliding and hopping modes of transportation, the role of cellular environment that contains many nonspecifically interacting proteins and other biomolecules is mostly overlooked. By performing large-scale computational simulations with an appropriately tuned model of protein and DNA in the presence of nonspecifically interacting bulk and DNA-bound crowders (genomic crowders), we demonstrate the structural basis of the enhanced facilitated diffusion of DBPs inside a crowded cellular milieu through, to our knowledge, novel 1D scanning mechanisms. In this one-dimensional scanning mode, the protein can float along the DNA under the influence of nonspecific interactions of bulk crowder molecules. The search mode is distinctly different compared to usual 1D sliding and hopping dynamics in which protein diffusion is regulated by the DNA electrostatics. In contrast, the presence of genomic crowders expedites the target search process by transporting the protein over DNA segments through the formation of a transient protein-crowder bridged complex. By analyzing the ruggedness of the associated potential energy landscape, we underpin the molecular origin of the kinetic advantages of these search modes and show that they successfully explain the experimentally observed acceleration of facilitated diffusion of DBPs by molecular crowding agents and crowder-concentration-dependent enzymatic activity of transcription factors. Our findings provide crucial insights into gene regulation kinetics inside the crowded cellular milieu.
Collapse
Affiliation(s)
- Pinki Dey
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Arnab Bhattacherjee
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India.
| |
Collapse
|
40
|
Ferreira PHB, Freitas FC, McCully ME, Slade GG, de Oliveira RJ. The Role of Electrostatics and Folding Kinetics on the Thermostability of Homologous Cold Shock Proteins. J Chem Inf Model 2020; 60:546-561. [PMID: 31910002 DOI: 10.1021/acs.jcim.9b00797] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding which aspects contribute to the thermostability of proteins is a challenge that has persisted for decades, and it is of great relevance for protein engineering. Several types of interactions can influence the thermostability of a protein. Among them, the electrostatic interactions have been a target of particular attention. Aiming to explore how this type of interaction can affect protein thermostability, this paper investigated four homologous cold shock proteins from psychrophilic, mesophilic, thermophilic, and hyperthermophilic organisms using a set of theoretical methodologies. It is well-known that electrostatics as well as hydrophobicity are key-elements for the stabilization of these proteins. Therefore, both interactions were initially analyzed in the native structure of each protein. Electrostatic interactions present in the native structures were calculated with the Tanford-Kirkwood model with solvent accessibility, and the amount of hydrophobic surface area buried upon folding was estimated by measuring both folded and extended structures. On the basis of Energy Landscape Theory, the local frustration and the simplified alpha-carbon structure-based model were modeled with a Debye-Hückel potential to take into account the electrostatics and the effects of an implicit solvent. Thermodynamic data for the structure-based model simulations were collected and analyzed using the Weighted Histogram Analysis and Stochastic Diffusion methods. Kinetic quantities including folding times, transition path times, folding routes, and Φ values were also obtained. As a result, we found that the methods are able to qualitatively infer that electrostatic interactions play an important role on the stabilization of the most stable thermophilic cold shock proteins, showing agreement with the experimental data.
Collapse
Affiliation(s)
- Paulo Henrique Borges Ferreira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação , Universidade Federal do Triângulo Mineiro , Uberaba , Minas Gerais 38064200 , Brazil
| | - Frederico Campos Freitas
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação , Universidade Federal do Triângulo Mineiro , Uberaba , Minas Gerais 38064200 , Brazil
| | - Michelle E McCully
- Department of Biology , Santa Clara University , Santa Clara , California 95050 , United States
| | - Gabriel Gouvêa Slade
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação , Universidade Federal do Triângulo Mineiro , Uberaba , Minas Gerais 38064200 , 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 38064200 , Brazil
| |
Collapse
|
41
|
de Oliveira VM, Caetano DLZ, da Silva FB, Mouro PR, de Oliveira AB, de Carvalho SJ, Leite VBP. pH and Charged Mutations Modulate Cold Shock Protein Folding and Stability: A Constant pH Monte Carlo Study. J Chem Theory Comput 2020; 16:765-772. [PMID: 31756296 DOI: 10.1021/acs.jctc.9b00894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The folding and stability of proteins is a fundamental problem in several research fields. In the present paper, we have used different computational approaches to study the effects caused by changes in pH and for charged mutations in cold shock proteins from Bacillus subtilis (Bs-CspB). First, we have investigated the contribution of each ionizable residue for these proteins to their thermal stability using the TKSA-MC, a Web server for rational mutation via optimizing the protein charge interactions. Based on these results, we have proposed a new mutation in an already optimized Bs-CspB variant. We have evaluated the effects of this new mutation in the folding energy landscape using structure-based models in Monte Carlo simulation at constant pH, SBM-CpHMC. Our results using this approach have indicated that the charge rearrangements already in the unfolded state are critical to the thermal stability of Bs-CspB. Furthermore, the conjunction of these simplified methods was able not only to predict stabilizing mutations in different pHs but also to provide essential information about their effects in each stage of protein folding.
Collapse
Affiliation(s)
- Vinícius M de Oliveira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, LNBio/CNPEM , Campinas , São Paulo , 13083-970 , Brazil
| | - Daniel L Z Caetano
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil
| | - Fernando B da Silva
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil
| | - Paulo R Mouro
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil
| | - Antonio B de Oliveira
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil
| | - Sidney J de Carvalho
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil
| | - Vitor B P Leite
- Department of Physics , São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences , São José do Rio Preto , São Paulo , 15054-000 , Brazil.,Center for Theoretical Biological Physics , Rice University , Houston , Texas 77005 , United States
| |
Collapse
|
42
|
Giri M, Maulik A, Singh M. Signatures of Specific DNA Binding by the AT-Rich Interaction Domain of BAF250a. Biochemistry 2019; 59:100-113. [PMID: 31825600 DOI: 10.1021/acs.biochem.9b00852] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The AT-rich interaction domain (ARID) containing BAF250a is a subunit of the BAF-A class of SWI/SNF chromatin remodeling complexes. The ARID belongs to a family of conserved DNA binding domains found in several eukaryotic proteins; however, its exact contribution to BAF250a function and the mechanism of its DNA binding are not well understood. Here we have probed the interaction of the BAF250a ARID with three different double-stranded DNA (dsDNA) sequences to understand its DNA binding properties. A comprehensive biophysical and thermodynamic study using nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry revealed the complex nature of BAF250a ARID-DNA interactions. The thermodynamic signatures of the BAF250a ARID with 12 A-T bp dsDNA (AT-12) are distinct from those of 12 G-C bp dsDNA (GC-12) or 12 bp Dickerson dodecamer DNA (DD-12) sequences. We observed that the binding of the BAF250a ARID with AT-12 DNA is enthalpically driven in a tested temperature range of 5-25 °C. BAF250a ARID/AT-12 DNA interaction exhibited a larger negative calorimetric specific heat change (ΔCp) compared to that of BAF250a ARID/GC-12 DNA or BAF250a ARID/DD-12 DNA interactions. In the presence of salt (NaCl), ARID/AT-12 DNA binding was less perturbed than ARID/GC-12 DNA or ARID/DD-12 DNA binding. Overall, these results show that BAF250a ARID/AT-12 DNA interaction has signatures of "specific" binding. Furthermore, using NMR chemical shift perturbation experiments, we have identified DNA binding residues on the BAF250a ARID and generated a data-driven HADDOCK model of the ARID/DNA complex that was further supported by mutating key lysine residues that were found to be important for DNA binding.
Collapse
Affiliation(s)
- Malyasree Giri
- Molecular Biophysics Unit , Indian Institute of Science , Bengaluru 560012 , India
| | - Aditi Maulik
- Molecular Biophysics Unit , Indian Institute of Science , Bengaluru 560012 , India
| | - Mahavir Singh
- Molecular Biophysics Unit , Indian Institute of Science , Bengaluru 560012 , India.,NMR Research Centre , Indian Institute of Science , Bengaluru 560012 , India
| |
Collapse
|
43
|
Dey P, Bhattacherjee A. Mechanism of Facilitated Diffusion of DNA Repair Proteins in Crowded Environment: Case Study with Human Uracil DNA Glycosylase. J Phys Chem B 2019; 123:10354-10364. [DOI: 10.1021/acs.jpcb.9b07342] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Pinki Dey
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India 110067
| | - Arnab Bhattacherjee
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India 110067
| |
Collapse
|
44
|
Freitas FC, Lima AN, Contessoto VDG, Whitford PC, Oliveira RJD. Drift-diffusion (DrDiff) framework determines kinetics and thermodynamics of two-state folding trajectory and tunes diffusion models. J Chem Phys 2019; 151:114106. [DOI: 10.1063/1.5113499] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Frederico Campos Freitas
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brazil
| | - Angelica Nakagawa Lima
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brazil
- Laboratório de Biologia Computacional e Bioinformática, Universidade Federal do ABC, Santo André, SP, Brazil
| | - Vinícius de Godoi Contessoto
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
- Departamento de Física, Universidade Estadual Paulista, São José do Rio Preto, SP, Brazil
- Brazilian Biorenewables National Laboratory - LNBR, Brazilian Center for Research in Energy and Materials - CNPEM, Campinas, SP, Brazil
| | - Paul C. Whitford
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Ronaldo Junio de Oliveira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brazil
| |
Collapse
|
45
|
Chu X, Wang J. Position-, disorder-, and salt-dependent diffusion in binding-coupled-folding of intrinsically disordered proteins. Phys Chem Chem Phys 2019; 21:5634-5645. [PMID: 30793144 DOI: 10.1039/c8cp06803h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Successful extensions of protein-folding energy landscape theory to intrinsically disordered proteins' (IDPs') binding-coupled-folding transition can enormously simplify this biomolecular process into diffusion along a limited number of reaction coordinates, and the dynamics subsequently is described by Kramers' rate theory. As the critical pre-factor, the diffusion coefficient D has direct implications on the binding kinetics. Here, we employ a structure-based model (SBM) to calculate D in the binding-folding of an IDP prototype. We identify a strong position-dependent D during binding by applying a reaction coordinate that directly measures the fluctuations in a Cartesian configuration space. Using the malleability of the SBM, we modulate the degree of conformational disorder in an isolated IDP and determine complex effects of intrinsic disorder on D varying for different binding stages. Here, D tends to increase with disorder during initial binding but shows a non-monotonic relationship with disorder in terms of a decrease-followed-by-increase in D during the late binding stage. The salt concentration, which correlates with electrostatic interactions via Debye-Hückel theory in our SBM, also modulates D in a stepwise way. The speeding up of diffusion by electrostatic interactions is observed during the formation of the encounter complex at the beginning of binding, while the last diffusive binding dynamics is hindered by non-native salt bridges. Because D describes the diffusive speed locally, which implicitly reflects the roughness of the energy landscape, we are eventually able to portray the binding energy landscape, including that from IDPs' binding, then to binding with partial folding, and finally to rigid docking, as well as that under different environmental salt concentrations. Our theoretical results provide key mechanistic insights into IDPs' binding-folding, which is internally conformation- and externally salt-controlled with respect to diffusion.
Collapse
Affiliation(s)
- Xiakun Chu
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794, USA
| | | |
Collapse
|
46
|
Maulik A, Giri M, Singh M. Molecular determinants of complex formation between
DNA
and the
AT
‐rich interaction domain of
BAF
250a. FEBS Lett 2019; 593:2716-2729. [DOI: 10.1002/1873-3468.13540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/08/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Aditi Maulik
- Molecular Biophysics Unit Indian Institute of Science Bengaluru India
| | - Malyasree Giri
- Molecular Biophysics Unit Indian Institute of Science Bengaluru India
| | - Mahavir Singh
- Molecular Biophysics Unit Indian Institute of Science Bengaluru India
- NMR Research Centre Indian Institute of Science Bengaluru India
| |
Collapse
|
47
|
Daitchman D, Greenblatt HM, Levy Y. Diffusion of ring-shaped proteins along DNA: case study of sliding clamps. Nucleic Acids Res 2019; 46:5935-5949. [PMID: 29860305 PMCID: PMC6158715 DOI: 10.1093/nar/gky436] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Several DNA-binding proteins, such as topoisomerases, helicases and sliding clamps, have a toroidal (i.e. ring) shape that topologically traps DNA, with this quality being essential to their function. Many DNA-binding proteins that function, for example, as transcription factors or enzymes were shown to be able to diffuse linearly (i.e. slide) along DNA during the search for their target binding sites. The protein's sliding properties and ability to search DNA, which often also involves hopping and dissociation, are expected to be different when it encircles the DNA. In this study, we explored the linear diffusion of four ring-shaped proteins of very similar structure: three sliding clamps (PCNA, β-clamp, and the gp45) and the 9-1-1 protein, with a particular focus on PCNA. Coarse-grained molecular dynamics simulations were performed to decipher the sliding mechanism adopted by these ring-shaped proteins and to determine how the molecular properties of the inner and outer ring govern its search speed. We designed in silico variants to dissect the contributions of ring geometry and electrostatics to the sliding speed of ring-shaped proteins along DNA. We found that the toroidal proteins diffuse when they are tilted relative to the DNA axis and able to rotate during translocation, but that coupling between rotation and translocation is quite weak. Their diffusion speed is affected by the shape of the inner ring and, to a lesser extent, by its electrostatic properties. However, breaking the symmetry of the electrostatic potential can result in deviation of the DNA from the center of the ring and cause slower linear diffusion. The findings are discussed in light of earlier computational and experimental studies on the sliding of clamps.
Collapse
Affiliation(s)
- Dina Daitchman
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
- To whom correspondence should be addressed. Tel: +972 8 9344587;
| |
Collapse
|
48
|
Cencini M, Pigolotti S. Energetic funnel facilitates facilitated diffusion. Nucleic Acids Res 2019; 46:558-567. [PMID: 29216364 PMCID: PMC5778461 DOI: 10.1093/nar/gkx1220] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/24/2017] [Indexed: 01/25/2023] Open
Abstract
Transcription factors (TFs) are able to associate to their binding sites on DNA faster than the physical limit posed by diffusion. Such high association rates can be achieved by alternating between three-dimensional diffusion and one-dimensional sliding along the DNA chain, a mechanism-dubbed facilitated diffusion. By studying a collection of TF binding sites of Escherichia coli from the RegulonDB database and of Bacillus subtilis from DBTBS, we reveal a funnel in the binding energy landscape around the target sequences. We show that such a funnel is linked to the presence of gradients of AT in the base composition of the DNA region around the binding sites. An extensive computational study of the stochastic sliding process along the energetic landscapes obtained from the database shows that the funnel can significantly enhance the probability of TFs to find their target sequences when sliding in their proximity. We demonstrate that this enhancement leads to a speed-up of the association process.
Collapse
Affiliation(s)
- Massimo Cencini
- Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via dei Taurini 19, 00185 Rome, Italy
| | - Simone Pigolotti
- Biological Complexity Unit, Okinawa Institute of Science and Technology and Graduate University, Onna, Okinawa 904-0495, Japan.,Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstraße 38, 01187 Dresden, Germany.,Departament de Fisica, Universitat Politecnica de Catalunya Edif. GAIA, Rambla Sant Nebridi 22, 08222 Terrassa, Barcelona, Spain
| |
Collapse
|
49
|
Leven I, Levy Y. Quantifying the two-state facilitated diffusion model of protein-DNA interactions. Nucleic Acids Res 2019; 47:5530-5538. [PMID: 31045207 PMCID: PMC6582340 DOI: 10.1093/nar/gkz308] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 04/13/2019] [Accepted: 04/17/2019] [Indexed: 01/13/2023] Open
Abstract
The current report extends the facilitated diffusion model to account for conflict between the search and recognition binding modes adopted by DNA-binding proteins (DBPs) as they search DNA and subsequently recognize and bind to their specific binding site. The speed of the search dynamics is governed by the energetic ruggedness of the protein-DNA landscape, whereas the rate for the recognition process is mostly dictated by the free energy barrier for the transition between the DBP's search and recognition binding modes. We show that these two modes are negatively coupled, such that fast 1D sliding and rapid target site recognition probabilities are unlikely to coexist. Thus, a tradeoff occurs between optimizing the timescales for finding and binding the target site. We find that these two kinetic properties can be balanced to produce a fast timescale for the total target search and recognition process by optimizing frustration. Quantification of the facilitated diffusion model by including a frustration term enables it to explain several experimental observations concerning search and recognition speeds. The extended model captures experimental estimate of the energetic ruggedness of the protein-DNA landscape and predicts how various molecular properties of protein-DNA binding affect recognition kinetics. Particularly, point mutations may change the frustration and so affect protein association with DNA, thus providing a means to modulate protein-DNA affinity by manipulating the protein's association or dissociation reactions.
Collapse
Affiliation(s)
- Itai Leven
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
50
|
Studying ribosome dynamics with simplified models. Methods 2019; 162-163:128-140. [DOI: 10.1016/j.ymeth.2019.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/22/2019] [Accepted: 03/23/2019] [Indexed: 12/24/2022] Open
|