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Fang J, Li T, Lee J, Im D, Xu L, Liu Y, Seo J, Zhang WB. A single-domain protein catenane of dihydrofolate reductase. Natl Sci Rev 2023; 10:nwad304. [PMID: 38188024 PMCID: PMC10769465 DOI: 10.1093/nsr/nwad304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 01/09/2024] Open
Abstract
A single-domain protein catenane refers to two mechanically interlocked polypeptide rings that fold synergistically into a compact and integrated structure, which is extremely rare in nature. Here, we report a single-domain protein catenane of dihydrofolate reductase (cat-DHFR). This design was achieved by rewiring the connectivity between secondary motifs to introduce artificial entanglement and synthesis was readily accomplished through a series of programmed and streamlined post-translational processing events in cells without any additional in vitro reactions. The target molecule contained few exogenous motifs and was thoroughly characterized using a combination of ultra-performance liquid chromatography-mass spectrometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, protease cleavage experiments and ion mobility spectrometry-mass spectrometry. Compared with the linear control, cat-DHFR retained its catalytic capability and exhibited enhanced stability against thermal or chemical denaturation due to conformational restriction. These results suggest that linear proteins may be converted into their concatenated single-domain counterparts with almost identical chemical compositions, well-preserved functions and elevated stabilities, representing an entirely new horizon in protein science.
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Affiliation(s)
- Jing Fang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Tianzuo Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jiyeon Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Dahye Im
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Lianjie Xu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yajie Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jongcheol Seo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Wen-Bin Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Beijing Academy of Artificial Intelligence, Beijing 100084, China
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2
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Cohen NR, Kayatekin C, Zitzewitz JA, Bilsel O, Matthews CR. Friction-Limited Folding of Disulfide-Reduced Monomeric SOD1. Biophys J 2020; 118:1992-2000. [PMID: 32191862 DOI: 10.1016/j.bpj.2020.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 02/04/2020] [Accepted: 02/28/2020] [Indexed: 11/16/2022] Open
Abstract
The folding reaction of a stable monomeric variant of Cu/Zn superoxide dismutase (mSOD1), an enzyme responsible for the conversion of superoxide free radicals into hydrogen peroxide and oxygen, is known to be among the slowest folding processes that adhere to two-state behavior. The long lifetime, ∼10 s, of the unfolded state presents ample opportunities for the polypeptide chain to transiently sample nonnative structures before the formation of the productive folding transition state. We recently observed the formation of a nonnative structure in a peptide model of the C-terminus of SOD1, a sequence that might serve as a potential source of internal chain friction-limited folding. To test for friction-limited folding, we performed a comprehensive thermodynamic and kinetic analysis of the folding mechanism of mSOD1 in the presence of the viscogens glycerol and glucose. Using a, to our knowledge, novel analysis of the folding reactions, we found the disulfide-reduced form of the protein that exposes the C-terminal sequence, but not its disulfide-oxidized counterpart that protects it, experiences internal chain friction during folding. The sensitivity of the internal friction to the disulfide bond status suggests that one or both of the cross-linked regions play a critical role in driving the friction-limited folding. We speculate that the molecular mechanisms giving rise to the internal friction of disulfide-reduced mSOD1 might play a role in the amyotrophic lateral sclerosis-linked aggregation of SOD1.
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Affiliation(s)
- Noah R Cohen
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Can Kayatekin
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts; Rare and Neurological Therapeutic Area, Sanofi, Framingham, Massachusetts
| | - Jill A Zitzewitz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Osman Bilsel
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - C R Matthews
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts.
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3
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Chen C, Yun JH, Kim JH, Park C. Effect of circular permutations on transient partial unfolding in proteins. Protein Sci 2016; 25:1483-91. [PMID: 27164316 DOI: 10.1002/pro.2945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 05/05/2016] [Accepted: 05/06/2016] [Indexed: 12/22/2022]
Abstract
Under native conditions, proteins can undergo transient partial unfolding, which may cause proteins to misfold or aggregate. A change in sequence connectivity by circular permutation may affect the energetics of transient partial unfolding in proteins without altering the three-dimensional structures. Using Escherichia coli dihydrofolate reductase (DHFR) as a model system, we investigated how circular permutation affects transient partial unfolding in proteins. We constructed three circular permutants, CP18, CP37, and CP87, with the new N-termini at residue 18, 37, and 87, respectively, and probed transient partial unfolding by native-state proteolysis. The new termini in CP18, CP37, and CP87 are within, near, and distal to the Met20 loop, which is known to be dynamic and also part of the region that undergoes transient unfolding in wild-type DHFR. The stabilities of both native and partially unfolded forms of CP18 are similar to those of wild-type DHFR, suggesting that the influence of introducing new termini in a dynamic region to the protein is minimal. CP37 has a significantly more accessible partially unfolded form than wild-type DHFR, demonstrating that introducing new termini near a dynamic region may promote transient partial unfolding. CP87 has significantly destabilized native and partially unfolded forms, confirming that modification of the folded region in a partially unfolded form destabilizes the partially unfolded form similar to the native form. Our findings provide valuable guidelines to control transient partial unfolding in designing circular permutants in proteins.
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Affiliation(s)
- Chen Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, 47907
| | - Jung-Hun Yun
- Faculty of Biotechnology, College of Applied Life Science, SARI, Jeju National University, Jeju-Do, 690-756, Korea
| | - Jae-Hoon Kim
- Faculty of Biotechnology, College of Applied Life Science, SARI, Jeju National University, Jeju-Do, 690-756, Korea
| | - Chiwook Park
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, 47907
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4
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Ohmae E, Tanaka S, Miyashita Y, Katayanagi K, Matsuo K. Vacuum-Ultraviolet Circular Dichroism Spectra of Escherichia coli Dihydrofolate Reductase and Its Mutants: Contributions of Phenylalanine and Tyrosine Side Chains and Exciton Coupling of Two Tryptophan Side Chains. J Phys Chem B 2015; 119:13002-8. [PMID: 26407224 DOI: 10.1021/acs.jpcb.5b07480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vacuum-ultraviolet (VUV) circular dichroism (CD) spectroscopy has recently been used for secondary structure analysis of proteins; however, the contribution of aromatic side chains to protein VUV CD spectra is unresolved. In this report, VUV CD spectra of 10 Escherichia coli dihydrofolate reductase (DHFR) mutants, in which each phenylalanine or tyrosine residue was mutated to leucine, were measured down to 175 nm at 25 °C and pH 8.0 to elucidate the contributions of these aromatic side chains to the high-energy transitions of peptide bonds. The VUV CD spectra of these mutants were different from the spectrum of the wild-type protein, indicating that the contribution of the phenylalanine and tyrosine side chains of DHFR extends to the VUV region. Furthermore, the VUV CD spectrum and the folate- or NADP(+)-induced spectral change of F103L mutant DHFR indicated a modification and regeneration of exciton coupling between the Trp47 and Trp74 side chains, respectively, suggesting that exciton coupling may also contribute to the CD spectrum of DHFR in the VUV region. These results should be useful for theoretically characterizing the contribution of aromatic side chains to protein CD spectra, leading to the improvement of protein secondary-structure analysis by VUV CD spectroscopy.
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Affiliation(s)
- Eiji Ohmae
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University , Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Suguru Tanaka
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University , Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Yurina Miyashita
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University , Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Katsuo Katayanagi
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University , Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Koichi Matsuo
- Hiroshima Synchrotron Radiation Center, Hiroshima University , 2-313 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan
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Folding pathway of a multidomain protein depends on its topology of domain connectivity. Proc Natl Acad Sci U S A 2014; 111:15969-74. [PMID: 25267632 DOI: 10.1073/pnas.1406244111] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
How do the folding mechanisms of multidomain proteins depend on protein topology? We addressed this question by developing an Ising-like structure-based model and applying it for the analysis of free-energy landscapes and folding kinetics of an example protein, Escherichia coli dihydrofolate reductase (DHFR). DHFR has two domains, one comprising discontinuous N- and C-terminal parts and the other comprising a continuous middle part of the chain. The simulated folding pathway of DHFR is a sequential process during which the continuous domain folds first, followed by the discontinuous domain, thereby avoiding the rapid decrease in conformation entropy caused by the association of the N- and C-terminal parts during the early phase of folding. Our simulated results consistently explain the observed experimental data on folding kinetics and predict an off-pathway structural fluctuation at equilibrium. For a circular permutant for which the topological complexity of wild-type DHFR is resolved, the balance between energy and entropy is modulated, resulting in the coexistence of the two folding pathways. This coexistence of pathways should account for the experimentally observed complex folding behavior of the circular permutant.
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Radou G, Enciso M, Krivov S, Paci E. Modulation of a protein free-energy landscape by circular permutation. J Phys Chem B 2013; 117:13743-7. [PMID: 24090448 PMCID: PMC3821731 DOI: 10.1021/jp406818t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
![]()
Circular
permutations usually retain the native structure and function
of a protein while inevitably perturbing its folding dynamics. By
using simulations with a structure-based model and a rigorous methodology
to determine free-energy surfaces from trajectories, we evaluate the
effect of a circular permutation on the free-energy landscape of the
protein T4 lysozyme. We observe changes which, although subtle, largely
affect the cooperativity between the two subdomains. Such a change
in cooperativity has been previously experimentally observed and recently
also characterized using single molecule optical tweezers and the
Crooks relation. The free-energy landscapes show that both the wild
type and circular permutant have an on-pathway intermediate, previously
experimentally characterized, in which one of the subdomains is completely
formed. The landscapes, however, differ in the position of the rate-limiting
step for folding, which occurs before the intermediate in the wild
type and after in the circular permutant. This shift of transition
state explains the observed change in the cooperativity. The underlying
free-energy landscape thus provides a microscopic description of the
folding dynamics and the connection between circular permutation and
the loss of cooperativity experimentally observed.
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Affiliation(s)
- Gaël Radou
- Astbury Centre for Structural Molecular Biology, University of Leeds , Leeds LS2 9JT, United Kingdom
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Abstract
Though lacking a well-defined three-dimensional structure, intrinsically unstructured proteins are ubiquitous in nature. These molecules play crucial roles in many cellular processes, especially signaling and regulation. Surprisingly, even enzyme catalysis can tolerate substantial disorder. This observation contravenes conventional wisdom but is relevant to an understanding of how protein dynamics modulates enzyme function. This chapter reviews properties and characteristics of disordered proteins, emphasizing examples of enzymes that lack defined structures, and considers implications of structural disorder for catalytic efficiency and evolution.
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Yeast hexokinase isoenzyme ScHxk2: stability of a two-domain protein with discontinuous domains. Protein Eng Des Sel 2010; 24:79-87. [DOI: 10.1093/protein/gzq098] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kinetic folding of Haloferax volcanii and Escherichia coli dihydrofolate reductases: haloadaptation by unfolded state destabilization at high ionic strength. J Mol Biol 2008; 376:1451-62. [PMID: 18207162 DOI: 10.1016/j.jmb.2007.12.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 12/15/2007] [Accepted: 12/20/2007] [Indexed: 11/24/2022]
Abstract
Salts affect protein stability by multiple mechanisms (e.g., the Hofmeister effect, preferential hydration, electrostatic effects and weak ion binding). These mechanisms can affect the stability of both the native state and the unfolded state. Previous equilibrium stability studies demonstrated that KCl stabilizes dihydrofolate reductases (DHFRs) from Escherichia coli (ecDHFR, E. coli DHFR) and Haloferax volcanii (hvDHFR1, H. volcanii DHFR encoded by the hdrA gene) with similar efficacies, despite adaptation to disparate physiological ionic strengths (0.2 M versus 2 M). Kinetic studies can provide insights on whether equilibrium effects reflect native state stabilization or unfolded state destabilization. Similar kinetic mechanisms describe the folding of urea-denatured ecDHFR and hvDHFR1: a 5-ms stopped-flow burst-phase species that folds to the native state through two sequential intermediates with relaxation times of 0.1-3 s and 25-100 s. The latter kinetic step is very similar to that observed for the refolding of hvDHFR1 from low ionic strength. The unfolding of hvDHFR1 at low ionic strength is relatively slow, suggesting kinetic stabilization as observed for some thermophilic enzymes. Increased KCl concentrations slow the urea-induced unfolding of ecDHFR and hvDHFR1, but much less than expected from equilibrium studies. Unfolding rates extrapolated to 0 M denaturant, k(unf)(H(2)O), are relatively independent of ionic strength, demonstrating that the KCl-induced stabilization of ecDHFR and hvDHFR1 results predominantly from destabilization of the unfolded state. This supports the hypothesis from previous equilibrium studies that haloadaptation harnesses the effects of elevated salt concentrations on the properties of the aqueous solvent to enhance protein stability.
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Hu Z, Bowen D, Southerland WM, del Sol A, Pan Y, Nussinov R, Ma B. Ligand binding and circular permutation modify residue interaction network in DHFR. PLoS Comput Biol 2007; 3:e117. [PMID: 17571919 PMCID: PMC1892607 DOI: 10.1371/journal.pcbi.0030117] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 05/11/2007] [Indexed: 01/14/2023] Open
Abstract
Residue interaction networks and loop motions are important for catalysis in dihydrofolate reductase (DHFR). Here, we investigate the effects of ligand binding and chain connectivity on network communication in DHFR. We carry out systematic network analysis and molecular dynamics simulations of the native DHFR and 19 of its circularly permuted variants by breaking the chain connections in ten folding element regions and in nine nonfolding element regions as observed by experiment. Our studies suggest that chain cleavage in folding element areas may deactivate DHFR due to large perturbations in the network properties near the active site. The protein active site is near or coincides with residues through which the shortest paths in the residue interaction network tend to go. Further, our network analysis reveals that ligand binding has “network-bridging effects” on the DHFR structure. Our results suggest that ligand binding leads to a modification, with most of the interaction networks now passing through the cofactor, shortening the average shortest path. Ligand binding at the active site has profound effects on the network centrality, especially the closeness. The cooperative movements within a protein concerning the binding and dissociation of the reactants and products could be important for protein function. Communication among the various parts of an enzyme can be achieved by the networks connecting amino acids through peptide backbone connections and nonbonded amino acid contact. We used dihydrofolate reductase (DHFR), a clinically important enzyme, as an example to explore the effects of amino acid communication on protein functions. We found that the peptide chain itself is an efficient “telephone wire” to transfer the communications. Breaking the telephone wire (peptide chain) at different points leads to differentiated behavior near the enzyme active site. The important points to keep the peptide chain communication are coupled with the place where protein folding occurs. On the other hand, ligand binding to the enzyme active site provides a “short cut” to the communication networks, with most of the interaction networks now passing through the added ligand and shortening the average communication path. We considered the short cuts to be “network-bridging effects” in the protein structure. The enzyme active site is the place where the short cut has the most dramatic effect in modifying protein communication networks.
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Affiliation(s)
- Zengjian Hu
- Department of Biochemistry and Molecular Biology, Howard University College of Medicine, Washington, District of Columbia, United States of America
| | - Donnell Bowen
- Department of Biochemistry and Molecular Biology, Howard University College of Medicine, Washington, District of Columbia, United States of America
| | - William M Southerland
- Department of Biochemistry and Molecular Biology, Howard University College of Medicine, Washington, District of Columbia, United States of America
- * To whom correspondence should be addressed. E-mail: (WMS); (BM)
| | - Antonio del Sol
- Bioinformatics Research Project, Research and Development Division, Fujirebio, Tokyo, Japan
| | - Yongping Pan
- Basic Research Program, Science Applications International Corporation—Frederick, Inc., Center for Cancer Research Nanobiology Program, National Cancer Institute—Frederick, Frederick, Maryland, United States of America
| | - Ruth Nussinov
- Basic Research Program, Science Applications International Corporation—Frederick, Inc., Center for Cancer Research Nanobiology Program, National Cancer Institute—Frederick, Frederick, Maryland, United States of America
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Buyong Ma
- Basic Research Program, Science Applications International Corporation—Frederick, Inc., Center for Cancer Research Nanobiology Program, National Cancer Institute—Frederick, Frederick, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail: (WMS); (BM)
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