1
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Pham TL, Thomas F. Design of Functional Globular β-Sheet Miniproteins. Chembiochem 2024; 25:e202300745. [PMID: 38275210 DOI: 10.1002/cbic.202300745] [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: 10/31/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/27/2024]
Abstract
The design of discrete β-sheet peptides is far less advanced than e. g. the design of α-helical peptides. The reputation of β-sheet peptides as being poorly soluble and aggregation-prone often hinders active design efforts. Here, we show that this reputation is unfounded. We demonstrate this by looking at the β-hairpin and WW domain. Their structure and folding have been extensively studied and they have long served as model systems to investigate protein folding and folding kinetics. The resulting fundamental understanding has led to the development of hyperstable β-sheet scaffolds that fold at temperatures of 100 °C or high concentrations of denaturants. These have been used to design functional miniproteins with protein or nucleic acid binding properties, in some cases with such success that medical applications are conceivable. The β-sheet scaffolds are not always completely rigid, but can be specifically designed to respond to changes in pH, redox potential or presence of metal ions. Some engineered β-sheet peptides also exhibit catalytic properties, although not comparable to those of natural proteins. Previous reviews have focused on the design of stably folded and non-aggregating β-sheet sequences. In our review, we now also address design strategies to obtain functional miniproteins from β-sheet folding motifs.
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Affiliation(s)
- Truc Lam Pham
- Truc Lam Pham, Prof. Dr. Franziska Thomas, Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Franziska Thomas
- Truc Lam Pham, Prof. Dr. Franziska Thomas, Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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2
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Abstract
The natural function of many proteins depends on their ability to switch their conformation driven by environmental changes. In this work, we present a small, monomeric β-sheet peptide that switches between a molten globule and a folded state through Zn(II) binding. The solvent-exposed hydrophobic core on the β-sheet surface was substituted by a His3-site, whereas the internal hydrophobic core was left intact. Zn(II) is specifically recognized by the peptide relative to other divalent metal ions, binds in the lower micromolar range, and can be removed and re-added without denaturation of the peptide. In addition, the peptide is fully pH-switchable, has a pKa of about 6, and survives several cycles of acidification and neutralization. In-depth structural characterization of the switch was achieved by concerted application of circular dichroism (CD) and multinuclear NMR spectroscopy. Thus, this study represents a viable approach toward a globular β-sheet Zn(II) mini-receptor prototype.
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Affiliation(s)
- Truc Lam Pham
- Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Centre for Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Franziska Thomas
- Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Centre for Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
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3
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Wu PY, Chen CY, Li JH, Lin JK, Chen TH, Huang SJ, Huang SL, Cheng RP. Effects of Arginine Deimination and Citrulline Side-Chain Length on Peptide Secondary Structure Formation. Chembiochem 2019; 20:2118-2124. [PMID: 31071235 DOI: 10.1002/cbic.201900231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Indexed: 01/07/2023]
Abstract
Post-translational modifications expand the chemical functionality of peptides and proteins beyond that originating from the encoded amino acids, but studies on the structural effects of these modifications have been limited. Arginine undergoes deimination to give citrulline (Cit), converting the positively charged guanidinium moiety into a neutral urea group. Herein, we report the effect of Arg deimination on secondary structure formation. To understand the reason for the number of methylene units in Cit, the effect of Cit side-chain length on secondary structure formation was also studied. Ala-based peptides and β-hairpin peptides were used to study α-helix and β-sheet formation, respectively. Peptides containing Cit analogues were prepared by an orthogonal protecting group strategy coupled with solid-phase carbamylation. The CD data for the Ala-based peptides were analyzed by using modified Lifson-Roig theory, showing that the helix propensity of Arg decreased upon deimination and that either shortening or lengthening Cit also decreased the helix propensity. The β-hairpin peptides were analyzed by NMR methods, showing minimal change in strand formation energetics upon Arg deimination. Altering the Cit side-chain length did not affect strand formation energetics either. These results should be useful for the preparation of urea-bearing systems and the design of peptides incorporating urea-bearing residues with varying side-chain length.
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Affiliation(s)
- Po-Yi Wu
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Chin-Yi Chen
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Jhe-Hao Li
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Jin-Kai Lin
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Ting-Hsuan Chen
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Shing-Jong Huang
- Instrument Center, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Shou-Ling Huang
- Instrument Center, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Richard P Cheng
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
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4
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Thomas NC, Bartlett GJ, Woolfson DN, Gellman SH. Toward a Soluble Model System for the Amyloid State. J Am Chem Soc 2017; 139:16434-16437. [PMID: 29116774 PMCID: PMC5939379 DOI: 10.1021/jacs.7b07225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The formation and deposition of amyloids is associated with many diseases. β-Sheet secondary structure is a common feature of amyloids, but the packing of sheets against one another is distinctive relative to soluble proteins. Standard methods that rely on perturbing a polypeptide's sequence and evaluating impact on folding can be problematic for amyloid aggregates because a single sequence can adopt multiple conformations and diverse packing arrangements. We describe initial steps toward a minimum-sized, soluble model system for the amyloid state that supports comparisons among sequence variants. Critical to this goal is development of a new linking strategy to enable intersheet association mediated by side chain interactions, which is characteristic of the amyloid state. The linker design we identified should ultimately support exploration of relationships between sequence and amyloid state stability for specific strand-association modes.
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Affiliation(s)
- Nicole C. Thomas
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Gail J. Bartlett
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, UK; School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1 TD, UK; BrisSynBio, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Derek N. Woolfson
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, UK; School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1 TD, UK; BrisSynBio, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706
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5
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DeBlase AF, Harrilal CP, Lawler JT, Burke NL, McLuckey SA, Zwier TS. Conformation-Specific Infrared and Ultraviolet Spectroscopy of Cold [YAPAA+H]+ and [YGPAA+H]+ Ions: A Stereochemical “Twist” on the β-Hairpin Turn. J Am Chem Soc 2017; 139:5481-5493. [PMID: 28353347 DOI: 10.1021/jacs.7b01315] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew F. DeBlase
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Christopher P. Harrilal
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - John T. Lawler
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Nicole L. Burke
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
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6
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Waters ML. From supramolecular chemistry to the nucleosome: studies in biomolecular recognition. Beilstein J Org Chem 2016; 12:1863-1869. [PMID: 27829892 PMCID: PMC5082656 DOI: 10.3762/bjoc.12.175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/05/2016] [Indexed: 11/23/2022] Open
Abstract
This review highlights the author’s indirect path to research at the interface of supramolecular chemistry and chemical biology.
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Affiliation(s)
- Marcey L Waters
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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7
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Körling M, Geyer A. Beyond Natural Limitations: Long-Range Influence of Non-Natural Flexible and Rigid β-Turn Mimetics in a Native β-Hairpin Motif. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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8
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Strumillo M, Beltrao P. Towards the computational design of protein post-translational regulation. Bioorg Med Chem 2015; 23:2877-82. [PMID: 25956846 PMCID: PMC4673319 DOI: 10.1016/j.bmc.2015.04.056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/16/2015] [Accepted: 04/17/2015] [Indexed: 12/19/2022]
Abstract
Protein post-translational modifications (PTMs) are a fast and versatility mechanism used by the cell to regulate the function of proteins in response to changing conditions. PTMs can alter the activity of proteins by allosteric regulation or by controlling protein interactions, localization and abundance. Recent advances in proteomics have revealed the extent of regulation by PTMs and the different mechanisms used in nature to exert control over protein function via PTMs. These developments can serve as the foundation for the rational design of protein regulation. Here we review the advances in methods to determine the function of PTMs, protein allosteric control and examples of rational design of PTM regulation. These advances create an opportunity to move synthetic biology forward by making use of a level of regulation that is of yet unexplored.
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Affiliation(s)
- Marta Strumillo
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
| | - Pedro Beltrao
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK; iBiMED and Department of Health Sciences, University of Aveiro, 3810-193 Aveiro, Portugal.
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9
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Maynard SJ, Almeida AM, Yoshimi Y, Gellman SH. New charge-bearing amino acid residues that promote β-sheet secondary structure. J Am Chem Soc 2014; 136:16683-8. [PMID: 25393077 PMCID: PMC4277779 DOI: 10.1021/ja510265e] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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Proteinogenic
amino acid residues that promote β-sheet secondary
structure are hydrophobic (e.g., Ile or Val) or only moderately polar
(e.g., Thr). The design of peptides intended to display β-sheet
secondary structure in water typically requires one set of residues
to ensure conformational stability and an orthogonal set, with charged
side chains, to ensure aqueous solubility and discourage self-association.
Here we describe new amino acids that manifest substantial β-sheet
propensity, by virtue of β-branching, and also bear an ionizable
group in the side chain.
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Affiliation(s)
- Stacy J Maynard
- Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States
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10
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Elbaum MB, Zondlo NJ. OGlcNAcylation and phosphorylation have similar structural effects in α-helices: post-translational modifications as inducible start and stop signals in α-helices, with greater structural effects on threonine modification. Biochemistry 2014; 53:2242-60. [PMID: 24641765 PMCID: PMC4004263 DOI: 10.1021/bi500117c] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
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OGlcNAcylation
and phosphorylation are the major competing intracellular
post-translational modifications of serine and threonine residues.
The structural effects of both post-translational modifications on
serine and threonine were examined within Baldwin model α-helical
peptides (Ac-AKAAAAKAAAAKAAGY-NH2 or Ac-YGAKAAAAKAAAAKAA-NH2). At the N-terminus of an α-helix, both phosphorylation
and OGlcNAcylation stabilized the α-helix relative to the free
hydroxyls, with a larger induced structure for phosphorylation than
for OGlcNAcylation, for the dianionic phosphate than for the monoanionic
phosphate, and for modifications on threonine than for modifications
on serine. Both phosphoserine and phosphothreonine resulted in peptides
more α-helical than alanine at the N-terminus, with dianionic
phosphothreonine the most α-helix-stabilizing residue here.
In contrast, in the interior of the α-helix, both post-translational
modifications were destabilizing with respect to the α-helix,
with the greatest destabilization seen for threonine OGlcNAcylation
at residue 5 and threonine phosphorylation at residue 10, with peptides
containing either post-translational modification existing as random
coils. At the C-terminus, both OGlcNAcylation and phosphorylation
were destabilizing with respect to the α-helix, though the induced
structural changes were less than in the interior of the α-helix.
In general, the structural effects of modifications on threonine were
greater than the effects on serine, because of both the lower α-helical
propensity of Thr and the more defined induced structures upon modification
of threonine than serine, suggesting threonine residues are particularly
important loci for structural effects of post-translational modifications.
The effects of serine and threonine post-translational modifications
are analogous to the effects of proline on α-helices, with the
effects of phosphothreonine being greater than those of proline throughout
the α-helix. These results provide a basis for understanding
the context-dependent structural effects of these competing protein
post-translational modifications.
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Affiliation(s)
- Michael B Elbaum
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
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11
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Brister M, Pandey AK, Bielska AA, Zondlo NJ. OGlcNAcylation and phosphorylation have opposing structural effects in tau: phosphothreonine induces particular conformational order. J Am Chem Soc 2014; 136:3803-16. [PMID: 24559475 PMCID: PMC4004249 DOI: 10.1021/ja407156m] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Indexed: 01/12/2023]
Abstract
Phosphorylation and OGlcNAcylation are dynamic intracellular protein post-translational modifications that frequently are alternatively observed on the same serine and threonine residues. Phosphorylation and OGlcNAcylation commonly occur in natively disordered regions of proteins, and often have opposing functional effects. In the microtubule-associated protein tau, hyperphosphorylation is associated with protein misfolding and aggregation as the neurofibrillary tangles of Alzheimer's disease, whereas OGlcNAcylation stabilizes the soluble form of tau. A series of peptides derived from the proline-rich domain (residues 174-251) of tau was synthesized, with free Ser/Thr hydroxyls, phosphorylated Ser/Thr (pSer/pThr), OGlcNAcylated Ser/Thr, and diethylphosphorylated Ser/Thr. Phosphorylation and OGlcNAcylation were found by CD and NMR to have opposing structural effects on polyproline helix (PPII) formation, with phosphorylation favoring PPII, OGlcNAcylation opposing PPII, and the free hydroxyls intermediate in structure, and with phosphorylation structural effects greater than OGlcNAcylation. For tau196-209, phosphorylation and OGlcNAcylation had similar structural effects, opposing a nascent α-helix. Phosphomimic Glu exhibited PPII-favoring structural effects. Structural changes due to Thr phosphorylation were greater than those of Ser phosphorylation or Glu, with particular conformational restriction as the dianion, with mean (3)JαN = 3.5 Hz (pThr) versus 5.4 Hz (pSer), compared to 7.2, 6.8, and 6.2 Hz for Thr, Ser, and Glu, respectively, values that correlate with the backbone torsion angle ϕ. Dianionic phosphothreonine induced strong phosphothreonine amide protection and downfield amide chemical shifts (δmean = 9.63 ppm), consistent with formation of a stable phosphate-amide hydrogen bond. These data suggest potentially greater structural importance of threonine phosphorylation than serine phosphorylation due to larger induced structural effects.
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Affiliation(s)
| | | | - Agata A. Bielska
- Department of Chemistry and
Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Neal J. Zondlo
- Department of Chemistry and
Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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12
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Kuo LH, Li JH, Kuo HT, Hung CY, Tsai HY, Chiu WC, Wu CH, Wang WR, Yang PA, Yao YC, Wong TW, Huang SJ, Huang SL, Cheng RP. Effect of charged amino acid side chain length at non-hydrogen bonded strand positions on β-hairpin stability. Biochemistry 2013; 52:7785-97. [PMID: 24156236 DOI: 10.1021/bi400911p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
β-Sheets have been implicated in various neurological disorders, and ∼20% of protein residues adopt a sheet conformation. Therefore, studies on the structural origin of sheet stability can provide fundamental knowledge with potential biomedical applications. Oppositely charged amino acids are frequently observed across one another in antiparallel β-sheets. Interestingly, the side chains of natural charged amino acids Asp, Glu, Arg, Lys have different numbers of hydrophobic methylenes linking the backbone to the hydrophilic charged functionalities. To explore the inherent effect of charged amino acid side chain length on antiparallel sheets, the stability of a designed hairpin motif containing charged amino acids with varying side chain lengths at non-hydrogen bonded positions was studied. Peptides with the guest position on the N-terminal strand and the C-terminal strand were investigated by NMR methods. The charged amino acids (Xaa) included negatively charged residues with a carboxylate group (Asp, Glu, Aad in increasing length), positively charged residues with an ammonium group (Dap, Dab, Orn, Lys in increasing length), and positively charged residues with a guanidinium group (Agp, Agb, Arg, Agh in increasing length). The fraction folded and folding free energy for each peptide were derived from the chemical shift deviation data. The stability of the peptides with the charged residues at the N-terminal guest position followed the trends: Asp > Glu > Aad, Dap < Dab < Orn ∼ Lys, and Agb < Arg < Agh < Agp. The stability of the peptides with the charged residues at the C-terminal guest position followed the trends: Asp < Glu < Aad, Dap ∼ Dab < Orn ∼ Lys, and Agb < Arg ∼ Agp < Agh. These trends were rationalized by thermodynamic sheet propensity and cross-strand interactions.
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Affiliation(s)
- Li-Hung Kuo
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
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13
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Edwards AVG, Edwards GJ, Schwämmle V, Saxtorph H, Larsen MR. Spatial and Temporal Effects in Protein Post-translational Modification Distributions in the Developing Mouse Brain. J Proteome Res 2013; 13:260-7. [DOI: 10.1021/pr4002977] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Alistair V. G. Edwards
- Department of Biochemistry
and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense, DK 5230, Denmark
| | | | - Veit Schwämmle
- Department of Biochemistry
and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense, DK 5230, Denmark
| | - Henrik Saxtorph
- Biomedical Laboratory, Odense University Hospital, Winsløwparken 23, Odense, DK 5000, Denmark
| | - Martin R. Larsen
- Department of Biochemistry
and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense, DK 5230, Denmark
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14
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Papamokos GV, Tziatzos G, Papageorgiou DG, Georgatos SD, Politou AS, Kaxiras E. Structural role of RKS motifs in chromatin interactions: a molecular dynamics study of HP1 bound to a variably modified histone tail. Biophys J 2012; 102:1926-33. [PMID: 22768949 DOI: 10.1016/j.bpj.2012.03.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 12/12/2011] [Accepted: 03/05/2012] [Indexed: 12/11/2022] Open
Abstract
The current understanding of epigenetic signaling assigns a central role to post-translational modifications that occur in the histone tails. In this context, it has been proposed that methylation of K9 and phosphorylation of S10 in the tail of histone H3 represent a binary switch that controls its reversible association to heterochromatin protein 1 (HP1). To test this hypothesis, we performed a comprehensive molecular dynamics study in which we analyzed a crystallographically defined complex that involves the HP1 chromodomain and an H3 tail peptide. Microsecond-long simulations show that the binding of the trimethylated K9 H3 peptide in the aromatic cage of HP1 is only slightly affected by S10 phosphorylation, because the modified K9 and S10 do not interact directly with one another. Instead, the phosphate group of S10 seems to form a persistent intramolecular salt bridge with R8, an interaction that can provoke a major structural change and alter the hydrogen-bonding regime in the H3-HP1 complex. These observations suggest that interactions between adjacent methyl-lysine and phosphoserine side chains do not by themselves provide a binary switch in the H3-HP1 system, but arginine-phosphoserine interactions, which occur in both histones and nonhistone proteins in the context of a conserved RKS motif, are likely to serve a key regulatory function.
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Affiliation(s)
- George V Papamokos
- Laboratory of Biological Chemistry, Medical School, University of Ioannina, Ioannina, Greece
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15
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Zheng X, Wu C, Ponder JW, Marshall GR. Molecular dynamics of β-hairpin models of epigenetic recognition motifs. J Am Chem Soc 2012; 134:15970-8. [PMID: 22934656 DOI: 10.1021/ja306803v] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The conformations and stabilities of the β-hairpin model peptides of Waters (Riemen, A. J.; Waters, M. L. Biochemistry 2009, 48, 1525; Hughes, R. M.; Benshoff, M. L.; Waters, M. L. Chemistry 2007, 13, 5753) have been experimentally characterized as a function of lysine ε-methylation. These models were developed to explore molecular recognition of known epigenetic recognition motifs. This system offered an opportunity to computationally examine the role of cation-π interactions, desolvation of the ε-methylated ammonium groups, and aromatic/aromatic interactions on the observed differences in NMR spectra. AMOEBA, a second-generation force field (Ponder, J. W.; Wu, C.; Ren, P.; Pande, V. S.; Chodera, J. D.; Schnieders, M. J.; Haque, I.; Mobley, D. L.; Lambrecht, D. S.; DiStasio, R. A., Jr.; Head-Gordon, M.; Clark, G. N.; Johnson, M. E.; Head-Gordon, T. J. Phys. Chem. B 2010, 114, 2549), was chosen as it includes both multipole electrostatics and polarizability thought to be essential to accurately characterize such interactions. Independent parametrization of ε-methylated amines was required from which aqueous solvation free energies were estimated and shown to agree with literature values. Molecular dynamics simulations (100 ns) using the derived parameters with model peptides, such as Ac-R-W-V-W-V-N-G-Orn-K(Me)(n)-I-L-Q-NH(2), where n = 0, 1, 2, or 3, were conducted in explicit solvent. Distances between the centers of the indole rings of the two-tryptophan residues, 2 and 4, and the ε-methylated ammonium group on Lys-9 as well as the distance between the N- and C-termini were monitored to estimate the strength and orientation of the cation-π and aromatic/aromatic interactions. In agreement with the experimental data, the stability of the β-hairpin increased significantly with lysine ε-methylation. The ability of MD simulations to reproduce the observed NOEs for the four peptides was further estimated for the monopole-based force fields, AMBER, CHARMM, and OPLSAA. AMOEBA correctly predicted over 80% of the observed NOEs for all 4 peptides, while the three-monopole force fields were 40-50% predictive in only 2 cases and approximately 10% in the other 10 examples. Preliminary analysis suggests that the decreased cost of desolvation of the substituted ammonium group significantly compensated for the reduced cation-π interaction resulting from the increased separation due to steric bulk of the ε-methylated amines.
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Affiliation(s)
- Xiange Zheng
- Department of Chemistry and of Biochemistry, Washington University, St. Louis, Missouri 63105, United States
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16
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Molecular dynamics simulation exploration of unfolding and refolding of a ten-amino acid miniprotein. Amino Acids 2011; 43:557-65. [DOI: 10.1007/s00726-011-1150-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
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17
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Contributions of cation–π interactions to the collagen triple helix stability. Arch Biochem Biophys 2011; 508:46-53. [DOI: 10.1016/j.abb.2011.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 01/07/2011] [Accepted: 01/12/2011] [Indexed: 11/20/2022]
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