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Qianzhu H, Abdelkader EH, Otting G, Huber T. Genetic Encoding of Fluoro-l-tryptophans for Site-Specific Detection of Conformational Heterogeneity in Proteins by NMR Spectroscopy. J Am Chem Soc 2024; 146:13641-13650. [PMID: 38687675 DOI: 10.1021/jacs.4c03743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The substitution of a single hydrogen atom in a protein by fluorine yields a site-specific probe for sensitive detection by 19F nuclear magnetic resonance (NMR) spectroscopy, where the absence of background signal from the protein facilitates the detection of minor conformational species. We developed genetic encoding systems for the site-selective incorporation of 4-fluorotryptophan, 5-fluorotryptophan, 6-fluorotryptophan, and 7-fluorotryptophan in response to an amber stop codon and used them to investigate conformational heterogeneity in a designed amino acid binding protein and in flaviviral NS2B-NS3 proteases. These proteases have been shown to present variable conformations in X-ray crystal structures, including flips of the indole side chains of tryptophan residues. The 19F NMR spectra of different fluorotryptophan isomers installed at the conserved site of Trp83 indicate that the indole ring flip is common in flaviviral NS2B-NS3 proteases in the apo state and suppressed by an active-site inhibitor.
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Affiliation(s)
- Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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2
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Frkic RL, Tan YJ, Abdelkader EH, Maleckis A, Tarcoveanu E, Nitsche C, Otting G, Jackson CJ. Conformational Preferences of the Non-Canonical Amino Acids (2 S,4 S)-5-Fluoroleucine, (2 S,4 R)-5-Fluoroleucine, and 5,5'-Difluoroleucine in a Protein. Biochemistry 2024. [PMID: 38742763 DOI: 10.1021/acs.biochem.4c00081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Proteins produced with leucine analogues, where CH2F groups substitute specific methyl groups, can readily be probed by 19F NMR spectroscopy. As CF and CH groups are similar in hydrophobicity and size, fluorinated leucines are expected to cause minimal structural perturbation, but the impact of fluorine on the rotational freedom of CH2F groups is unclear. We present high-resolution crystal structures of Escherichia coli peptidyl-prolyl cis-trans isomerase B (PpiB) prepared with uniform high-level substitution of leucine by (2S,4S)-5-fluoroleucine, (2S,4R)-5-fluoroleucine, or 5,5'-difluoroleucine. Apart from the fluorinated leucine residues, the structures show complete structural conservation of the protein backbone and the amino acid side chains except for a single isoleucine side chain located next to a fluorine atom in the hydrophobic core of the protein. The carbon skeletons of the fluorinated leucine side chains are also mostly conserved. The CH2F groups show a strong preference for staggered rotamers and often appear locked into single rotamers. Substitution of leucine CH3 groups for CH2F groups is thus readily tolerated in the three-dimensional (3D) structure of a protein, and the rotation of CH2F groups can be halted at cryogenic temperatures.
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Affiliation(s)
- Rebecca L Frkic
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Yi Jiun Tan
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Ansis Maleckis
- Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia
| | - Eliza Tarcoveanu
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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3
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Maxwell M, Tan YJ, Lee R, Huber T, Otting G. Correction to "Electrostatic Contribution to 19F Chemical Shifts in Fluorotryptophans in Proteins". Biochemistry 2024; 63:367. [PMID: 38241226 DOI: 10.1021/acs.biochem.3c00723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2024]
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Abdelkader EH, Qianzhu H, Huber T, Otting G. Genetic Encoding of 7-Aza-l-tryptophan: Isoelectronic Substitution of a Single CH-Group in a Protein for a Nitrogen Atom for Site-Selective Isotope Labeling. ACS Sens 2023; 8:4402-4406. [PMID: 37890165 DOI: 10.1021/acssensors.3c01904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Abstract
Genetic encoding of a noncanonical amino acid (ncAA) in an in vivo expression system requires an aminoacyl-tRNA synthetase that specifically recognizes the ncAA, while the ncAA must not be recognized by the canonical protein expression machinery. We succeeded in genetically encoding 7-aza-tryptophan (7AW), which is isoelectronic with tryptophan. The system is fully orthogonal to protein expression in Escherichia coli, enabling high-yielding site-selective isotope labeling in vivo. 7AW is readily synthesized from serine and 7-aza-indole using a tryptophan synthetase β-subunit (TrpB) mutant, affording easy access to isotope-labeled 7AW. Using labeled 7AW produced from 15N/13C-labeled serine, we produced 7AW mutants of the 25 kDa Zika virus NS2B-NS3 protease. 15N-HSQC spectra display single cross-peaks at chemical shifts near those observed for the wild-type protein labeled with 15N/13C-tryptophan, confirming the structural integrity of the protein and yielding straightforward NMR resonance assignments for site-specific probing.
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Affiliation(s)
- Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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5
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Maxwell M, Tan YJ, Lee R, Huber T, Otting G. Electrostatic Contribution to 19F Chemical Shifts in Fluorotryptophans in Proteins. Biochemistry 2023; 62:3255-3264. [PMID: 37934875 DOI: 10.1021/acs.biochem.3c00408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
DFT calculations indicate that the 19F chemical shifts of aromatic rings containing single fluorine substituents are sensitive to the electric fields and electric field gradients at the position of the fluorine atom. The present work explores whether long-range structure restraints can be gained from changes in 19F chemical shifts following mutations of charged to uncharged residues. 19F chemical shifts of fluorotryptophan residues were measured in two different proteins, GB1 and the NT* domain, following mutations of single asparagine residues to aspartic acid. Four different versions of fluorotryptophan were investigated, including 4-, 5-, 6-, and 7-fluorotryptophan, which were simultaneously installed by cell-free protein synthesis using 4-, 5-, 6-, and 7-fluoroindole as precursors for the tryptophan synthase present in the S30 extract. For comparison, the 1H chemical shifts of the corresponding nonfluorinated protein mutants produced with 13C-labeled tryptophan were also measured. The results show that the 19F chemical shifts respond more sensitively to the charge mutations than the 1H chemical shifts in the nonfluorinated references, but the chemical shift changes were much smaller than predicted by DFT calculations of fluoroindoles in the electric field of a partial charge in vacuum, indicating comprehensive dielectric shielding by water and protein. No straightforward correlation with the location of the charge mutation could be established.
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Affiliation(s)
- Michael Maxwell
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Yi Jiun Tan
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Richmond Lee
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2500, New South Wales, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Gottfried Otting
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
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Van Raad D, Huber T, Otting G. Improved spectral resolution of [ 13C, 1H]-HSQC spectra of aromatic amino acid residues in proteins produced by cell-free synthesis from inexpensive 13C-labelled precursors. J Biomol NMR 2023; 77:183-190. [PMID: 37338652 PMCID: PMC10406723 DOI: 10.1007/s10858-023-00420-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/23/2023] [Indexed: 06/21/2023]
Abstract
Cell-free protein synthesis using eCells allows production of amino acids from inexpensive 13C-labelled precursors. We show that the metabolic pathway converting pyruvate, glucose and erythrose into aromatic amino acids is maintained in eCells. Judicious choice of 13C-labelled starting material leads to proteins, where the sidechains of aromatic amino acids display [13C,1H]-HSQC cross-peaks free of one-bond 13C-13C couplings. Selective 13C-labelling of tyrosine and phenylalanine residues is achieved simply by using different compositions of the reaction buffers.
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Affiliation(s)
- Damian Van Raad
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
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7
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Van Raad D, Otting G, Huber T. Cell-free synthesis of proteins with selectively 13C-labelled methyl groups from inexpensive precursors. Magn Reson (Gott) 2023; 4:187-197. [PMID: 37904855 PMCID: PMC10583297 DOI: 10.5194/mr-4-187-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/30/2023] [Indexed: 11/01/2023]
Abstract
The novel eCell system maintains the activity of the entire repertoire of metabolic Escherichia coli enzymes in cell-free protein synthesis. We show that this can be harnessed to produce proteins with selectively 13 C-labelled amino acids from inexpensive 13 C-labelled precursors. The system is demonstrated with selective 13 C labelling of methyl groups in the proteins ubiquitin and peptidyl-prolyl cis-trans isomerase B. Starting from 3-13 C-pyruvate, 13 C-HSQC cross-peaks are obtained devoid of one-bond 13 C-13 C scalar couplings. Starting from 2-13 C-methyl-acetolactate, single methyl groups of valine and leucine are labelled. Labelling efficiencies are 70 % or higher, and the method allows us to produce perdeuterated proteins with protonated methyl groups in a residue-selective manner. The system uses the isotope-labelled precursors sparingly and is readily scalable.
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Affiliation(s)
- Damian Van Raad
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Innovations in Peptide & Protein
Science, Research School of Chemistry, Australian National University,
Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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Ekanayake KB, Mahawaththa MC, Qianzhu H, Abdelkader EH, George J, Ullrich S, Murphy RB, Fry SE, Johansen-Leete J, Payne RJ, Nitsche C, Huber T, Otting G. Probing Ligand Binding Sites on Large Proteins by Nuclear Magnetic Resonance Spectroscopy of Genetically Encoded Non-Canonical Amino Acids. J Med Chem 2023; 66:5289-5304. [PMID: 36920850 DOI: 10.1021/acs.jmedchem.3c00222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
N6-(((trimethylsilyl)-methoxy)carbonyl)-l-lysine (TMSK) and N6-trifluoroacetyl-l-lysine (TFAK) are non-canonical amino acids, which can be installed in proteins by genetic encoding. In addition, we describe a new aminoacyl-tRNA synthetase specific for N6-(((trimethylsilyl)methyl)-carbamoyl)-l-lysine (TMSNK), which is chemically more stable than TMSK. Using the dimeric SARS-CoV-2 main protease (Mpro) as a model system with three different ligands, we show that the 1H and 19F nuclei of the solvent-exposed trimethylsilyl and CF3 groups produce intense signals in the nuclear magnetic resonance (NMR) spectrum. Their response to active-site ligands differed significantly when positioned near rather than far from the active site. Conversely, the NMR probes failed to confirm the previously reported binding site of the ligand pelitinib, which was found to enhance the activity of Mpro by promoting the formation of the enzymatically active dimer. In summary, the amino acids TMSK, TMSNK, and TFAK open an attractive path for site-specific NMR analysis of ligand binding to large proteins of limited stability and at low concentrations.
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Affiliation(s)
- Kasuni B Ekanayake
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Acton, Canberra, Australian Capital Territory 2601, Australia
| | - Mithun C Mahawaththa
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Acton, Canberra, Australian Capital Territory 2601, Australia
| | - Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Elwy H Abdelkader
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Acton, Canberra, Australian Capital Territory 2601, Australia
| | - Josemon George
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Sven Ullrich
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Rhys B Murphy
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Sarah E Fry
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jason Johansen-Leete
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Richard J Payne
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Acton, Canberra 2601, Australia
| | - Gottfried Otting
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Acton, Canberra, Australian Capital Territory 2601, Australia
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Mekkattu Tharayil S, Mahawaththa MC, Feintuch A, Maleckis A, Ullrich S, Morewood R, Maxwell MJ, Huber T, Nitsche C, Goldfarb D, Otting G. Site-selective generation of lanthanoid binding sites on proteins using 4-fluoro-2,6-dicyanopyridine. Magn Reson (Gott) 2022; 3:169-182. [PMID: 37904871 PMCID: PMC10539774 DOI: 10.5194/mr-3-169-2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/18/2022] [Indexed: 11/01/2023]
Abstract
The paramagnetism of a lanthanoid tag site-specifically installed on a protein provides a rich source of structural information accessible by nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy. Here we report a lanthanoid tag for selective reaction with cysteine or selenocysteine with formation of a (seleno)thioether bond and a short tether between the lanthanoid ion and the protein backbone. The tag is assembled on the protein in three steps, comprising (i) reaction with 4-fluoro-2,6-dicyanopyridine (FDCP); (ii) reaction of the cyano groups with α -cysteine, penicillamine or β -cysteine to complete the lanthanoid chelating moiety; and (iii) titration with a lanthanoid ion. FDCP reacts much faster with selenocysteine than cysteine, opening a route for selective tagging in the presence of solvent-exposed cysteine residues. Loaded with Tb 3 + and Tm 3 + ions, pseudocontact shifts were observed in protein NMR spectra, confirming that the tag delivers good immobilisation of the lanthanoid ion relative to the protein, which was also manifested in residual dipolar couplings. Completion of the tag with different 1,2-aminothiol compounds resulted in different magnetic susceptibility tensors. In addition, the tag proved suitable for measuring distance distributions in double electron-electron resonance experiments after titration with Gd 3 + ions.
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Affiliation(s)
| | - Mithun C. Mahawaththa
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ansis Maleckis
- Latvian Institute of Organic Synthesis, Aizkraukles 21, 1006 Riga, Latvia
| | - Sven Ullrich
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Richard Morewood
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Michael J. Maxwell
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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Abstract
Paramagnetic chemical probes have been used in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy for more than four decades. Recent years witnessed a great increase in the variety of probes for the study of biological macromolecules (proteins, nucleic acids, and oligosaccharides). This Review aims to provide a comprehensive overview of the existing paramagnetic chemical probes, including chemical synthetic approaches, functional properties, and selected applications. Recent developments have seen, in particular, a rapid expansion of the range of lanthanoid probes with anisotropic magnetic susceptibilities for the generation of structural restraints based on residual dipolar couplings and pseudocontact shifts in solution and solid state NMR spectroscopy, mostly for protein studies. Also many new isotropic paramagnetic probes, suitable for NMR measurements of paramagnetic relaxation enhancements, as well as EPR spectroscopic studies (in particular double resonance techniques) have been developed and employed to investigate biological macromolecules. Notwithstanding the large number of reported probes, only few have found broad application and further development of probes for dedicated applications is foreseen.
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Affiliation(s)
- Qing Miao
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- School
of Chemistry &Chemical Engineering, Shaanxi University of Science & Technology, Xi’an710021, China
| | - Christoph Nitsche
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Henry Orton
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Mark Overhand
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gottfried Otting
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Marcellus Ubbink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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Orton HW, Abdelkader EH, Topping L, Butler SJ, Otting G. Localising nuclear spins by pseudocontact shifts from a single tagging site. Magn Reson (Gott) 2022; 3:65-76. [PMID: 37905181 PMCID: PMC10539793 DOI: 10.5194/mr-3-65-2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/18/2022] [Indexed: 11/01/2023]
Abstract
Ligating a protein at a specific site with a tag molecule containing a paramagnetic metal ion provides a versatile way of generating pseudocontact shifts (PCSs) in nuclear magnetic resonance (NMR) spectra. PCSs can be observed for nuclear spins far from the tagging site, and PCSs generated from multiple tagging sites have been shown to enable highly accurate structure determinations at specific sites of interest, even when using flexible tags, provided the fitted effective magnetic susceptibility anisotropy (Δ χ ) tensors accurately back-calculate the experimental PCSs measured in the immediate vicinity of the site of interest. The present work investigates the situation where only the local structure of a protein region or bound ligand is to be determined rather than the structure of the entire molecular system. In this case, the need for gathering structural information from tags deployed at multiple sites may be queried. Our study presents a computational simulation of the structural information available from samples produced with single tags attached at up to six different sites, up to six different tags attached to a single site, and in-between scenarios. The results indicate that the number of tags is more important than the number of tagging sites. This has important practical implications, as it is much easier to identify a single site that is suitable for tagging than multiple ones. In an initial experimental demonstration with the ubiquitin mutant S57C, PCSs generated with four different tags at a single site are shown to accurately pinpoint the location of amide protons in different segments of the protein.
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Affiliation(s)
- Henry W Orton
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Lydia Topping
- Department of Chemistry, Loughborough University, Epinal Way, Loughborough, LE11 3TU, United Kingdom
| | - Stephen J Butler
- Department of Chemistry, Loughborough University, Epinal Way, Loughborough, LE11 3TU, United Kingdom
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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Jash C, Feintuch A, Nudelman S, Manukovsky N, Abdelkader EH, Bhattacharya S, Jeschke G, Otting G, Goldfarb D. DEER experiments reveal fundamental differences between calmodulin complexes with IQ and MARCKS peptides in solution. Structure 2022; 30:813-827.e5. [PMID: 35397204 DOI: 10.1016/j.str.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 02/09/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022]
Abstract
Calmodulin (CaM) is a calcium-binding protein that regulates the function of many proteins by indirectly conferring Ca2+ sensitivity, and it undergoes a large conformational change on partners' binding. We compared the solution binding mode of the target peptides MARCKS and IQ by double electron-electron resonance (DEER) distance measurements and paramagnetic NMR. We combined nitroxide and Gd(III) spin labels, including specific substitution of one of the Ca2+ ions in the CaM mutant N60D by a Gd(III) ion. The binding of MARCKS to holo-CaM resulted neither in a closed conformation nor in a unique relative orientation between the two CaM domains, in contrast with the crystal structure. Binding of IQ to holo-CaM did generate a closed conformation. Using elastic network modeling and 12 distance restraints obtained from multiple holo-CaM/IQ DEER data, we derived a model of the solution structure, which is in reasonable agreement with the crystal structure.
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Affiliation(s)
- Chandrima Jash
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Akiva Feintuch
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Shira Nudelman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Nurit Manukovsky
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Sudeshna Bhattacharya
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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13
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Maleckis A, Abdelkader EH, Herath ID, Otting G. Synthesis of fluorinated leucines, valines and alanines for use in protein NMR. Org Biomol Chem 2022; 20:2424-2432. [PMID: 35262139 DOI: 10.1039/d2ob00145d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Efficient syntheses of fluorinated leucines, valines and alanines are described. The synthetic routes provide expedient access to various 13C/15N/D isotopologues requiring solely readily available and inexpensive isotope containing reagents such as NaBD4, carbon-13C dioxide and sodium azide-1-15N. The lightly fluorinated leucines and valines were found to be good substrates for cell-free protein expression and even 3-fluoroalanine, which is highly toxic to bacteria in vivo, could be incorporated into proteins this way. 19F-NMR spectra of the protein GB1 produced with these amino acids showed large chemical shift dispersions. Particularly high incorporation yields and clean 19F-NMR spectra were obtained for GB1 produced with valine residues, which had been synthesized with a single fluorine substituting a hydrogen stereospecifically in one of the methyl groups.
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Affiliation(s)
- Ansis Maleckis
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia.
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Iresha D Herath
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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14
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Abdelkader EH, Qianzhu H, George J, Frkic RL, Jackson CJ, Nitsche C, Otting G, Huber T. Genetic Encoding of Cyanopyridylalanine for In‐Cell Protein Macrocyclization by the Nitrile–Aminothiol Click Reaction. Angew Chem Int Ed Engl 2022; 61:e202114154. [PMID: 35102680 PMCID: PMC9304162 DOI: 10.1002/anie.202114154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Indexed: 12/04/2022]
Abstract
Cyanopyridylalanines are non‐canonical amino acids that react with aminothiol compounds under physiological conditions in a biocompatible manner without requiring added catalyst. Here we present newly developed aminoacyl‐tRNA synthetases for genetic encoding of meta‐ and para‐cyanopyridylalanine to enable the site‐specific attachment of a wide range of different functionalities. The outstanding utility of the cyanopyridine moiety is demonstrated by examples of i) post‐translational functionalization of proteins, ii) in‐cell macrocyclization of peptides and proteins, and iii) protein stapling. The biocompatible nature of the protein ligation chemistry enabled by the cyanopyridylalanine amino acid opens a new path to specific in vivo protein modifications in complex biological environments.
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Affiliation(s)
- Elwy H. Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Haocheng Qianzhu
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Josemon George
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Rebecca L. Frkic
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Colin J. Jackson
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Christoph Nitsche
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Thomas Huber
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
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15
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Abdelkader EH, Qianzhu H, George J, Frkic RL, Jackson CJ, Nitsche C, Otting G, Huber T. Genetic Encoding of Cyanopyridylalanine for In‐Cell Protein Macrocyclization by the Nitrile–Aminothiol Click Reaction. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Elwy H. Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Haocheng Qianzhu
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Josemon George
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Rebecca L. Frkic
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Colin J. Jackson
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Christoph Nitsche
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science Research School of Chemistry Australian National University Canberra ACT 2601 Australia
| | - Thomas Huber
- Research School of Chemistry Australian National University Canberra ACT 2601 Australia
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16
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Qianzhu H, Abdelkader EH, Herath ID, Otting G, Huber T. Site-Specific Incorporation of 7-Fluoro-L-tryptophan into Proteins by Genetic Encoding to Monitor Ligand Binding by 19F NMR Spectroscopy. ACS Sens 2022; 7:44-49. [PMID: 35005899 DOI: 10.1021/acssensors.1c02467] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A mutant aminoacyl-tRNA synthetase identified by a library selection system affords site-specific incorporation of 7-fluoro-L-tryptophan in response to an amber stop codon. The enzyme allows the production of proteins with a single hydrogen atom replaced by a fluorine atom as a sensitive nuclear magnetic resonance (NMR) probe. The substitution of a single hydrogen atom by another element that is as closely similar in size and hydrophobicity as possible minimizes possible perturbations in the structure, stability, and solubility of the protein. The fluorine atom enables site-selective monitoring of the protein response to ligand binding by 19F NMR spectroscopy, as demonstrated with the Zika virus NS2B-NS3 protease.
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Affiliation(s)
- Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H. Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Iresha D. Herath
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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17
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Orton H, Herath I, Maleckis A, Jabar S, Szabo M, Graham B, Breen C, Topping L, Butler S, Otting G. Localising individual atoms of tryptophan side chains in the metallo- β-lactamase IMP-1 by pseudocontact shifts from paramagnetic lanthanoid tags at multiple sites. Magn Reson (Gott) 2022; 3:1-13. [PMID: 37905175 PMCID: PMC10583275 DOI: 10.5194/mr-3-1-2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/21/2021] [Indexed: 11/01/2023]
Abstract
The metallo-β -lactamase IMP-1 features a flexible loop near the active site that assumes different conformations in single crystal structures, which may assist in substrate binding and enzymatic activity. To probe the position of this loop, we labelled the tryptophan residues of IMP-1 with 7-13 C-indole and the protein with lanthanoid tags at three different sites. The magnetic susceptibility anisotropy (Δ χ ) tensors were determined by measuring pseudocontact shifts (PCSs) of backbone amide protons. The Δ χ tensors were subsequently used to identify the atomic coordinates of the tryptophan side chains in the protein. The PCSs were sufficient to determine the location of Trp28, which is in the active site loop targeted by our experiments, with high accuracy. Its average atomic coordinates showed barely significant changes in response to the inhibitor captopril. It was found that localisation spaces could be defined with better accuracy by including only the PCSs of a single paramagnetic lanthanoid ion for each tag and tagging site. The effect was attributed to the shallow angle with which PCS isosurfaces tend to intersect if generated by tags and tagging sites that are identical except for the paramagnetic lanthanoid ion.
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Affiliation(s)
- Henry W. Orton
- ARC Centre of Excellence for Innovations in Peptide & Protein
Science, Research School of Chemistry, Australian National University,
Canberra, ACT 2601, Australia
| | - Iresha D. Herath
- Research School of Chemistry, The Australian National University,
Sullivans Creek Road, Canberra ACT 2601, Australia
| | - Ansis Maleckis
- Latvian Institute of Organic Synthesis, Aizkraukles 21, 1006 Riga,
Latvia
| | - Shereen Jabar
- Research School of Chemistry, The Australian National University,
Sullivans Creek Road, Canberra ACT 2601, Australia
| | - Monika Szabo
- Monash Institute of Pharmaceutical Sciences, Monash University,
Parkville, VIC 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University,
Parkville, VIC 3052, Australia
| | - Colum Breen
- Department of Chemistry, Loughborough University, Epinal Way, Loughborough, LE11 3TU, United Kingdom
| | - Lydia Topping
- Department of Chemistry, Loughborough University, Epinal Way, Loughborough, LE11 3TU, United Kingdom
| | - Stephen J. Butler
- Department of Chemistry, Loughborough University, Epinal Way, Loughborough, LE11 3TU, United Kingdom
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein
Science, Research School of Chemistry, Australian National University,
Canberra, ACT 2601, Australia
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18
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Johansen-Leete J, Ullrich S, Fry SE, Frkic R, Bedding MJ, Aggarwal A, Ashhurst AS, Ekanayake KB, Mahawaththa MC, Sasi VM, Luedtke S, Ford DJ, O'Donoghue AJ, Passioura T, Larance M, Otting G, Turville S, Jackson CJ, Nitsche C, Payne RJ. Antiviral cyclic peptides targeting the main protease of SARS-CoV-2. Chem Sci 2022; 13:3826-3836. [PMID: 35432913 PMCID: PMC8966731 DOI: 10.1039/d1sc06750h] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 02/28/2022] [Indexed: 12/17/2022] Open
Abstract
Antivirals that specifically target SARS-CoV-2 are needed to control the COVID-19 pandemic. The main protease (Mpro) is essential for SARS-CoV-2 replication and is an attractive target for antiviral development. Here we report the use of the Random nonstandard Peptide Integrated Discovery (RaPID) mRNA display on a chemically cross-linked SARS-CoV-2 Mpro dimer, which yielded several high-affinity thioether-linked cyclic peptide inhibitors of the protease. Structural analysis of Mpro complexed with a selenoether analogue of the highest-affinity peptide revealed key binding interactions, including glutamine and leucine residues in sites S1 and S2, respectively, and a binding epitope straddling both protein chains in the physiological dimer. Several of these Mpro peptide inhibitors possessed antiviral activity against SARS-CoV-2 in vitro with EC50 values in the low micromolar range. These cyclic peptides serve as a foundation for the development of much needed antivirals that specifically target SARS-CoV-2. RaPID mRNA display was used for the discovery of antiviral cyclic peptides that potently and selectively inhibit SARS-CoV-2 Mpro. The most potent inhibitor exhibited a novel binding mode, interacting with residues across the homodimer interface.![]()
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Affiliation(s)
- Jason Johansen-Leete
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Sven Ullrich
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Sarah E. Fry
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rebecca Frkic
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | - Max J. Bedding
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Anneliese S. Ashhurst
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Kasuni B. Ekanayake
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | - Mithun C. Mahawaththa
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | - Vishnu M. Sasi
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | - Stephanie Luedtke
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Daniel J. Ford
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Anthony J. O'Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Toby Passioura
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Sydney Analytical, The University of Sydney, Sydney, NSW 2006, Australia
| | - Mark Larance
- Sydney Analytical, The University of Sydney, Sydney, NSW 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW 2006, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | | | - Colin J. Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Australian National University, Canberra, ACT 2601, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Richard J. Payne
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, NSW 2006, Australia
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19
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Judd M, Abdelkader EH, Qi M, Harmer JR, Huber T, Godt A, Savitsky A, Otting G, Cox N. Short-range ENDOR distance measurements between Gd(III) and trifluoromethyl labels in proteins. Phys Chem Chem Phys 2022; 24:25214-25226. [DOI: 10.1039/d2cp02889a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The measurement of distances in proteins can be challenging in the 5–20 Å range, which is outside the range accessible through conventional NMR and EPR methods. Recently it was demonstrated...
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20
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Mahawaththa MC, Orton HW, Adekoya I, Huber T, Otting G, Nitsche C. Organoarsenic probes to study proteins by NMR spectroscopy. Chem Commun (Camb) 2021; 58:701-704. [PMID: 34927186 DOI: 10.1039/d1cc06497e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Arsenical probes enable structural studies of proteins. We report the first organoarsenic probes for nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy to study proteins in solutions. These probes can be attached to irregular loop regions. A lanthanide-binding tag induces sizable pseudocontact shifts in protein NMR spectra of a magnitude never observed for small paramagnetic probes before.
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Affiliation(s)
- Mithun C Mahawaththa
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Henry W Orton
- ARC Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Ibidolapo Adekoya
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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21
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Orton HW, Qianzhu H, Abdelkader EH, Habel EI, Tan YJ, Frkic RL, Jackson CJ, Huber T, Otting G. Through-Space Scalar 19F- 19F Couplings between Fluorinated Noncanonical Amino Acids for the Detection of Specific Contacts in Proteins. J Am Chem Soc 2021; 143:19587-19598. [PMID: 34780162 DOI: 10.1021/jacs.1c10104] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorine atoms are known to display scalar 19F-19F couplings in nuclear magnetic resonance (NMR) spectra when they are sufficiently close in space for nonbonding orbitals to overlap. We show that fluorinated noncanonical amino acids positioned in the hydrophobic core or on the surface of a protein can be linked by scalar through-space 19F-19F (TSJFF) couplings even if the 19F spins are in the time average separated by more than the van der Waals distance. Using two different aromatic amino acids featuring CF3 groups, O-trifluoromethyl-tyrosine and 4-trifluoromethyl-phenylalanine, we show that 19F-19F TOCSY experiments are sufficiently sensitive to detect TSJFF couplings between 2.5 and 5 Hz in the 19 kDa protein PpiB measured on a two-channel 400 MHz NMR spectrometer with a regular room temperature probe. A quantitative J evolution experiment enables the measurement of TSJFF coupling constants that are up to five times smaller than the 19F NMR line width. In addition, a new aminoacyl-tRNA synthetase was identified for genetic encoding of N6-(trifluoroacetyl)-l-lysine (TFA-Lys) and 19F-19F TOCSY peaks were observed between two TFA-Lys residues incorporated into the proteins AncCDT-1 and mRFP despite high solvent exposure and flexibility of the TFA-Lys side chains. With the ready availability of systems for site-specific incorporation of fluorinated amino acids into proteins by genetic encoding, 19F-19F interactions offer a straightforward way to probe the spatial proximity of selected sites without any assignments of 1H NMR resonances.
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Affiliation(s)
- Henry W Orton
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Edan I Habel
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Yi Jiun Tan
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Rebecca L Frkic
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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22
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Ullrich S, Sasi VM, Mahawaththa MC, Ekanayake KB, Morewood R, George J, Shuttleworth L, Zhang X, Whitefield C, Otting G, Jackson C, Nitsche C. Challenges of short substrate analogues as SARS-CoV-2 main protease inhibitors. Bioorg Med Chem Lett 2021; 50:128333. [PMID: 34418570 PMCID: PMC8378659 DOI: 10.1016/j.bmcl.2021.128333] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/09/2021] [Accepted: 08/16/2021] [Indexed: 12/22/2022]
Abstract
Specific anti-coronaviral drugs complementing available vaccines are urgently needed to fight the COVID-19 pandemic. Given its high conservation across the betacoronavirus genus and dissimilarity to human proteases, the SARS-CoV-2 main protease (Mpro) is an attractive drug target. SARS-CoV-2 Mpro inhibitors have been developed at unprecedented speed, most of them being substrate-derived peptidomimetics with cysteine-modifying warheads. In this study, Mpro has proven resistant towards the identification of high-affinity short substrate-derived peptides and peptidomimetics without warheads. 20 cyclic and linear substrate analogues bearing natural and unnatural residues, which were predicted by computational modelling to bind with high affinity and designed to establish structure-activity relationships, displayed no inhibitory activity at concentrations as high as 100 μM. Only a long linear peptide covering residues P6 to P5' displayed moderate inhibition (Ki = 57 µM). Our detailed findings will inform current and future drug discovery campaigns targeting Mpro.
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Affiliation(s)
- Sven Ullrich
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Vishnu M Sasi
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Mithun C Mahawaththa
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Kasuni B Ekanayake
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Richard Morewood
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Josemon George
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Laura Shuttleworth
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Xiaobai Zhang
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Cassidy Whitefield
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Colin Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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23
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Herath ID, Breen C, Hewitt SH, Berki TR, Kassir AF, Dodson C, Judd M, Jabar S, Cox N, Otting G, Butler SJ. A Chiral Lanthanide Tag for Stable and Rigid Attachment to Single Cysteine Residues in Proteins for NMR, EPR and Time-Resolved Luminescence Studies. Chemistry 2021; 27:13009-13023. [PMID: 34152643 PMCID: PMC8518945 DOI: 10.1002/chem.202101143] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Indexed: 12/12/2022]
Abstract
A lanthanide-binding tag site-specifically attached to a protein presents a tool to probe the protein by multiple spectroscopic techniques, including nuclear magnetic resonance, electron paramagnetic resonance and time-resolved luminescence spectroscopy. Here a new stable chiral LnIII tag, referred to as C12, is presented for spontaneous and quantitative reaction with a cysteine residue to generate a stable thioether bond. The synthetic protocol of the tag is relatively straightforward, and the tag is stable for storage and shipping. It displays greatly enhanced reactivity towards selenocysteine, opening a route towards selective tagging of selenocysteine in proteins containing cysteine residues. Loaded with TbIII or TmIII ions, the C12 tag readily generates pseudocontact shifts (PCS) in protein NMR spectra. It produces a relatively rigid tether between lanthanide and protein, which is beneficial for interpretation of the PCSs by single magnetic susceptibility anisotropy tensors, and it is suitable for measuring distance distributions in double electron-electron resonance experiments. Upon reaction with cysteine or other thiol compounds, the TbIII complex exhibits a 100-fold enhancement in luminescence quantum yield, affording a highly sensitive turn-on luminescence probe for time-resolved FRET assays and enzyme reaction monitoring.
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Affiliation(s)
- Iresha D. Herath
- Research School of ChemistryThe Australian National UniversityCanberraACT 2605Australia
| | - Colum Breen
- Department of ChemistryLoughborough UniversityEpinal WayLoughboroughLE11 3TUUK
| | - Sarah H. Hewitt
- Department of ChemistryLoughborough UniversityEpinal WayLoughboroughLE11 3TUUK
| | - Thomas R. Berki
- Department of ChemistryLoughborough UniversityEpinal WayLoughboroughLE11 3TUUK
| | - Ahmad F. Kassir
- Department of ChemistryLoughborough UniversityEpinal WayLoughboroughLE11 3TUUK
| | - Charlotte Dodson
- Department of Pharmacy & PharmacologyUniversity of Bath Claverton DownBathBA2 7AYUK
| | - Martyna Judd
- Research School of ChemistryThe Australian National UniversityCanberraACT 2605Australia
| | - Shereen Jabar
- Research School of ChemistryThe Australian National UniversityCanberraACT 2605Australia
| | - Nicholas Cox
- Research School of ChemistryThe Australian National UniversityCanberraACT 2605Australia
| | - Gottfried Otting
- Research School of ChemistryThe Australian National UniversityCanberraACT 2605Australia
| | - Stephen J. Butler
- Department of ChemistryLoughborough UniversityEpinal WayLoughboroughLE11 3TUUK
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24
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Maleckis A, Herath ID, Otting G. Synthesis of 13C/ 19F/ 2H labeled indoles for use as tryptophan precursors for protein NMR spectroscopy. Org Biomol Chem 2021; 19:5133-5147. [PMID: 34032255 DOI: 10.1039/d1ob00611h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Synthesis of indoles labeled with 13C-1H and 13C-19F spin pairs is described. All syntheses utilize inexpensive carbon-13C dioxide as the 13C isotope source. Ruthenium-mediated ring-closing metathesis is the key step in construction of the 13C containing indole carbocycle. Fluorine is introduced via electrophilic fluorination at the 7-position and via palladium-mediated cross-coupling at the 4-position. Indole and fluoroindoles are viable tryptophan precursors for in vivo protein expression. We show that they are viable also in in vitro protein synthesis using standard E. coli S30 extracts. Incorporation of the synthesized 13C-1H and 13C-19F spin pair labeled tryptophans into proteins enables high-resolution and high-sensitivity nuclear magnetic resonance (NMR) spectroscopy.
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Affiliation(s)
- Ansis Maleckis
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia.
| | - Iresha D Herath
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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25
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Welegedara AP, Maleckis A, Bandara R, Mahawaththa MC, Dilhani Herath I, Jiun Tan Y, Giannoulis A, Goldfarb D, Otting G, Huber T. Cell-Free Synthesis of Selenoproteins in High Yield and Purity for Selective Protein Tagging. Chembiochem 2021; 22:1480-1486. [PMID: 33319405 DOI: 10.1002/cbic.202000785] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/10/2020] [Indexed: 01/10/2023]
Abstract
The selenol group of selenocysteine is much more nucleophilic than the thiol group of cysteine. Selenocysteine residues in proteins thus offer reactive points for rapid post-translational modification. Herein, we show that selenoproteins can be expressed in high yield and purity by cell-free protein synthesis by global substitution of cysteine by selenocysteine. Complete alkylation of solvent-exposed selenocysteine residues was achieved in 10 minutes with 4-chloromethylene dipicolinic acid (4Cl-MDPA) under conditions that left cysteine residues unchanged even after overnight incubation. GdIII -GdIII distances measured by double electron-electron resonance (DEER) experiments of maltose binding protein (MBP) containing two selenocysteine residues tagged with 4Cl-MDPA-GdIII were indistinguishable from GdIII -GdIII distances measured of MBP containing cysteine reacted with 4Br-MDPA tags.
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Affiliation(s)
- Adarshi P Welegedara
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia.,Department of Chemistry, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Ansis Maleckis
- Latvian Institute of Organic Synthesis, 1006, Riga, Latvia
| | - Ruchira Bandara
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Mithun C Mahawaththa
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Iresha Dilhani Herath
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Yi Jiun Tan
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Angeliki Giannoulis
- Department of Chemical and Biological Physics Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Gottfried Otting
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
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26
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Abdelkader EH, Otting G. NT*-HRV3CP: An optimized construct of human rhinovirus 14 3C protease for high-yield expression and fast affinity-tag cleavage. J Biotechnol 2021; 325:145-151. [PMID: 33166527 DOI: 10.1016/j.jbiotec.2020.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/28/2020] [Accepted: 11/01/2020] [Indexed: 12/20/2022]
Abstract
The human rhinovirus 14 3C protease (HRV3C protease), in fusion with glutathione S-transferase also referred to as PreScission™ protease, is a cysteine protease of particular interest for affinity tag removal from fusion proteins due to its stringent recognition sequence specificity (LEVLFQ/GX) and superior activity at low temperature. Here we report the expression, purification and use of a fusion construct of HRV3C protease, NT*-HRV3CP, that affords high expression yield in E. coli (over 300 mg/L cell culture), facile single-step purification, high solubility (>10 mg/mL) and excellent storage properties. NT*-HRV3CP cleaves affinity tags at 4 °C in minutes, making it an attractive tool for the production of recombinant proteins for biotechnological, industrial and pharmaceutical applications.
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Affiliation(s)
- Elwy H Abdelkader
- ARC Centre of Excellence in Innovations in Peptide and Protein Science, Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence in Innovations in Peptide and Protein Science, Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia.
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27
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Mekkattu Tharayil S, Mahawaththa M, Loh CT, Adekoya I, Otting G. Phosphoserine for the generation of lanthanide-binding sites on proteins for paramagnetic nuclear magnetic resonance spectroscopy. Magn Reson (Gott) 2021; 2:1-13. [PMID: 37904776 PMCID: PMC10539748 DOI: 10.5194/mr-2-1-2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/12/2020] [Indexed: 11/01/2023]
Abstract
Pseudocontact shifts (PCSs) generated by paramagnetic lanthanide ions provide valuable long-range structural information in nuclear magnetic resonance (NMR) spectroscopic analyses of biological macromolecules such as proteins, but labelling proteins site-specifically with a single lanthanide ion remains an ongoing challenge, especially for proteins that are not suitable for ligation with cysteine-reactive lanthanide complexes. We show that a specific lanthanide-binding site can be installed on proteins by incorporation of phosphoserine in conjunction with other negatively charged residues, such as aspartate, glutamate or a second phosphoserine residue. The close proximity of the binding sites to the protein backbone leads to good immobilization of the lanthanide ion, as evidenced by the excellent quality of fits between experimental PCSs and PCSs calculated with a single magnetic susceptibility anisotropy (Δ χ ) tensor. An improved two-plasmid system was designed to enhance the yields of proteins with genetically encoded phosphoserine, and good lanthanide ion affinities were obtained when the side chains of the phosphoserine and aspartate residues are not engaged in salt bridges, although the presence of too many negatively charged residues in close proximity can also lead to unfolding of the protein. In view of the quality of the Δ χ tensors that can be obtained from lanthanide-binding sites generated by site-specific incorporation of phosphoserine, this method presents an attractive tool for generating PCSs in stable proteins, particularly as it is independent of cysteine residues.
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Affiliation(s)
- Sreelakshmi Mekkattu Tharayil
- ARC Centre of Excellence for Innovations in Peptide and Protein
Science, Research School of Chemistry, Australian National University,
Canberra ACT 2601, Australia
| | - Mithun Chamikara Mahawaththa
- ARC Centre of Excellence for Innovations in Peptide and Protein
Science, Research School of Chemistry, Australian National University,
Canberra ACT 2601, Australia
| | - Choy-Theng Loh
- ARC Centre of Excellence for Innovations in Peptide and Protein
Science, Research School of Chemistry, Australian National University,
Canberra ACT 2601, Australia
- present address: Hangzhou Wayland Bioscience Co. Ltd, Hangzhou
310030, PR China
| | - Ibidolapo Adekoya
- ARC Centre of Excellence for Innovations in Peptide and Protein
Science, Research School of Chemistry, Australian National University,
Canberra ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide and Protein
Science, Research School of Chemistry, Australian National University,
Canberra ACT 2601, Australia
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28
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Abdelkader EH, Qianzhu H, Tan YJ, Adams LA, Huber T, Otting G. Genetic Encoding of N6-(((Trimethylsilyl)methoxy)carbonyl)-l-lysine for NMR Studies of Protein–Protein and Protein–Ligand Interactions. J Am Chem Soc 2021; 143:1133-1143. [DOI: 10.1021/jacs.0c11971] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Elwy H. Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Yi Jiun Tan
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Luke A. Adams
- ARC Training Centre for Fragment Based Design and Monash Fragment Platform, Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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29
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Kaczmarski JA, Mahawaththa MC, Feintuch A, Clifton BE, Adams LA, Goldfarb D, Otting G, Jackson CJ. Altered conformational sampling along an evolutionary trajectory changes the catalytic activity of an enzyme. Nat Commun 2020; 11:5945. [PMID: 33230119 PMCID: PMC7683729 DOI: 10.1038/s41467-020-19695-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023] Open
Abstract
Several enzymes are known to have evolved from non-catalytic proteins such as solute-binding proteins (SBPs). Although attention has been focused on how a binding site can evolve to become catalytic, an equally important question is: how do the structural dynamics of a binding protein change as it becomes an efficient enzyme? Here we performed a variety of experiments, including propargyl-DO3A-Gd(III) tagging and double electron-electron resonance (DEER) to study the rigid body protein dynamics of reconstructed evolutionary intermediates to determine how the conformational sampling of a protein changes along an evolutionary trajectory linking an arginine SBP to a cyclohexadienyl dehydratase (CDT). We observed that primitive dehydratases predominantly populate catalytically unproductive conformations that are vestiges of their ancestral SBP function. Non-productive conformational states, including a wide-open state, are frozen out of the conformational landscape via remote mutations, eventually leading to extant CDT that exclusively samples catalytically relevant compact states. These results show that remote mutations can reshape the global conformational landscape of an enzyme as a mechanism for increasing catalytic activity.
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Affiliation(s)
- Joe A Kaczmarski
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Mithun C Mahawaththa
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Akiva Feintuch
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Ben E Clifton
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia.,Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, 904-0412, Japan
| | - Luke A Adams
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel.
| | - Gottfried Otting
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia. .,Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia.
| | - Colin J Jackson
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia. .,Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia. .,Australian Research Council Centre of Excellence in Synthetic Biology, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia.
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30
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Qianzhu H, Welegedara AP, Williamson H, McGrath AE, Mahawaththa MC, Dixon NE, Otting G, Huber T. Genetic Encoding of para-Pentafluorosulfanyl Phenylalanine: A Highly Hydrophobic and Strongly Electronegative Group for Stable Protein Interactions. J Am Chem Soc 2020; 142:17277-17281. [DOI: 10.1021/jacs.0c07976] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Adarshi P. Welegedara
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Holly Williamson
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Amy E. McGrath
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Mithun C. Mahawaththa
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Nicholas E. Dixon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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31
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Orton H, Huber T, Otting G. Paramagpy: software for fitting magnetic susceptibility tensors using paramagnetic effects measured in NMR spectra. Magn Reson (Gott) 2020; 1:1-12. [PMID: 37904891 PMCID: PMC10500712 DOI: 10.5194/mr-1-1-2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/20/2020] [Indexed: 11/01/2023]
Abstract
Paramagnetic metal ions with fast-relaxing electrons generate pseudocontact shifts (PCSs), residual dipolar couplings (RDCs), paramagnetic relaxation enhancements (PREs) and cross-correlated relaxation (CCR) in the nuclear magnetic resonance (NMR) spectra of the molecules they bind to. These effects offer long-range structural information in molecules equipped with binding sites for such metal ions. Here we present the new open-source software Paramagpy, which has been written in Python 3 with a graphic user interface. Paramagpy combines the functionalities of different currently available programs to support the fitting of magnetic susceptibility tensors using PCS, RDC, PRE and CCR data and molecular coordinates in Protein Data Bank (PDB) format, including a convenient graphical user interface. Paramagpy uses efficient fitting algorithms to avoid local minima and supports corrections to back-calculated PCS and PRE data arising from cross-correlation effects with chemical shift tensors. The source code is available from 10.5281/zenodo.3594568 .
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Affiliation(s)
- Henry William Orton
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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32
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Siddiquee R, Choi SSC, Lam SS, Wang P, Qi R, Otting G, Sunde M, Kwan AHY. Cell-free expression of natively folded hydrophobins. Protein Expr Purif 2020; 170:105591. [PMID: 32032769 DOI: 10.1016/j.pep.2020.105591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 01/07/2023]
Abstract
Hydrophobins are a family of cysteine-rich proteins unique to filamentous fungi. The proteins are produced in a soluble form but self-assemble into organised amphipathic layers at hydrophilic:hydrophobic interfaces. These layers contribute to transitions between wet and dry environments, spore dispersal and attachment to surfaces for growth and infection. Hydrophobins are characterised by four disulphide bonds that are critical to their structure and function. Thus, obtaining correctly folded, soluble and functional hydrophobins directly from bacterial recombinant expression is challenging and in most cases, initial denaturation from inclusion bodies followed by oxidative refolding are required to obtain folded proteins. Here, we report the use of cell-free expression with E. coli cell lysate to directly obtain natively folded hydrophobins. All six of the hydrophobins tested could be expressed after optimisation of redox conditions. For some hydrophobins, the inclusion of the disulfide isomerase DsbC further enhanced expression levels. We are able to achieve a yield of up to 1 mg of natively folded hydrophobin per mL of reaction. This has allowed the confirmation of the correct folding of hydrophobins with the use of 15N-cysteine and 15N-1H nuclear magnetic resonance experiments within 24 h of starting from plasmid stocks.
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Affiliation(s)
- Rezwan Siddiquee
- The University of Sydney, School of Life and Environmental Sciences and SydneyNano, Australia
| | - Samuel Sung-Chan Choi
- The University of Sydney, School of Life and Environmental Sciences and SydneyNano, Australia
| | - Shirley Siuley Lam
- The University of Sydney, School of Life and Environmental Sciences and SydneyNano, Australia
| | - Patrick Wang
- The University of Sydney, School of Life and Environmental Sciences and SydneyNano, Australia
| | - Ruhu Qi
- Australian National University, Research School of Chemistry, Australia
| | - Gottfried Otting
- Australian National University, Research School of Chemistry, Australia
| | - Margaret Sunde
- The University of Sydney, School of Medical Sciences and SydneyNano, Australia
| | - Ann Hau-Yu Kwan
- The University of Sydney, School of Life and Environmental Sciences and SydneyNano, Australia.
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33
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Bahramzadeh A, Huber T, Otting G. Three-Dimensional Protein Structure Determination Using Pseudocontact Shifts of Backbone Amide Protons Generated by Double-Histidine Co 2+-Binding Motifs at Multiple Sites. Biochemistry 2019; 58:3243-3250. [PMID: 31282649 DOI: 10.1021/acs.biochem.9b00404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Pseudocontact shifts (PCSs) generated by paramagnetic metal ions contribute highly informative long-range structure restraints that can be measured in solution and are ideally suited to guide structure prediction algorithms in determining global protein folds. We recently demonstrated that PCSs, which are relatively small but of high quality, can be generated by a double-histidine (dHis) motif in an α-helix, which provides a well-defined binding site for a single Co2+ ion. Here we show that PCSs of backbone amide protons generated by dHis-Co2+ motifs positioned in four different α-helices of a protein deliver excellent restraints to determine the three-dimensional (3D) structure of a protein in a way akin to the global positioning system (GPS). We demonstrate the approach with GPS-Rosetta calculations of the 3D structure of the C-terminal domain of the chaperone ERp29 (ERp29-C). Despite the relatively small size of the PCSs generated by the dHis-Co2+ motifs, the structure calculations converged readily. Generating PCSs by the dHis-Co2+ motif thus presents an excellent alternative to the use of lanthanide tags.
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Affiliation(s)
- Alireza Bahramzadeh
- Research School of Chemistry , Australian National University , Canberra , ACT 2601 , Australia
| | - Thomas Huber
- Research School of Chemistry , Australian National University , Canberra , ACT 2601 , Australia
| | - Gottfried Otting
- Research School of Chemistry , Australian National University , Canberra , ACT 2601 , Australia
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34
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Dalaloyan A, Martorana A, Barak Y, Gataulin D, Reuveny E, Howe A, Elbaum M, Albeck S, Unger T, Frydman V, Abdelkader EH, Otting G, Goldfarb D. Tracking Conformational Changes in Calmodulin in vitro, in Cell Extract, and in Cells by Electron Paramagnetic Resonance Distance Measurements. Chemphyschem 2019; 20:1860-1868. [PMID: 31054266 DOI: 10.1002/cphc.201900341] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Indexed: 12/12/2022]
Abstract
It is an open question whether the conformations of proteins sampled in dilute solutions are the same as in the cellular environment. Here we address this question by double electron-electron resonance (DEER) distance measurements with Gd(III) spin labels to probe the conformations of calmodulin (CaM) in vitro, in cell extract, and in human HeLa cells. Using the CaM mutants N53C/T110C and T34C/T117C labeled with maleimide-DOTA-Gd(III) in the N- and C-terminal domains, we observed broad and varied interdomain distance distributions. The in vitro distance distributions of apo-CaM and holo-CaM in the presence and absence of the IQ target peptide can be described by combinations of closed, open, and collapsed conformations. In cell extract, apo- and holo-CaM bind to target proteins in a similar way as apo- and holo-CaM bind to IQ peptide in vitro. In HeLa cells, however, in the presence or absence of elevated in-cell Ca2+ levels CaM unexpectedly produced more open conformations and very broad distance distributions indicative of many different interactions with in-cell components. These results show-case the importance of in-cell analyses of protein structures.
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Affiliation(s)
| | | | | | | | | | - Andrew Howe
- Department of Chemical and Biological Physics
| | | | - Shira Albeck
- Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Unger
- Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot, Israel
| | | | - Elwy H Abdelkader
- Research School of Chemistry, Australian National University, Canberra, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, Australia
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35
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Nitsche C, Onagi H, Quek JP, Otting G, Luo D, Huber T. Biocompatible Macrocyclization between Cysteine and 2-Cyanopyridine Generates Stable Peptide Inhibitors. Org Lett 2019; 21:4709-4712. [DOI: 10.1021/acs.orglett.9b01545] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Hideki Onagi
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Jun-Ping Quek
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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36
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Nitsche C, Passioura T, Varava P, Mahawaththa MC, Leuthold MM, Klein CD, Suga H, Otting G. De Novo Discovery of Nonstandard Macrocyclic Peptides as Noncompetitive Inhibitors of the Zika Virus NS2B-NS3 Protease. ACS Med Chem Lett 2019; 10:168-174. [PMID: 30783498 PMCID: PMC6378662 DOI: 10.1021/acsmedchemlett.8b00535] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/02/2019] [Indexed: 12/18/2022] Open
Abstract
The Zika virus presents a major public health concern due to severe fetal neurological disorders associated with infections in pregnant women. In addition to vaccine development, the discovery of selective antiviral drugs is essential to combat future epidemic Zika virus outbreaks. The Zika virus NS2B-NS3 protease, which performs replication-critical cleavages of the viral polyprotein, is a promising drug target. We report the first macrocyclic peptide-based inhibitors of the NS2B-NS3 protease, discovered de novo through in vitro display screening of a genetically reprogrammed library including noncanonical residues. Six compounds were selected, resynthesized, and isolated, all of which displayed affinities in the low nanomolar concentration range. Five compounds showed significant protease inhibition. Two of these were validated as hits with submicromolar inhibition constants and selectivity toward Zika over the related proteases from dengue and West Nile viruses. The compounds were characterized as noncompetitive inhibitors, suggesting allosteric inhibition.
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Affiliation(s)
- Christoph Nitsche
- Research
School of Chemistry, Australian National
University, Canberra, ACT 2601, Australia
| | - Toby Passioura
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Paul Varava
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Mithun C. Mahawaththa
- Research
School of Chemistry, Australian National
University, Canberra, ACT 2601, Australia
| | - Mila M. Leuthold
- Medicinal
Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Christian D. Klein
- Medicinal
Chemistry, Institute of Pharmacy and Molecular Biotechnology IPMB, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Hiroaki Suga
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Gottfried Otting
- Research
School of Chemistry, Australian National
University, Canberra, ACT 2601, Australia
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37
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Wang X, Chen JL, Otting G, Su XC. Conversion of an amide to a high-energy thioester by Staphylococcus aureus sortase A is powered by variable binding affinity for calcium. Sci Rep 2018; 8:16371. [PMID: 30401805 PMCID: PMC6219580 DOI: 10.1038/s41598-018-34752-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 10/25/2018] [Indexed: 12/21/2022] Open
Abstract
Thioesters are key intermediates in biology, which often are generated from less energy-rich amide precursors. Staphylococcus aureus sortase A (SrtA) is an enzyme widely used in biotechnology for peptide ligation. The reaction proceeds in two steps, where the first step involves the conversion of an amide bond of substrate peptide into a thioester intermediate with the enzyme. Here we show that the free energy required for this step is matched by an about 30-fold increase in binding affinity of a calcium ion at the calcium binding site of SrtA, which is remote from the thioester bond. The magnitude of this allosteric effect highlights the importance of calcium for the activity of SrtA. The increase in calcium binding affinity upon binding of substrate not only achieves catalytic formation of an energy-rich intermediate in the absence of nucleotide triphosphates or any tight non-covalent enzyme-substrate interactions, but is also accompanied by accumulation of the labile thioester intermediate, which makes it directly observable in nuclear magnetic resonance (NMR) spectra.
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Affiliation(s)
- Xiao Wang
- State Key Laboratory of Elemento-Organic Chemistry, Department of Chemical Biology, College of Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China
| | - Jia-Liang Chen
- State Key Laboratory of Elemento-Organic Chemistry, Department of Chemical Biology, College of Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-Organic Chemistry, Department of Chemical Biology, College of Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
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38
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Loh CT, Adams LA, Graham B, Otting G. Genetically encoded amino acids with tert-butyl and trimethylsilyl groups for site-selective studies of proteins by NMR spectroscopy. J Biomol NMR 2018; 71:287-293. [PMID: 29197976 DOI: 10.1007/s10858-017-0157-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
The amino acids 4-(tert-butyl)phenylalanine (Tbf) and 4-(trimethylsilyl)phenylalanine (TMSf), as well as a partially deuterated version of Tbf (dTbf), were chemically synthesized and site-specifically incorporated into different proteins, using an amber stop codon, suppressor tRNA and the broadband aminoacyl-tRNA synthetase originally evolved for the incorporation of p-cyano-phenylalanine. The 1H-NMR signals of the tert-butyl and TMS groups were compared to the 1H-NMR signal of tert-butyltyrosine (Tby) in protein systems with molecular weights ranging from 8 to 54 kDa. The 1H-NMR resonance of the TMS group appeared near 0 ppm in a spectral region with few protein resonances, facilitating the observation of signal changes in response to ligand binding. In all proteins, the R 2 relaxation rate of the tert-butyl group of Tbf was only little greater than that of Tby (less than two-fold). Deuteration of the phenyl ring of Tbf made only a relatively small difference. The effective T 2 relaxation time of the TMS signal was longer than 140 ms even in the 54 kDa system.
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Affiliation(s)
- Choy Theng Loh
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
- Zhejiang Provincial Key Laboratory of Chemical and Biological Processing Technology of Farm Products, Zhejiang University of Science and Technology, Hangzhou, 310023, People's Republic of China
| | - Luke A Adams
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Bim Graham
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
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39
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Abstract
Measurements of paramagnetic relaxation enhancements (PREs) in 1H NMR spectra are an important tool to obtain long-range distance information in proteins, but quantitative interpretation is easily compromised by nonspecific intermolecular PREs. Here we show that PREs generated by lanthanides with anisotropic magnetic susceptibilities offer a route to accurate calibration-free distance measurements. As these lanthanides change 1H chemical shifts due to pseudocontact shifts, the relaxation rates in the paramagnetic and diamagnetic state can be measured with a single sample that simultaneously contains the protein labeled with a paramagnetic and a diamagnetic lanthanide ion. Nonspecific intermolecular PREs are thus automatically subtracted when calculating the PREs as the difference in nuclear relaxation rates between paramagnetic and diamagnetic protein. Although PREs from lanthanides with anisotropic magnetic susceptibilities are complicated by additional cross-correlation effects and residual dipolar couplings (RDCs) in the paramagnetic state, these effects can be controlled by the choice of lanthanide ion and experimental conditions. Using calbindin D9k with erbium, we succeeded in measuring intramolecular PREs with unprecedented accuracy, resulting in distance predictions with a root-mean-square-deviation of <0.9 Å in the range 11-24 Å.
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Affiliation(s)
- Henry W Orton
- Research School of Chemistry , Australian National University , Canberra , Australian Capital Territory 2601 , Australia
| | - Gottfried Otting
- Research School of Chemistry , Australian National University , Canberra , Australian Capital Territory 2601 , Australia
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40
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Welegedara AP, Adams LA, Huber T, Graham B, Otting G. Site-Specific Incorporation of Selenocysteine by Genetic Encoding as a Photocaged Unnatural Amino Acid. Bioconjug Chem 2018; 29:2257-2264. [DOI: 10.1021/acs.bioconjchem.8b00254] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Adarshi P. Welegedara
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Luke A. Adams
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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41
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Bahramzadeh A, Jiang H, Huber T, Otting G. Two Histidines in an α‐Helix: A Rigid Co
2+
‐Binding Motif for PCS Measurements by NMR Spectroscopy. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Alireza Bahramzadeh
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Hailun Jiang
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Thomas Huber
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Gottfried Otting
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
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42
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Bahramzadeh A, Jiang H, Huber T, Otting G. Two Histidines in an α‐Helix: A Rigid Co
2+
‐Binding Motif for PCS Measurements by NMR Spectroscopy. Angew Chem Int Ed Engl 2018; 57:6226-6229. [DOI: 10.1002/anie.201802501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 01/26/2023]
Affiliation(s)
- Alireza Bahramzadeh
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Hailun Jiang
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Thomas Huber
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
| | - Gottfried Otting
- Research School of Chemistry The Australian National University Canberra ACT 2601 Australia
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43
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Watson EE, Liu X, Thompson RE, Ripoll-Rozada J, Wu M, Alwis I, Gori A, Loh CT, Parker BL, Otting G, Jackson S, Pereira PJ, Payne RJ. Mosquito-Derived Anophelin Sulfoproteins Are Potent Antithrombotics. ACS Cent Sci 2018; 4:468-476. [PMID: 29721529 PMCID: PMC5920608 DOI: 10.1021/acscentsci.7b00612] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Indexed: 06/08/2023]
Abstract
The anophelins are small protein thrombin inhibitors that are produced in the salivary glands of the Anopheles mosquito to fulfill a vital role in blood feeding. A bioinformatic analysis of anophelin sequences revealed the presence of conserved tyrosine residues in an acidic environment that were predicted to be post-translationally sulfated in vivo. To test this prediction, insect cell expression of two anophelin proteins, from Anopheles albimanus and Anopheles gambiae, was performed, followed by analysis by mass spectrometry, which showed heterogeneous sulfation at the predicted sites. Homogeneously sulfated variants of the two proteins were subsequently generated by chemical synthesis via a one-pot ligation-desulfurization strategy. Tyrosine sulfation of the anophelins was shown to significantly enhance the thrombin inhibitory activity, with a doubly sulfated variant of the anophelin from A. albimanus exhibiting a 100-fold increase in potency compared with the unmodified homologue. Sulfated anophelins were also shown to exhibit potent in vivo anticoagulant and antithrombotic activity.
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Affiliation(s)
- Emma E. Watson
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Xuyu Liu
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Robert E. Thompson
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jorge Ripoll-Rozada
- IBMC
− Instituto de Biologia Molecular e Celular, Universidade do
Porto, 4200-135 Porto, Portugal
- Instituto
de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Mike Wu
- Heart
Research Institute, Newtown, New South Wales 2042, Australia
- Charles
Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Imala Alwis
- Heart
Research Institute, Newtown, New South Wales 2042, Australia
- Charles
Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Alessandro Gori
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Choy-Theng Loh
- Research
School of Chemistry, Australian National
University, Canberra, Australian Capital Territory 2601, Australia
| | - Benjamin L. Parker
- Charles
Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Gottfried Otting
- Research
School of Chemistry, Australian National
University, Canberra, Australian Capital Territory 2601, Australia
| | - Shaun Jackson
- Heart
Research Institute, Newtown, New South Wales 2042, Australia
- Charles
Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
- Department
of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Pedro José
Barbosa Pereira
- IBMC
− Instituto de Biologia Molecular e Celular, Universidade do
Porto, 4200-135 Porto, Portugal
- Instituto
de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Richard J. Payne
- School
of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
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44
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Prokopiou G, Lee MD, Collauto A, Abdelkader EH, Bahrenberg T, Feintuch A, Ramirez-Cohen M, Clayton J, Swarbrick JD, Graham B, Otting G, Goldfarb D. Small Gd(III) Tags for Gd(III)–Gd(III) Distance Measurements in Proteins by EPR Spectroscopy. Inorg Chem 2018; 57:5048-5059. [DOI: 10.1021/acs.inorgchem.8b00133] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Georgia Prokopiou
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael D. Lee
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Alberto Collauto
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Elwy H. Abdelkader
- Research School of Chemistry, Australian National University, Canberra, ACT 2601,Australia
| | - Thorsten Bahrenberg
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Marie Ramirez-Cohen
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jessica Clayton
- Department of Physics, University of California, Santa Barbara, California 93106-9530, United States
| | - James D. Swarbrick
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601,Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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45
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Becker W, Adams LA, Graham B, Wagner GE, Zangger K, Otting G, Nitsche C. Trimethylsilyl tag for probing protein-ligand interactions by NMR. J Biomol NMR 2018; 70:211-218. [PMID: 29564580 DOI: 10.1007/s10858-018-0173-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/01/2018] [Indexed: 06/08/2023]
Abstract
Protein-ligand titrations can readily be monitored with a trimethylsilyl (TMS) tag. Owing to the intensity, narrow line shape and unique chemical shift of a TMS group, dissociation constants can be determined from straightforward 1D 1H-NMR spectra not only in the fast but also in the slow exchange limit. The tag is easily attached to cysteine residues and a sensitive reporter of ligand binding also at sites where it does not interfere with ligand binding or catalytic efficiency of the target protein. Its utility is demonstrated for the Zika virus NS2B-NS3 protease and the human prolyl isomerase FK506 binding protein.
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Affiliation(s)
- Walter Becker
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
- Institute of Chemistry, University of Graz, 8010, Graz, Austria
| | - Luke A Adams
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Gabriel E Wagner
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, 8010, Graz, Austria
| | - Klaus Zangger
- Institute of Chemistry, University of Graz, 8010, Graz, Austria
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
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46
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Chilingaryan Z, Headey SJ, Lo ATY, Xu ZQ, Otting G, Dixon NE, Scanlon MJ, Oakley AJ. Fragment-Based Discovery of Inhibitors of the Bacterial DnaG-SSB Interaction. Antibiotics (Basel) 2018; 7:E14. [PMID: 29470422 PMCID: PMC5872125 DOI: 10.3390/antibiotics7010014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/09/2018] [Accepted: 02/13/2018] [Indexed: 12/30/2022] Open
Abstract
In bacteria, the DnaG primase is responsible for synthesis of short RNA primers used to initiate chain extension by replicative DNA polymerase(s) during chromosomal replication. Among the proteins with which Escherichia coli DnaG interacts is the single-stranded DNA-binding protein, SSB. The C-terminal hexapeptide motif of SSB (DDDIPF; SSB-Ct) is highly conserved and is known to engage in essential interactions with many proteins in nucleic acid metabolism, including primase. Here, fragment-based screening by saturation-transfer difference nuclear magnetic resonance (STD-NMR) and surface plasmon resonance assays identified inhibitors of the primase/SSB-Ct interaction. Hits were shown to bind to the SSB-Ct-binding site using 15N-¹H HSQC spectra. STD-NMR was used to demonstrate binding of one hit to other SSB-Ct binding partners, confirming the possibility of simultaneous inhibition of multiple protein/SSB interactions. The fragment molecules represent promising scaffolds on which to build to discover new antibacterial compounds.
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Affiliation(s)
- Zorik Chilingaryan
- Molecular Horizons and School of Chemistry, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
| | - Stephen J Headey
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
| | - Allen T Y Lo
- Molecular Horizons and School of Chemistry, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
| | - Zhi-Qiang Xu
- Molecular Horizons and School of Chemistry, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
| | - Nicholas E Dixon
- Molecular Horizons and School of Chemistry, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
| | - Martin J Scanlon
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
| | - Aaron J Oakley
- Molecular Horizons and School of Chemistry, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
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47
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Chen WN, Otting G. Using tert-Butyl Groups in a Ligand To Identify Its Binding Site on a Protein. ACS Med Chem Lett 2018; 9:109-113. [PMID: 29456797 DOI: 10.1021/acsmedchemlett.7b00464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/12/2018] [Indexed: 01/16/2023] Open
Abstract
Few methods allow determining the binding site of tightly binding ligands. We show that ligands containing a tert-butyl (e.g., Boc) group produce easily observable nuclear Overhauser effects (NOE) with the target protein even when the tert-butyl group is not highly solvent exposed. NOEs with methyl groups of the target protein are readily assigned by selectively isotope labeling, presenting a practical and quick way to pinpoint the location of the ligand without any prior specific nuclear magnetic resonance assignments of the protein. The approach works for nonexchanging ligands as well as for weakly binding ligands.
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Affiliation(s)
- Wan-Na Chen
- Research
School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
- College
of Pharmacy, Jinan University, Guangzhou, Guangdong 510632, China
| | - Gottfried Otting
- Research
School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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48
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Mahawaththa MC, Lee MD, Giannoulis A, Adams LA, Feintuch A, Swarbrick JD, Graham B, Nitsche C, Goldfarb D, Otting G. Small neutral Gd(iii) tags for distance measurements in proteins by double electron–electron resonance experiments. Phys Chem Chem Phys 2018; 20:23535-23545. [DOI: 10.1039/c8cp03532f] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Small Gd(iii) tags based on DO3A deliver narrow and readily predictable distances by double electron–electron resonance (DEER) measurements.
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Affiliation(s)
| | - Michael D. Lee
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - Angeliki Giannoulis
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 76100
- Israel
| | - Luke A. Adams
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - Akiva Feintuch
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 76100
- Israel
| | - James D. Swarbrick
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - Christoph Nitsche
- Research School of Chemistry
- The Australian National University
- Canberra
- Australia
| | - Daniella Goldfarb
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 76100
- Israel
| | - Gottfried Otting
- Research School of Chemistry
- The Australian National University
- Canberra
- Australia
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49
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Wu Z, Feintuch A, Collauto A, Adams LA, Aurelio L, Graham B, Otting G, Goldfarb D. Selective Distance Measurements Using Triple Spin Labeling with Gd 3+, Mn 2+, and a Nitroxide. J Phys Chem Lett 2017; 8:5277-5282. [PMID: 28990781 DOI: 10.1021/acs.jpclett.7b01739] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Distance measurements by pulse electron paramagnetic resonance techniques, such as double electron-electron resonance (DEER, also called PELDOR), have become an established tool to explore structural properties of biomacromolecules and their assemblies. In such measurements a pair of spin labels provides a single distance constraint. Here we show that by employing three different types of spin labels that differ in their spectroscopic and spin dynamics properties it is possible to extract three independent distances from a single sample. We demonstrate this using the Antennapedia homeodomain orthogonally labeled with Gd3+ and Mn2+ tags in complex with its cognate DNA binding site labeled with a nitroxide.
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Affiliation(s)
- Zuyan Wu
- Research School of Chemistry, Australian National University , Canberra ACT 2601, Australia
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel
| | - Alberto Collauto
- Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel
| | - Luke A Adams
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - Luigi Aurelio
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University , Canberra ACT 2601, Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel
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50
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Abstract
NMR spectroscopy is an established tool in drug discovery, but its strength is commonly regarded to be largely confined to the early stages of hit discovery and fragment based drug design, where NMR offers unique capabilities of characterizing the binding modes of ligand molecules that bind sufficiently weakly to be in rapid exchange between bound and free state. Here we, first, provide a meta-review of recent reviews on NMR studies of ligand binding and, second, review recent progress towards NMR characterization of the ligand binding mode in stable protein-ligand complexes, with particular emphasis on the global positioning system (GPS) approach enabled by paramagnetic lanthanide tags.
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Affiliation(s)
- Christoph Nitsche
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
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