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Loynd C, Singha Roy SJ, Ovalle VJ, Canarelli SE, Mondal A, Jewel D, Ficaretta ED, Weerapana E, Chatterjee A. Electrochemical labelling of hydroxyindoles with chemoselectivity for site-specific protein bioconjugation. Nat Chem 2024; 16:389-397. [PMID: 38082177 PMCID: PMC10932882 DOI: 10.1038/s41557-023-01375-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/18/2023] [Indexed: 02/06/2024]
Abstract
Electrochemistry has recently emerged as a powerful approach in small-molecule synthesis owing to its numerous attractive features, including precise control over the fundamental reaction parameters, mild reaction conditions and innate scalability. Even though these advantages also make it an attractive strategy for chemoselective modification of complex biomolecules such as proteins, such applications remain poorly developed. Here we report an electrochemically promoted coupling reaction between 5-hydroxytryptophan (5HTP) and simple aromatic amines-electrochemical labelling of hydroxyindoles with chemoselectivity (eCLIC)-that enables site-specific labelling of full-length proteins under mild conditions. Using genetic code expansion technology, the 5HTP residue can be incorporated into predefined sites of a recombinant protein expressed in either prokaryotic or eukaryotic hosts for subsequent eCLIC labelling. We used the eCLIC reaction to site-specifically label various recombinant proteins, including a full-length human antibody. Furthermore, we show that eCLIC is compatible with strain-promoted alkyne-azide and alkene-tetrazine click reactions, enabling site-specific modification of proteins at two different sites with distinct labels.
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Affiliation(s)
- Conor Loynd
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | | | - Vincent J Ovalle
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Sarah E Canarelli
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Atanu Mondal
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Delilah Jewel
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Elise D Ficaretta
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Eranthie Weerapana
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA
| | - Abhishek Chatterjee
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, USA.
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Singha Roy SJ, Loynd C, Jewel D, Canarelli SE, Ficaretta ED, Pham QA, Weerapana E, Chatterjee A. Photoredox-Catalyzed Labeling of Hydroxyindoles with Chemoselectivity (PhotoCLIC) for Site-Specific Protein Bioconjugation. Angew Chem Int Ed Engl 2023; 62:e202300961. [PMID: 37219923 PMCID: PMC10330600 DOI: 10.1002/anie.202300961] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Indexed: 05/24/2023]
Abstract
We have developed a novel visible-light-catalyzed bioconjugation reaction, PhotoCLIC, that enables chemoselective attachment of diverse aromatic amine reagents onto a site-specifically installed 5-hydroxytryptophan residue (5HTP) on full-length proteins of varied complexity. The reaction uses catalytic amounts of methylene blue and blue/red light-emitting diodes (455/650 nm) for rapid site-specific protein bioconjugation. Characterization of the PhotoCLIC product reveals a unique structure formed likely through a singlet oxygen-dependent modification of 5HTP. PhotoCLIC has a wide substrate scope and its compatibility with strain-promoted azide-alkyne click reaction, enables site-specific dual-labeling of a target protein.
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Affiliation(s)
| | - Conor Loynd
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Delilah Jewel
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Sarah E Canarelli
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Elise D Ficaretta
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Quan A Pham
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Eranthie Weerapana
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Abhishek Chatterjee
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
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Osgood AO, Zheng Y, Roy SJS, Biris N, Hussain M, Loynd C, Jewel D, Italia JS, Chatterjee A. An Efficient Opal-Suppressor Tryptophanyl Pair Creates New Routes for Simultaneously Incorporating up to Three Distinct Noncanonical Amino Acids into Proteins in Mammalian Cells. Angew Chem Int Ed Engl 2023; 62:e202219269. [PMID: 36905325 PMCID: PMC10133189 DOI: 10.1002/anie.202219269] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/12/2023]
Abstract
Site-specific incorporation of multiple distinct noncanonical amino acids (ncAAs) into proteins in mammalian cells is a promising technology, where each ncAA must be assigned to a different orthogonal aminoacyl-tRNA synthetase (aaRS)/tRNA pair that reads a distinct nonsense codon. Available pairs suppress TGA or TAA codons at a considerably lower efficiency than TAG, limiting the scope of this technology. Here we show that the E. coli tryptophanyl (EcTrp) pair is an excellent TGA-suppressor in mammalian cells, which can be combined with the three other established pairs to develop three new routes for dual-ncAA incorporation. Using these platforms, we site-specifically incorporated two different bioconjugation handles into an antibody with excellent efficiency, and subsequently labeled it with two distinct cytotoxic payloads. Additionally, we combined the EcTrp pair with other pairs to site-specifically incorporate three distinct ncAAs into a reporter protein in mammalian cells.
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Affiliation(s)
- Arianna O Osgood
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Yunan Zheng
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | | | | | - Myer Hussain
- BrickBio, Inc., 600 Winter St, Waltham, MA, 02451, USA
| | - Conor Loynd
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | - Delilah Jewel
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
| | | | - Abhishek Chatterjee
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA, 02467, USA
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Pastore AJ, Montoya A, Kamat M, Basso KB, Italia JS, Chatterjee A, Drosou M, Pantazis DA, Angerhofer A. Selective incorporation of 5-hydroxytryptophan blocks long range electron transfer in oxalate decarboxylase. Protein Sci 2023; 32:e4537. [PMID: 36482787 PMCID: PMC9801070 DOI: 10.1002/pro.4537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 12/13/2022]
Abstract
Oxalate decarboxylase from Bacillus subtilis is a binuclear Mn-dependent acid stress response enzyme that converts the mono-anion of oxalic acid into formate and carbon dioxide in a redox neutral unimolecular disproportionation reaction. A π-stacked tryptophan dimer, W96 and W274, at the interface between two monomer subunits facilitates long-range electron transfer between the two Mn ions and plays an important role in the catalytic mechanism. Substitution of W96 with the unnatural amino acid 5-hydroxytryptophan leads to a persistent EPR signal which can be traced back to the neutral radical of 5-hydroxytryptophan with its hydroxyl proton removed. 5-Hydroxytryptophan acts as a hole sink preventing the formation of Mn(III) at the N-terminal active site and strongly suppresses enzymatic activity. The lower boundary of the standard reduction potential for the active site Mn(II)/Mn(III) couple can therefore be estimated as 740 mV against the normal hydrogen electrode at pH 4, the pH of maximum catalytic efficiency. Our results support the catalytic importance of long-range electron transfer in oxalate decarboxylase while at the same time highlighting the utility of unnatural amino acid incorporation and specifically the use of 5-hydroxytryptophan as an energetic sink for hole hopping to probe electron transfer in redox proteins.
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Affiliation(s)
| | - Alvaro Montoya
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - Manasi Kamat
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - Kari B. Basso
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - James S. Italia
- Department of ChemistryBoston CollegeChestnut HillMassachusettsUSA
| | | | - Maria Drosou
- Max‐Planck‐Institut für KohlenforschungMülheim an der RuhrGermany
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Berkeley RF, Debelouchina GT. Chemical tools for study and modulation of biomolecular phase transitions. Chem Sci 2022; 13:14226-14245. [PMID: 36545140 PMCID: PMC9749140 DOI: 10.1039/d2sc04907d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 11/21/2022] [Indexed: 11/23/2022] Open
Abstract
Biomolecular phase transitions play an important role in organizing cellular processes in space and time. Methods and tools for studying these transitions, and the intrinsically disordered proteins (IDPs) that often drive them, are typically less developed than tools for studying their folded protein counterparts. In this perspective, we assess the current landscape of chemical tools for studying IDPs, with a specific focus on protein liquid-liquid phase separation (LLPS). We highlight methodologies that enable imaging and spectroscopic studies of these systems, including site-specific labeling with small molecules and the diverse range of capabilities offered by inteins and protein semisynthesis. We discuss strategies for introducing post-translational modifications that are central to IDP and LLPS function and regulation. We also investigate the nascent field of noncovalent small-molecule modulators of LLPS. We hope that this review of the state-of-the-art in chemical tools for interrogating IDPs and LLPS, along with an associated perspective on areas of unmet need, can serve as a valuable and timely resource for these rapidly expanding fields of study.
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Affiliation(s)
- Raymond F. Berkeley
- Department of Chemistry and Biochemistry, University of California San DiegoLa JollaCAUSA
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, University of California San DiegoLa JollaCAUSA
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Pastore AJ, Ficaretta E, Chatterjee A, Davidson VL. Substitution of the sole tryptophan of the cupredoxin, amicyanin, with 5-hydroxytryptophan alters fluorescence properties and energy transfer to the type 1 copper site. J Inorg Biochem 2022; 234:111895. [PMID: 35696758 PMCID: PMC9753554 DOI: 10.1016/j.jinorgbio.2022.111895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/17/2022] [Accepted: 06/02/2022] [Indexed: 12/01/2022]
Abstract
Amicyanin is a type 1 copper protein with a single tryptophan residue. Using genetic code expansion, the tryptophan was selectively replaced with the unnatural amino acid, 5-hydroxytryptophan (5-HTP). The 5-HTP substituted amicyanin exhibited absorbance at 300-320 nm, characteristic of 5-HTP and not seen in native amicyanin. The fluorescence emission maximum in 5-HTP substituted amicyanin is redshifted from 318 nm in native amicyanin to 331 nm and to 348 nm in the unfolded protein. The fluorescence quantum yield of 5-HTP substituted amicyanin mutant was much less than that of native amicyanin. Differences in intrinsic fluorescence are explained by differences in the excited states of tryptophan versus 5-HTP and the intraprotein environment. The substitution of tryptophan with 5-HTP did not affect the visible absorbance and redox potential of the copper, which is 10 Å away. In amicyanin and other cupredoxins, an unexplained quenching of the intrinsic fluorescence by the bound copper is observed. However, the fluorescence of 5-HTP substituted amicyanin is not quenched by the copper. It is shown that the mechanism of quenching in native amicyanin is Förster, or fluorescence, resonance energy transfer (FRET). This does not occur in 5-HTP substituted amicyanin because the fluorescence quantum yield is significantly lower and the red-shift of fluorescence emission maximum decreases overlap with the near UV absorbance of copper. Characterization of the distinct fluorescence properties of 5-HTP relative to tryptophan in amicyanin provides a basis for spectroscopic interrogation of the protein microenvironment using 5-HTP, and long-distance interactions with transition metals.
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Affiliation(s)
- Anthony J Pastore
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, 32827, USA
| | - Elise Ficaretta
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA 02467, USA
| | - Abhishek Chatterjee
- Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA 02467, USA
| | - Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, 32827, USA.
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Liu T. Recent advances in Genetic Code Expansion: from cell engineering to protein design. J Mol Biol 2022; 434:167565. [PMID: 35341745 DOI: 10.1016/j.jmb.2022.167565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Tao Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, China.
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