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Zhan Q, Shi C, Jiang Y, Gao X, Lin Y. Efficient splicing of the CPE intein derived from directed evolution of the Cryptococcus neoformans PRP8 intein. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1310-1318. [PMID: 37489009 PMCID: PMC10448054 DOI: 10.3724/abbs.2023135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/19/2023] [Indexed: 07/26/2023] Open
Abstract
Intein-mediated protein splicing has been widely used in protein engineering; however, the splicing efficiency and extein specificity usually limit its further application. Thus, there is a demand for more general inteins that can overcome these limitations. Here, we study the trans-splicing of CPE intein obtained from the directed evolution of Cne PRP8, which shows that its splicing rate is ~29- fold higher than that of the wild-type. When the +1 residue of C-extein is changed to cysteine, CPE also shows high splicing activity. Faster association and higher affinity may contribute to the high splicing rate compared with wild-type intein. These findings have important implications for the future engineering of inteins and provide clues for fundamental studies of protein structure and folding.
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Affiliation(s)
- Qin Zhan
- College of Biological Science and Medical EngineeringDonghua UniversityShanghai201620China
| | - Changhua Shi
- College of Biological Science and Medical EngineeringDonghua UniversityShanghai201620China
| | - Yu Jiang
- College of Biological Science and Medical EngineeringDonghua UniversityShanghai201620China
| | - Xianling Gao
- Shandong Guoli Biotechnology Co.Ltd.Jinan250101China
| | - Ying Lin
- College of Biological Science and Medical EngineeringDonghua UniversityShanghai201620China
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Hinterholzer A, Stanojlovic V, Regl C, Huber CG, Cabrele C, Schubert M. Detecting aspartate isomerization and backbone cleavage after aspartate in intact proteins by NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2021; 75:71-82. [PMID: 33475951 PMCID: PMC7897204 DOI: 10.1007/s10858-020-00356-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/23/2020] [Indexed: 05/14/2023]
Abstract
The monitoring of non-enzymatic post-translational modifications (PTMs) in therapeutic proteins is important to ensure drug safety and efficacy. Together with methionine and asparagine, aspartic acid (Asp) is very sensitive to spontaneous alterations. In particular, Asp residues can undergo isomerization and peptide-bond hydrolysis, especially when embedded in sequence motifs that are prone to succinimide formation or when followed by proline (Pro). As Asp and isoAsp have the same mass, and the Asp-Pro peptide-bond cleavage may lead to an unspecific mass difference of + 18 Da under native conditions or in the case of disulfide-bridged cleavage products, it is challenging to directly detect and characterize such modifications by mass spectrometry (MS). Here we propose a 2D NMR-based approach for the unambiguous identification of isoAsp and the products of Asp-Pro peptide-bond cleavage, namely N-terminal Pro and C-terminal Asp, and demonstrate its applicability to proteins including a therapeutic monoclonal antibody (mAb). To choose the ideal pH conditions under which the NMR signals of isoAsp and C-terminal Asp are distinct from other random coil signals, we determined the pKa values of isoAsp and C-terminal Asp in short peptides. The characteristic 1H-13C chemical shift correlations of isoAsp, N-terminal Pro and C-terminal Asp under standardized conditions were used to identify these PTMs in lysozyme and in the therapeutic mAb rituximab (MabThera) upon prolonged storage under acidic conditions (pH 4-5) and 40 °C. The results show that the application of our 2D NMR-based protocol is straightforward and allows detecting chemical changes of proteins that may be otherwise unnoticed with other analytical methods.
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Affiliation(s)
- Arthur Hinterholzer
- Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
- Department of Biosciences, University of Salzburg, Billrothstrasse 11, 5020, Salzburg, Austria
| | - Vesna Stanojlovic
- Department of Biosciences, University of Salzburg, Billrothstrasse 11, 5020, Salzburg, Austria
| | - Christof Regl
- Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
- Department of Biosciences, Division of Chemistry and Bioanalytics, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
| | - Christian G Huber
- Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
- Department of Biosciences, Division of Chemistry and Bioanalytics, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
| | - Chiara Cabrele
- Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria
- Department of Biosciences, University of Salzburg, Billrothstrasse 11, 5020, Salzburg, Austria
| | - Mario Schubert
- Christian Doppler Laboratory for Innovative Tools for Biosimilar Characterization, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.
- Department of Biosciences, University of Salzburg, Billrothstrasse 11, 5020, Salzburg, Austria.
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Zatopek KM, Alpaslan E, Evans T, Sauguet L, Gardner A. Novel ribonucleotide discrimination in the RNA polymerase-like two-barrel catalytic core of Family D DNA polymerases. Nucleic Acids Res 2020; 48:12204-12218. [PMID: 33137176 PMCID: PMC7708050 DOI: 10.1093/nar/gkaa986] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023] Open
Abstract
Family D DNA polymerase (PolD) is the essential replicative DNA polymerase for duplication of most archaeal genomes. PolD contains a unique two-barrel catalytic core absent from all other DNA polymerase families but found in RNA polymerases (RNAPs). While PolD has an ancestral RNA polymerase catalytic core, its active site has evolved the ability to discriminate against ribonucleotides. Until now, the mechanism evolved by PolD to prevent ribonucleotide incorporation was unknown. In all other DNA polymerase families, an active site steric gate residue prevents ribonucleotide incorporation. In this work, we identify two consensus active site acidic (a) and basic (b) motifs shared across the entire two-barrel nucleotide polymerase superfamily, and a nucleotide selectivity (s) motif specific to PolD versus RNAPs. A novel steric gate histidine residue (H931 in Thermococcus sp. 9°N PolD) in the PolD s-motif both prevents ribonucleotide incorporation and promotes efficient dNTP incorporation. Further, a PolD H931A steric gate mutant abolishes ribonucleotide discrimination and readily incorporates a variety of 2' modified nucleotides. Taken together, we construct the first putative nucleotide bound PolD active site model and provide structural and functional evidence for the emergence of DNA replication through the evolution of an ancestral RNAP two-barrel catalytic core.
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Affiliation(s)
| | - Ece Alpaslan
- New England Biolabs, 240 County Road Ipswich, MA 01938, USA
| | - Thomas C Evans
- New England Biolabs, 240 County Road Ipswich, MA 01938, USA
| | - Ludovic Sauguet
- Institut Pasteur, Unité de Dynamique Structurale des Macromolécules, 75015 Paris, France
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Robinzon S, Cawood AR, Ruiz MA, Gophna U, Altman-Price N, Mills KV. Protein Splicing Activity of the Haloferax volcanii PolB-c Intein Is Sensitive to Homing Endonuclease Domain Mutations. Biochemistry 2020; 59:3359-3367. [PMID: 32822531 DOI: 10.1021/acs.biochem.0c00512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Inteins are selfish genetic elements residing in open reading frames that can splice post-translationally, resulting in the ligation of an uninterrupted, functional protein. Like other inteins, the DNA polymerase B (PolB) intein of the halophilic archaeon Haloferax volcanii has an active homing endonuclease (HEN) domain, facilitating its horizontal transmission. Previous work has shown that the presence of the PolB intein exerts a significant fitness cost on the organism compared to an intein-free isogenic H. volcanii. Here, we show that mutation of a conserved residue in the HEN domain not only reduces intein homing but also slows growth. Surprisingly, although this mutation is far from the protein splicing active site, it also significantly reduces in vitro protein splicing. Moreover, two additional HEN domain mutations, which could not be introduced to H. volcanii, presumably due to lethality, also eliminate protein splicing activity in vitro. These results suggest an interplay between HEN residues and the protein splicing domain, despite an over 35 Å separation in a PolB intein homology model. The combination of in vivo and in vitro evidence strongly supports a model of codependence between the self-splicing domain and the HEN domain that has been alluded to by previous in vitro studies of protein splicing with HEN domain-containing inteins.
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Affiliation(s)
- Shachar Robinzon
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Alexandra R Cawood
- Department of Chemistry, College of the Holy Cross, Worcester, Massachusetts 01610, United States
| | - Mercedes A Ruiz
- Department of Chemistry, College of the Holy Cross, Worcester, Massachusetts 01610, United States
| | - Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Neta Altman-Price
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.,The Open University, Raanana 43107, Israel
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, Worcester, Massachusetts 01610, United States
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Chiarolanzio KC, Pusztay JM, Chavez A, Zhao J, Xie J, Wang C, Mills KV. Allosteric Influence of Extremophile Hairpin Motif Mutations on the Protein Splicing Activity of a Hyperthermophilic Intein. Biochemistry 2020; 59:2459-2467. [PMID: 32559373 DOI: 10.1021/acs.biochem.0c00348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein splicing is a post-translational process mediated by an intein, whereby the intein excises itself from a precursor protein with concomitant ligation of the two flanking polypeptides. The intein that interrupts the DNA polymerase II in the extreme hyperthermophile Pyrococcus abyssi has a β-hairpin that extends the central β-sheet of the intein. This β-hairpin is mostly found in inteins from archaea, as well as halophilic eubacteria, and is thus called the extremophile hairpin (EXH) motif. The EXH is stabilized by multiple favorable interactions, including electrostatic interactions involving Glu29, Glu31, and Arg40. Mutations of these residues diminish the extent of N-terminal cleavage and the extent of protein splicing, likely by interfering with the coordination of the steps of splicing. These same mutations decrease the global stability of the intein fold as measured by susceptibility to thermolysin cleavage. 15N-1H heteronuclear single-quantum coherence demonstrated that these mutations altered the chemical environment of active site residues such as His93 (B-block histidine) and Ser166 (F-block residue 4). This work again underscores the connected and coordinated nature of intein conformation and dynamics, where remote mutations can disturb a finely tuned interaction network to inhibit or enhance protein splicing.
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Affiliation(s)
- Kathryn C Chiarolanzio
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| | - Jennifer M Pusztay
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| | - Angel Chavez
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| | - Jing Zhao
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Jian Xie
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Chunyu Wang
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
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Shi Y, Hong X, Fan H, Wu Z, Liu A. Characterizing Novel Modifications of a Therapeutic Protein Using Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry, Sedimentation Velocity Analytical Ultracentrifugation, and Structural Modeling. Anal Chem 2018; 90:12870-12877. [PMID: 30295031 DOI: 10.1021/acs.analchem.8b03459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heterogeneity of biopharmaceutical products is common due to various co- and post-translational modifications and degradation events that occur during the biological production process and throughout the shelf life. Product-related variants resulting from these modifications potentially affect a product's biological activity and safety, and thus, their detailed structure characterization is of great importance for successful development of protein therapeutics. Specifically, in this study, two novel low-level product variants in a recombinant therapeutic protein were characterized via chromatographic enrichment followed by proteolytic digestion and analysis using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). One of the variants was identified to be the therapeutic protein missing a 61-amino-acid fragment from its N-terminus. Consequently, the other variant was found to be the therapeutic protein carrying the 61-amino-acid long peptide. Furthermore, detailed structure at the modification site of the latter variant was determined as that amino group from the protein's N-terminus linked to side chain carbonyl carbon at Asp 61 residue of the peptide, based on the complementary information from collision induced dissociation and electron transfer dissociation MS/MS analysis. Results from sedimentation velocity analytical ultracentrifugation and computational structural modeling supported the hypothesis that formation of these two variants was a result of protein self-association. In dimeric state, the head-to-toe stacking conformation of two therapeutic protein molecules allowed spatial closeness between the N-terminus of one molecule and the 61st amino acid of the other molecule, resulting in a novel peptide transfer between the two protein molecules.
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Devaraj NK, Perrin CL. Approach control. Stereoelectronic origin of geometric constraints on N-to-S and N-to-O acyl shifts in peptides. Chem Sci 2018; 9:1789-1794. [PMID: 29675223 PMCID: PMC5892126 DOI: 10.1039/c7sc04046f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/06/2018] [Indexed: 11/21/2022] Open
Abstract
Intramolecular N-to-S or N-to-O acyl shifts in peptides are of fundamental and practical importance, as they constitute the first step in protein splicing and can be used for the synthesis of thioester-modified peptides required for native chemical ligation. It has been stated that the nucleophile must be positioned anti to the carbonyl oxygen, as in a cis amide. Despite the importance of such reactions, an understanding of this geometric restriction remains obscure. Here we argue that the empirical requirement for positioning the nucleophile is a stereoelectronic effect arising from the ease of approach of the nucleophile to a carbonyl group, not ground-state destabilization. DFT calculations on model amides support our explanation and indicate a significant decrease in both the transition-state energy and the activation energy for a cis amide. However, the approach of the nucleophile must be anti not only to the carbonyl oxygen but also to the nitrogen. The direction of approach is expressed by a new, modified Bürgi-Dunitz angle. Our data shed light on the mechanisms of acyl shifts in peptides, and they explain why a cis peptide might be required for protein splicing. The further implications for acyl shits in homoserine and homocysteine peptides and for aldol condensations are also considered.
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Affiliation(s)
- Neal K Devaraj
- Dept. of Chemistry & Biochemistry , Univ. Calif. San Diego , La Jolla , CA 92093-0358 , USA .
| | - Charles L Perrin
- Dept. of Chemistry & Biochemistry , Univ. Calif. San Diego , La Jolla , CA 92093-0358 , USA .
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Huang H, Yang B, Ge B, Lao J, Zhou S, Huang F. Using self-cleavable ternary fusion pattern for efficient preparation of Bacteriorhodopsin. Process Biochem 2018. [DOI: 10.1016/j.procbio.2017.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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