1
|
Lei B, Wang S, Zhang X, Chen T, Lin Y. Novel protein ligase based on dual split intein. Biochem Biophys Res Commun 2024; 720:150097. [PMID: 38754162 DOI: 10.1016/j.bbrc.2024.150097] [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: 04/18/2024] [Accepted: 05/08/2024] [Indexed: 05/18/2024]
Abstract
Inteins are unique single-turnover enzymes that can excise themselves from the precursor protein without the aid of any external cofactors or energy. In most cases, inteins are covalently linked with the extein sequences and protein splicing happens spontaneously. In this study, a novel protein ligation system was developed based on two atypical split inteins without cross reaction, in which the large segments of one S1 and one S11 split intein fusion protein acted as a protein ligase, the small segments (only several amino acids long) was fused to the N-extein and C-extein, respectively. The splicing activity was demonstrated in E. coli and in vitro with different extein sequences, which showed ∼15% splicing efficiency in vitro. The protein trans-splicing in vitro was further optimized, and possible reaction explanations were explored. As a proof of concept, we expect this approach to expand the scope of trans-splicing-based protein engineering and provide new clues for intein based protein ligase.
Collapse
Affiliation(s)
- Bing Lei
- College of Biological Science and Medical Engineering, Donghua University, Shanghai, 201620, PR China
| | - Suyang Wang
- College of Biological Science and Medical Engineering, Donghua University, Shanghai, 201620, PR China
| | - Xiaomeng Zhang
- College of Biological Science and Medical Engineering, Donghua University, Shanghai, 201620, PR China
| | - Tianqi Chen
- College of Biological Science and Medical Engineering, Donghua University, Shanghai, 201620, PR China
| | - Ying Lin
- College of Biological Science and Medical Engineering, Donghua University, Shanghai, 201620, PR China.
| |
Collapse
|
2
|
Gallot-Lavallée L, Jerlström-Hultqvist J, Zegarra-Vidarte P, Salas-Leiva DE, Stairs CW, Čepička I, Roger AJ, Archibald JM. Massive intein content in Anaeramoeba reveals aspects of intein mobility in eukaryotes. Proc Natl Acad Sci U S A 2023; 120:e2306381120. [PMID: 38019867 PMCID: PMC10710043 DOI: 10.1073/pnas.2306381120] [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: 04/19/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Inteins are self-splicing protein elements found in viruses and all three domains of life. How the DNA encoding these selfish elements spreads within and between genomes is poorly understood, particularly in eukaryotes where inteins are scarce. Here, we show that the nuclear genomes of three strains of Anaeramoeba encode between 45 and 103 inteins, in stark contrast to four found in the most intein-rich eukaryotic genome described previously. The Anaeramoeba inteins reside in a wide range of proteins, only some of which correspond to intein-containing proteins in other eukaryotes, prokaryotes, and viruses. Our data also suggest that viruses have contributed to the spread of inteins in Anaeramoeba and the colonization of new alleles. The persistence of Anaeramoeba inteins might be partly explained by intragenomic movement of intein-encoding regions from gene to gene. Our intein dataset greatly expands the spectrum of intein-containing proteins and provides insights into the evolution of inteins in eukaryotes.
Collapse
Affiliation(s)
- Lucie Gallot-Lavallée
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Jon Jerlström-Hultqvist
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Microbiology and Immunology, Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala751 24, Sweden
| | - Paula Zegarra-Vidarte
- Microbiology and Immunology, Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala751 24, Sweden
| | - Dayana E. Salas-Leiva
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Courtney W. Stairs
- Microbiology Group, Department of Biology, Lund University, Lund223 62, Sweden
| | - Ivan Čepička
- Department of Zoology, Charles University, Prague128 00, Czech Republic
| | - Andrew J. Roger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - John M. Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| |
Collapse
|
3
|
Turgeman-Grott I, Arsenault D, Yahav D, Feng Y, Miezner G, Naki D, Peri O, Papke RT, Gogarten JP, Gophna U. Neighboring inteins interfere with one another's homing capacity. PNAS NEXUS 2023; 2:pgad354. [PMID: 38024399 PMCID: PMC10643990 DOI: 10.1093/pnasnexus/pgad354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
Inteins are mobile genetic elements that invade conserved genes across all domains of life and viruses. In some instances, a single gene will have several intein insertion sites. In Haloarchaea, the minichromosome maintenance (MCM) protein at the core of replicative DNA helicase contains four intein insertion sites within close proximity, where two of these sites (MCM-a and MCM-d) are more likely to be invaded. A haloarchaeon that harbors both MCM-a and MCM-d inteins, Haloferax mediterranei, was studied in vivo to determine intein invasion dynamics and the interactions between neighboring inteins. Additionally, invasion frequencies and the conservation of insertion site sequences in 129 Haloferacales mcm homologs were analyzed to assess intein distribution across the order. We show that the inteins at MCM-a and MCM-d recognize and cleave their respective target sites and, in the event that only one empty intein invasion site is present, readily initiate homing (i.e. single homing). However, when two inteins are present co-homing into an intein-free target sequence is much less effective. The two inteins are more effective when invading alleles that already contain an intein at one of the two sites. Our in vivo and computational studies also support that having a proline in place of a serine as the first C-terminal extein residue of the MCM-d insertion site prevents successful intein splicing, but does not stop recognition of the insertion site by the intein's homing endonuclease.
Collapse
Affiliation(s)
- Israela Turgeman-Grott
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| | - Danielle Arsenault
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06268-3125, USA
| | - Dekel Yahav
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| | - Yutian Feng
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06268-3125, USA
| | - Guy Miezner
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| | - Doron Naki
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| | - Omri Peri
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06268-3125, USA
| | - Johann Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06268-3125, USA
- Institute for Systems Genomics, University of Connecticut, 67 North Eagleville Road, Storrs, CT 06268-3003, USA
| | - Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801 Tel Aviv, Israel
| |
Collapse
|
4
|
Liu H, Zhang L, Wang W, Hu H, Ouyang X, Xu P, Tang H. An Intelligent Synthetic Bacterium for Chronological Toxicant Detection, Biodegradation, and Its Subsequent Suicide. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2304318. [PMID: 37705081 PMCID: PMC10625131 DOI: 10.1002/advs.202304318] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/24/2023] [Indexed: 09/15/2023]
Abstract
Modules, toolboxes, and synthetic biology systems may be designed to address environmental bioremediation. However, weak and decentralized functional modules require complex control. To address this issue, an integrated system for toxicant detection and biodegradation, and subsequent suicide in chronological order without exogenous inducers is constructed. Salicylic acid, a typical pollutant in industrial wastewater, is selected as an example to demonstrate this design. Biosensors are optimized by regulating the expression of receptors and reporters to get 2-fold sensitivity and 6-fold maximum output. Several stationary phase promoters are compared, and promoter Pfic is chosen to express the degradation enzyme. Two concepts for suicide circuits are developed, with the toxin/antitoxin circuit showing potent lethality. The three modules are coupled in a stepwise manner. Detection and biodegradation, and suicide are sequentially completed with partial attenuation compared to pre-integration, except for biodegradation, being improved by the replacements of ribosome binding site. Finally, a long-term stability test reveals that the engineered strain maintained its function for ten generations. The study provides a novel concept for integrating and controlling functional modules that can accelerate the transition of synthetic biology from conceptual to practical applications.
Collapse
Affiliation(s)
- Huan Liu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Lige Zhang
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Weiwei Wang
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Haiyang Hu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Xingyu Ouyang
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Ping Xu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| | - Hongzhi Tang
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiP. R. China
| |
Collapse
|
5
|
Wang Y, Shi Y, Hellinga HW, Beese LS. Thermally controlled intein splicing of engineered DNA polymerases provides a robust and generalizable solution for accurate and sensitive molecular diagnostics. Nucleic Acids Res 2023; 51:5883-5894. [PMID: 37166959 PMCID: PMC10287962 DOI: 10.1093/nar/gkad368] [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: 02/27/2023] [Revised: 04/18/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023] Open
Abstract
DNA polymerases are essential for nucleic acid synthesis, cloning, sequencing and molecular diagnostics technologies. Conditional intein splicing is a powerful tool for controlling enzyme reactions. We have engineered a thermal switch into thermostable DNA polymerases from two structurally distinct polymerase families by inserting a thermally activated intein domain into a surface loop that is integral to the polymerase active site, thereby blocking DNA or RNA template access. The fusion proteins are inactive, but retain their structures, such that the intein excises during a heat pulse delivered at 70-80°C to generate spliced, active polymerases. This straightforward thermal activation step provides a highly effective, one-component 'hot-start' control of PCR reactions that enables accurate target amplification by minimizing unwanted by-products generated by off-target reactions. In one engineered enzyme, derived from Thermus aquaticus DNA polymerase, both DNA polymerase and reverse transcriptase activities are controlled by the intein, enabling single-reagent amplification of DNA and RNA under hot-start conditions. This engineered polymerase provides high-sensitivity detection for molecular diagnostics applications, amplifying 5-6 copies of the tested DNA and RNA targets with >95% certainty. The design principles used to engineer the inteins can be readily applied to construct other conditionally activated nucleic acid processing enzymes.
Collapse
Affiliation(s)
- You Wang
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Yuqian Shi
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Homme W Hellinga
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Lorena S Beese
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
6
|
Pasch T, Schröder A, Kattelmann S, Eisenstein M, Pietrokovski S, Kümmel D, Mootz HD. Structural and biochemical analysis of a novel atypically split intein reveals a conserved histidine specific to cysteine-less inteins. Chem Sci 2023; 14:5204-5213. [PMID: 37206380 PMCID: PMC10189870 DOI: 10.1039/d3sc01200j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 04/23/2023] [Indexed: 05/21/2023] Open
Abstract
Protein trans-splicing mediated by a split intein reconstitutes a protein backbone from two parts. This virtually traceless autoprocessive reaction provides the basis for numerous protein engineering applications. Protein splicing typically proceeds through two thioester or oxyester intermediates involving the side chains of cysteine or serine/threonine residues. A cysteine-less split intein has recently attracted particular interest as it can splice under oxidizing conditions and is orthogonal to disulfide or thiol bioconjugation chemistries. Here, we report the split PolB16 OarG intein, a second such cysteine-independent intein. As a unique trait, it is atypically split with a short intein-N precursor fragment of only 15 amino acids, the shortest characterized to date, which was chemically synthesized to enable protein semi-synthesis. By rational engineering we obtained a high-yielding, improved split intein mutant. Structural and mutational analysis revealed the dispensability of the usually crucial conserved motif N3 (block B) histidine as an obvious peculiar property. Unexpectedly, we identified a previously unnoticed histidine in hydrogen-bond forming distance to the catalytic serine 1 as critical for splicing. This histidine has been overlooked so far in multiple sequence alignments and is highly conserved only in cysteine-independent inteins as a part of a newly discovered motif NX. The motif NX histidine is thus likely of general importance to the specialized environment in the active site required in this intein subgroup. Together, our study advances the toolbox as well as the structural and mechanistic understanding of cysteine-less inteins.
Collapse
Affiliation(s)
- Tim Pasch
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Alexander Schröder
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Sabrina Kattelmann
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Miriam Eisenstein
- Department of Molecular Genetics, Weizmann Institute of Science Rehovot 76100 Israel
| | - Shmuel Pietrokovski
- Department of Molecular Genetics, Weizmann Institute of Science Rehovot 76100 Israel
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Henning D Mootz
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| |
Collapse
|
7
|
Akram F, Shah FI, Ibrar R, Fatima T, Haq IU, Naseem W, Gul MA, Tehreem L, Haider G. Bacterial thermophilic DNA polymerases: A focus on prominent biotechnological applications. Anal Biochem 2023; 671:115150. [PMID: 37054862 DOI: 10.1016/j.ab.2023.115150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/24/2023] [Accepted: 04/03/2023] [Indexed: 04/15/2023]
Abstract
DNA polymerases are the enzymes able to replicate the genetic information in nucleic acid. As a result, they are necessary to copy the complete genome of every living creature before cell division and sustain the integrity of the genetic information throughout the life of each cell. Any organism that uses DNA as its genetic information, whether unicellular or multicellular, requires one or more thermostable DNA polymerases to thrive. Thermostable DNA polymerase is important in modern biotechnology and molecular biology because it results in methods such as DNA cloning, DNA sequencing, whole genome amplification, molecular diagnostics, polymerase chain reaction, synthetic biology, and single nucleotide polymorphism detection. There are at least 14 DNA-dependent DNA polymerases in the human genome, which is remarkable. These include the widely accepted, high-fidelity enzymes responsible for replicating the vast majority of genomic DNA and eight or more specialized DNA polymerases discovered in the last decade. The newly discovered polymerases' functions are still being elucidated. Still, one of its crucial tasks is to permit synthesis to resume despite the DNA damage that stops the progression of replication-fork. One of the primary areas of interest in the research field has been the quest for novel DNA polymerase since the unique features of each thermostable DNA polymerase may lead to the prospective creation of novel reagents. Furthermore, protein engineering strategies for generating mutant or artificial DNA polymerases have successfully generated potent DNA polymerases for various applications. In molecular biology, thermostable DNA polymerases are extremely useful for PCR-related methods. This article examines the role and importance of DNA polymerase in a variety of techniques.
Collapse
Affiliation(s)
- Fatima Akram
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan.
| | - Fatima Iftikhar Shah
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan; The University of Lahore, Pakistan
| | - Ramesha Ibrar
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Taseer Fatima
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Ikram Ul Haq
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan; Pakistan Academy of Sciences, Islamabad, Pakistan
| | - Waqas Naseem
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Mahmood Ayaz Gul
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Laiba Tehreem
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| | - Ghanoor Haider
- Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan
| |
Collapse
|
8
|
Tharappel AM, Li Z, Zhu YC, Wu X, Chaturvedi S, Zhang QY, Li H. Calcimycin Inhibits Cryptococcus neoformans In Vitro and In Vivo by Targeting the Prp8 Intein Splicing. ACS Infect Dis 2022; 8:1851-1868. [PMID: 35948057 PMCID: PMC9464717 DOI: 10.1021/acsinfecdis.2c00137] [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] [Indexed: 01/29/2023]
Abstract
Drug resistance is a significant concern in the treatment of diseases, including cryptococcosis caused by Cryptococcus neoformans (Cne) and Cryptococcus gattii (Cga). Alternative drug targets are necessary to overcome drug resistance before it attains a critical stage. Splicing of inteins from pro-protein precursors is crucial for activities of essential proteins hosting intein elements in many organisms, including human pathogens such as Cne and Cga. Through a high-throughput screening, we identified calcimycin (CMN) as a potent Prp8 intein splicing inhibitor with a minimum inhibitory concentration (MIC) of 1.5 μg/mL against the wild-type Cne-H99 (Cne-WT or Cne). In contrast, CMN inhibited the intein-less mutant strain (Cne-Mut) with a 16-fold higher MIC. Interestingly, Aspergillus fumigatus and a few Candida species were resistant to CMN. Further studies indicated that CMN reduced virulence factors such as urease activity, melanin production, and biofilm formation in Cne. CMN also inhibited Cne intracellular infection in macrophages. In a target-specific split nanoluciferase assay, the IC50 of CMN was 4.6 μg/mL. Binding of CMN to recombinant Prp8 intein was demonstrated by thermal shift assay and microscale thermophoresis. Treating Cne cells with CMN reduced intein splicing. CMN was fungistatic and showed a synergistic effect with the known antifungal drug amphotericin B. Finally, CMN treatment at 20 mg/kg body weight led to 60% reduction in lung fungal load in a cryptococcal pulmonary infection mouse model. Overall, CMN represents a potent antifungal with a novel mechanism of action to treat Cne and possibly Cga infections.
Collapse
Affiliation(s)
- Anil Mathew Tharappel
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson Arizona 85721-0207, United States
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
| | - Zhong Li
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson Arizona 85721-0207, United States
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
| | - Yan Chun Zhu
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
| | - Xiangmeng Wu
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson Arizona 85721-0207, United States
| | - Sudha Chaturvedi
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
| | - Qing-Yu Zhang
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson Arizona 85721-0207, United States
| | - Hongmin Li
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson Arizona 85721-0207, United States
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
- The BIO5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| |
Collapse
|
9
|
Fernandes JAL, Zatti MDS, Arantes TD, de Souza MFB, Santoni MM, Rossi D, Zanelli CF, Liu XQ, Bagagli E, Theodoro RC. Cryptococcus neoformans Prp8 Intein: An In Vivo Target-Based Drug Screening System in Saccharomyces cerevisiae to Identify Protein Splicing Inhibitors and Explore Its Dynamics. J Fungi (Basel) 2022; 8:jof8080846. [PMID: 36012834 PMCID: PMC9410109 DOI: 10.3390/jof8080846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
Inteins are genetic mobile elements that are inserted within protein-coding genes, which are usually housekeeping genes. They are transcribed and translated along with the host gene, then catalyze their own splicing out of the host protein, which assumes its functional conformation thereafter. As Prp8 inteins are found in several important fungal pathogens and are absent in mammals, they are considered potential therapeutic targets since inhibiting their splicing would selectively block the maturation of fungal proteins. We developed a target-based drug screening system to evaluate the splicing of Prp8 intein from the yeast pathogen Cryptococcus neoformans (CnePrp8i) using Saccharomyces cerevisiae Ura3 as a non-native host protein. In our heterologous system, intein splicing preserved the full functionality of Ura3. To validate the system for drug screening, we examined cisplatin, which has been described as an intein splicing inhibitor. By using our system, new potential protein splicing inhibitors may be identified and used, in the future, as a new class of drugs for mycosis treatment. Our system also greatly facilitates the visualization of CnePrp8i splicing dynamics in vivo.
Collapse
Affiliation(s)
- José Alex Lourenço Fernandes
- Institute of Tropical Medicine, Federal University of Rio Grande do Norte (UFRN), Natal 59077-080, Rio Grande do Norte, Brazil
- Department of Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte (UFRN), Natal 59078-900, Rio Grande do Norte, Brazil
- Ottawa Hospital Research Institute (OHRI), The University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Correspondence: (J.A.L.F.); (R.C.T.)
| | - Matheus da Silva Zatti
- Institute of Tropical Medicine, Federal University of Rio Grande do Norte (UFRN), Natal 59077-080, Rio Grande do Norte, Brazil
- Department of Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte (UFRN), Natal 59078-900, Rio Grande do Norte, Brazil
| | - Thales Domingos Arantes
- Department of Biosciences and Technology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia 74605-050, Goiás, Brazil
| | - Maria Fernanda Bezerra de Souza
- Department of Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte (UFRN), Natal 59078-900, Rio Grande do Norte, Brazil
| | - Mariana Marchi Santoni
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, São Paulo, Brazil
| | - Danuza Rossi
- Pensabio, São Paulo 05005-010, São Paulo, Brazil
| | - Cleslei Fernando Zanelli
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, São Paulo, Brazil
| | - Xiang-Qin Liu
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Eduardo Bagagli
- Microbiology and Immunology Department, Biosciences Institute of Botucatu, São Paulo State University (UNESP), Botucatu 18618-689, São Paulo, Brazil
| | - Raquel Cordeiro Theodoro
- Institute of Tropical Medicine, Federal University of Rio Grande do Norte (UFRN), Natal 59077-080, Rio Grande do Norte, Brazil
- Correspondence: (J.A.L.F.); (R.C.T.)
| |
Collapse
|
10
|
Prabhala SV, Gierach I, Wood DW. The Evolution of Intein-Based Affinity Methods as Reflected in 30 years of Patent History. Front Mol Biosci 2022; 9:857566. [PMID: 35463948 PMCID: PMC9033041 DOI: 10.3389/fmolb.2022.857566] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/04/2022] [Indexed: 11/18/2022] Open
Abstract
Self-cleaving affinity tags, based on engineered intein protein domains, have been touted as a universal single step purification platform for tagless non-mAb proteins. These approaches provide all of the power and flexibility of tag-based affinity methods, but deliver a tagless target protein suitable for clinical applications without complex process development. This combination of features might accelerate and de-risk biopharmaceutical development by bridging early discovery to full-scale manufacturing under a single platform. Despite this profound promise, intein-based technologies have yet to reach their full potential. This review examines the evolution of intein-based purification methods in the light of several significant intein patents filed over the last 3 decades. Illustrated with actual key figures from each of the relevant patents, key advances are described with a focus on applications in basic research and biopharmaceutical production. Suggestions for extending intein-based purification systems to emerging therapies and non-protein applications are presented as concluding remarks.
Collapse
Affiliation(s)
- Sai Vivek Prabhala
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, United States
| | | | - David W. Wood
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, United States,Protein Capture Science, Columbus, OH, United States,*Correspondence: David W. Wood,
| |
Collapse
|
11
|
SufB intein splicing in Mycobacterium tuberculosis is influenced by two remote conserved N-extein histidines. Biosci Rep 2022; 42:230724. [PMID: 35234249 PMCID: PMC8891592 DOI: 10.1042/bsr20212207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/11/2022] [Accepted: 01/27/2022] [Indexed: 11/24/2022] Open
Abstract
Inteins are auto-processing domains that implement a multistep biochemical reaction termed protein splicing, marked by cleavage and formation of peptide bonds. They excise from a precursor protein, generating a functional protein via covalent bonding of flanking exteins. We report the kinetic study of splicing and cleavage reaction in [Fe–S] cluster assembly protein SufB from Mycobacterium tuberculosis (Mtu). Although it follows a canonical intein splicing pathway, distinct features are added by extein residues present in the active site. Sequence analysis identified two conserved histidines in the N-extein region; His-5 and His-38. Kinetic analyses of His-5Ala and His-38Ala SufB mutants exhibited significant reductions in splicing and cleavage rates relative to the SufB wildtype (WT) precursor protein. Structural analysis and molecular dynamics (MD) simulations suggested that Mtu SufB displays a unique mechanism where two remote histidines work concurrently to facilitate N-terminal cleavage reaction. His-38 is stabilized by the solvent-exposed His-5, and can impact N–S acyl shift by direct interaction with the catalytic Cys1. Development of inteins as biotechnological tools or as pathogen-specific novel antimicrobial targets requires a more complete understanding of such unexpected roles of conserved extein residues in protein splicing.
Collapse
|
12
|
Wang H, Wang L, Zhong B, Dai Z. Protein Splicing of Inteins: A Powerful Tool in Synthetic Biology. Front Bioeng Biotechnol 2022; 10:810180. [PMID: 35265596 PMCID: PMC8899391 DOI: 10.3389/fbioe.2022.810180] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 01/25/2022] [Indexed: 12/21/2022] Open
Abstract
Inteins are protein segments that are capable of enabling the ligation of flanking extein into a new protein, a process known as protein splicing. Since its discovery, inteins have become powerful biotechnological tools for applications such as protein engineering. In the last 10 years, the development in synthetic biology has further endowed inteins with enhanced functions and diverse utilizations. Here we review these efforts and discuss the future directions.
Collapse
Affiliation(s)
- Hao Wang
- Materials Synthetic Biology Center, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Lin Wang
- Materials Synthetic Biology Center, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Baihua Zhong
- Materials Interfaces Center, Institute of Advanced Materials Science and Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhuojun Dai
- Materials Synthetic Biology Center, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| |
Collapse
|
13
|
Yalala VR, Lynch AK, Mills KV. Conditional Alternative Protein Splicing Promoted by Inteins from Haloquadratum walsbyi. Biochemistry 2022; 61:294-302. [PMID: 35073064 PMCID: PMC8847336 DOI: 10.1021/acs.biochem.1c00788] [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] [Indexed: 11/28/2022]
Abstract
Protein splicing is a post-translational process by which an intervening protein, or an intein, catalyzes its own excision from flanking polypeptides, or exteins, coupled to extein ligation. Four inteins interrupt the MCM helicase of the halophile Haloquadratum walsbyi, two of which are mini-inteins that lack a homing endonuclease. Both inteins can be overexpressed in Escherichia coli and purified as unspliced precursors; splicing can be induced in vitro by incubation with salt. However, one intein can splice in 0.5 M NaCl in vitro, whereas the other splices efficiently only in buffer containing over 2 M NaCl; the organism also requires high salt to grow, with the standard growth media containing over 3 M NaCl and about 0.75 M magnesium salts. Consistent with this difference in salt-dependent activity, an intein-containing precursor protein with both inteins promotes conditional alternative protein splicing (CAPS) to yield different spliced products dependent on the salt concentration. Native Trp fluorescence of the inteins suggests that the difference in activity may be due to partial unfolding of the inteins at lower salt concentrations. This differential salt sensitivity of intein activity may provide a useful mechanism for halophiles to respond to environmental changes.
Collapse
Affiliation(s)
- Vaishnavi R Yalala
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| | - Abigeal K Lynch
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, Massachusetts 01610, United States
| |
Collapse
|
14
|
Kaur V, Garg S, Rakshit S. Instantaneous splicing and excision of inteins to synthesize polyproteins on a substrate with tunable linkers. SOFT MATTER 2022; 18:602-608. [PMID: 34928293 DOI: 10.1039/d1sm01469b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nature has adapted chimeric polyproteins to achieve superior and multiplexed functionality in a single protein. However, the hurdles in in vitro synthesis have restricted the biomimicry of and subsequent fundamental studies on the structure-function relationship of polyproteins. Recombinant expression of polyproteins and the synthesis of polyproteins via the enzyme-mediated repetitive digestion and ligation of individual protein domains have been widely practiced. However, recombinant expression often suffers from an in vitro refolding process, whereas enzyme-assisted peptide conjugation results in heterogeneous products, primarily due to enzymatic re-digestion, and prolonged and multistep reactions. Moreover, both methods incorporate enzyme-recognition residues of varying lengths as artifacts at interdomain linkers. The linkers, although tiny, regulate the spatiotemporal conformations of the polyproteins differentially and tune the folding dynamics, stability, and functions of the constituent protein. In an attempt to leave no string behind at the interdomain junctions, here, we develop a 'splice and excise' synthetic route for polyproteins on a substrate using two orthogonal split inteins. Inteins self-excise and conjugate the protein units covalently and instantaneously, without any cofactors, and incorporate a single cysteine or serine residue at the interdomain junctions.
Collapse
Affiliation(s)
- Veerpal Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, 140306, Punjab, India.
| | - Surbhi Garg
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, 140306, Punjab, India.
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, 140306, Punjab, India.
- Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research Mohali, 140306, Punjab, India
| |
Collapse
|
15
|
Abstract
Intervening proteins, or inteins, are mobile genetic elements that are translated within host polypeptides and removed at the protein level by splicing. In protein splicing, a self-mediated reaction removes the intein, leaving a peptide bond in place. While protein splicing can proceed in the absence of external cofactors, several examples of conditional protein splicing (CPS) have emerged. In CPS, the rate and accuracy of splicing are highly dependent on environmental conditions. Because the activity of the intein-containing host protein is compromised prior to splicing and inteins are highly abundant in the microbial world, CPS represents an emerging form of posttranslational regulation that is potentially widespread in microbes. Reactive chlorine species (RCS) are highly potent oxidants encountered by bacteria in a variety of natural environments, including within cells of the mammalian innate immune system. Here, we demonstrate that two naturally occurring RCS, namely, hypochlorous acid (the active compound in bleach) and N-chlorotaurine, can reversibly block splicing of DnaB inteins from Mycobacterium leprae and Mycobacterium smegmatis in vitro. Further, using a reporter that monitors DnaB intein activity within M. smegmatis, we show that DnaB protein splicing is inhibited by RCS in the native host. DnaB, an essential replicative helicase, is the most common intein-housing protein in bacteria. These results add to the growing list of environmental conditions that are relevant to the survival of the intein-containing host and influence protein splicing, as well as suggesting a novel mycobacterial response to RCS. We propose a model in which DnaB splicing, and therefore replication, is paused when these mycobacteria encounter RCS. IMPORTANCE Inteins are both widespread and abundant in microbes, including within several bacterial and fungal pathogens. Inteins are domains translated within host proteins and removed at the protein level by splicing. Traditionally considered molecular parasites, some inteins have emerged in recent years as adaptive posttranslational regulatory elements. Several studies have demonstrated CPS, in which the rate and accuracy of protein splicing, and thus host protein functions, are responsive to environmental conditions relevant to the intein-containing organism. In this work, we demonstrate that two naturally occurring RCS, including the active compound in household bleach, reversibly inhibit protein splicing of Mycobacterium leprae and Mycobacterium smegmatis DnaB inteins. In addition to describing a new physiologically relevant condition that can temporarily inhibit protein splicing, this study suggests a novel stress response in Mycobacterium, a bacterial genus of tremendous importance to humans.
Collapse
|
16
|
Williams JE, Jaramillo MV, Li Z, Zhao J, Wang C, Li H, Mills KV. An alternative domain-swapped structure of the Pyrococcus horikoshii PolII mini-intein. Sci Rep 2021; 11:11680. [PMID: 34083592 PMCID: PMC8175363 DOI: 10.1038/s41598-021-91090-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/19/2021] [Indexed: 01/09/2023] Open
Abstract
Protein splicing is a post-translational process by which an intein catalyzes its own excision from flanking polypeptides, or exteins, concomitant with extein ligation. Many inteins have nested homing endonuclease domains that facilitate their propagation into intein-less alleles, whereas other inteins lack the homing endonuclease (HEN) and are called mini-inteins. The mini-intein that interrupts the DNA PolII of Pyrococcus horikoshii has a linker region in place of the HEN domain that is shorter than the linker in a closely related intein from Pyrococcus abyssi. The P. horikoshii PolII intein requires a higher temperature for catalytic activity and is more stable to digestion by the thermostable protease thermolysin, suggesting that it is more rigid than the P. abyssi intein. We solved a crystal structure of the intein precursor that revealed a domain-swapped dimer. Inteins found as domain swapped dimers have been shown to promote intein-mediated protein alternative splicing, but the solved P. horikoshii PolII intein structure has an active site unlikely to be catalytically competent.
Collapse
Affiliation(s)
- Jennie E Williams
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, MA, USA
| | - Mario V Jaramillo
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, MA, USA
| | - Zhong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, 12208, USA
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, 85721, USA
| | - Jing Zhao
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
- China Agricultural University, Beijing, China
| | - Chunyu Wang
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Hongmin Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, 12208, USA
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, 85721, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, 1 College Street, Worcester, MA, USA.
| |
Collapse
|
17
|
Panda S, Nanda A, Nasker SS, Sen D, Mehra A, Nayak S. Metal effect on intein splicing: A review. Biochimie 2021; 185:53-67. [PMID: 33727137 DOI: 10.1016/j.biochi.2021.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/04/2021] [Accepted: 03/06/2021] [Indexed: 02/08/2023]
Abstract
Inteins are intervening polypeptides that interrupt the functional domains of several important proteins across the three domains of life. Inteins excise themselves from the precursor protein, ligating concomitant extein residues in a process called protein splicing. Post-translational auto-removal of inteins remain critical for the generation of active proteins. The perspective of inteins in science is a robust field of research, however fundamental studies centralized upon splicing regulatory mechanism are imperative for addressing more intricate issues. Controlled engineering of intein splicing has many applications; intein inhibition can facilitate novel drug design, while activation of intein splicing is exploited in protein purification. This paper provides a comprehensive review of the past and recent advances in the splicing regulation via metal-intein interaction. We compare the behavior of different metal ions on diverse intein systems. Though metals such as Zn, Cu, Pt, Cd, Co, Ni exhibit intein inhibitory effect heterogeneously on different inteins, divalent metal ions such as Ca and Mg fail to do so. The observed diversity in the metal-intein interaction arises mostly due to intein polymorphism and variations in atomic structure of metals. A mechanistic understanding of intein regulation by metals in native as well as synthetically engineered intein systems may yield potent intein inhibitors via direct or indirect approach.
Collapse
Affiliation(s)
- Sunita Panda
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Ananya Nanda
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Sourya Subhra Nasker
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Debjani Sen
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Ashwaria Mehra
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Sasmita Nayak
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India.
| |
Collapse
|
18
|
Porzio E, Faraone Mennella MR, Manco G. DING Proteins Extend to the Extremophilic World. Int J Mol Sci 2021; 22:2035. [PMID: 33670786 PMCID: PMC7922408 DOI: 10.3390/ijms22042035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/04/2021] [Accepted: 02/16/2021] [Indexed: 11/16/2022] Open
Abstract
The DING proteins are ubiquitous in the three domains of life, from mesophiles to thermo- and hyperthermophiles. They belong to a family of more than sixty members and have a characteristic N-terminus, DINGGG, which is considered a "signature" of these proteins. Structurally, they share a highly conserved phosphate binding site, and a three dimensional organization resembling the "Venus Flytrap", both reminding the ones of PstS proteins. They have unusually high sequence conservation, even between distantly related species. Nevertheless despite that the genomes of most of these species have been sequenced, the DING gene has not been reported for all the relative characterized DING proteins. Identity of known DING proteins has been confirmed immunologically and, in some cases, by N-terminal sequence analysis. Only a few of the DING proteins have been purified and biochemically characterized. DING proteins are heterogeneous for their wide range of biological activities and some show different activities not always correlated with each other. Most of them have been originally identified for different biological properties, or rather for binding to phosphate and also to other ligands. Their involvement in pathologies is described. This review is an update of the most recent findings on old and new DING proteins.
Collapse
Affiliation(s)
- Elena Porzio
- Institute of Biochemistry and Cell Biology, CNR, Via P. Castellino 111, 80131 Naples, Italy;
| | | | - Giuseppe Manco
- Institute of Biochemistry and Cell Biology, CNR, Via P. Castellino 111, 80131 Naples, Italy;
| |
Collapse
|
19
|
Liu C, Kobashigawa Y, Yamauchi S, Fukuda N, Sato T, Masuda T, Ohtsuki S, Morioka H. Convenient method of producing cyclic single-chain Fv antibodies by split-intein-mediated protein ligation and chaperone co-expression. J Biochem 2021; 168:257-263. [PMID: 32275752 DOI: 10.1093/jb/mvaa042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/31/2020] [Indexed: 11/13/2022] Open
Abstract
Single-chain Fv (scFv) is a recombinant antibody in which the variable regions of the heavy chain (VH) and light chain (VL) are connected by a short flexible polypeptide linker. Compared with monoclonal antibodies, scFvs have the advantages of low-cost production using Escherichia coli and easy genetic manipulation. ScFvs are, therefore, regarded as useful modules for producing next-generation medical antibodies. The practical use of scFvs has been limited due to their aggregation propensity mediated by interchain VH-VL interactions. To overcome this problem, we recently reported a cyclic scFv whose N-terminus and C-terminus were connected by sortase A-mediated ligation. Preparation of cyclic scFv is, however, a time-consuming process. To accelerate the application study of cyclic scFv, we developed a method to produce cyclic scFv by the combined use of a protein ligation technique based on protein trans-splicing reaction (PTS) by split intein and a chaperone co-expression system. This method allows for the preparation of active cyclic scFv from the cytoplasm of E. coli. The present method was applied to the production of cyclic 73MuL9-scFv, a GA-pyridine antibody, as a kind of advanced glycation end-product. These findings are expected to evoke further application study of cyclic scFv.
Collapse
Affiliation(s)
| | | | | | | | - Takashi Sato
- Department of Analytical and Biophysical Chemistry
| | - Takeshi Masuda
- Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Sumio Ohtsuki
- Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | | |
Collapse
|
20
|
Boral S, Maiti S, Basak AJ, Lee W, De S. Structural, Dynamic, and Functional Characterization of a DnaX Mini-intein Derived from Spirulina platensis Provides Important Insights into Intein-Mediated Catalysis of Protein Splicing. Biochemistry 2020; 59:4711-4724. [PMID: 33289560 DOI: 10.1021/acs.biochem.0c00828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein splicing is a self-catalyzed post-translational modification in which the intein enzyme excises itself from a precursor protein and ligates the flanking sequences to produce a mature protein. We report the solution structure of a 136-residue DnaX mini-intein enzyme derived from the cyanobacterium Spirulina platensis. This sequence adopts a well-defined globular structure and forms a horseshoe-shaped fold commonly found in the HINT (hedgehog intein) topology. Backbone dynamics and hydrogen exchange experiments revealed conserved motions on various time scales, which is proposed to be a characteristic of the intein fold. Interestingly, several dynamic motions were found in symmetrically equivalent positions within the protein structure, which might be a consequence of the symmetrical intein fold. In cell splicing activity showed that Spl DnaX mini-intein is a highly active enzyme. The precursor protein was not detected at any timepoint of the assay. Apart from the splicing reaction, catalytic cleavage at the N- and C-termini of the precursor protein was also observed. To determine the roles of the catalytic residues in splicing and cleavage reactions, all combinations of alanine mutations of these residues were generated and functionally characterized. This in-depth analysis revealed cooperativity between these catalytic residues, which suppresses the N- and C-terminal cleavage reactions and enhances the yield of the spliced product. Overall, this study provides a thorough structural, dynamic, and functional characterization of a new intein sequence and adds to the collection of these unique enzymes that have found tremendous applications in biochemistry and biotechnology.
Collapse
Affiliation(s)
- Soumendu Boral
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Snigdha Maiti
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Aditya J Basak
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Woonghee Lee
- Department of Chemistry, University of Colorado Denver, Denver, Colorado 80217, United States
| | - Soumya De
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| |
Collapse
|
21
|
Inteins in Science: Evolution to Application. Microorganisms 2020; 8:microorganisms8122004. [PMID: 33339089 PMCID: PMC7765530 DOI: 10.3390/microorganisms8122004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022] Open
Abstract
Inteins are mobile genetic elements that apply standard enzymatic strategies to excise themselves post-translationally from the precursor protein via protein splicing. Since their discovery in the 1990s, recent advances in intein technology allow for them to be implemented as a modern biotechnological contrivance. Radical improvement in the structure and catalytic framework of cis- and trans-splicing inteins devised the development of engineered inteins that contribute to various efficient downstream techniques. Previous literature indicates that implementation of intein-mediated splicing has been extended to in vivo systems. Besides, the homing endonuclease domain also acts as a versatile biotechnological tool involving genetic manipulation and control of monogenic diseases. This review orients the understanding of inteins by sequentially studying the distribution and evolution pattern of intein, thereby highlighting a role in genetic mobility. Further, we include an in-depth summary of specific applications branching from protein purification using self-cleaving tags to protein modification, post-translational processing and labelling, followed by the development of intein-based biosensors. These engineered inteins offer a disruptive approach towards research avenues like biomaterial construction, metabolic engineering and synthetic biology. Therefore, this linear perspective allows for a more comprehensive understanding of intein function and its diverse applications.
Collapse
|
22
|
Pérez-Arnaiz P, Dattani A, Smith V, Allers T. Haloferax volcanii-a model archaeon for studying DNA replication and repair. Open Biol 2020; 10:200293. [PMID: 33259746 PMCID: PMC7776575 DOI: 10.1098/rsob.200293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
The tree of life shows the relationship between all organisms based on their common ancestry. Until 1977, it comprised two major branches: prokaryotes and eukaryotes. Work by Carl Woese and other microbiologists led to the recategorization of prokaryotes and the proposal of three primary domains: Eukarya, Bacteria and Archaea. Microbiological, genetic and biochemical techniques were then needed to study the third domain of life. Haloferax volcanii, a halophilic species belonging to the phylum Euryarchaeota, has provided many useful tools to study Archaea, including easy culturing methods, genetic manipulation and phenotypic screening. This review will focus on DNA replication and DNA repair pathways in H. volcanii, how this work has advanced our knowledge of archaeal cellular biology, and how it may deepen our understanding of bacterial and eukaryotic processes.
Collapse
Affiliation(s)
| | | | | | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| |
Collapse
|
23
|
Beyer HM, Virtanen SI, Aranko AS, Mikula KM, Lountos GT, Wlodawer A, Ollila OHS, Iwaï H. The Convergence of the Hedgehog/Intein Fold in Different Protein Splicing Mechanisms. Int J Mol Sci 2020; 21:ijms21218367. [PMID: 33171880 PMCID: PMC7664689 DOI: 10.3390/ijms21218367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/01/2020] [Accepted: 11/05/2020] [Indexed: 11/16/2022] Open
Abstract
Protein splicing catalyzed by inteins utilizes many different combinations of amino-acid types at active sites. Inteins have been classified into three classes based on their characteristic sequences. We investigated the structural basis of the protein splicing mechanism of class 3 inteins by determining crystal structures of variants of a class 3 intein from Mycobacterium chimaera and molecular dynamics simulations, which suggested that the class 3 intein utilizes a different splicing mechanism from that of class 1 and 2 inteins. The class 3 intein uses a bond cleavage strategy reminiscent of proteases but share the same Hedgehog/INTein (HINT) fold of other intein classes. Engineering of class 3 inteins from a class 1 intein indicated that a class 3 intein would unlikely evolve directly from a class 1 or 2 intein. The HINT fold appears as structural and functional solution for trans-peptidyl and trans-esterification reactions commonly exploited by diverse mechanisms using different combinations of amino-acid types for the active-site residues.
Collapse
Affiliation(s)
- Hannes M. Beyer
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
| | - Salla I. Virtanen
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
| | - A. Sesilja Aranko
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
| | - Kornelia M. Mikula
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
| | - George T. Lountos
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA;
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA;
| | - O. H. Samuli Ollila
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland; (H.M.B.); (S.I.V.); (A.S.A.); (K.M.M.); (O.H.S.O.)
- Correspondence: ; Tel.: +358-2941-59752
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Zheng L, Prestwich BD, Harrison PT, Mackrill JJ. Polycystic Kidney Disease Ryanodine Receptor Domain (PKDRR) Proteins in Oomycetes. Pathogens 2020; 9:pathogens9070577. [PMID: 32708691 PMCID: PMC7399828 DOI: 10.3390/pathogens9070577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 11/16/2022] Open
Abstract
In eukaryotes, two sources of Ca2+ are accessed to allow rapid changes in the cytosolic levels of this second messenger: the extracellular medium and intracellular Ca2+ stores, such as the endoplasmic reticulum. One class of channel that permits Ca2+ entry is the transient receptor potential (TRP) superfamily, including the polycystic kidney disease (PKD) proteins, or polycystins. Channels that release Ca2+ from intracellular stores include the inositol 1,4,5-trisphosphate/ryanodine receptor (ITPR/RyR) superfamily. Here, we characterise a family of proteins that are only encoded by oomycete genomes, that we have named PKDRR, since they share domains with both PKD and RyR channels. We provide evidence that these proteins belong to the TRP superfamily and are distinct from the ITPR/RyR superfamily in terms of their evolutionary relationships, protein domain architectures and predicted ion channel structures. We also demonstrate that a hypothetical PKDRR protein from Phytophthora infestans is produced by this organism, is located in the cell-surface membrane and forms multimeric protein complexes. Efforts to functionally characterise this protein in a heterologous expression system were unsuccessful but support a cell-surface localisation. These PKDRR proteins represent potential targets for the development of new "fungicides", since they are of a distinctive structure that is only found in oomycetes and not in any other cellular organisms.
Collapse
Affiliation(s)
- Limian Zheng
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
| | - Barbara Doyle Prestwich
- School of Biological, Earth and Environmental Sciences, University College Cork, T23 TK30 Cork, Ireland;
| | - Patrick T. Harrison
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
| | - John J. Mackrill
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
- Correspondence:
| |
Collapse
|
26
|
Woods D, Vangaveti S, Egbanum I, Sweeney AM, Li Z, Bacot-Davis V, LeSassier DS, Stanger M, Hardison GE, Li H, Belfort M, Lennon CW. Conditional DnaB Protein Splicing Is Reversibly Inhibited by Zinc in Mycobacteria. mBio 2020; 11:e01403-20. [PMID: 32665276 PMCID: PMC7360933 DOI: 10.1128/mbio.01403-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 11/20/2022] Open
Abstract
Inteins, as posttranslational regulatory elements, can tune protein function to environmental changes by conditional protein splicing (CPS). Translated as subdomains interrupting host proteins, inteins splice to scarlessly join flanking sequences (exteins). We used DnaB-intein1 (DnaBi1) from a replicative helicase of Mycobacterium smegmatis to build a kanamycin intein splicing reporter (KISR) that links splicing of DnaBi1 to kanamycin resistance. Using expression in heterologous Escherichia coli, we observed phenotypic classes of various levels of splicing-dependent resistance (SDR) and related these to the insertion position of DnaBi1 within the kanamycin resistance protein (KanR). The KanR-DnaBi1 construct demonstrating the most stringent SDR was used to probe for CPS of DnaB in the native host environment, M. smegmatis We show here that zinc, important during mycobacterial pathogenesis, inhibits DnaB splicing in M. smegmatis Using an in vitro reporter system, we demonstrated that zinc potently and reversibly inhibited DnaBi1 splicing, as well as splicing of a comparable intein from Mycobacterium leprae Finally, in a 1.95 Å crystal structure, we show that zinc inhibits splicing through binding to the very cysteine that initiates the splicing reaction. Together, our results provide compelling support for a model whereby mycobacterial DnaB protein splicing, and thus DNA replication, is responsive to environmental zinc.IMPORTANCE Inteins are present in a large fraction of prokaryotes and localize within conserved proteins, including the mycobacterial replicative helicase DnaB. In addition to their extensive protein engineering applications, inteins have emerged as environmentally responsive posttranslational regulators of the genes that encode them. While several studies have shown compelling evidence of conditional protein splicing (CPS), examination of splicing in the native host of the intein has proven to be challenging. Here, we demonstrated through a number of measures, including the use of a splicing-dependent sensor capable of monitoring intein activity in the native host, that zinc is a potent and reversible inhibitor of mycobacterial DnaB splicing. This work also expands our knowledge of site selection for intein insertion within nonnative proteins, demonstrating that splicing-dependent host protein activation correlates with proximity to the active site. Additionally, we surmise that splicing regulation by zinc has mycobacteriocidal and CPS application potential.
Collapse
Affiliation(s)
- Daniel Woods
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Sweta Vangaveti
- The RNA Institute, University at Albany, Albany, New York, USA
| | - Ikechukwu Egbanum
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Allison M Sweeney
- Department of Biology, Murray State University, Murray, Kentucky, USA
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Valjean Bacot-Davis
- Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | | | - Matthew Stanger
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | | | - Hongmin Li
- Department of Biological Sciences, University at Albany, Albany, New York, USA
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Marlene Belfort
- Department of Biological Sciences, University at Albany, Albany, New York, USA
- The RNA Institute, University at Albany, Albany, New York, USA
| | | |
Collapse
|
27
|
Khoo ATT, Kim PJ, Kim HM, Je HS. Neural circuit analysis using a novel intersectional split intein-mediated split-Cre recombinase system. Mol Brain 2020; 13:101. [PMID: 32616061 PMCID: PMC7331137 DOI: 10.1186/s13041-020-00640-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/23/2020] [Indexed: 11/10/2022] Open
Abstract
The defining features of a neuron are its functional and anatomical connections with thousands of other neurons in the brain. Together, these neurons form functional networks that direct animal behavior. Current approaches that allow the interrogation of specific populations of neurons and neural circuits rely heavily on targeting their gene expression profiles or connectivity. However, these approaches are often unable to delineate specific neuronal populations. Here, we developed a novel intersectional split intein-mediated split-Cre recombinase system that can selectively label specific types of neurons based on their gene expression profiles and structural connectivity. We developed this system by splitting Cre recombinase into two fragments with evolved split inteins and subsequently expressed one fragment under the influence of a cell type-specific promoter in a transgenic animal, and delivered the other fragment via retrograde viral gene transfer. This approach results in the reconstitution of Cre recombinase in only specific population of neurons projecting from a specific brain region or in those of a specific neuronal type. Taken together, our split intein-based split-Cre system will be useful for sophisticated characterization of mammalian brain circuits.
Collapse
Affiliation(s)
- Audrey Tze Ting Khoo
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Paul Jong Kim
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Ho Min Kim
- Graduate School of Medical Science & Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - H Shawn Je
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore.
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Jaakkonen A, Volkmann G, Iwaï H. An off-the-Shelf Approach for the Production of Fc Fusion Proteins by Protein Trans-Splicing towards Generating a Lectibody In Vitro. Int J Mol Sci 2020; 21:ijms21114011. [PMID: 32503354 PMCID: PMC7313076 DOI: 10.3390/ijms21114011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 12/19/2022] Open
Abstract
Monoclonal antibodies, engineered antibodies, and antibody fragments have become important biological therapeutic platforms. The IgG format with bivalent binding sites has a modular structure with different biological roles, i.e., effector and binding functions, in different domains. We demonstrated the reconstruction of an IgG-like domain structure in vitro by protein ligation using protein trans-splicing. We produced various binding domains to replace the binding domain of IgG from Escherichia coli and the Fc domain of human IgG from Brevibacillus choshinensis as split-intein fusions. We showed that in vitro protein ligation could produce various Fc-fusions at the N-terminus in vitro from the independently produced domains from different organisms. We thus propose an off-the-shelf approach for the combinatorial production of Fc fusions in vitro with several distinct binding domains, particularly from naturally occurring binding domains. Antiviral lectins from algae are known to inhibit virus entry of HIV and SARS coronavirus. We demonstrated that a lectin could be fused with the Fc-domain in vitro by protein ligation, producing an IgG-like molecule as a “lectibody”. Such an Fc-fusion could be produced in vitro by this approach, which could be an attractive method for developing potential therapeutic agents against rapidly emerging infectious diseases like SARS coronavirus without any genetic fusion and expression optimization.
Collapse
Affiliation(s)
- Anniina Jaakkonen
- Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; (A.J.); (G.V.)
- Present Address: Microbiology Unit, Finnish Food Authority, FI-00790 Helsinki, Finland
| | - Gerrit Volkmann
- Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; (A.J.); (G.V.)
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; (A.J.); (G.V.)
- Correspondence: ; Tel.: +358-2941-59752
| |
Collapse
|
30
|
Seo HN, Bang D. Promiscuous Trans-splicing Activities Revealed by Next Generation Sequencing-based Analysis of 298 Split Inteins. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
31
|
Expression and one step intein-mediated purification of biologically active human G-CSF in Escherichia coli. Mol Biol Rep 2020; 47:2861-2869. [DOI: 10.1007/s11033-020-05404-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/25/2020] [Indexed: 01/15/2023]
|
32
|
Abstract
Protein semisynthesis-defined herein as the assembly of a protein from a combination of synthetic and recombinant fragments-is a burgeoning field of chemical biology that has impacted many areas in the life sciences. In this review, we provide a comprehensive survey of this area. We begin by discussing the various chemical and enzymatic methods now available for the manufacture of custom proteins containing noncoded elements. This section begins with a discussion of methods that are more chemical in origin and ends with those that employ biocatalysts. We also illustrate the commonalities that exist between these seemingly disparate methods and show how this is allowing for the development of integrated chemoenzymatic methods. This methodology discussion provides the technical foundation for the second part of the review where we cover the great many biological problems that have now been addressed using these tools. Finally, we end the piece with a short discussion on the frontiers of the field and the opportunities available for the future.
Collapse
Affiliation(s)
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, United States
| |
Collapse
|
33
|
Pinto F, Thornton EL, Wang B. An expanded library of orthogonal split inteins enables modular multi-peptide assemblies. Nat Commun 2020; 11:1529. [PMID: 32251274 PMCID: PMC7090010 DOI: 10.1038/s41467-020-15272-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/26/2020] [Indexed: 01/03/2023] Open
Abstract
Inteins are protein segments capable of joining adjacent residues via a peptide bond. In this process known as protein splicing, the intein itself is not present in the final sequence, thus achieving scarless peptide ligation. Here, we assess the splicing activity of 34 inteins (both uncharacterized and known) using a rapid split fluorescent reporter characterization platform, and establish a library of 15 mutually orthogonal split inteins for in vivo applications, 10 of which can be simultaneously used in vitro. We show that orthogonal split inteins can be coupled to multiple split transcription factors to implement complex logic circuits in living organisms, and that they can also be used for the in vitro seamless assembly of large repetitive proteins with biotechnological relevance. Our work demonstrates the versatility and vast potential of an expanded library of orthogonal split inteins for their use in the fields of synthetic biology and protein engineering.
Collapse
Affiliation(s)
- Filipe Pinto
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Ella Lucille Thornton
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Baojun Wang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK.
| |
Collapse
|
34
|
Bahrami A, Najafi A, Hashemi M, Miraie-Ashtiani SR. PSSP: Protein splice site prediction algorithm using Bayesian approach. J Bioinform Comput Biol 2020; 17:1950034. [PMID: 32019415 DOI: 10.1142/s0219720019500343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study aimed to introduce an algorithm and identify intein motif and blocks involved in protein splicing, and explore the underlying methods in the development of detection of protein motifs. Inteins are mobile protein splicing elements capable of self-splicing post-translationally. They exist in viruses and bacteriophage, notwithstanding this broad phylogenetic distribution, all inteins apportion common structural features. A method was developed to predict intein in a raw sequence, using a ranking and scoring scheme based on amino acid θ value tables. This method aided in the identification and assessment of patterns characterizing the intein sequences. New intein conserved properties are revealed and the known ones are described and localized. We have computed the θ value of each amino acid at block A positions +1 to +13, block B positions l+13 to l+26 and block G positions -7 to +1 for the three categories. The consensus amino acids thus found are listed at the end of each row. We gave statistics for the distance between the blocks, block A to B, block B to F, and block F to G with the average being 66.1, 294, and 10.2 amino acids, respectively. The actual blocks A, B, and G of the one intein found in vacuolar membrane ATPase subunit, a precursor protein, are ranked 1. The results indicate all of the block sequences that are found in nine proteins are ranked at top of the list. The intein sequence is used to search the databases for intein-like proteins. Understanding the functional, structural, and dynamical aspects of inteins is important for intein engineering and the betterment of intein database.
Collapse
Affiliation(s)
- Abolfazl Bahrami
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
| | - Ali Najafi
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Hashemi
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
| | - Seyed Reza Miraie-Ashtiani
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
| |
Collapse
|
35
|
Abstract
In recent years, split inteins have seen widespread use as molecular platforms for the design of a variety of peptide and protein chemistry technologies, most notably protein ligation. The development of these approaches is dependent on the identification and/or design of split inteins with robust activity, stability, and solubility. Here, we describe two approaches to characterize and compare the activities of newly identified or engineered split inteins. The first assay employs an E. coli-based selection system to rapidly screen the activities of many inteins and can be repurposed for directed evolution. The second assay utilizes reverse-phase high-performance liquid chromatography (RP-HPLC) to provide insights into individual chemical steps in the protein splicing reaction, information that can guide further engineering efforts. These techniques provide useful alternatives to common assays that utilize SDS-PAGE to analyze splicing reaction progress.
Collapse
|
36
|
Romero-Casañas A, Gordo V, Castro J, Ribó M. Protein Splicing: From the Foundations to the Development of Biotechnological Applications. Methods Mol Biol 2020; 2133:15-29. [PMID: 32144661 DOI: 10.1007/978-1-0716-0434-2_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Expressed protein ligation is a simple and powerful method in protein engineering to introduce sequences of unnatural amino acids, posttranslational modifications, and biophysical probes into proteins of any size. This methodology has been developed based on the knowledge obtained from protein splicing. Protein splicing is a multistep biochemical reaction that includes the concomitant cleavage and formation of peptide bonds carried out by self-processing domains named inteins. The natural substrates of protein splicing are essential proteins found in intein-containing organisms; inteins are also functional in nonnative frameworks and can be used to alter nearly any protein's primary amino acid sequence. Accordingly, different reactivity features of inteins have been largely exploited to manipulate proteins in countless methods encompassing fields from biochemical research to the development of biotechnological applications including the study of disease progression and validation of potential drug candidates. Here, we review almost three decades of research to uncover the chemical and biochemical enigmas of protein splicing and the development of inteins as potent protein engineering tools.
Collapse
Affiliation(s)
- Alejandro Romero-Casañas
- Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Girona, Spain
| | - Verónica Gordo
- Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Girona, Spain
| | - Jessica Castro
- Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Girona, Spain
| | - Marc Ribó
- Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Girona, Spain.
| |
Collapse
|
37
|
Abstract
The development of expressed protein ligation (EPL) widened the scope of questions that could be addressed by mechanistic biochemistry. Protein trans-splicing (PTS) relies on the same basic chemical principles, but utilizes split inteins to tracelessly ligate distinct peptide or polypeptide fragments together with native peptide bonds. Here we present a method to adapt PTS methodologies for their use in live cells, in order to deliver synthetic or native histone modifications. As an example, we provide a protocol to incorporate a small molecule fluorophore into chromatinized histones. The protocol should be easily adaptable to incorporate other modifications to chromatin in vivo.
Collapse
|
38
|
Gale GAR, Schiavon Osorio AA, Mills LA, Wang B, Lea-Smith DJ, McCormick AJ. Emerging Species and Genome Editing Tools: Future Prospects in Cyanobacterial Synthetic Biology. Microorganisms 2019; 7:E409. [PMID: 31569579 PMCID: PMC6843473 DOI: 10.3390/microorganisms7100409] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
Recent advances in synthetic biology and an emerging algal biotechnology market have spurred a prolific increase in the availability of molecular tools for cyanobacterial research. Nevertheless, work to date has focused primarily on only a small subset of model species, which arguably limits fundamental discovery and applied research towards wider commercialisation. Here, we review the requirements for uptake of new strains, including several recently characterised fast-growing species and promising non-model species. Furthermore, we discuss the potential applications of new techniques available for transformation, genetic engineering and regulation, including an up-to-date appraisal of current Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein (CRISPR/Cas) and CRISPR interference (CRISPRi) research in cyanobacteria. We also provide an overview of several exciting molecular tools that could be ported to cyanobacteria for more advanced metabolic engineering approaches (e.g., genetic circuit design). Lastly, we introduce a forthcoming mutant library for the model species Synechocystis sp. PCC 6803 that promises to provide a further powerful resource for the cyanobacterial research community.
Collapse
Affiliation(s)
- Grant A R Gale
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - Alejandra A Schiavon Osorio
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
| | - Lauren A Mills
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Baojun Wang
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - David J Lea-Smith
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Alistair J McCormick
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
| |
Collapse
|
39
|
Mahmoodi S, Pourhassan-Moghaddam M, Wood DW, Majdi H, Zarghami N. Current affinity approaches for purification of recombinant proteins. ACTA ACUST UNITED AC 2019. [DOI: 10.1080/23312025.2019.1665406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Sahar Mahmoodi
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Pourhassan-Moghaddam
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - David W. Wood
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Hasan Majdi
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nosratollah Zarghami
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| |
Collapse
|
40
|
Expanding the Diversity of Myoviridae Phages Infecting Lactobacillus plantarum-A Novel Lineage of Lactobacillus Phages Comprising Five New Members. Viruses 2019; 11:v11070611. [PMID: 31277436 PMCID: PMC6669764 DOI: 10.3390/v11070611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/07/2019] [Accepted: 07/02/2019] [Indexed: 01/01/2023] Open
Abstract
Lactobacillus plantarum is a bacterium with probiotic properties and promising applications in the food industry and agriculture. So far, bacteriophages of this bacterium have been moderately addressed. We examined the diversity of five new L. plantarum phages via whole genome shotgun sequencing and in silico protein predictions. Moreover, we looked into their phylogeny and their potential genomic similarities to other complete phage genome records through extensive nucleotide and protein comparisons. These analyses revealed a high degree of similarity among the five phages, which extended to the vast majority of predicted virion-associated proteins. Based on these, we selected one of the phages as a representative and performed transmission electron microscopy and structural protein sequencing tests. Overall, the results suggested that the five phages belong to the family Myoviridae, they have a long genome of 137,973-141,344 bp, a G/C content of 36.3-36.6% that is quite distinct from their host's, and surprisingly, 7 to 15 tRNAs. Only an average 41/174 of their predicted genes were assigned a function. The comparative analyses unraveled considerable genetic diversity for the five L. plantarum phages in this study. Hence, the new genus "Semelevirus" was proposed, comprising exclusively of the five phages. This novel lineage of Lactobacillus phages provides further insight into the genetic heterogeneity of phages infecting Lactobacillus sp. The five new Lactobacillus phages have potential value for the development of more robust starters through, for example, the selection of mutants insensitive to phage infections. The five phages could also form part of phage cocktails, which producers would apply in different stages of L. plantarum fermentations in order to create a range of organoleptic outputs.
Collapse
|
41
|
Salwig I, Spitznagel B, Vazquez-Armendariz AI, Khalooghi K, Guenther S, Herold S, Szibor M, Braun T. Bronchioalveolar stem cells are a main source for regeneration of distal lung epithelia in vivo. EMBO J 2019; 38:embj.2019102099. [PMID: 31028085 DOI: 10.15252/embj.2019102099] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 12/22/2022] Open
Abstract
Bronchioalveolar stem cells (BASCs) are a potential source for lung regeneration, but direct in vivo evidence for a multipotential lineage contribution during homeostasis and disease is critically missing, since specific genetic labeling of BASCs has not been possible. We developed a novel cell tracing approach based on intein-mediated assembly of newly engineered split-effectors, allowing selective targeting of dual-marker expressing BASCs in the mouse lung. RNA sequencing of isolated BASCs demonstrates that BASCs show a distinct transcriptional profile, characterized by co-expression of bronchiolar and alveolar epithelial genes. We found that BASCs generate the majority of distal lung airway cells after bronchiolar damage but only moderately contribute to cellular turnover under homeostatic conditions. Importantly, DTA-mediated ablation of BASCs compromised proper regeneration of distal airways. The study defines BASCs as crucial components of the lung repair machinery and provides a paradigmatic example for the detection and manipulation of stem cells that cannot be recognized by a single marker alone.
Collapse
Affiliation(s)
- Isabelle Salwig
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Birgit Spitznagel
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Ana Ivonne Vazquez-Armendariz
- Department of Internal Medicine II, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Keynoosh Khalooghi
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Stefan Guenther
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Susanne Herold
- Department of Internal Medicine II, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Marten Szibor
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| |
Collapse
|
42
|
Sarmiento C, Camarero JA. Biotechnological Applications of Protein Splicing. Curr Protein Pept Sci 2019; 20:408-424. [PMID: 30734675 PMCID: PMC7135711 DOI: 10.2174/1389203720666190208110416] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/22/2018] [Accepted: 12/25/2018] [Indexed: 12/12/2022]
Abstract
Protein splicing domains, also called inteins, have become a powerful biotechnological tool for applications involving molecular biology and protein engineering. Early applications of inteins focused on self-cleaving affinity tags, generation of recombinant polypeptide α-thioesters for the production of semisynthetic proteins and backbone cyclized polypeptides. The discovery of naturallyoccurring split-inteins has allowed the development of novel approaches for the selective modification of proteins both in vitro and in vivo. This review gives a general introduction to protein splicing with a focus on their role in expanding the applications of intein-based technologies in protein engineering and chemical biology.
Collapse
Affiliation(s)
- Corina Sarmiento
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA9033 USA
| | - Julio A. Camarero
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA9033 USA
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA9033 USA
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-9121, USA
| |
Collapse
|
43
|
Genomic Characterization of Cyanophage vB_AphaS-CL131 Infecting Filamentous Diazotrophic Cyanobacterium Aphanizomenon flos-aquae Reveals Novel Insights into Virus-Bacterium Interactions. Appl Environ Microbiol 2018; 85:AEM.01311-18. [PMID: 30367000 PMCID: PMC6293099 DOI: 10.1128/aem.01311-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 10/07/2018] [Indexed: 12/29/2022] Open
Abstract
While filamentous cyanobacteria play a crucial role in food web dynamics and biogeochemical cycling of many aquatic ecosystems around the globe, the knowledge regarding the phages infecting them is limited. Here, we describe the complete genome of the virulent cyanophage vB_AphaS-CL131 (here, CL 131), a Siphoviridae phage that infects the filamentous diazotrophic bloom-forming cyanobacterium Aphanizomenon flos-aquae in the brackish Baltic Sea. CL 131 features a 112,793-bp double-stranded DNA (dsDNA) genome encompassing 149 putative open reading frames (ORFs), of which the majority (86%) lack sequence homology to genes with known functions in other bacteriophages or bacteria. Phylogenetic analysis revealed that CL 131 possibly represents a new evolutionary lineage within the group of cyanophages infecting filamentous cyanobacteria, which form a separate cluster from phages infecting unicellular cyanobacteria. CL 131 encodes a putative type V-U2 CRISPR-Cas system with one spacer (out of 10) targeting a DNA primase pseudogene in a cyanobacterium and a putative type II toxin-antitoxin system, consisting of a GNAT family N-acetyltransferase and a protein of unknown function containing the PRK09726 domain (characteristic of HipB antitoxins). Comparison of CL 131 proteins to reads from Baltic Sea and other available fresh- and brackish-water metagenomes and analysis of CRISPR-Cas arrays in publicly available A. flos-aquae genomes demonstrated that phages similar to CL 131 are present and dynamic in the Baltic Sea and share a common history with their hosts dating back at least several decades. In addition, different CRISPR-Cas systems within individual A. flos-aquae genomes targeted several sequences in the CL 131 genome, including genes related to virion structure and morphogenesis. Altogether, these findings revealed new genomic information for exploring viral diversity and provide a model system for investigation of virus-host interactions in filamentous cyanobacteria.IMPORTANCE The genomic characterization of novel cyanophage vB_AphaS-CL131 and the analysis of its genomic features in the context of other viruses, metagenomic data, and host CRISPR-Cas systems contribute toward a better understanding of aquatic viral diversity and distribution in general and of brackish-water cyanophages infecting filamentous diazotrophic cyanobacteria in the Baltic Sea in particular. The results of this study revealed previously undescribed features of cyanophage genomes (e.g., self-excising intein-containing putative dCTP deaminase and putative cyanophage-encoded CRISPR-Cas and toxin-antitoxin systems) and can therefore be used to predict potential interactions between bloom-forming cyanobacteria and their cyanophages.
Collapse
|
44
|
Pearson CS, Nemati R, Liu B, Zhang J, Scalabrin M, Li Z, Li H, Fabris D, Belfort M, Belfort G. Structure of an engineered intein reveals thiazoline ring and provides mechanistic insight. Biotechnol Bioeng 2018; 116:709-721. [PMID: 30450538 DOI: 10.1002/bit.26875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/18/2018] [Accepted: 10/26/2018] [Indexed: 11/08/2022]
Abstract
We have engineered an intein which spontaneously and reversibly forms a thiazoline ring at the native N-terminal Lys-Cys splice junction. We identified conditions to stablize the thiazoline ring and provided the first crystallographic evidence, at 1.54 Å resolution, for its existence at an intein active site. The finding bolsters evidence for a tetrahedral oxythiazolidine splicing intermediate. In addition, the pivotal mutation maps to a highly conserved B-block threonine, which is now seen to play a causative role not only in ground-state destabilization of the scissile N-terminal peptide bond, but also in steering the tetrahedral intermediate toward thioester formation, giving new insight into the splicing mechanism. We demonstrated the stability of the thiazoline ring at neutral pH as well as sensitivity to hydrolytic ring opening under acidic conditions. A pH cycling strategy to control N-terminal cleavage is proposed, which may be of interest for biotechnological applications requiring a splicing activity switch, such as for protein recovery in bioprocessing.
Collapse
Affiliation(s)
- C Seth Pearson
- Howard P Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Reza Nemati
- Department of Chemistry, State University of New York, Albany, New York
| | - Binbin Liu
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Jing Zhang
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Matteo Scalabrin
- Department of Chemistry, State University of New York, Albany, New York
| | - Zhong Li
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Hongmin Li
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York.,Department of Biomedical Sciences, School of Public Health, Albany, State University of New York, Albany, New York
| | - Dan Fabris
- Department of Chemistry, State University of New York, Albany, New York
| | - Marlene Belfort
- Department of Biomedical Sciences, School of Public Health, Albany, State University of New York, Albany, New York.,Department of Biological Sciences, Albany, State University of New York, Albany, New York
| | - Georges Belfort
- Howard P Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| |
Collapse
|
45
|
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] [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.
Collapse
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.
| |
Collapse
|
46
|
Kelley DS, Lennon CW, Li Z, Miller MR, Banavali NK, Li H, Belfort M. Mycobacterial DnaB helicase intein as oxidative stress sensor. Nat Commun 2018; 9:4363. [PMID: 30341292 PMCID: PMC6195587 DOI: 10.1038/s41467-018-06554-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/10/2018] [Indexed: 11/09/2022] Open
Abstract
Inteins are widespread self-splicing protein elements emerging as potential post-translational environmental sensors. Here, we describe two inteins within one protein, the Mycobacterium smegmatis replicative helicase DnaB. These inteins, DnaBi1 and DnaBi2, have homology to inteins in pathogens, splice with vastly varied rates, and are differentially responsive to environmental stressors. Whereas DnaBi1 splicing is reversibly inhibited by oxidative and nitrosative insults, DnaBi2 is not. Using a reporter that measures splicing in a native intein-containing organism and western blotting, we show that H2O2 inhibits DnaBi1 splicing in M. smegmatis. Intriguingly, upon oxidation, the catalytic cysteine of DnaBi1 forms an intramolecular disulfide bond. We report a crystal structure of the class 3 DnaBi1 intein at 1.95 Å, supporting our findings and providing insight into this splicing mechanism. We propose that this cysteine toggle allows DnaBi1 to sense stress, pausing replication to maintain genome integrity, and then allowing splicing immediately when permissive conditions return.
Collapse
Affiliation(s)
- Danielle S Kelley
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA
| | - Christopher W Lennon
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY, 12222, USA
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA
| | - Michael R Miller
- Department of Chemistry, University at Albany, Albany, NY, 12222, USA
| | - Nilesh K Banavali
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA
| | - Hongmin Li
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA.
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA.
| | - Marlene Belfort
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA.
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY, 12222, USA.
| |
Collapse
|
47
|
Friedel K, Popp MA, Matern JCJ, Gazdag EM, Thiel IV, Volkmann G, Blankenfeldt W, Mootz HD. A functional interplay between intein and extein sequences in protein splicing compensates for the essential block B histidine. Chem Sci 2018; 10:239-251. [PMID: 30713635 PMCID: PMC6333167 DOI: 10.1039/c8sc01074a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/03/2018] [Indexed: 01/28/2023] Open
Abstract
Steric bulk can compensate for a catalytically critical histidine in an intein's active site and promote the N–S acyl shift.
Inteins remove themselves from a precursor protein by protein splicing. Due to the concomitant structural changes of the host protein, this self-processing reaction has enabled many applications in protein biotechnology and chemical biology. We show that the evolved M86 mutant of the Ssp DnaB intein displays a significantly improved tolerance towards non-native amino acids at the N-terminally flanking (–1) extein position compared to the parent intein, in the form of both an artificially trans-splicing split intein and the cis-splicing mini-intein. Surprisingly, side chains with increased steric bulk compared to the native Gly(–1) residue, including d-amino acids, were found to compensate for the essential block B histidine in His73Ala mutants in the initial N–S acyl shift of the protein splicing pathway. In the case of the M86 intein, large (–1) side chains can even rescue protein splicing activity as a whole. With the comparison of three crystal structures, namely of the M86 intein as well as of its Gly(–1)Phe and Gly(–1)Phe/His73Ala mutants, our data supports a model in which the intein's active site can exert a strain by varying mechanisms on the different angles of the scissile bond at the extein–intein junction to effect a ground-state destabilization. The compensatory mechanism of the block B histidine is the first example for the direct functional role of an extein residue in protein splicing. It sheds new light on the extein–intein interplay and on possible consequences of their co-evolution as well as on the laboratory engineering of improved inteins.
Collapse
Affiliation(s)
- Kristina Friedel
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Monika A Popp
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany
| | - Julian C J Matern
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Emerich M Gazdag
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany
| | - Ilka V Thiel
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Gerrit Volkmann
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Wulf Blankenfeldt
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany.,Institute for Biochemistry, Biotechnology and Bioinformatics , Technische Universität Braunschweig , Spielmannstraße 7 , 38106 Braunschweig , Germany
| | - Henning D Mootz
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| |
Collapse
|
48
|
Pirzer T, Becher KS, Rieker M, Meckel T, Mootz HD, Kolmar H. Generation of Potent Anti-HER1/2 Immunotoxins by Protein Ligation Using Split Inteins. ACS Chem Biol 2018; 13:2058-2066. [PMID: 29920062 DOI: 10.1021/acschembio.8b00222] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cell targeting protein toxins have gained increasing interest for cancer therapy aimed at increasing the therapeutic window and reducing systemic toxicity. Because recombinant expression of immunotoxins consisting of a receptor-binding and a cell-killing moiety is hampered by their high toxicity in a eukaryotic production host, most applications rely on recombinant production of fusion proteins consisting of an antibody fragment and a protein toxin in bacterial hosts such as Escherichia coli ( E. coli). These fusions often lack beneficial properties of whole antibodies like extended serum half-life or efficient endocytic uptake via receptor clustering. Here, we describe the production of full-length antibody immunotoxins using self-splicing split inteins. To this end, the short (11 amino acids) N-terminal intein part of the artificially designed split intein M86, a derivative of the Ssp DnaB intein, was recombinantly fused to the heavy chain of trastuzumab, a human epidermal growth factor receptor 2 (HER2) receptor targeting antibody and to a nanobody-Fc fusion targeting the HER1 receptor, respectively. Both antibodies were produced in Expi293F cells. The longer C-terminal counterpart of the intein was genetically fused to the protein toxins gelonin or Pseudomonas Exotoxin A, respectively, and expressed in E. coli via fusion to maltose binding protein. Using optimized in vitro splicing conditions, we were able to generate a set of specific and potent immunotoxins with IC50 values in the mid- to subpicomolar range.
Collapse
Affiliation(s)
- Thomas Pirzer
- Institute for Organic Chemistry and Biochemistry , Technische Universität Darmstadt , Alarich-Weiss-Strasse 4 , D-64287 Darmstadt , Germany
| | - Kira-Sophie Becher
- Institute of Biochemistry , University of Münster , Wilhelm-Klemm-Straße 2 , D-48149 Münster , Germany
| | - Marcel Rieker
- Antibody Drug Conjugates and Targeted NBE Therapeutics , Merck KGaA , Frankfurter Straße 250 , D-64293 Darmstadt , Germany
- Protein Engineering and Antibody Technologies , Merck KGaA , Frankfurter Straße 250 , D-64293 Darmstadt , Germany
| | - Tobias Meckel
- Macromolecular Chemistry & Paper Chemistry, Department of Chemistry , Technische Universität Darmstadt , Alarich-Weiss-Straße 8 , D-64287 Darmstadt , Germany
| | - Henning D Mootz
- Institute of Biochemistry , University of Münster , Wilhelm-Klemm-Straße 2 , D-48149 Münster , Germany
| | - Harald Kolmar
- Institute for Organic Chemistry and Biochemistry , Technische Universität Darmstadt , Alarich-Weiss-Strasse 4 , D-64287 Darmstadt , Germany
| |
Collapse
|
49
|
Clouthier S, Anderson E, Kurath G, Breyta R. Molecular systematics of sturgeon nucleocytoplasmic large DNA viruses. Mol Phylogenet Evol 2018; 128:26-37. [PMID: 30059742 DOI: 10.1016/j.ympev.2018.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/06/2018] [Accepted: 07/20/2018] [Indexed: 12/23/2022]
Abstract
Namao virus (NV) is a sturgeon nucleocytoplasmic large DNA virus (sNCLDV) that can cause a lethal disease of the integumentary system in lake sturgeon Acipenser fulvescens. As a group, the sNCLDV have not been assigned to any currently recognized taxonomic family of viruses. In this study, a data set of NV DNA sequences was generated and assembled as two non-overlapping contigs of 306,448 bp and then used to conduct a comprehensive systematics analysis using Bayesian inference of phylogeny for NV, other sNCLDV and representative members of six families of the NCLDV superfamily. The phylogeny of NV was reconstructed using protein homologues encoded by nine nucleocytoplasmic virus orthologous genes (NCVOGs): NCVOG0022 - mcp, NCVOG0038 - DNA polymerase B elongation subunit, NCVOG0076 - VV A18-type helicase, NCVOG0249 - VV A32-type ATPase, NCVOG0262 - AL2 VLTF3-like transcription factor, NCVOG0271 - RNA polymerase II subunit II, NCVOG0274 - RNA polymerase II subunit I, NCVOG0276 - ribonucleotide reductase small subunit and NCVOG1117 - mRNA capping enzyme. The accuracy of our phylogenetic method was evaluated using a combination of Bayesian statistical analysis and congruence analysis. Stable tree topologies were obtained with data sets differing in target molecule(s), sequence length and taxa. Congruent topologies were obtained in phylogenies constructed using individual protein data sets. The major capsid protein phylogeny inferred that ten representative sNCLDV form a monophyletic group comprised of four lineages within a polyphyletic Mimi-Phycodnaviridae group of taxa. Overall, the analyses revealed that Namao virus is a member of the Mimiviridae family with strong and consistent support for a clade containing NV and CroV as sister taxa.
Collapse
Affiliation(s)
- Sharon Clouthier
- Fisheries & Oceans Canada, Freshwater Institute, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada.
| | - Eric Anderson
- Box 28, Group 30, RR2, Ste Anne, Manitoba R5H 1R2, Canada
| | - Gael Kurath
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA 98115, USA
| | - Rachel Breyta
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA 98115, USA; Department of Microbiology, Oregon State University, 2820 SW Campus Way, Corvallis, OR 97331, USA
| |
Collapse
|
50
|
Xu Y, Zhang L, Ma B, Hu L, Lu H, Dou T, Chen J, Zhu J. Intermolecular disulfide bonds between unpaired cysteines retard the C-terminal trans-cleavage of Npu DnaE. Enzyme Microb Technol 2018; 118:6-12. [PMID: 30143201 DOI: 10.1016/j.enzmictec.2018.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 06/15/2018] [Accepted: 06/27/2018] [Indexed: 10/28/2022]
Abstract
Npu DnaE is a naturally occurred split intein possessing robust trans-splicing activity and could be engineered to perform rapid C-terminal cleavage module by a single mutation D118G. Unfortunately, however, for this modified selfcleaving module, reducing agents were needed to trigger the rapid cleavage, which prevents the utilization in purification of disulfide bonds containing recombinant proteins. In this study, we demonstrated that the unpaired cysteine residues in Npu DnaE tend to form disulfide bonds, and contributed to the reduction of the cleavage under non-reducing conditions. This redox trap can be disrupted by site-directed mutation of these unpaired cysteines. The results further indicated that the position 28 and 59 may play certain roles in the correct folding of the active conformation.
Collapse
Affiliation(s)
- Yanran Xu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lei Zhang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Lifu Hu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Huili Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tonglu Dou
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junsheng Chen
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jianwei Zhu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; Jecho Laboratories, Inc., Frederick, MD, USA.
| |
Collapse
|