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Keijzer JF, Albada B. DNA-assisted site-selective protein modification. Biopolymers 2021; 113:e23483. [PMID: 34878181 PMCID: PMC9285461 DOI: 10.1002/bip.23483] [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: 08/06/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/09/2022]
Abstract
Protein modification is important for various types of biomedical research, including proteomics and therapeutics. Many methodologies for protein modification exist, but not all possess the required level of efficiency and site selectivity. This review focuses on the use of DNA to achieve the desired conversions and levels of accuracy in protein modification by using DNA (i) as a template to help concentrate dilute reactants, (ii) as a guidance system to achieve selectivity by binding specific proteins, and (iii) even as catalytic entity or construct to enhance protein modification reactions.
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Affiliation(s)
- Jordi F Keijzer
- Laboratory of Organic Chemistry, Wageningen University and Research, Wageningen, The Netherlands
| | - Bauke Albada
- Laboratory of Organic Chemistry, Wageningen University and Research, Wageningen, The Netherlands
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2
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Kohata A, Ueki R, Okuro K, Hashim PK, Sando S, Aida T. Photoreactive Molecular Glue for Enhancing the Efficacy of DNA Aptamers by Temporary-to-Permanent Conjugation with Target Proteins. J Am Chem Soc 2021; 143:13937-13943. [PMID: 34424707 DOI: 10.1021/jacs.1c06816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We developed a photoreactive molecular glue, BPGlue-N3, which can provide a universal strategy to enhance the efficacy of DNA aptamers by temporary-to-permanent stepwise stabilization of their conjugates with target proteins. As a proof-of-concept study, we applied BPGlue-N3 to the SL1 (DNA aptamer)/c-Met (target protein) conjugate system. BPGlue-N3 can adhere to and temporarily stabilize this aptamer/protein conjugate multivalently using its guanidinium ion (Gu+) pendants that form a salt bridge with oxyanionic moieties (e.g., carboxylate and phosphate) and benzophenone (BP) group that is highly affinitive to DNA duplexes. BPGlue-N3 is designed to carry a dual-mode photoreactivity; upon exposure to UV light, the temporarily stabilized aptamer/protein conjugate reacts with the photoexcited BP unit of adhering BPGlue-N3 and also a nitrene species, possibly generated by the BP-to-N3 energy transfer in BPGlue-N3. We confirmed that SL1, covalently conjugated with c-Met, hampered the binding of hepatocyte growth factor (HGF) onto c-Met, even when the SL1/c-Met conjugate was rinsed prior to the treatment with HGF, and suppressed cell migration caused by HGF-induced c-Met phosphorylation.
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Affiliation(s)
- Ai Kohata
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryosuke Ueki
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kou Okuro
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - P K Hashim
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Shinsuke Sando
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takuzo Aida
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.,Riken Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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3
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Parsa SF, Vafajoo A, Rostami A, Salarian R, Rabiee M, Rabiee N, Rabiee G, Tahriri M, Yadegari A, Vashaee D, Tayebi L, Hamblin MR. Early diagnosis of disease using microbead array technology: A review. Anal Chim Acta 2018; 1032:1-17. [PMID: 30143206 PMCID: PMC6152944 DOI: 10.1016/j.aca.2018.05.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022]
Abstract
Early diagnosis of diseases (before they become advanced and incurable) is essential to reduce morbidity and mortality rates. With the advent of novel technologies in clinical laboratory diagnosis, microbead-based arrays have come to be recognized as an efficient approach, that demonstrates useful advantages over traditional assay methods for multiple disease-related biomarkers. Multiplexed microbead assays provide a robust, rapid, specific, and cost-effective approach for high-throughput and simultaneous screening of many different targets. Biomolecular binding interactions occur after applying a biological sample (such as blood plasma, saliva, cerebrospinal fluid etc.) containing the target analyte(s) to a set of microbeads with different ligand-specificities that have been coded in planar or suspension arrays. The ligand-receptor binding activity is tracked by optical signals generated by means of flow cytometry analysis in the case of suspension arrays, or by image processing devices in the case of planar arrays. In this review paper, we discuss diagnosis of cancer, neurological and infectious diseases by using optically-encoded microbead-based arrays (both multiplexed and single-analyte assays) as a reliable tool for detection and quantification of various analytes.
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Affiliation(s)
- Sanam Foroutan Parsa
- Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Atieh Vafajoo
- Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Azin Rostami
- Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Reza Salarian
- Biomedical Engineering Department, Maziar University, Noor, Royan, Iran
| | - Mohammad Rabiee
- Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Navid Rabiee
- Department of Chemistry, Shahid Beheshti University, Tehran, Iran
| | - Ghazal Rabiee
- Department of Chemistry, Shahid Beheshti University, Tehran, Iran
| | | | - Amir Yadegari
- Marquette University School of Dentistry, Milwaukee, WI 53233, USA
| | - Daryoosh Vashaee
- Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606, USA
| | - Lobat Tayebi
- Marquette University School of Dentistry, Milwaukee, WI 53233, USA; Biomaterials and Advanced Drug Delivery Laboratory, School of Medicine, Stanford University, Palo Alto, CA 94304, USA
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
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4
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Huh JW, Kim SC, Sohn I, Jung SH, Kim HC. Serum protein profiling using an aptamer array predicts clinical outcomes of stage IIA colon cancer: A leave-one-out crossvalidation. Oncotarget 2017; 7:16338-48. [PMID: 26908450 PMCID: PMC4941318 DOI: 10.18632/oncotarget.7488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/11/2016] [Indexed: 11/29/2022] Open
Abstract
Background In this study, we established and validated a model for predicting prognosis of stage IIA colon cancer patients based on expression profiles of aptamers in serum. Methods Bloods samples were collected from 227 consecutive patients with pathologic T3N0M0 (stage IIA) colon cancer. We incubated 1,149 serum molecule-binding aptamer pools of clinical significance with serum from patients to obtain aptamers bound to serum molecules, which were then amplified and marked. Oligonucleotide arrays were constructed with the base sequences of the 1,149 aptamers, and the marked products identified above were reacted with one another to produce profiles of the aptamers bound to serum molecules. These profiles were organized into low- and high-risk groups of colon cancer patients based on clinical information for the serum samples. Cox proportional hazards model and leave-one-out cross-validation (LOOCV) were used to evaluate predictive performance. Results During a median follow-up period of 5 years, 29 of the 227 patients (11.9%) experienced recurrence. There were 212 patients (93.4%) in the low-risk group and 15 patients (6.6%) in the high-risk group in our aptamer prognosis model. Postoperative recurrence significantly correlated with age and aptamer risk stratification (p = 0.046 and p = 0.001, respectively). In multivariate analysis, aptamer risk stratification (p < 0.001) was an independent predictor of recurrence. Disease-free survival curves calculated according to aptamer risk level predicted through a LOOCV procedure and age showed significant differences (p < 0.001 from permutations). Conclusion Aptamer risk stratification can be a valuable prognostic factor in stage II colon cancer patients.
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Affiliation(s)
- Jung Wook Huh
- Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | | | - Insuk Sohn
- Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul, Korea
| | - Sin-Ho Jung
- Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul, Korea.,Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
| | - Hee Cheol Kim
- Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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5
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Bukharina NS, Ivanov YD, Pleshakova TO, Frantsuzov PA, Andreeva EY, Kaysheva AL, Izotov AA, Pavlova TI, Ziborov VS, Radko SP, Archakov AI. [Atomic force microscopy fishing of gp120 on immobilized aptamer and its mass spectrometry identification]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2016. [PMID: 26215414 DOI: 10.18097/pbmc20156103363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A method of atomic force microscopy-based fishing (AFM fishing) has been developed for protein detection in the analyte solution using a chip with an immobilized aptamer. This method is based on the biospecific fishing of a target protein from a bulk solution onto the small AFM chip area with the immobilized aptamer to this protein used as the molecular probe. Such aptamer-based approach allows to increase an AFM image contrast compared to the antibody-based approach. Mass spectrometry analysis used after the biospecific fishing to identify the target protein on the AFM chip has proved complex formation. Use of the AFM chip with the immobilized aptamer avoids interference of the antibody and target protein peaks in a mass spectrum.
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Affiliation(s)
| | - Yu D Ivanov
- Institute of Biomedical Chemistry, Moscow, Russia
| | | | | | | | - A L Kaysheva
- Institute of Biomedical Chemistry, Moscow, Russia
| | - A A Izotov
- Institute of Biomedical Chemistry, Moscow, Russia
| | - T I Pavlova
- Institute of Biomedical Chemistry, Moscow, Russia
| | - V S Ziborov
- Institute of Biomedical Chemistry, Moscow, Russia
| | - S P Radko
- Institute of Biomedical Chemistry, Moscow, Russia
| | - A I Archakov
- Institute of Biomedical Chemistry, Moscow, Russia
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Wang R, Lu D, Bai H, Jin C, Yan G, Ye M, Qiu L, Chang R, Cui C, Liang H, Tan W. Using modified aptamers for site specific protein-aptamer conjugations. Chem Sci 2015; 7:2157-2161. [PMID: 28044095 PMCID: PMC5201207 DOI: 10.1039/c5sc02631h] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We have developed a new method for the selective conjugation of target proteins at lysine residues through a protein–aptamer template-directed reaction.
Conjugation of DNA to defined locations on a protein surface will be a powerful tool for positioning functional groups and molecules in biological and biomedical studies. However, tagging protein with DNA is challenging in physiological environments, and requires a bioorthogonal approach. Here, we report a chemical solution to selectively conjugate DNA aptamers with a protein by protein–aptamer template (PAT)-directed reactions. Since protein–aptamer interactions are bioorthogonal, we exploit the PAT as a unique platform for specific DNA–protein cross-linking. We develop a series of modified oligonucleotides for PAT-directed reactions and find an F-carboxyl group as a suitable functionality for selective and site-specific conjugation. The functionality is incorporated into aptamers in our F-carboxyl phosphoramidite with an easy synthesis. We also demonstrate the necessity of a linker between the reactive functionality and the aptamer sequences.
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Affiliation(s)
- Ruowen Wang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China; Departments of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida32611-7200, United States
| | - Danqing Lu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Huarong Bai
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Cheng Jin
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Guobei Yan
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Mao Ye
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Liping Qiu
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China; Departments of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida32611-7200, United States
| | - Rongshan Chang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Cheng Cui
- Departments of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida32611-7200, United States
| | - Hao Liang
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China
| | - Weihong Tan
- Molecular Sciences and Biomedicine Laboratory, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, Collaborative Innovation Center for Molecular Engineering and Theranostics, Hunan University, Changsha 410082, China; Departments of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida32611-7200, United States
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7
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Kopra K, Syrjänpää M, Hänninen P, Härmä H. Non-competitive aptamer-based quenching resonance energy transfer assay for homogeneous growth factor quantification. Analyst 2015; 139:2016-23. [PMID: 24611155 DOI: 10.1039/c3an01814h] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A non-competitive homogeneous, single-label quenching resonance energy transfer (QRET) assay for protein quantification is now presented using lanthanide-chelate labeled nucleic acid aptamers. A labeled ssDNA aptamer binding to a growth factor has been successfully used to provide luminescence signal protection of the lanthanide label. The QRET technology has previously been applied to competitive assay formats, but now for the first time a direct non-competitive assay is presented. The QRET system is based on the protection of the Eu(iii)-chelate from a soluble quencher molecule when the aptamer interacts with a specific target protein. The direct QRET assay is possible as the aptamer structure itself cannot protect the Eu(iii)-label from quenching. The dynamic range for the optimized vascular endothelial growth factor (VEGF) assay is 0.25-10 nM. A successful quantification of the basic fibroblast growth factor (bFGF) is also demonstrated using the same QRET assay format with a dynamic range of 0.75-50 nM. These assays evidently show the suitability of the direct QRET technique to simple and efficient detection of large biomolecules. The QRET assay can potentially be applied as a detection platform for any other protein targets with a known aptamer sequence.
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Affiliation(s)
- Kari Kopra
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku, Tykistökatu 6 A 5th floor, FI-20520 Turku, Finland.
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Ivanov YD, Bukharina NS, Pleshakova TO, Frantsuzov PA, Andreeva EY, Kaysheva AL, Zgoda VG, Izotov AA, Pavlova TI, Ziborov VS, Radko SP, Moshkovskii SA, Archakov AI. Atomic force microscopy fishing and mass spectrometry identification of gp120 on immobilized aptamers. Int J Nanomedicine 2014; 9:4659-70. [PMID: 25336946 PMCID: PMC4200055 DOI: 10.2147/ijn.s66946] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Atomic force microscopy (AFM) was applied to carry out direct and label-free detection of gp120 human immunodeficiency virus type 1 envelope glycoprotein as a target protein. This approach was based on the AFM fishing of gp120 from the analyte solution using anti-gp120 aptamers immobilized on the AFM chip to count gp120/aptamer complexes that were formed on the chip surface. The comparison of image contrasts of fished gp120 against the background of immobilized aptamers and anti-gp120 antibodies on the AFM images was conducted. It was shown that an image contrast of the protein/aptamer complexes was two-fold higher than the contrast of the protein/antibody complexes. Mass spectrometry identification provided an additional confirmation of the target protein presence on the AFM chips after biospecific fishing to avoid any artifacts.
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Affiliation(s)
- Yuri D Ivanov
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Natalia S Bukharina
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Tatyana O Pleshakova
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Pavel A Frantsuzov
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Elena Yu Andreeva
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Anna L Kaysheva
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
- PostgenTech Ltd., Moscow, Russia
| | - Victor G Zgoda
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Alexander A Izotov
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Tatyana I Pavlova
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Vadim S Ziborov
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Sergey P Radko
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Sergei A Moshkovskii
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
| | - Alexander I Archakov
- Department of Personalized Medicine, Orekhovich Institute of Biomedical Chemistry of the Russian Academy of Medical Sciences, Moscow, Russia
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9
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Stovall GM, Bedenbaugh RS, Singh S, Meyer AJ, Hatala PJ, Ellington AD, Hall B. In vitro selection using modified or unnatural nucleotides. ACTA ACUST UNITED AC 2014; 56:9.6.1-33. [PMID: 25606981 DOI: 10.1002/0471142700.nc0906s56] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Incorporation of modified nucleotides into in vitro RNA or DNA selections offers many potential advantages, such as the increased stability of selected nucleic acids against nuclease degradation, improved affinities, expanded chemical functionality, and increased library diversity. This unit provides useful information and protocols for in vitro selection using modified nucleotides. It includes a discussion of when to use modified nucleotides; protocols for evaluating and optimizing transcription reactions, as well as confirming the incorporation of the modified nucleotides; protocols for evaluating modified nucleotide transcripts as template in reverse transcription reactions; protocols for the evaluation of the fidelity of modified nucleotides in the replication and the regeneration of the pool; and a protocol to compare modified nucleotide pools and selection conditions.
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Affiliation(s)
- Gwendolyn M Stovall
- The University of Texas at Austin, Austin, Texas; Altermune Technologies LLC, Austin, Texas
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10
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Nonaka Y, Yoshida W, Abe K, Ferri S, Schulze H, Bachmann TT, Ikebukuro K. Affinity improvement of a VEGF aptamer by in silico maturation for a sensitive VEGF-detection system. Anal Chem 2012; 85:1132-7. [PMID: 23237717 DOI: 10.1021/ac303023d] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Systematic evolution of ligands by exponential enrichment (SELEX) is an efficient method to identify aptamers; however, it sometimes fails to identify aptamers that bind to their target with high affinity. Thus, post-SELEX optimization of aptamers is required to improve aptamer binding affinity. We developed in silico maturation based on a genetic algorithm (1) as an efficient mutagenesis method to improve aptamer binding affinity. In silico maturation was performed to improve a VEGF-binding DNA aptamer (VEap121). The VEap121 aptamer is considered to fold into a G-quadruplex structure and this structure may be important for VEGF recognition. Using in silico maturation, VEap121 was mutated with the exception of the guanine tracts that are considered to form the G-quartet. As a result, four aptamers were obtained that showed higher affinity compared with VEap121. The dissociation constant (K(d)) of the most improved aptamer (3R02) was 300 pM. The affinity of 3R02 was 16-fold higher than that of VEap121. Moreover, a bivalent aptamer was constructed by connecting two identical 3R02s through a 10-mer thymine linker for further improvement of affinity. The bivalent aptamer (3R02 Bivalent) bound to VEGF with a K(d) value of 30 pM. Finally, by constructing a VEGF-detection system using a VEGF antibody as the capture molecule and monovalent 3R02 as the detection molecule, a more sensitive assay was developed compared with the system using VEap121. These results indicate that in silico maturation could be an efficient method to improve aptamer affinity for construction of sensitive detection systems.
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Affiliation(s)
- Yoshihiko Nonaka
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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11
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Chen LC, Tzeng SC, Peck K. Aptamer microarray as a novel bioassay for protein-protein interaction discovery and analysis. Biosens Bioelectron 2012. [PMID: 23208094 DOI: 10.1016/j.bios.2012.10.082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Aptamer microarray is investigated as a novel bioassay for protein-protein interaction (PPI) discovery and analysis. Assaying a mixture of fluorescence-labeled thrombin and Escherichia coli proteins with an aptamer microarray, we found that thrombin and an unknown protein of E. coli (protein X) formed a complex of PPI, which was captured by an anti-thrombin aptamer probe. The PPI observed on the microarray was double-checked by protein microarrays and confirmed by aptamer-baited co-immunoprecipitation (Co-IP) assays. Characterizing the Co-IP products, we identified protein X as an E. coli Dps protein (DNA-binding protein from starved cells). A SDS-PAGE analysis suggested that Dps should be a substrate for thrombin, a trypsin-like serine protease. A dose-response microarray experiment predicted an apparent dissociation constant of 1.33 μM for the PPI. Moreover, an on-microarray competition assay revealed that the capture of the PPI by the anti-thrombin aptamer probe would be blocked by an E. coli aptamer via complementary base pairing. Thus, a network of protein-protein, protein-DNA, and DNA-DNA interactions and their interaction orders could be addressed in addition to simple PPI discovery.
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Affiliation(s)
- Lin-Chi Chen
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 10617, Taiwan.
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12
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Brody EN, Gold L, Lawn RM, Walker JJ, Zichi D. High-content affinity-based proteomics: unlocking protein biomarker discovery. Expert Rev Mol Diagn 2011; 10:1013-22. [PMID: 21080818 DOI: 10.1586/erm.10.89] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Single protein biomarkers measured with antibody-based affinity assays are the basis of molecular diagnostics in clinical practice today. There is great hope in discovering new protein biomarkers and combinations of protein biomarkers for advancing medicine through monitoring health, diagnosing disease, guiding treatment, and developing new therapeutics. The goal of high-content proteomics is to unlock protein biomarker discovery by measuring many (thousands) or all (∼23,000) proteins in the human proteome in an unbiased, data-driven approach. High-content proteomics has proven technically difficult due to the diversity of proteins, the complexity of relevant biological samples, such as blood and tissue, and large concentration ranges (in the order of 10(12) in blood). Mass spectrometry and affinity methods based on antibodies have dominated approaches to high-content proteomics. For technical reasons, neither has achieved adequate simultaneous performance and high-content. Here we review antibody-based protein measurement, multiplexed antibody-based protein measurement, and limitations of antibodies for high-content proteomics due to their inherent cross-reactivity. Finally, we review a new affinity-based proteomic technology developed from the ground up to solve the problem of high content with high sensitivity and specificity. Based on a new generation of slow off-rate modified aptamers (SOMAmers), this technology is unlocking biomarker discovery.
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Affiliation(s)
- Edward N Brody
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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13
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Rakhmetova SI, Rad'ko SP, Gnedenko OV, Bodoev NV, Ivanov AS, Archakov AI. [Photoaptamer heterodimeric constructs as a new approach to enhance the efficiency of formation of photocrosslinking with a target protein]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2011; 56:72-81. [PMID: 21328912 DOI: 10.18097/pbmc20105601072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Using two DNA aptamers selectively recognizing anion-binding exosites 1 and 2 of thrombin as a model, it has been demonstrated that their conjugation by a poly-(dT)-linker (ranging from 5 to 65 nt in length) to produce aptamer heterodimeric constructs results into affinity enhancement. The apparent dissociation constant (Kd(app)) measured at the optical biosensor Biacore-3000 for complexes of thrombin with the heterodimeric constructs reached minimum values (Kd(app) = 0.2-0.4 nM) which were approximately 30-fold less than for the complexes with the primary aptamers. A photoaptamer heterodimeric construct was designed connecting photoaptamer and aptamer sequences with the poly-(dT)-linker of 35 nt long. The photoaptamer used could form photo-induced cross-links with the exosite 2 of thrombin and the aptamer used could bind to the exosite 1. The measured value of Kd(app) for the photoaptamer construct was approximately 40-fold less than that for the primary photoaptamer (5.3 and 190 nM, respectively). Upon exposure to the UV radiation at 308 nm of the equimolar mixtures of thrombin with the photoaptamer construct, the equal yield of the crosslinked complexes was observed at concentrations which were lower by two orders of magnitude than in the case of the primary photoaptamer. It was found that concurrently with crosslinking to thrombin a photo-induced inactivation of the photoaptamer occurs presumably due to formation of the intermolecular crosslinking.
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14
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Krishhan VV, Khan IH, Luciw PA. Multiplexed microbead immunoassays by flow cytometry for molecular profiling: Basic concepts and proteomics applications. Crit Rev Biotechnol 2009; 29:29-43. [PMID: 19514901 DOI: 10.1080/07388550802688847] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Flow cytometry was originally established as an automated method for measuring optical or fluorescence characteristics of cells or particles in suspension. With the enormous increase in development of reliable electronics, lasers, micro-fluidics, as well as many advances in immunology and other fields, flow cytometers have become user-friendlier, less-expensive instruments with an increasing importance for both basic research and clinical applications. Conventional uses of flow cytometry include immunophenotyping of blood cells and the analysis of the cell cycle. Importantly, methods for labeling microbeads with unique combinations of fluorescent spectral signatures have made multiplex analysis of soluble analytes (i.e. the ability to detect multiple targets in a single test sample) feasible by flow cytometry. The result is a rapid, high-throughput, sensitive, and reproducible detection technology for a wide range of biomedical applications requiring detection of proteins (in cells and biofluids) and nucleic acids. Thus, novel methods of flow cytometry are becoming important for diagnostic purposes (e.g. identifying multiple clinical biomarkers for a wide range of diseases) as well as for developing novel therapies (e.g. elucidating drug mechanisms and potential toxicities). In addition, flow cytometry for multiplex analysis, coupled with automated sample handling devices, has the potential to significantly enhance proteomics research, particularly analysis of post-translational modifications of proteins, on a large scale. Inherently, flow cytometry methods are strongly rooted in the laws of the physics of optics, fluidics, and electromagnetism. This review article describes principles and early sources of flow cytometry, provides an introduction to the multiplex microbead technology, and discusses its applications and advantages in comparison to other methods. Anticipated future directions, particularly for translational research in medicine, are also discussed.
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Affiliation(s)
- V V Krishhan
- Department of Chemistry, California State University, Fresno, CA 93740, USA.
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15
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Knudsen SM, Robertson MP, Ellington AD. In vitro selection using modified or unnatural nucleotides. ACTA ACUST UNITED AC 2008; Chapter 9:Unit 9.6. [PMID: 18428900 DOI: 10.1002/0471142700.nc0906s07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The use of modified nucleotides in an RNA or DNA pool to be used for in vitro selection offers many potential advantages, such as the increased stability of the selected nucleic acid against nuclease degradation. This unit provides useful information and protocols for in vitro selection using modified nucleotides. It includes a discussion of when to use modified nucleotides; protocols for preparing a modified RNA pool and verifying its suitability for in vitro selection; and protocols for selecting and amplifying a functionally enriched pool.
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16
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Kulbachinskiy AV. Methods for selection of aptamers to protein targets. BIOCHEMISTRY (MOSCOW) 2008; 72:1505-18. [PMID: 18282139 DOI: 10.1134/s000629790713007x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aptamers are synthetic single-stranded RNA or DNA molecules capable of specific binding to other target molecules. In this review, the main aptamer properties are considered and methods for selection of aptamers against various protein targets are described. Special attention is given to the methods for directed selection of aptamers, which allow one to obtain ligands with specified properties.
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Affiliation(s)
- A V Kulbachinskiy
- Institute of Molecular Genetics, Russian Academy of Sciences, pl. Kurchatova 2, 123182 Moscow, Russia.
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17
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Mallikaratchy P, Tang Z, Kwame S, Meng L, Shangguan D, Tan W. Aptamer directly evolved from live cells recognizes membrane bound immunoglobin heavy mu chain in Burkitt's lymphoma cells. Mol Cell Proteomics 2007; 6:2230-8. [PMID: 17875608 DOI: 10.1074/mcp.m700026-mcp200] [Citation(s) in RCA: 233] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The identification of tumor related cell membrane protein targets is important in understanding tumor progression, the development of new diagnostic tools, and potentially for identifying new therapeutic targets. Here we present a novel strategy for identifying proteins that are altered in their expression levels in a diseased cell using cell specific aptamers. Using an intact viable B-cell Burkitt's lymphoma cell line (Ramos cells) as the target, we have selected aptamers that recognize cell membrane proteins with high affinity. Among the selected aptamers that showed different recognition patterns with different cell lines of leukemia, the aptamer TD05 showed binding with Ramos cells. By chemically modifying TD05 to covalently cross-link with its target on Ramos cells to capture and to enrich the target receptors using streptavidin coated magnetic beads followed by mass spectrometry, we were able to identify membrane bound immunoglobin heavy mu chain as the target for TD05 aptamer. Immunoglobin heavy mu chain is a major component of the B-cell antigen receptor, which is expressed in Burkitt's lymphoma cells. This study demonstrates that this two step strategy, the development of high quality aptamer probes and then the identification of their target proteins, can be used to discover new disease related potential markers and thus enhance tumor diagnosis and therapy. The aptamer based strategy will enable effective molecular elucidation of disease related biomarkers and other interesting molecules.
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Affiliation(s)
- Prabodhika Mallikaratchy
- Department of Chemistry, Shands Cancer Center, University of Florida Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611, USA
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Radko SP, Rakhmetova SY, Bodoev NV, Archakov AI. Aptamers as affinity reagents for clinical proteomics. BIOCHEMISTRY MOSCOW-SUPPLEMENT SERIES B-BIOMEDICAL CHEMISTRY 2007. [DOI: 10.1134/s1990750807030043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Abstract
The establishment of an aptamer-based biochip for protein detection is described. Using a model system comprising human IgE as the analyte and single-stranded DNA aptamers specific for IgE or anti-IgE antibodies as immobilized ligands on chips, we could demonstrate that aptamers were equivalent or superior to antibodies in terms of specificity and sensitivity, respectively. Aptamer-based analyte detection on glass slides could clearly be demonstrated at minimum concentrations of 10 ng/mL IgE. In addition, we successfully showed specific analyte recognition in complex protein samples by the aptamer-based biochip system. Using DNA aptamers specific for human thrombin as an additional model receptor/ligand system, dual protein detection on a single slide could be proven. In conclusion, we could show the suitability of nucleic acid aptamers as low molecular weight receptors on biochips for sensitive and specific protein detection, representing an innovative tool for future proteomics.
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Affiliation(s)
- Karin Stadtherr
- Institut für Medizinische Mikrobiologie und Hygiene, Universität Regensburg, Regensburg, Germany
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20
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Mascini M, Papamichael K, Mevola I, Pravda M, Guilbault GG. Ghrelin Detection Using Spiegelmer‐Capture Molecules. ANAL LETT 2007. [DOI: 10.1080/00032710601102391] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Niu W, Jiang N, Hu Y. Detection of proteins based on amino acid sequences by multiple aptamers against tripeptides. Anal Biochem 2006; 362:126-35. [PMID: 17223063 DOI: 10.1016/j.ab.2006.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 11/30/2006] [Accepted: 12/05/2006] [Indexed: 12/26/2022]
Abstract
A number of different ligands have been tested in the course of the development of protein array technology. The most extensively studied example of protein ligands has been based on antibody-antigen interaction. Other examples include protein-protein, protein-nucleic acid, and protein-small molecule interactions. All these ligands can recognize and specifically bind to protein epitopes. In this study, we have developed a novel technology using DNA-based aptamers to detect proteins based on their amino acid sequences. Mouse cathepsin D was used for the proof of principle experiment. Four tripeptides, Leu-Ala-Ser, Asp-Gly-Ile, Gly-Glu-Leu, and Lys-Ala-Ile, were selected based on the published amino acid sequence of mouse cathepsin D. DNA aptamers against the tripeptides were isolated using the systematic evolution of ligands of exponential enrichment method. We have demonstrated that the aptamers specifically interacted with mouse cathepsin D using the structure-switch method. We further performed a proximity-dependent ligation assay to demonstrate that multiple aptamers could specifically detect the protein from cell extracts. In principle, one library containing 8000 aptamers should be enough to detect almost all proteins in the whole proteome in all organisms. This technology could be applied to generate a new generation of protein arrays.
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Affiliation(s)
- Wenze Niu
- Key Lab of Brain Functional Genomics, MOE and STCSM, Shanghai Institute of Brain Functional Genomics, East China Normal University, 3663 Zhongshan Road N., Shanghai 200062, China
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22
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Wang L, Liu X, Hu X, Song S, Fan C. Unmodified gold nanoparticles as a colorimetric probe for potassium DNA aptamers. Chem Commun (Camb) 2006:3780-2. [PMID: 16969455 DOI: 10.1039/b607448k] [Citation(s) in RCA: 287] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Unmodified gold nanoparticles effectively differentiate unfolded and folded DNA, thus providing a novel approach to colorimetrically probe aptamer-based recognition processes.
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Affiliation(s)
- Lihua Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
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Abstract
Proteomics is the study of the entire protein complement of the genome (the proteome) in a biological system. Proteomic studies require a multidisciplinary approach and have only been practical with the convergence of technical and methodologic improvements including the following: advances in mass spectrometry and genomic sequencing that now permit the identification and relative quantization of small amounts (femtomole) of nearly any single protein; new methods in gel electrophoresis that allow the detection of subtle changes in protein expression, including posttranslational modifications; automation and miniaturization that permit high-throughput analysis of clinical samples; and new bioinformatics and computational methods that facilitate analysis and interpretation of the abundant data that are generated by proteomics experiments. This convergence makes proteomics studies practical for pulmonary researchers using BAL fluid, lung tissue, blood, and exhaled breath condensates, and will facilitate the research of complex, multifactorial lung diseases such as acute lung injury and COPD. This review describes how proteomics experiments are conducted and interpreted, their limitations, and how proteomics has been used in clinical pulmonary medicine.
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Affiliation(s)
- Russell P Bowler
- Department of Medicine, University of Colorado Health Sciences Center, Denver, 80206, USA.
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24
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Walton S, Li Z, Chan C. Biological network analyses: computational genomics and systems approaches. MOLECULAR SIMULATION 2006. [DOI: 10.1080/08927020600647052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Tomizaki KY, Usui K, Mihara H. Protein-detecting microarrays: current accomplishments and requirements. Chembiochem 2006; 6:782-99. [PMID: 15791688 DOI: 10.1002/cbic.200400232] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The sequencing of the human genome has been successfully completed and offers the chance of obtaining a large amount of valuable information for understanding complex cellular events simply and rapidly in a single experiment. Interestingly, in addressing these proteomic studies, the importance of protein-detecting microarray technology is increasing. In the coming few years, microarray technology will become a significantly promising and indispensable research/diagnostic tool from just a speculative technology. It is clear that the protein-detecting microarray is supported by three independent but strongly related technologies (surface chemistry, detection methods, and capture agents). Firstly, a variety of surface-modification methodologies are now widely available and offer site-specific immobilization of capture agents onto surfaces in such a way as to keep the native conformation and activity. Secondly, sensitive and parallel detection apparatuses are being developed to provide highly engineered microarray platforms for simultaneous data acquisition. Lastly, in the development of capture agents, antibodies are now probably the most prominent capture agents for analyzing protein abundances. Alternative scaffolds, such as phage-displayed antibody and protein fragments, which provide the advantage of increasing diversity of proteinic capture agents, however, are under development. An approach involving recombinant proteins fused with affinity tag(s) and coupled with a highly engineered surface chemistry will provide simple production protocols and specific orientations of capture agents on the microarray formats. Peptides and other small molecules can be employed in screening highly potent ligands as well as in measuring enzymatic activities. Protein-detecting microarrays supported by the three key technologies should contribute in accelerating diagnostic/biological research and drug discovery.
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Affiliation(s)
- Kin-ya Tomizaki
- Department of Bioengineering and The COE21 Program, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, B-40, 4259 Nagatsuta, Midori, Yokohama 226-8501, Japan
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26
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Lim DV, Simpson JM, Kearns EA, Kramer MF. Current and developing technologies for monitoring agents of bioterrorism and biowarfare. Clin Microbiol Rev 2005; 18:583-607. [PMID: 16223949 PMCID: PMC1265906 DOI: 10.1128/cmr.18.4.583-607.2005] [Citation(s) in RCA: 218] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent events have made public health officials acutely aware of the importance of rapidly and accurately detecting acts of bioterrorism. Because bioterrorism is difficult to predict or prevent, reliable platforms to rapidly detect and identify biothreat agents are important to minimize the spread of these agents and to protect the public health. These platforms must not only be sensitive and specific, but must also be able to accurately detect a variety of pathogens, including modified or previously uncharacterized agents, directly from complex sample matrices. Various commercial tests utilizing biochemical, immunological, nucleic acid, and bioluminescence procedures are currently available to identify biological threat agents. Newer tests have also been developed to identify such agents using aptamers, biochips, evanescent wave biosensors, cantilevers, living cells, and other innovative technologies. This review describes these current and developing technologies and considers challenges to rapid, accurate detection of biothreat agents. Although there is no ideal platform, many of these technologies have proved invaluable for the detection and identification of biothreat agents.
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Affiliation(s)
- Daniel V Lim
- Department of Biology, Center for Biological Defense, University of South Florida, Tampa, FL 33620-5200, USA.
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27
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Special-Purpose Modifications and Immobilized Functional Nucleic Acids for Biomolecular Interactions. Top Curr Chem (Cham) 2005. [DOI: 10.1007/b136673] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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28
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Synthesis and properties of oligodeoxyribonucleotides containing 2’-O-(2,3-dihydroxypropyl)- and 2’-O-(2-oxoethyl)arabinouridine residues. Russ Chem Bull 2005. [DOI: 10.1007/s11172-005-0243-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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29
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Koch TH, Smith D, Tabacman E, Zichi DA. Kinetic analysis of site-specific photoaptamer-protein cross-linking. J Mol Biol 2004; 336:1159-73. [PMID: 15037076 DOI: 10.1016/j.jmb.2004.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Revised: 12/29/2003] [Accepted: 01/05/2004] [Indexed: 10/26/2022]
Abstract
ssDNA oligonucleotides containing bromodeoxyuridine, BrdU-photoaptamers, are rapidly emerging as specific protein capture reagents in protein microarray technologies. A mathematical model for the kinetic analysis of photoaptamer-protein photocross-linking reactions is presented. The model is based on specific aptamer/protein binding followed by laser excitation that can lead to either covalent cross-linking of the photoaptamer and protein in the complex or irreversible photodamage to the aptamer. Two distinct kinetic regimes, (1) frozen and (2) rapid equilibrium, are developed analytically to model binding kinetics between laser pulses. The models are used to characterize the photocross-linking between three photoaptamers and their cognate protein targets; photoaptamers 0650 and 0615 cross-link human basic fibroblast growth factor and 0518 cross-links HIV MN envelope glycoprotein. Data for cross-linking reaction yields as a function of both laser energy dose and target protein concentration are analyzed for affinity constants and cross-link reaction rates. The binding dissociation constants derived from the cross-linking data are in good accord with independent measurements; the rapid equilibrium model appears to produce results more consistent with the experimental observations, although there is significant overlap between the two models for most conditions explored here. The rate of photodamage for 0615 and 0518 is 3.5 and 2.5 times that of the specific cross-link, giving low maximum reaction yields of approximately 20% and approximately 30%, whereas 0650 cross-links with a rate over five times higher than its photodamage rate and has a maximum reaction yield exceeding 80%. Quantum yields for the three systems are estimated from the data; photoaptamer 0650 has a reasonably high quantum yield of approximately 0.2 for protein cross-linking, while 0518 and 0615 have quantum yields of 0.07 and 0.02. The work presented here provides a useful set of metrics that allow for refinement of photoaptamer properties.
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Affiliation(s)
- Tad H Koch
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
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30
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Abstract
Following the age of genomics having sequenced the human genome, interest is shifted towards the function of genes. This new age of proteomics brings about a change of methods to study the properties of gene products on a large scale. Protein separation technologies are now applied to allow high-throughput purification and characterisation of proteins. Two-dimensional-gel electrophoresis (2DE) and mass spectrometry (MS) have become widely used tools in the field of proteomics. At the same time, protein and antibody microarrays have been developed as successor of DNA microarrays to soon allow the proteome-wide screening of protein function in parallel. This review is aimed to introduce this new technology and to highlight its current prospects and limitations.
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Affiliation(s)
- Jörn Glökler
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany
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Affiliation(s)
- K K Jain
- Jain PharmaBiotech, Blaesiring 7, CH-4057 Basel, Switzerland.
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