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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

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Miniaturized and Automated Synthesis of Biomolecules—Overview and Perspectives

Mattes, Daniela S.; Jung, Nicole; Weber, Laura K.; Bräse, Stefan; Breitling, Frank
Adv. Mater..
Jun 2019
10.1002/adma.201806656
Chemical synthesis is performed by reacting different chemical building blocks with defined stoichiometry, while meeting additional conditions, such as temperature and reaction time. Such a procedure is especially suited for automation and miniaturization. Life sciences lead the way to synthesizing millions of different oligonucleotides in extremely miniaturized reaction sites, e.g., pinpointing active genes in whole genomes, while chemistry advances different types of automation. Recent progress in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging could match miniaturized chemical synthesis with a powerful analytical tool to validate the outcome of many different synthesis pathways beyond applications in the life sciences. Thereby, due to the radical miniaturization of chemical synthesis, thousands of molecules can be synthesized. This in turn should allow ambitious research, e.g., finding novel synthesis routes or directly screening for photocatalysts. Herein, different technologies are discussed that might be involved in this endeavor. A special emphasis is given to the obstacles that need to be tackled when depositing tiny amounts of materials to many different extremely miniaturized reaction sites.

A high-sensitivity enzyme immunoassay for the quantification of soluble human semaphorin 4D in plasma

Laber, Anna; Gadermaier, Elisabeth; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
Analytical Biochemistry.
Jun 2019
10.1016/j.ab.2019.03.004
Human semaphorin 4D (SEMA4D), a type I integral membrane glycoprotein, regulates key cellular functions (e.g. cell-cell communication, platelet activation). Its 120 kDa extracellular region can be shed from the membrane to release soluble SEMA4D (sSEMA4D). Studies on circulating sSEMA4D levels are mostly performed with poorly characterized assays and use serum and plasma as matrix. We developed and validated a sandwich ELISA utilizing two monoclonal antibodies with resolved epitopes and determined affinities. Human serum and plasma samples were analyzed, and the influence of protease activity on sSEMA4D concentration was tested by collecting samples in the presence of the protease inhibitor TAPI-1. Both antibodies recognize conformational epitopes in the sema domain. Validation for plasma (EDTA, citrate, heparin) showed valid specificity, precision, accuracy, dilution linearity, and robustness. The assay shows a calibration range from 62.5 to 2000 pmol/L with a quantification limit of 31 pmol/L. sSEMA4D was significantly higher in serum than in plasma, whereas serum and plasma levels from samples collected in the presence of TAPI-1 showed no statistical difference. This ELISA provides a reliable tool for the quantification of sSEMA4D in human plasma. Serum is not recommended as matrix due to the accumulation of shed SEMA4D during blood coagulation altering serum sSEMA4D levels.

Autoantibodies to a novel Rpp38 (Th/To) derived B-cell epitope are specific for systemic sclerosis and associate with a distinct clinical phenotype

Koenig, Martial; Bentow, Chelsea; Satoh, Minoru; Fritzler, Marvin J; Senécal, Jean-Luc; Mahler, Michael
Apr 2019
10.1093/rheumatology/kez123
Abstract Objective Detection of antinuclear antibodies and specific autoantibodies is important in the diagnosis and classification of SSc. Several proteins of the Th/To complex, including Rpp25, Rpp38 and hPop1 are the target of autoantibodies in SSc patients. However, very little is known about the epitope distribution of this autoantigen. Consequently, we screened Rpp25, Rpp38 and hPop1 for B cell epitopes and evaluated their clinical relevance. Methods Serum pools with (n = 2) and without (n = 1) anti-Th/To autoantibodies were generated and used for epitope discovery. Identified biomarker candidate sequences were then utilized to synthesize synthetic, biotinylated, soluble peptides. The peptides were tested to determine reactivity with sera from SSc cohorts (n = 202) and controls (n = 159) using a chemiluminescence immunoassay. Additionally, samples were also tested for antibodies to full-length recombinant Rpp25 antibodies by chemiluminescence immunoassay. Results Several immunodominant regions were found on the three proteins. The strongest reactivity was observed with an Rpp38 peptide (aa 229–243). Autoantibodies to the Rpp38 peptide were detected in 8/149 (5.4%) limited cutaneous SSc patients, but not in any of 159 controls (P = 0.003 by two-sided Fisher’s exact probability test). Although reactivity to the novel antigenic peptide was correlated with the binding to Rpp25 (rho = 0.44; P < 0.0001), subsets of patient sera either reacted strongly with Rpp25 or with the novel Rpp38-derived peptide. Conclusion A novel Rpp38 epitope holds promise to increase the sensitivity in the detection of anti-Th/To autoantibodies, thus enhancing the serological diagnosis of SSc.

In-depth serum proteomics reveals biomarkers of psoriasis severity and response to traditional Chinese medicine

Xu, Meng; Deng, Jingwen; Xu, Kaikun; Zhu, Tiansheng; Han, Ling; Yan, Yuhong; Yao, Danni; Deng, Hao; Wang, Dan; Sun, Yaoting; Chang, Cheng; Zhang, Xiaomei; Dai, Jiayu; Yue, Liang; Zhang, Qiushi; Cai, Xue; Zhu, Yi; Duan, Hu; Liu, Yuan; Li, Dong; Zhu, Yunping; Radstake, Timothy R. D. J.; Balak, Deepak M.W.; Xu, Danke; Guo, Tiannan; Lu, Chuanjian; Yu, Xiaobo
Theranostics.
Apr 2019
10.7150/thno.31144
Serum and plasma contain abundant biological information that reflect the body’s physiological and pathological conditions and are therefore a valuable sample type for disease biomarkers. However, comprehensive profiling of the serological proteome is challenging due to the wide range of protein concentrations in serum. Methods: To address this challenge, we developed a novel in-depth serum proteomics platform capable of analyzing the serum proteome across ~10 orders or magnitude by combining data obtained from Data Independent Acquisition Mass Spectrometry (DIA-MS) and customizable antibody microarrays. Results: Using psoriasis as a proof-of-concept disease model, we screened 50 serum proteomes from healthy controls and psoriasis patients before and after treatment with traditional Chinese medicine (YinXieLing) on our in-depth serum proteomics platform. We identified 106 differentially-expressed proteins in psoriasis patients involved in psoriasis-relevant biological processes, such as blood coagulation, inflammation, apoptosis and angiogenesis signaling pathways. In addition, unbiased clustering and principle component analysis revealed 58 proteins discriminating healthy volunteers from psoriasis patients and 12 proteins distinguishing responders from non-responders to YinXieLing. To further demonstrate the clinical utility of our platform, we performed correlation analyses between serum proteomes and psoriasis activity and found a positive association between the psoriasis area and severity index (PASI) score with three serum proteins (PI3, CCL22, IL-12B). Conclusion: Taken together, these results demonstrate the clinical utility of our in-depth serum proteomics platform to identify specific diagnostic and predictive biomarkers of psoriasis and other immune-mediated diseases.

Automated laser-assisted synthesis of microarrays for infectious disease research

Paris, Grigori; Heidepriem, Jasmin; Tsouka, Alexandra; Mende, Marco; Eickelmann, Stephan; Loeffler, Felix F.
Mar 2019
10.1117/12.2516781
We developed a next-generation method for chemical in–situ combinatorial biomolecule array synthesis. This allows for an unprecedented combinatorial freedom in the automated chemical synthesis of molecule arrays with very high spot densities. Key feature of this new method is an automated positioning and laser transfer process: Small solid material spots are rapidly transferred from a donor film to an acceptor surface, requiring only minute amounts of materials. The transfer is performed with different and easy-to-produce donor slides. Each donor slide bears a thin polymer film, embedding one type of monomer. The coupling reaction occurs in a separate heating step, where the matrix becomes viscous and building blocks can diffuse within the material and couple to the acceptor surface. Since these transferred material spots are only several nanometers thin, this method allows for a consecutive multi-layer material deposition of e.g. activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in–situ activation and coupling of the monomers. Positioning several of such resin spots, containing different chemical reagents, on top of each other, will enable for the first time in such small dimensions unique chemical synthesis strategies for each spot. Amount and concentration of the deposited materials can be adjusted with the laser parameters. Employing similar arrays, we can analyze the human immune response towards the proteome of different pathogens. We screened several peptide array replicas with different patient sera. The screenings resulted in significant hits in several proteins with interesting implications for future diagnostics and vaccine development.

Methods of Selecting Binding Reagents

Mallick, Parag; Egertson, Jarrett
Feb 2019
Methods and systems are provided herein for selecting an affinity reagent which binds a desired peptide epitope in a plurality of sequence contexts. The method relies on obtaining a peptide library, each peptide having the sequence αΧβ, wherein X is the desired peptide epitope, wherein each of a and β comprise an amino acid, using the peptide library to select an affinity reagent.

Single-Molecule Detection on a Protein-Array Assay Platform for the Exposure of a Tuberculosis Antigen

Schmidt, Ronny; Jacak, Jaroslaw; Schirwitz, Christopher; Stadler, Volker; Michel, Gerd; Marmé, Nicole; Schütz, Gerhard J.; Hoheisel, Jörg D.; Knemeyer, Jens-Peter
J. Proteome Res..
Jan 2011
10.1021/pr101070j

Combinatorial Peptide Synthesis on a Microchip

Schirwitz, Christopher; Block, Ines; König, Kai; Nesterov, Alexander; Fernandez, Simon; Felgenhauer, Thomas; Leibe, Klaus; Torralba, Gloria; Hausmann, Michael; Lindenstruth, Volker; Stadler, Volker; Breitling, Frank; Bischoff, F. Ralf
Current Protocols in Protein Science.
Aug 2009
10.1002/0471140864.ps1802s57
Microchips are used in the combinatorial synthesis of peptide arrays by means of amino acid microparticle deposition. The surface of custom-built microchips can be equipped with an amino-modified poly(ethylene glycol)methacrylate (PEGMA) graft polymer coating, which permits high loading of functional groups and resists nonspecific protein adsorption. Specific microparticles that are addressed to the polymer-coated microchip surface in a well defined pattern release preactivated amino acids upon melting, and thus allow combinatorial synthesis of high-complexity peptide arrays directly on the chip surface. Currently, arrays with densities of up to 40,000 peptide spots/cm2 can be generated in this way, with a minimum of coupling cycles required for full combinatorial synthesis. Without using any additional blocking agent, specific peptide recognition has been verified by background-free immunostaining on the chip-based array. This unit describes microchip surface modification, combinatorial peptide array synthesis on the chip, and a typical immunoassay employing the resulting high-density peptide arrays.

Particle-Based Synthesis of Peptide Arrays

Breitling, Frank; Felgenhauer, Thomas; Nesterov, Alexander; Lindenstruth, Volker; Stadler, Volker; Bischoff, F. Ralf
ChemBioChem.
Mar 2009
10.1002/cbic.200800735
Lithographic methods allow for the combinatorial synthesis of >50,000 oligonucleotides per cm(2), and this has revolutionized the field of genomics. High-density peptide arrays promise to advance the field of proteomics in a similar way, but currently lag behind. This is mainly due to the monomer-by-monomer repeated consecutive coupling of 20 different amino acids associated with lithography, which adds up to an excessive number of coupling cycles. Combinatorial synthesis based on electrically charged solid amino acid particles resolves this problem. A color laser printer or a chip addresses the different charged particles consecutively to a solid support, where, when completed, the whole layer of solid amino acid particles is melted at once. This frees hitherto immobilized amino acids to couple all 20 different amino acids to the support in one single coupling reaction. The method should allow for the translation of entire genomes into sets of overlapping peptides to be used in proteome research.

High-density peptide arrays

Breitling, Frank; Nesterov, Alexander; Stadler, Volker; Felgenhauer, Thomas; Bischoff, F. Ralf
Mol. BioSyst..
Jan 2009
10.1039/b819850k
Arrays promise to advance biology by allowing parallel screening for many different binding partners. Meanwhile, lithographic methods enable combinatorial synthesis of >50 000 oligonucleotides per cm2, an advance that has revolutionized the whole field of genomics. A similar development is expected for the field of proteomics, provided that affordable, very high-density peptide arrays are available. However, peptide arrays lag behind oligonucleotide arrays. This review discusses recent developments in the field with an emphasis on methods that lead to very high-density peptide arrays.

A Novel Combinatorial Approach to High-Density Peptide Arrays

Beyer, Mario; Block, Ines; König, Kai; Nesterov, Alexander; Fernandez, Simon; Felgenhauer, Thomas; Schirwitz, Christopher; Leibe, Klaus; Bischoff, Ralf F.; Breitling, Frank; Stadler, Volker
Jan 2009
10.1007/978-1-60327-394-7_16
Combinatorial synthesis of peptides on solid supports (1), either as spots on cellulose membranes (2) or with split-pool-libraries on polymer beads (3), substantially forwarded research in the field of peptide-protein interactions. Admittedly, these concepts have specific limitations, on one hand the number of synthesizable peptide sequences per area, on the other hand elaborate decoding/encoding strategies, false-positive results and sequence limitations. We recently established a method to produce high-density peptide arrays on microelectronic chips (4). Solid amino acid microparticles were charged by friction and transferred to defined pixel electrodes onto the chip’s surface, where they couple to a functional polymer coating simply upon melting (Fig. 16.1 A-D,F). By applying standard Fmoc chemistry according to Merrifield, peptide array densities of up to 40,000 spots per square centimetre were achieved (Fig. 16.1G). The term Merrifield synthesis describes the consecutive linear coupling and deprotecting of L-amino acids modified with base-labile fluorenylmethoxy (Fmoc) groups at the N-terminus and different acid-sensitive protecting groups at their side chains. Removing side chain protecting groups takes place only once at the very end of each synthesis and generates the natural peptide sequence thereby.

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