TY - JOUR A1 - Remmler, Dario A1 - Schwaar, Timm A1 - Pickhardt, M. A1 - Donth, C. A1 - Mandelkow, E. A1 - Weller, Michael G. A1 - Börner, H. T1 - On the way to precision formulation additives: 2D-screening to select solubilizers with tailored host and release capabilities N2 - A 2-dimensional high-throughput screening method is presented to select peptide sequences from large peptide libraries for precision formulation additives, having a high capacity to specifically host a drug of interest and provide tailored drug release properties. The identified sequences are conjugated with poly(ethylene glycol) (PEG) to obtain peptide-PEG conjugates that proved to be valuable as solubilizers for small organic molecule drugs to overcome limitations of poor water-solubility and low bio-availability. The 2D-screening method selects peptide sequences on both (i) high loading capacities and (ii) preferred drug-release capabilities as demonstrated on an experimental Tau-protein aggregation inhibitor/Tau- deaggregator with potentials for an anti-Alzheimer disease drug (BB17). To enable 2D-screening, a one-bead one-compound (OBOC) peptide library was immobilized on a glass slide, allocating individual beads to permanent positions. While the first screening step involved incubation of the supported OBOC library with BB17 to identify beads with high drug binding capacities by fluorescence scanner readouts, the second step reveals release properties of the high capacity binders by incubation with blood plasma protein model solutions. Efficiently peptides with high BB17 capacities and either keeper or medium or fast releaser properties can be identified by direct sequence readouts from the glass slide supported resin beads via matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry. Four peptides are synthesized as peptide-PEG solubilizers representing strong, medium, weak releasers and non-binders. Loading capacities reached up to 1:3.4 (mol drug per mol carrier) and release kinetics (fast/medium/slow) are in agreement with the selection process as investigated by fluorescence anisotropy and fluorescence correlation spectroscopy. The ability of BB17/conjugate complexes to inhibit the aggregation of Tau4RDΔK (four repeat Tau ((M)Q244-E372 with deletion of K280), 129 residues) in N2a cells is studied by a Tau-pelleting assay showing the modulation of cellular Tau aggregation. Promising effects such as the reduction of 55% of total Tau load are observed for the strong releaser additive. Studies of in vitro Thioflavin S Tau-aggregation assays show half-maximal inhibitory activities (IC50 values) of BB17/conjugates in the low micro-molar range. KW - Block copolymer KW - Drug transporters KW - Peptide library screening KW - Formulation additives PY - 2018 U6 - https://doi.org/10.1016/j.jconrel.2018.06.032 SN - 0168-3659 SN - 1873-4995 VL - 285 SP - 96 EP - 105 PB - Elsevier CY - Amsterdam AN - OPUS4-45483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tscheuschner, Georg A1 - Schwaar, Timm A1 - Weller, Michael G. T1 - Fast Confirmation of Antibody Identity by MALDI-TOF MS Fingerprints N2 - Thousands of antibodies for diagnostic and other analytical purposes are on the market. However, it is often difficult to identify duplicates, reagent changes, and to assign the correct original publications to an antibody. This slows down scientific progress and might even be a cause of irreproducible research and a waste of resources. Recently, activities were started to suggest the sole use of recombinant antibodies in combination with the open communication of their sequence. In this case, such uncertainties should be eliminated. Unfortunately, this approach seems to be rather a long-term vision since the development and manufacturing of recombinant antibodies remain quite expensive in the foreseeable future. Nearly all commercial antibody suppliers also may be reluctant to publish the sequence of their antibodies, since they fear counterfeiting. De novo sequencing of antibodies is also not feasible today for a reagent user without access to the hybridoma clone. Nevertheless, it seems to be crucial for any scientist to have the opportunity to identify an antibody undoubtedly to guarantee the traceability of any research activity using antibodies from a third party as a tool. For this purpose, we developed a method for the identification of antibodies based on a MALDI-TOF MS fingerprint. To circumvent lengthy denaturation, reduction, alkylation, and enzymatic digestion steps, the fragmentation was performed with a simple formic acid hydrolysis step. Eighty-nine unknown monoclonal antibodies were used for this study to examine the feasibility of this approach. Although the molecular assignment of peaks was rarely possible, antibodies could be easily recognized in a blinded test, simply from their mass-spectral fingerprint. A general protocol is given, which could be used without any optimization to generate fingerprints for a database. We want to propose that, in most scientific projects relying critically on antibody reagents, such a fingerprint should be established to prove and document the identity of the used antibodies, as well as to assign a specific reagent to a datasheet of a commercial supplier, public database record, or antibody ID. KW - Reproducibility KW - Quality Control KW - Traceability KW - Diagnostics KW - Hybridoma KW - Monoclonal Antibody KW - Recombinant Antibody PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-506611 SN - 2310-287X VL - 9 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-50661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Tscheuschner, Georg A1 - Schwaar, Timm A1 - Weller, Michael G. T1 - Fast Confirmation of Antibody Identity by MALDI-TOF-MS Fingerprints N2 - Thousands of antibodies for diagnostic and other analytical purposes are on the market. However, it is often difficult to identify duplicates, reagent changes, and to assign the correct original publications to an antibody. This slows down scientific progress and might even be a cause of irreproducible research and a waste of resources. Recently, activities were started to suggest the sole use of recombinant antibodies in combination with the open communication of their sequence. In this case, such uncertainties should be eliminated. Unfortunately, this approach seems to be rather a long-term vision since the development and manufacturing of recombinant antibodies remain quite expensive in the foreseeable future. Also, nearly all commercial antibody suppliers may be reluctant to publish the sequence of their antibodies, since they fear counterfeiting. De-novo sequencing of antibodies is also not feasible today for a reagent user without access to the hybridoma clone. Nevertheless, it seems to be crucial for any scientist to have the opportunity to identify an antibody undoubtedly to guarantee the traceability of any research activity using antibodies from a third party as a tool. For this purpose, we developed a method for the identification of antibodies based on a MALDI-TOF-MS fingerprint. To circumvent lengthy denaturation, reduction, alkylation, and enzymatic digestion steps, the fragmentation was performed with a simple formic acid hydrolysis step. Eighty-nine unknown monoclonal antibodies were used for this study to examine the feasibility of this approach. Although the molecular assignment of peaks was rarely possible, antibodies could be easily recognized in a blinded test, simply from their mass-spectral fingerprint. A general protocol is given, which could be used without any optimization to generate fingerprints for a database. We want to propose that in most scientific projects relying critically on antibody reagents, such a fingerprint should be established to prove and document the identity of the used antibodies and to assign a specific reagent to a datasheet of a commercial supplier, a public database record or an antibody ID. KW - Reproducibility KW - Quality Control KW - Traceability KW - Diagnostics KW - ELISA KW - Immunoassay PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-506590 SN - 2310-287X SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-50659 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Celasun, S. A1 - Remmler, D. A1 - Schwaar, Timm A1 - Weller, Michael G. A1 - Du Prez, F. A1 - Börner, H. G. T1 - Digging into the sequential space of thiolactone precision polymers: A combinatorial strategy to identify functional domains N2 - Functional sequences of precision polymers based on thiolactone/Michael chemistry are identified from a large one-bead one-compound library. Single-bead readout by MALDI-TOF MS/MS identifies sequences that host m-THPC that is a second Generation photo-sensitizer drug. The corresponding Tla/Michael-PEG conjugates make m-THPC available in solution and drug payload as well as drug release kinetics can be fine-tuned by the precision segment. KW - Combinatorial chemistry KW - Combinatorial polymer libraries KW - Sequence-defined oligomer KW - Precision polymer sequencing KW - Pseudo peptides KW - MALDI-TOF KW - ESI MS KW - Mass spectrometry KW - Sequencing KW - PEG KW - Polyethylene glycol KW - Solubilizer KW - Drug KW - Conjugates PY - 2019 U6 - https://doi.org/10.1002/anie.201810393 SN - 1521-3773 VL - 58 IS - 7 SP - 1960 EP - 1964 PB - Wiley-VCH CY - Weinheim AN - OPUS4-47323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abbas, Ioana M. A1 - Schwaar, Timm A1 - Bienwald, Frank A1 - Weller, Michael G. T1 - Predictable Peptide Conjugation Ratios by Activation of Proteins with Succinimidyl Iodoacetate (SIA) N2 - The small heterobifunctional linker succinimidyl iodoacetate (SIA) was examined for the preparation of peptide–protein bioconjugates with predicable conjugation ratios. For many conjugation protocols, the protein is either treated with a reductant to cleave disulfide bonds or is reacted with thiolation chemicals, such as Traut’s reagent. Both approaches are difficult to control, need individual optimization and often lead to unsatisfactory results. In another popular approach, a heterobifunctional linker with a N-hydroxysuccinimide (NHS) and a maleimide functionality is applied to the protein. After the activation of some lysine ε-amino groups with the NHS ester functionality, a cysteine-containing peptide is attached to the activated carrier protein via maleimide. Particularly, the maleimide reaction leads to some unwanted byproducts or even cleavage of the linker. Many protocols end up with conjugates with unpredictable and irreproducible conjugation ratios. In addition, the maleimide-thiol addition product should be assumed immunogenic in vivo. To avoid these and other disadvantages of the maleimide approach, we examined the known linker succinimidyl iodoacetate (SIA) in more detail and developed two protocols, which lead to peptide–protein conjugates with predefined average conjugation ratios. This holds potential to eliminate tedious and expensive optimization steps for the synthesis of a bioconjugate of optimal composition. KW - Bioconjugate KW - Carrier protein KW - Immunogen KW - Hapten KW - Linker KW - Antibody drug conjugate KW - ADC KW - Drug-to-antibody ratio KW - DAR KW - Conjugation ratio KW - Conjugation density KW - Carrier load KW - Click reaction KW - Click chemistry PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-427188 UR - http://www.mdpi.com/2409-9279/1/1/2 SN - 2409-9279 VL - 1 SP - 1 EP - 14 PB - MDPI CY - Basel, Schweiz AN - OPUS4-42718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwaar, Timm A1 - Lettow, Maike A1 - Remmler, Dario A1 - Börner, H. G. A1 - Weller, Michael G. T1 - Efficient Screening of Combinatorial Peptide Libraries by Spatially Ordered Beads Immobilized on Conventional Glass Slides N2 - Screening of one-bead-one-compound (OBOC) libraries is a proven procedure for the identification of protein-binding ligands. The demand for binders with high affinity and specificity towards various targets has surged in the biomedical and pharmaceutical field in recent years. The traditional peptide screening involves tedious steps such as affinity selection, bead picking, sequencing, and characterization. Herein, we present a high-throughput “all-on-one chip” system to avoid slow and technically complex bead picking steps. On a traditional glass slide provided with an electrically conductive tape, beads of a combinatorial peptide library are aligned and immobilized by application of a precision sieve. Subsequently, the chip is incubated with a fluorophore-labeled target protein. In a fluorescence scan followed by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry, high-affinity binders are directly and unambiguously sequenced with high accuracy without picking of the positive beads. The use of an optimized ladder sequencing approach improved the accuracy of the de-novo sequencing step to nearly 100%. The new technique was validated by employing a FLAG-based model system, identifying new peptide binders for the monoclonal M2 anti-FLAG antibody, and was finally utilized to search for IgG-binding peptides. In the present format, more than 30,000 beads can be screened on one slide. KW - Peptide library KW - HTS KW - Target KW - MALDI KW - Mass spectrometry KW - Biochip KW - Lab-on-a-Chip KW - Array KW - Screening KW - Ladder sequencing KW - Binder KW - Pharmaceutical PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-478973 UR - https://www.mdpi.com/2571-5135/8/2/11 VL - 8 IS - 2 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-47897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -