Combinatorial ligand library bead

Screening combinatorial peptide libraries with intact cells is a rapid way of discovering cell surface-binding ligands.22 25 The procedure is divided into three sections (1) preparation and sterilization of the bead library,... 

The modified mix-and-splif combinatorial method is used for the synthesis of the ligand library yields n<->n members, where n represents the number of different amines chosen. Usually 5 g of each immobilized ligand are synthesized however, this amount depends on the screening strategy preferred (for example, the FITC-based system or the ELISA on beads require less resin than the conventional affinity chromatography). 

The equalization approach is based on the opposite strategy, in that only low-abundance proteins are collected and subjected to LC-MS analysis. The method relies on bead-bound combinatorial peptide ligand libraries (10) that enrich low-abundance proteins. This strategy is much cheaper than antibody precipitation, but it has the clear drawback that only proteins that have affinity to one of the millions of beads present in the library used can be equalized for further analysis. 

To avoid the possibility that a small peptide from a phage-displayed library will not bind adequately when immobilized on a solid support, Baumbach and Hammond suggested that combinatorial peptide libraries for protein purification be synthesized directly on resins that could be used as chromatographic supports on a large scaled, in this way, any ligand that is identified is already on a platform or format that would facilitate implementation in downstream processing. The one-bead-one-peptide solid phase library format is ideally suited for this purpose, if the library is built on chromatographic resins that can withstand the harsh solvent conditions used for peptide synthesis. 

Park SI, Renil M, Vikstrom B et al (2002) The use of one-bead one-compound combinatorial library method to identify peptide ligands for cz4f31 integrin receptor in non-Hodgkin s lymphoma. Lett Pept Sci 8 171-178... 

In 1991, we first introduced the one-bead one-compound (OBOC ) combinatorial library method.1 Since then, it has been successfully applied to the identification of ligands for a large number of biological targets.2,3 Using well-established on-bead binding or functional assays, the OBOC method is highly efficient and practical. A random library of millions of beads can be rapidly screened in parallel for a specific acceptor molecule (receptor, antibody, enzyme, virus, etc.). The amount of acceptor needed is minute compared to solution phase assay in microtiter plates. The positive beads with active compounds are easily isolated and subjected to structural determination. For peptides that contain natural amino acids and have a free N-terminus, we routinely use an automatic protein sequencer with Edman chemistry, which converts each a-amino acid sequentially to its phenylthiohydantoin (PTH) derivatives, to determine the structure of peptide on the positive beads. 

Nestler HP, Wennemers H, Sherlock R, Dong DLY, Microautoradiographic identification of receptor-ligand interactions in bead-supported combinatorial libraries, Bioorg. Med. Chem. Lett., 6 1327-1330, 1996. 

Lathrop JT, Fijalkowska, I, Hammond D. The Bead blot A method for identifying ligand-protein and protein-protein interactions using combinatorial libraries of peptide ligands. Anal. Biochem. 2007 361 65-76. 

Tlie basic study of intermolecular interactions is facihtated by one-bead-one-stRicture libraries which can be powerful tools for the discovery of hgands to synthetic receptors and vice versa. Encoded combinatorial libraries have been useful for disclosing ligands for well-designed macrocyclic host molecules and to elucidate their specificities for peptide sequences. These studies led via receptors with more flexibility to simple host molecules without elaborate design that ai e accessible to combinatorial synthesis. One application is the development of chemical sensors for analytes that are otherwise difficult to detect or only non-specificaUy detected. Such hbraries have been used to find new catalysts and enzyme mimics. 

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