Combinatorial peptide library materials

Fig. 6 Dynamic combinatorial peptide library that expioits enzyme reactions to control self-assembly processes under thermodynamic controi. (a) Emergence of the potentiai peptide derivatives of varying length in a library of interconverting molecules formed from the staring materials of Fmoc L/L2 system. Fmoc-Ls is preferentially formed. Corresponding AFM images of the fibrillar structures formed at 5 min after the addition of enzyme, and the sheet-like structures observed after 2000 h show that redistribution of the derivatives is accompanied by the remodelling from fibres (Fmoc L3) to sheet-like structures (Fmoc L5). (b) HPLC analysis of the composition of the system reveals the formation and the stabilisation of Fmoc-Ls over time. Modified from [21]...

These approaches are time-consuming and limited by the amount of biological materials. A fast method to define recognition patterns of MHC molecules has been introduced by screening synthetic combinatorial peptide libraries [31]. 

IR spectroscopy is not a very sensitive analytical tool and is, therefore, not well suited to the detection of small amounts of material. If, however, intermediates have intense and well-resolved IR absorptions, the progress of their chemical transformation can be followed by IR spectroscopy [83,88,91-93], Near-infrared spectroscopy, in combination with an acousto-optic tunable filter, can be sufficiently sensitive to enable the on-bead identification of polystyrene-bound di- and tripeptides, even if the peptides have very similar structures (e.g., Leu-Ala-Gly-PS and Val-Ala-Gly-PS) or differ only in their amino acid sequence (e.g., Leu-Val-Gly-PS and Val-Leu-Gly-PS) [94]. Special resins displaying an IR and Raman barcode have been developed, which may facilitate the deconvolution of combinatorial compound libraries prepared by the mix-and-split method [48]. 

The resin-bound polyamine was used as a template for the solid-phase synthesis of a range of heterocyclic compounds, such as cyclic ureas 25 and cyclic thioureas 26. This work exemplifies our ongoing efforts on the solid-phase assembly of individual acyclic and heterocyclic compounds and combinatorial libraries using short peptides as starting materials. 

We selected scFvs from a combinatorial phage display library using both phosphorylated and nonphosphorylated forms of a C-terminal y-H2AX peptide. Figure 2B shows die peptide sequence used for selection. Ten separate bacteriophage isolates were chosen for further characterization. Soluble scFvs were produced in the periplasm of an E. coli host. Periplasmic extracts were either used direcdy or as a source of material for further purification. 

Chitosan, the deacetylated form of chitin, is a plentiful and naturally occurring aminopolysaccharide obtained fl om shellfish and other marine species. Most of the research on applying this to fibers and films has been conducted in Japan and to a lesser extent Korea. Micromilled chitosan powder has been blended with rayon fibers, followed by subsequent lamination, to produce a variety of nonwoven fabrics known as Chitopoly. These modified materials were even effective against a methacillin-strain of S. aureus [37], Numerous other publications and patents describe incorporation of chitosan in various forms to produce antimicrobial fibers and polymers. One of the more recent examples is the binding of a quaternary ammonium derivative of chitosan to cotton fabric to produce an antibacterial finish [38]. The other area of current interest is the use of naturally occurring peptides as antimicrobial agents. The use of combinatorial libraries allows one to systematically examine ten to hundreds of millions of peptides for their antimicrobial activity. This was demonstrated with various strains... 

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