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Abstract:
The poor hit rates associated with conventional random peptide libraries present formidable challenges in genetic screening formats with limited throughput, such as mammalian phenotypic or two-hybrid screeningplatforms. Unfortunately, this problem cannot always be addressed with higher-throughput platforms such as in vitro or ribosome display for screening random peptide libraries. The peptides of standard random libraries produced by synthetic combinatorial chemistry are limited in size and the method of production does not necessarily allow them to express amino acids in the proportion found in nature. Moreover, peptide interactor hunts in mammalian phenotypic or two-hybrid platforms are conducted in living cells, making them particularly suited for intracellular screening applications.1 High-affinity primary hits are critical for reliable identification of cognate targets using standard pull-down mass spectroscopy approaches. Unfortunately, hits of such quality are rare in mammalian phenotypic screens of random peptides.2 This explains why random peptide libraries are rarely employed for phenotypic screening for target discovery and validation.