Library sequencing

The coiled-coil library sequence and helical-wheel diagram of this coiled-coil template is shown in Scheme 9. 

Landgraf, P. et al. 2007. A mammalian microRNA expression atlas based on small RNA library sequencing. Cell 129, 1401-1414. 

Nabeshima et al. (1987) have isolated two cDNA clones for LC17 mRNA from chicken gizzard and fibroblast cDNA libraries. Sequence analysis of the two... 

Now that we have briefly introduced some of the most important tools and techniques of molecularbiology, we can return to the isolation, cloningand identification of genes ofinterest from within prokaryotic genomic DNA or eukaryotic cDNA library sequences. There are two main approaches for this. 

We screened our libraries for the site-selective epoxidation of famesol (120) [182]. Either the peracid reagent /mCPBA, or catalytic n-alkyl acids, provided a benchmark for the intrinsic and poorly selective product distribution of monoepoxides (see Fig. 13b inset for schematic of famesol nomenclature). Hits from the initial libraries, however, showed selectivity toward 2,3-epoxide 121 and 6,7-epoxide 122, inspiring the development of biased combinatorial libraries to select further for these oxidation sites (Fig. 13b). Further optimization of the sequences after additional library sequences yielded peptide 123, which provided 2,3-epoxy famesol 121 with 1 1 >100 site selectivity (10,11 6,7 2,3) in 81% yield and 86% ee. These values are comparable to those provided for this substrate by the venerable Sharpless asymmetric epoxidation [187]. Optimization of the 6,7-biased sequence led to peptide 124, which provided 6,7-epoxy famesol 122 in 1.2 8.0 1.0 site selectivity (10,11 6,7 2,3) in 43% yield and 10% ee. Despite the modest ee of 122, we note that, to our knowledge, no existing catalytic epoxidation method is capable of providing 122 directly in reasonable purity. 

The information that is obtained from large scale library sequencing as described in Section 2.3 can be further refined by cluster-... 

Brown, J.M., Hoffmann, W.D., Alvey, C.M., Wood, A.R., Verbeck, G.F. and Petros, RA. (2010) One-bead, one-compound peptide library sequencing via high-pressure ammonia cleavage coupled to nanomanipulation/nanoelectrospray ionization mass spectrometry. Anal. Biochem. 398, 7-14. 

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