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Knottins can be obtained either:
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Serine protease inhibitors |
Combined chemical and recombinant route to cyclic squash inhibitor analogsIn this approach, a cheap and high-yelding recombinant production of folded and oxidized linear presursors is combined with efficient chemical linkage of the termini to yield the cyclic knottins [Avrutina et al, 2008]. Biomimetic synthesis of the cyclic squash inhibitor MCoTI-IIIn 2008, Thongyoo et al. [Thongyoo et al, 2008] proposed a new biomimetic method for the synthesis of MCoTI-II and analogs. In this method, a commercially available polymer-supported protease (trypsin or chymotrypsin) acts as a ligase for cyclisation of the refolded MCoTI-II backbone. The method also allows in situ affinity purification of the cyclic knottin. Biosynthesis of the cyclic squash inhibitor MCoTI-IIA fully functional sample of he cyclic knottin MCoTI-II has been produced in living bacterial cells via an intramolecular version of the native chemical ligation using intein. [Camarero et al, 2007]. Synthesis of a photoactive analog of the squash inhibitor EETI-IIUsing a combination of solid phase-peptide synthesis and chemical ligation, a photoactive methionine was incorporated into EETI-II. This or similar molecules will be useful for photoaffinity cross-linking studies [Durek et al, 2007]. Use of a Super Permeable Organic Combinatirial Chemistry (SPOCC) resinIn 2006, Johnson et al. [Johnson et al, 2006] reported an original synthesis of EETI-II based on the use of a superpermeable organic combinatorial chemistry (SPOCC) resin and thiazolidine-4-carboxylic acid (Thz) in place of cysteine. The combination of SPOCC resin and Thz allowed all synthetic steps to be achieved directly on the solid support, including 3 NCL and folding. Early syntheses of CMTI-III and EETI-IIThe squash inhibitors were among the first knottins to be chemically synthesized in the late 80s [Kupryszewski et al, 1986; Le-Nguyen et al, 1989], |