Turn mimic

Winningham MJ, Sogah DY. A modular approach to polymer architecture control via catenation of prefabricated biomolecular segments polymers containing parallel /8-sheets templated by a phenoxathiin-based reverse turn mimic. Macromolecules 1997 30 862-876. 

One strategy to control folding is to direct folds by introduction of S-hairpins, turns which are often associated with Pro incorporation in a polypeptide sequence. Constrained turn mimics have previously been employed in investigations of the active conformation of peptides. Clearly, from the above discussion of CyP and... 

The intramolecular Diels-Alder reaction of l-(A -a -alkenyl)-2(l//)-pyrazinones generates m-[l,7]naphthyridines in good yields (Scheme 62) <2001TL7397>. This method has been used in the development of a r-[l,7]naphthyr-idine-based scaffold on which to build a type VI external /3-turn mimic <2003EJ01868>, and for the synthesis and conformational analysis of [l,7]naphthyridine-based substance P antagonist analogues <2003T4721>. 

Evidence for this conformation was provided by NMR and X-ray, but finally by synthesis of constrained analogues, including 43 which incorporates a y-lactam /3-turn mimic developed by Freidinger et al. (1989). Compound 43 was found to be 10 000 times more potent than 42 in enhancing the binding of the agonist 2-amino-6,7-dihydroxy-l,2,3,4-tctrahydronaphthalene. 

Generic scaffold for peptide reverse turn mimics claimed Libraries based on claimed scaffolds were claimed Biological activity of claimed libraries were claimed... 

Ball JB, Alewood PF. Conformational constraints nonpeptide P-turn mimics. J. Mol. Recogn. 1990 3 55-64. 

More recently, studies on Campylobacter jejuni have demonstrated how specific bacterial carbohydrate antigens can mimic the fine structure of human cell surface glycolipid structures and elicit autoimmune reactivity. Yuki et al.61 first identified that the lipooligosaccharide (LOS) of C. jejuni mimicked human G(M)1 ganglioside and subsequently extended these studies to demonstrate that specific single amino acid variants of the C. jejuni Cst-II sialyltransferase protein are responsible for the synthesis of LOS variants that in turn, mimic different... 

The usefulness of a mutant dehydrogenase was demonstrated in a practical synthesis of 4-amino-2-hydroxy acids, which themselves are valuable as y-turn mimics for investigations into the secondary structure of peptides[146]. Chemoenzymatic synthesis of these compounds were achieved by lipase catalyzed hydrolysis of a a-keto esters to the corresponding a-keto acids followed by reduction employing a lactate dehydrogenase in one pot. Wild type lactate dehydrogenase from either Bacillus... 

D. J. Kyle, L. M. Green, P. R. Blake, D. Smithwick, and M. F. Summers, Peptide Res., 5,206 (1992). A Novel p-Turn Mimic Useful for Mapping the Unknown Topology of Peptide Receptors. 

Finally, the macdermotti males will be selected to approach cautiously the mistake flash since it may actually come from a macdermotti male near a macdermotti female, and their reproductive success will be improved. However, if Photuris again counters in the co-evolutionary process, it can in turn mimic this last signal into a mimetic advantage (Lloyd, 1981). While all the details of these complex signals have not been worked out and there may well be variants, it is obvious that the entire mimetic complex is of considerable interest. 

Figure 13 Examples of secondary structure mimics. A cyclic /S-hairpin (5) prepared by Robinson et al., and a / -peptide (6) developed by Schepartz et al. that are both designed to emulate the functional group projection patterns of an a-helix. A S-turn mimic (7) developed by Burgess et al. and a cross-linked peptide (8) that serves to emulate a /S-strand, prepared by the Chmielewski group.

Scheme 10.7 ji-turn mimics produced from piperazine amides and dichlorotriazines... 

Figure 10.3 Copper(l)-catalyzed azide-alkyne cycloadditions were used to incorporate triazoles into a-helical structures 25 and fi-turn mimics 26, respectively, and the secondary structures were spectroscopically verified...

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