Development of a Series of Cross‐Linking Agents that Effectively Stabilize α‐Helical Structures in Various Short Peptides

Abstract

A series of cross-linking agents of varying rigidity and length were designed to stabilize helical structures in short peptides and were then synthesized. The sequences of the short peptides employed in this study each include two X residues (X=Dap, Dab, Orn, and Lys) at the i/i+4, i/i+7, or i/i+11 positions to provide the sites for cross-linking. These peptides were subjected to reaction with the synthesized cross-linking agents, and the helical content of the resulting cross-linked peptides were analyzed in detail by circular dichroism. For each of the peptide classes we found combinations with the cross-linking agents suitable for the construction of stable helical structures up to >95 % helicity at 5 degrees C. Our method could also be applied to biologically related sequences seen in native proteins such as Rev.

Tightening up the structure, lighting up the pathway: application of molecular constraints and light to manipulate protein folding, self-assembly and function

“…Therefore, various sidechain-to-sidechain cross-linking strategies have been put forth to reduce the conformational entropy of the unfolded state, thus forcing short peptides to fold into α-helices or β-sheets (Figure 1). Such examples include disulfide bond formation [4-10], ring-closing metathesis [11-14], lactam bridge formation [15-19], hydrocarbon bridges [20-23], and hydrazone [24] and oxime linkages [25-27]. In particular, due to the ease of incorporation and natural abundance of cysteines in biological systems, cysteine alkylation [28-30] has become a popular method for incorporating cross-linkers that stabilize α-helical conformations [31, 32].…”

Synthesis of Heterocycle‐Bridged Peptidic Macrocycles through 1,3‐Diyne Transformations

“…[1][2][3][4] Cyclic peptides containing a 1,3diyne moiety can be prepared by either derivatization of peptide side chains with difunctionalized 1,3-diynes [5] or by Glaser-Hay-type oxidative alkyne-alkyne coupling reactions of α,ω-dialkynylated peptides. [1][2][3][4] Cyclic peptides containing a 1,3diyne moiety can be prepared by either derivatization of peptide side chains with difunctionalized 1,3-diynes [5] or by Glaser-Hay-type oxidative alkyne-alkyne coupling reactions of α,ω-dialkynylated peptides.…”

Bridged Analogues for p53-Dependent Cancer Therapy Obtained by S-Alkylation

“…These include hydrazone bridge (Cabezas and Satterthwait, 1999), oxime bridge (Haney et al, 2011), 1,4-disubstituted-[1,2,3]-triazole linkage (Holland-Nell and Meldal, 2011; Ingale and Dawson, 2011; Kawamoto et al, 2012; Lau et al, 2014c; Lau et al, 2014b; Lau et al, 2014a; Lau et al, 2015b; Scrima et al, 2010), metal chelation (Ghadiri and Choi, 1990; Ruan et al, 1990), disulfide bond formation (Almeida et al, 2012; Jackson et al, 1991; Leduc et al, 2003), lactam ring formation (Fujimoto et al, 2008; Geistlinger and Guy, 2001; Geistlinger and Guy, 2003; Houston, Jr. et al, 1995; Osapay and Taylor, 1992; Phelan et al, 1997) and S-alkylation based staples employing either α-haloacetamide alkylation of single cysteine (Brunel and Dawson, 2005; Cardoso et al, 2007; Galande et al, 2004; Woolley, 2005) or bridging two cysteines with bis-S-alkylating linker(s) (de Araujo et al, 2014; Jo et al, 2012; Muppidi et al, 2011b; Muppidi et al, 2011a; Muppidi et al, 2012; Spokoyny et al, 2013; Szewczuk et al, 1992; Timmerman et al, 2005; Wilkinson et al, 2007; Zhang et al, 2007; Zhang et al, 2008). Among these, the last seems to be most flexible approach as a wide range of inexpensive bis-thiol-reactive linkers is commercially available, including rigid aromatic derivatives (Chua et al, 2015; Jo et al, 2012; Muppidi et al, 2011b; Muppidi et al, 2011a; Muppidi et al, 2012; Timmerman et al, 2005; Zhang et al, 2007) and aliphatic counterparts (Byrne and Stites, 1995; Chua et al, 2015; Lindman et al, 2001; Wilkinson et al, 2007).…”