Surfaces peptide self-assembly

Biancalana M, Makabe K, Koide A, Koide S (2009) Molecular mechanism of thioflavin-T binding to the surface of b-rich peptide self-assemblies. J Mol Biol 385(4) 1052-1063... 

The utilization of peptide self-assembly additionally allows control of structural parameters and the rational control of functionalities, which are displayed at the nanofiber surface. This makes the presentation of biological signals and thus the introduction of bioactivity feasible. Stupp and coworkers investigated the self-assembly of peptide-amphiphiles (Fig. 4) [87, 115], The resulting worm-like, cylindrical nanostructures consist of a hydrophobic core that is formed by the alkyl... 

To demonstrate the existence of functional elements responsible for pore properties of channel proteins, peptides with sequences that represent such functional segments are synthesized and their ability to mimic the targeted biological activity is tested by incorporation of the peptides into lipid bilayers. This approach allows rapid determination of which presumed transmembrane helices may form functional channels. The peptides self-assemble in the membrane to generate conductive oligomers, presumably with hydrophobic surfaces that face the phospholipid and hydrophilic residues that fine the pore. Channels of different sizes (oligomeric number) result (37, 48). 

Another approach for fabricating the peptide-polymer hybrid nanofibers is the polymerization method at the surface of self-assembled /3-sheet nanofibers (or nanotubes). In the jd-sheet structure, adjacent /3-strands align... 

Fig. 17 Radical polymerization of diene (DE) groups attached to the /3-sheet peptides at the surface of self-assembled nanofibers. (Adapted from [58])...

Atom transfer radical polymerization (ATRP) is also an interesting strategy to construct peptide-polymer hybrid ID-arrays. Graft-polymerization of AT-isopropylacrylamide was carried out from the surface of self-assembled peptide nanotube in water, and as a result, cyclicpeptide-poly(f -isopropyl-acrylamide) hybrid nanotube was successfully prepared (Fig. 19) [61]. fii other words, this research indicates that surface chemistry of ID-peptide nano-assembly can be adjusted by the grafted synthetic polymers, such as thermo-sensitive PNIPAM and polyelectrolytes. 

The characteristic coiled-coil motifs found in proteins share an (abcdefg) heptad repeat of polar and nonpolar amino acid residues (Fig. 1). In this motif, positions a, d, e, and g are responsible for directing the dimer interface, whereas positions b, c, and f are exposed on the surfaces of coiled-coil assemblies. Positions a and d are usually occupied by hydrophobic residues responsible for interhelical hydrophobic interactions. Tailoring positions a, d, e, and g facilitates responsiveness to environmental conditions. Two or more a-helix peptides can self-assemble with one another and exclude hydrophobic regions from the aqueous environment [74]. Seven-helix coiled-coil geometries have also been demonstrated [75]. 

Kretsinger JK, Haines LA, Ozbas B et al (2005) Cytocompatibility of self-assembled ss-hairpin peptide hydrogel surfaces. Biomaterials 26 5177-5186... 

Figure 5.25 AFM images of intermediate stmctures in self-assembly of peptide KFE8 in aqueous solution deposited on freshly cleaved mica surface (a) 8 min after preparation of solution. Inset electron micrograph of sample of peptide solution obtained using quick-freeze deep-etch technique (b) 35 min, (c) 2 h, and (d) 30 h after preparation. Reprinted with permission from Ref. 110. Copyright 2002 by the American Chemical Society.

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