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MagicWand: A Single, Designed Peptide That Assembles to Stable, Ordered (2008)
BibTeX
@MISC{08magicwand:a,
author = {},
title = {MagicWand: A Single, Designed Peptide That Assembles to Stable, Ordered},
year = {2008}
}
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Abstract
ABSTRACT: We describe a straightforward single-peptide design that self-assembles into extended and thickened nano-to-mesoscale fibers of remarkable stability and order. The basic chassis of the design is the well-understood dimeric R-helical coiled-coil motif. As such, the peptide has a heptad sequence repeat, abcdefg, with isoleucine and leucine residues at the a and d sites to ensure dimerization. In addition, to direct staggered assembly of peptides and to foster fibrillogenesissthat is, as opposed to blunt-ended discrete speciessthe terminal quarters of the peptide are cationic and the central half anionic with lysine and glutamate, respectively, at core-flanking e and g positions. This +,-,-,+ arrangement gives the peptide its name, MagicWand (MW). As judged by circular dichroism (CD) spectra, MW assembles to R-helical structures in the sub-micromolar range and above. The thermal unfolding of MW is reversible with a melting temperature>70 °C at 100 µM peptide concentration. Negative-stain transmission electron microscopy (TEM) of MW assemblies reveals stiff, straight, fibrous rods that extended for tens of microns. Moreover, different stains highlight considerable order both perpendicular and parallel to the fiber long axis. The dimensions of these features are consistent with bundles of long, straight coiled R-helical coiled coils with their axes aligned parallel to the long axis of the fibers. The fiber thickening indicates inter-coiled-coil interactions. Mutagenesis of the outer surface of the peptidesi.e., at the b and f
Keyphrases
designed peptide peptide concentration fibrous rod well-understood dimeric r-helical coiled-coil motif melting temperature circular dichroism heptad sequence repeat fiber long axis mw assembly negative-stain transmission electron microscopy basic chassis long axis r-helical structure outer surface straightforward single-peptide design considerable order inter-coiled-coil interaction nano-to-mesoscale fiber leucine residue staggered assembly blunt-ended discrete speciessthe terminal quarter thermal unfolding sub-micromolar range central half remarkable stability different stain
