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Nano Lett. 2014 Nov 12;14(11):6590-8. doi: 10.1021/nl503221p. Epub 2014 Oct 2.

Noncanonical self-assembly of highly asymmetric genetically encoded polypeptide amphiphiles into cylindrical micelles.

Author information

1
Department of Biomedical Engineering and Research Triangle MRSEC, Duke University , Durham, North Carolina 27708, United States.

Abstract

Elastin-like polypeptides (ELPs) are a class of biopolymers consisting of the pentameric repeat (VPGαG)n based on the sequence of mammalian tropoelastin that display a thermally induced soluble-to-insoluble phase transition in aqueous solution. We have discovered a remarkably simple approach to driving the spontaneous self-assembly of high molecular weight ELPs into nanostructures by genetically fusing a short 1.5 kDa (XGy)z assembly domain to one end of the ELP. Classical theories of self-assembly based on the geometric mass balance of hydrophilic and hydrophobic block copolymers suggest that these highly asymmetric polypeptides should form spherical micelles. Surprisingly, when sufficiently hydrophobic amino acids (X) are presented in a periodic sequence such as (FGG)8 or (YG)8, these highly asymmetric polypeptides self-assemble into cylindrical micelles whose length can be tuned by the sequence of the morphogenic tag. These nanostructures were characterized by light scattering, tunable resistive pulse sensing, fluorescence spectrophotometry, and thermal turbidimetry, as well as by cryogenic transmission electron microscopy (cryo-TEM) and small-angle neutron scattering (SANS). These short assembly domains provide a facile strategy to control the size, shape, and stability of stimuli responsive polypeptide nanostructures.

KEYWORDS:

Self-assembly; biomaterials; cryo-TEM; elastin-like polypeptides; protein polymers; small-angle neutron scattering

PMID:
25268037
PMCID:
PMC4246002
DOI:
10.1021/nl503221p
[Indexed for MEDLINE]
Free PMC Article

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