title: Micelle density regulated by a reversible switch of protein secondary structure.
abstract: Protein secondary structures may exhibit reversible transitions that occur in an abrupt and controllable manner. In this report, we demonstrate that such transitions may be utilized in the design of a "smart" protein micellar system, in which a stimulus-induced change in protein structure triggers a rapid change in micelle compacticity and size. Specifically, recombinant DNA methods were used to prepare a protein triblock copolymer containing a central hydrophilic block and two hydrophobic end blocks derived from elastin-mimetic peptide sequences. Below the copolymer inverse transition temperature (T(t)), dilute solutions of this amphiphilic protein formed monodispersed micelles in a narrow range of R(H) of approximately 100 nm. When the the temperature was raised above T(t), an abrupt increase in micelle internal density was observed with a concomitant reduction in micelle size. This reversible change in micelle compacticity was triggered by helix-to-sheet protein folding transition. Significantly, these protein polymer-based micelles, which are rapidly responsive to environmental stimuli, establish a new mechanism for the design of controlled drug delivery vehicles.
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Rory E
authors.initials: RE
authors.lastname: Sallach
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: Nilanjana
authors.initials: N
authors.lastname: Biswas
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Conticello
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lecommandoux
authors.forename: Richard A
authors.initials: RA
authors.lastname: Dluhy
authors.forename: Elliot L
authors.initials: EL
authors.lastname: Chaikof
mesh_terms: D000595:Amino Acid Sequence; D040761:Biomimetic Materials / Q000737:chemistry; D002942:Circular Dichroism; D004549:Elastin / Q000737:chemistry*; D008027:Light; D008823:Micelles; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D012542:Scattering, Radiation
chemical_list: D008823:Micelles; D010455:Peptides; D011994:Recombinant Proteins; D004549:Elastin