3 research outputs found
Calcium Binding Peptide Motifs from Calmodulin Confer Divalent Ion Selectivity to Elastin-Like Polypeptides
Calcium-sensitive elastin-like polypeptides
(CELPs) were synthesized
by periodically interspersing a calcium-binding peptide sequence from
calmodulin within an elastin-like polypeptide (ELP) with the goal
of creating thermal and calcium responsive peptide polymers. The CELPs
exhibit high sensitivity to calcium compared to monovalent cations
but do not exhibit the exquisite selectivity for calcium over other
divalent cations, such as magnesium, that is displayed by calmodulin.
The CELPs were further used as a building block for the synthesis
of calcium-sensitive nanoparticles by fusing a hydrophilic, noncalcium-sensitive
ELP block with a CELP block that becomes more hydrophobic upon calcium
binding. We show that addition of calcium at concentrations between
50 and 500 mM imparts sufficient amphiphilicity to the diblock polypeptide
between 33 and 46 °C to trigger its self-assembly into monodisperse
spherical micelles with a hydrodynamic radius of ∼50 nm