Elastin-Like Polypeptides (ELPs)
A current focus of our efforts in Bioinspired
Materials Engineering is the genetically encoded recombinant
synthesis of artificial elastin-like polypeptides (ELPs),
their biophysical characterization, and their application
in medicine and biotechnology. ELPs are a family of biopolymers
composed of Val-Pro-Gly-Xaa-Gly amino acid repeat units,
found in the structural protein elastin, which undergo a
thermally reversible phase transition. Below a characteristic
inverse transition temperature (Tt), ELPs are
soluble in aqueous solution, but when the temperature is
raised above their Tt, they form micron size
aggregates, which are insoluble in water. This transition
is thermodynamically reversible; when the solution temperature
is lowered to below the Tt, the aggregates completely
redissolve in water.
ELP fusion tags can be viewed as a new
tool in the biomolecular toolbox, which can be easily used
to modulate the properties of a protein of interest for
a specific biomedical application. ELP fusion proteins are
stimuli responsive “smart” proteins whose physico-chemical
and functional properties can be modulated as a function
of the solution environment. In addition to temperature
and ionic strength, other environmental variables that can
used to modulate the inverse transition of ELPs and ELP
fusion proteins include pH, the addition of organic solutes
and solvents, side-chain ionization or chemical modification,
pressure, and light. The outcome of this research, the ability
to rationally and generically modulate the solution and
interfacial properties of proteins is significant, because
proteins are ubiquitous in medicine and biotechnology, as
reagents, therapeutic and diagnostic agents.
