4 research outputs found
ATP-independent contractile proteins from plants
Emerging technologies are creating increasing interest in smart
materials that may serve as actuators in micro- and nanodevices. Mechanically active polymers currently studied include a
variety of materials. ATP-driven motor proteins,
the actuators of living cells, possess promising
characteristics, but their dependence on strictly
defined chemical environments can be disadvantagous. Natural
proteins that deform reversibly by entropic mechanisms might serve as models
for artificial contractile polypeptides with useful functionality, but they are rare. Protein bodies from sieve
elements of higher plants provide a novel example.
sieve elements form microfluidics systems for pressure-driven transport of
photo-assimilates throughout the plant. Unique protein
bodies in the sieve elements of legumes act as cellular stopcocks, by
undergoing a Ca2+-dependent conformational switch in which they
plug the sieve element. In living cells, this reaction is
probably controlled by Ca2+-transporters in the cell
membrane. Here we report the rapid, reversible, anisotropic
and ATP-independent contractility in these protein bodies in vitro.
Considering the unique biological function of the legume 'crystalloid' protein
bodies and their contractile properties, we suggest to give them the
distinctive name forisome ('gate-body'; from the Latin foris, the wing
of a gate)