Michael Knoblauch's Proposal
Molecular Structure and Interaction of Forisome Filaments
EMSL Project ID
25612
Abstract
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 disadvantageous. Protein bodies from sieve elements of higher plants which we called forisomes provide a unique and novel example. Sieve elements form microfluidics systems for pressure-driven transport of photoassimilates throughout the plant. Forisomes, which consist of co aligned fibrils, act as cellular stopcocks in the sieve elements of legumes, by undergoing Ca2+ regulated conformational switches which let them reversibly plug the sieve element. Isolated forisomes contract anisotropically in response to divalent cations like Ca2+ or to pH without requirement for a source of chemical energy such as ATP. The response is fully reversible; similar mechanical forces are exerted in contraction and expansion. Diffusional electrotitration allows electric control of forisome contraction and bending. Forisomes can be isolated in large numbers and remain functional after prolonged periods of storage. This unique combination of useful properties renders forisomes a paradigmatic model for protein-based biomimetic nano- and micro-actuators. Here we propose to use high resolution Cryo Transmission Electron Microscopy and Field Emission Gun-Environmental Scanning Electron Microscopy to gain high resolution ultrastructural and tomographical information on forisome structure in various conformational states. This information combined with our molecular and biophysical results will provide crucial insights into the molecular mechanisms involved in forisome contraction.
Appropriate equipment to address these questions is not available at Washington State University.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-08-01
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members