A team headed by Arizona State University chemistry professors Thomas Moore and Devens Gust has developed a light-powered molecular pump that shuttles calcium ions through a phospholipid membrane calcium ion pumping that resembles various key cellular activities in living organisms, but engineered to be powered by light through specially designed molecules.
The research is reported in the November 28 issue of the journal Nature by Ira M. Bennett, Hebe M. Vanegas Farfano, Federica Bogani, Alex Primak, Paul A. Liddell, Ana L. Moore, Thomas A. Moore and Gust from Arizona State University and Luis Otero, Leonides Sereno and Juana J. Silber from Universidad National de Rio Cuarto in Argentina.
Beginning with an artificial membrane composed of a bilayer of phopholipids (similar to the lipid bilayers that form the membranes of living cells), the team created "shuttle" molecules that were soluble inside the lipid layer of the membrane, but not in the water inside and outside the "cell." These molecules, through the addition or removal of electrons, bind calcium ions at the outside surface of the liposome (these ions are water soluble and not ordinarily able to enter the oily lipid environment of the membrane), take them across the membrane, and release them at the membrane's inner surface. The ions, which cannot remain in the lipid environment, go to the water solution inside the cell, raising its concentration of calcium ions.
The operation is controlled by an "artificial reaction center" molecule (modeled after similar natural molecules used in the biological process of photosynthesis) which is directionally positioned across the membrane and donates and reabsorbs electrons at its opposite ends in re
Contact: James Hathaway
Arizona State University