Active transport of Ca2+ by an artificial photosynthetic membrane

Ira M. Bennett, Hebe M. Vanegas Farfano, Federica Bogani, Alex Primak, Paul A. Liddell, Luis Otero, Leonides Sereno, Juana J. Silber, Ana L. Moore, Thomas A. Moore and Devens Gust ()
Additional contact information
Ira M. Bennett: Arizona State University
Hebe M. Vanegas Farfano: Arizona State University
Federica Bogani: Arizona State University
Alex Primak: Arizona State University
Paul A. Liddell: Arizona State University
Luis Otero: Universidad National de Río Cuarto
Leonides Sereno: Universidad National de Río Cuarto
Juana J. Silber: Universidad National de Río Cuarto
Ana L. Moore: Arizona State University
Thomas A. Moore: Arizona State University
Devens Gust: Arizona State University

Nature, 2002, vol. 420, issue 6914, 398-401

Abstract: Abstract Transport of calcium ions across membranes and against a thermodynamic gradient is essential to many biological processes, including muscle contraction, the citric acid cycle, glycogen metabolism, release of neurotransmitters, vision, biological signal transduction and immune response. Synthetic systems that transport metal ions across lipid or liquid membranes are well known1,2,3,4,5,6, and in some cases light has been used to facilitate transport7. Typically, a carrier molecule located in a symmetric membrane binds the ion from aqueous solution on one side and releases it on the other. The thermodynamic driving force is provided by an ion concentration difference between the two aqueous solutions, coupling to such a gradient in an auxiliary species, or photomodulation of the carrier by an asymmetric photon flux7. Here we report a different approach, in which active transport is driven not by concentration gradients, but by light-induced electron transfer in a photoactive molecule that is asymmetrically disposed across a lipid bilayer. The system comprises a synthetic, light-driven transmembrane Ca2+ pump based on a redox-sensitive, lipophilic Ca2+-binding shuttle molecule whose function is powered by an intramembrane artificial photosynthetic reaction centre. The resulting structure transports calcium ions across the bilayer of a liposome to develop both a calcium ion concentration gradient and a membrane potential, expanding Mitchell's concept of a redox loop mechanism for protons8 to include divalent cations. Although the quantum yield is relatively low (∼1 per cent), the Ca2+ electrochemical potential developed is significant.

Date: 2002
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/nature01209 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:420:y:2002:i:6914:d:10.1038_nature01209

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/nature01209

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().