Deeply Inverted Electron-Hole Recombination in a Luminescent Antibody-Stilbene Complex
Erik W. Debler,1,2*
Gunnar F. Kaufmann,2,3,4
Michael M. Meijler,2,3
Andreas Heine,1
Jenny M. Mee,2,3
Goran Pljevalj
i
,1
Angel J. Di Bilio,5
Peter G. Schultz,2,3
David P. Millar,1
Kim D. Janda,2,3,4,6
Ian A. Wilson,1,2
Harry B. Gray,5
Richard A. Lerner1,2,3
The blue-emissive antibody EP2-19G2 that has been elicited against
trans-stilbene has unprecedented ability to produce bright luminescence
and has been used as a biosensor in various applications. We
show that the prolonged luminescence is not stilbene fluorescence.
Instead, the emissive species is a charge-transfer excited complex
of an anionic stilbene and a cationic, parallel
-stacked tryptophan.
Upon charge recombination, this complex generates exceptionally
bright blue light. Complex formation is enabled by a deeply
penetrating ligand-binding pocket, which in turn results from
a noncanonical interface between the two variable domains of
the antibody.
2 The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
3 Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
4 Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
5 Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
6 Worm Institute of Research and Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
* Present address: Laboratory of Cell Biology, The Rockefeller University, New York, NY 10065, USA.
Present address: Department of Chemistry, Ben-Gurion University of the Negev, Israel.
Present address: Institute of Pharmaceutical Chemistry, Philipps-University Marburg, 35032 Marburg, Germany.
To whom correspondence should be addressed. E-mail: rlerner{at}scripps.edu (R.A.L.); hbgray{at}caltech.edu (H.B.G.)
