Structural basis for photo-induced protein cleavage and green-to-red conversion of fluorescent protein EosFP

doi:10.1073/pnas.0501874102

Structural basis for photo-induced protein cleavage and green-to-red conversion of fluorescent protein EosFP

Departments of ^*Biophysics and ^§General Zoology and Endocrinology, University of Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany; ^†Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801; and ^¶Department of Lead Discovery, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, D-88397 Biberach/Riss, Germany

Edited by Peter G. Wolynes, University of California at San Diego, La Jolla, CA, and approved May 18, 2005 (received for review March 8, 2005)

Abstract

Genetically encoded fusion constructs derived from fluorescent proteins (FPs) can be designed to report on a multitude of events and signals in cells, tissues, and entire organs without interfering with the complex machinery of life. EosFP is a novel FP from the scleractinian coral Lobophyllia hemprichii that switches its fluorescence emission from green (516 nm) to red (581 nm) upon irradiation with ≈400-nm light. This property enables localized tagging of proteins and thus provides a valuable tool for tracking protein movements within live cells. Here, we present the x-ray structures of the green and red forms of WT EosFP. They reveal that formation of the red chromophore is associated with cleavage of the peptide backbone, with surprisingly little change elsewhere in the structure, and provide insights into the mechanism that generates this interesting posttranslational polypeptide modification.

Footnotes

↵ ‡ To whom correspondence should be addressed. E-mail: uli{at}uiuc.edu.
Author contributions: K.N. and G.U.N. designed research; K.N., G.U.N., and H.N. performed research; K.N., G.U.N., and J.W. contributed new reagents/analytic tools; H.N. analyzed data; and K.N., G.U.N., and H.N. wrote the paper.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviation: FP, fluorescent protein.
Data deposition: The atomic coordinates and structure factors have been deposited in the Protein Data Bank, www.pdb.org (PDB ID codes 2BTJ and 1ZUX).