Ultrafast and low-barrier motions in the photoreactions of the green fluorescent protein

Jasper J. van Thor; Michael Towrie; Kate Ronayne; Georgi Y. Georgiev; J. Timothy Sage

doi:10.1117/12.651278

23 February 2006 Ultrafast and low-barrier motions in the photoreactions of the green fluorescent protein

Jasper J. van Thor, Michael Towrie, Kate Ronayne, Georgi Y. Georgiev, J. Timothy Sage

Proceedings Volume 6098, Genetically Engineered Probes for Biomedical Applications; 609806 (2006) https://doi.org/10.1117/12.651278
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

Green fluorescent protein (GFP) is highly fluorescent with blue excitation despite the creation of a buried charge resulting from photoionization of the chromophore and neutralization of Glu 222. These major electrostatic rearrangements do not lead to rapid internal conversion processes. A competing phototransformation reaction, which ionizes the chromophore and decarboxylates Glu 222, causes electrostatic and structural changes which are very similar to those in the fluorescence photocycle. The X-ray crystallography and IR spectroscopy of phototransformed GFP provides evidence for relaxations involving protein, chromophore, solvent, and CO₂. Time-resolved and static infrared spectroscopy and X-ray crystallography to 1.85 Å resolution identify structural mechanisms common to phototransformation and to the fluorescence photocycle. A detailed study of the ps time-resolved IR absorption during the fluorescence photocycle has been reported. Through global fitting the species associated difference spectra were determined showing the vibrational response to excited state proton transfer in addition to the transient population of a late ground state photocycle intermediate 'I₂'. We additionally used pump-dump-probe spectroscopy to dump the deprotonated radiative state 'I*' and directly provide the I₂-I* difference spectrum, which strongly resembled its photocycle counterpart. We discuss spectral markers that specifically report on structural relaxation during the photocycle which may be compared with structural relaxations in the competing phototransformation reaction.

Citation Download Citation

Jasper J. van Thor, Michael Towrie, Kate Ronayne, Georgi Y. Georgiev, and J. Timothy Sage "Ultrafast and low-barrier motions in the photoreactions of the green fluorescent protein", Proc. SPIE 6098, Genetically Engineered Probes for Biomedical Applications, 609806 (23 February 2006); https://doi.org/10.1117/12.651278

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Green fluorescent protein

Chromophores

Picosecond phenomena

Absorption

Luminescence

Spectroscopy

X-rays

Show All Keywords

Keywords/Phrases

Search In:

Publication Years