Help Privacy Policy Disclaimer
  Advanced SearchBrowse




Journal Article

Resonance energy transfer in a calcium concentration-dependent cameleon protein


Subramaniam,  V.
Department of Molecular Biology, MPI for biophysical chemistry, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)

(Publisher version), 258KB

Supplementary Material (public)
There is no public supplementary material available

Habuchi, S., Cotlet, M., Hofkens, J., Dirix, G., Michiels, J., Vanderleyden, J., et al. (2002). Resonance energy transfer in a calcium concentration-dependent cameleon protein. Biophysical Journal, 83(6), 3499-3506. Retrieved from http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B94RW-4V466WB-1V-1&_cdi=56421&_user=38661&_pii=S0006349502753496&_orig=search&_coverDate=12%2F31%2F2002&_sk=999169993&view=c&wchp=dGLbVlW-zSkWA&md5=7689621a4a2332505e2382f52eee0115&ie=/sdarticle.pdf.

Cite as: http://hdl.handle.net/11858/00-001M-0000-0012-F26B-8
We report investigations of resonance energy transfer in the green fluorescent protein and calmodulin-based fluorescent indicator constructs for Ca2+ called cameleons using steady- state and time-resolved spectroscopy of the full construct and of the component green fluorescent protein mutants, namely ECFP (donor) and EYFP (acceptor). EYFP displays a complicated photophysical behavior including protonated and deprotonated species involved in an excited-state proton transfer. When EYFP is excited in the absorption band of the protonated species, a fast nonradiative deactivation occurs involving almost 97% of the excited protonated population and leading to a low efficiency of excited-state proton transfer to the deprotonated species. ECFP displays a multiexponential fluorescence decay with a major contributing component of 3.2 ns. The time- resolved fluorescence data obtained upon excitation at 420 nm of Ca2+-free and Ca2+-bound YC3.1 cameleon constructs point to the existence of different conformations of calmodulin dependent on Ca2+ binding. Whereas steady-state data show only an increase in the efficiency of energy transfer upon Ca2+ binding, the time-resolved data demonstrate the existence of three distinct conformations/populations within the investigated sample. Although the mechanism of the interconversion between the different conformations and the extent of interconversion are still unclear, the time-resolved fluorescence data offer an estimation of the rate constants, of the efficiency of the energy transfer, and of the donor- acceptor distances in the Ca2+-free and Ca2+-bound YC3.1 samples.