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DsRed-Monomer fluorescent protein |
Green fluorescent proteins have been used to great effect in biological
research as reporters of gene expression or to indicate the presence of
particular cells in living organisms. However, the low
penetration of green light in biological tissue has meant that
application of GFPs has been limited to studies in smaller cell cultures.
Red light
has a higher penetration in living tissue,
so red fluorescent proteins (RFPs) hold great promise
for in vivo imaging studies of larger samples.
The application of RFPs is quite often hampered by a low quantum yield. Seth Olsen of CCMS at UQ has been modelling the chromophore of the red fluorescent protein Rtms5H146S in order to determine which variants of the chromophore have a higher level of fluorescence. Once found, these brighter RFPs are useful in deep-tissue biomedical imaging, allowing visualization of processes in living organisms.
Using computational chemistry packages such as Gaussian 03 and NWChem on QCIF and APAC supercomputers, Dr Olsen and his team have been able to calculate the excitation energies of variants of the chromophore found in RFP. Dr Olsen is now working on building a quantum mechanical model for the chromophore, and hopes to carry out molecular dynamics and quantum mechanical calculations by the end of the year. He is also planning on carrying out all electron calculations, in collaboration with AIST in Japan.
Contacts
Dr Seth Olsen,
Prof. Sean Smith and colleagues
Centre for Computational Molecular Science,
University of Queensland
Publications
P.G. Wilman et. al., 'The 2.1 A Crystal Structure of the Far-Red fluorescent protein HcRed: Inherent Conformational Flexibility of the Chromophore', J. Mol. Bio. 349 (2005) 223.
S. Olsen et. al., 'Determination of the chromophore charge states in the low pH color transition of the fluorescent protein Rtms5(H146S) via time-dependent DFT', Chem. Phys. Lett. 420 (2006) 507.
Written by T. Curtis, July 2006.