We have constructed (and continue to develop) a laser-based facility for time-resolved fluorescence spectroscopy of biomolecules. This facility provides rapid collection and analysis of luminescence data related to macromolecular size, flexibility, folding and structural fluctuations. This gives us insight into the structure and movements of proteins and membranes. The method is also sensitive enough to study nanogram quantities (100 fold more sensitive than nmr). Our main """"""""time-correlated"""""""" fluorometer was utilized to study the folding and dynamics of many different proteins: interleukin-1-beta, a potent immunomodulator that is drawing interest in AIDS and cancer therapies; vl & v2, cloned fragments of the T-cell receptor """"""""targeted"""""""" by HIV particles; TF3A, a DNA-binding protein whose zinc """"""""fingers"""""""" control transcription; 'HApep', a protein fragment that the influenza virus uses to anchor to and fuse with our cell membranes; thioredoxin, an important cofactor for genetic processing; actin, actobindin and tubulin, structural elements in the """"""""self-assembling scaffolding"""""""" of cells called cytoskeleton; arginase, a metabolic enzyme complex with manganese-controlled """"""""switching"""""""", and several other proteins and membranes.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Intramural Research (Z01)
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National Heart, Lung, and Blood Institute
United States
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Michelman-Ribeiro, Ariel; Mazza, Davide; Rosales, Tilman et al. (2009) Direct measurement of association and dissociation rates of DNA binding in live cells by fluorescence correlation spectroscopy. Biophys J 97:337-46
Rosales, Tilman; Xu, Jianhua; Wu, Xiongwu et al. (2008) Molecular dynamics simulations of perylene and tetracene librations: comparison with femtosecond upconversion data. J Phys Chem A 112:5593-7
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Rosales, Tilman; Georget, Virginie; Malide, Daniela et al. (2007) Quantitative detection of the ligand-dependent interaction between the androgen receptor and the co-activator, Tif2, in live cells using two color, two photon fluorescence cross-correlation spectroscopy. Eur Biophys J 36:153-61
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Xu, Jianhua; Toptygin, Dmitri; Graver, Karen J et al. (2006) Ultrafast fluorescence dynamics of tryptophan in the proteins monellin and IIAGlc. J Am Chem Soc 128:1214-21
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He, Liusheng; Bradrick, Thomas D; Karpova, Tatiana S et al. (2003) Flow cytometric measurement of fluorescence (Forster) resonance energy transfer from cyan fluorescent protein to yellow fluorescent protein using single-laser excitation at 458 nm. Cytometry A 53:39-54
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