Cited by 926
Peking University
Publishes on Spectroscopy Techniques in Biomedical and Chemical Research, Photosynthetic Processes and Mechanisms, Advanced Fluorescence Microscopy Techniques. 30 papers and 1.2k citations.
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Recent advances in single-molecule enzymology are reviewed. The theoretical underpinning of sincle-molecule enzymatic behaviors is discussed and exemplified by experiements and statistical analyses. In particular, the manifestations of the Michaelis-Menten mechanism, the kinetic scheme with sequential intermediates, and dynamic disorder in single molecule data are presented. A survey of current methods for single molecule enzymatic assays, especially those based on fluorescence detection, is presented as well.
We report coherent anti-Stokes Raman scattering correlation spectroscopy (CARS-CS) that measures the fluctuation of the CARS signal from scatterers in a subfemtoliter excitation volume. This method probes dynamical processes with chemical selectivity based on vibration spectroscopy. High-sensitivity CARS-CS measurements are carried out with epi-detection or polarization-sensitive detection. Theoretical expressions of CARS intensity autocorrelation functions are derived and supported by experimental data. The properties of CARS-CS are characterized with measurements of diffusion dynamics of small polystyrene spheres.
Recent single-molecule measurements have revealed the DNA allostery in protein/DNA binding. MD simulations showed that this allosteric effect is associated with the deformation properties of DNA. In this study, we used MD simulations to further investigate the mechanism of DNA structural correlation, its dependence on DNA sequence, and the chemical modification of the bases. Besides a random sequence, poly d(AT) and poly d(GC) are also used as simpler model systems, which show the different bending and twisting flexibilities. The base-stacking interactions and the methyl group on the 5-carbon site of thymine causes local structures and flexibility to be very different for the two model systems, which further lead to obviously different tendencies of the conformational deformations, including the long-range allosteric effects.
C-phycocyanin (CPC) and Allophycocyanin (APC) are pigment-protein complexes isolated from antenna systems in cyanobacteria. The crystal structure of CPC has recently been solved and APC has a similar structure. CPC and APC have a trimeric structure, monomeric subunits are composed of an (alpha) and (beta) polypeptide chain, each has a tetrapyrrole chromophore chemically bound to position 84. In CPC and APC trimers, the (alpha) 84 and (beta) 84 chromophores in adjacent monomers are in close proximity, forming relatively strong coupled pairs. Calculation of pairwise energy transfer rates using Foerster theory has suggested an extremely fast transfer (> 1 ps<SUP>-1</SUP>) between the (alpha) 84 and (beta) 84 pair in CPC. A femtosecond fluorescence up-conversion apparatus was constructed which achieves subhundred femtosecond time resolution. This allows experimental observation of the fast energy transfer process between the (alpha) 84 and (beta) 84 pair in both CPC and APC. There was also a wavelength dependence of the fluorescence depolarization kinetics which is inconsistent with Foerster inductive resonance energy transfer theory.