Dr. Chen, Hsin-Lung
Institution
Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
Presentation day
wednesday 10:20 AM
TITLE
Structure of DNA-dendrimer complexes and its implication on DNA-histone interaction in nucleosome
Abstract
Using small angle X-ray scattering (SAXS), here we show that the electrostatic attraction
between DNA and polyamidoamine (PAMAM) dendrimer of generation six (G6), which is geometrically
similar to histone, led to the formation of beads-on-string structure, where DNA wrapped around the
spherical dendrimer macrocations to yield the “chromatin-like fiber” composing of the interconnected
“nucleosome-like particles”. A “wormlike chromatin-like fiber model” was introduced to obtain the theoretical
scattering patterns closely resembling the experimentally observed ones, from which the pitch length of the
DNA superhelix wrapping around the dendrimer and the interparticle distance of the nucleosome-like
particles were deduced. The pitch length (ca. 3 nm) was similar to that associated with the nucleosome;
however, the wrapping of DNA around the dendrimer was not tight, but showed obvious fluctuations of the
superhelix radius. The interparticle distance in the chromatin-like fiber was close to that of the dendrimer
diameter, indicating that the linker DNA was very short. On the other hand, the SAXS profile in the
intermediate to high q region of the nucleosome array in aqueous solution was fitted very well by the form
factor of the mono-nucleosome particle based on the rigid crystal structure model. This means that the
fluctuation of the beads-on-string structure of nucleosome was strongly suppressed and the linker DNA was
long. The comparison between the structure features of the dendriplex and those of the nucleosome
revealed that the attraction free energy arising from the electrostatic interaction energy and the counterion
entropy was not sufficient to stabilize the beads-on-string structure and regulate the length of linker DNA in
chromatin. Additional binding forces and regulation factors are hence involved in creating the chromatin
structure in vivo.
CV
Education
1994 Ph.D. in Polymer Science and Engineering, University of Massachusetts Amherst, U.S.A.
Thesis Advisor: Professor Roger S. Porter
1990 M.S. in Polymer Science and Engineering, University of Massachusetts at Amherst, U.S.A..
1988 Diploma in Chemical Engineering, Ming-Chi Institute of Technology, Taipei, Taiwan
Work Experience
2008-present Tsing Hua Chair Professor, National Tsing Hua University, Taiwan
2010-present Chairman, Department of Chemical Engineering, National Tsing Hua Unversity
2001-present Professor, Department of Chemical Engineering, National Tsing Hua University, Taiwan.
2006-2008 Tsing Hua Distinguished Professor, National Tsing Hua University, Taiwan
2001.6-2001.9 Visiting Professor, Department of Polymer Chemistry, Kyoto University, Japan.
1997-2001 Associate Professor, Department of Chemical Engineering, National Tsing Hua University, Taiwan.
1995-1997 Associate Professor, Department of Chemical Engineering, Chang Gung University, Taiwan
Other Academic Appointments
1998-present Associate Editor, Journal of Polymer Research
2008-present Editorial board member, The Open Macromolecules Journal
2006-2008 Coordinator, Polymer Science and Engineering Program, National Science Council, Taiwan
2006-2008 Coordinator, Interdisciplinary Projects on Flexible Electronics, National Science Council, Taiwan 2
2007 Chair of the Technical Program Committee, International Symposium on Flexible Electronics and Displays
2007 Principal Guest Editor of the Journal of Display Technology for a special issue on Flexible Electronics and Displays
2006-2008 Member of the User Executive Committee (UEC), National Synchrotron Radiation Research Center, Taiwan
2004-2006 Member of the Proposal Evaluation Committee (PEC), National Synchrotron Radiation Research Center, Taiwan
Academic Honors
1998 Young Faculty Research Award, National Tsing Hua University
1999 Outstanding Teacher Award, National Tsing Hua University
2000 Best Paper Award, The Polymer Society, Taipei
2001 Outstanding Research Award, National Science Council
2002 Ta-Yu Wu Memorial Award, National Science Council
2002 Outstanding Teacher Award, National Tsing Hua University
2003 Outstanding Research Award, National Science Council
2004 Best Paper Award, The Polymer Society, Taipei
2006 Appointed as the Tsing Hua Distinguished Professor
2008 Outstanding Teacher Award, National Tsing Hua University
2008 Appointed as the Tsing Hua Chair Professor
2010 Outstanding Academic Polymer Research Award, The Society of Polymer, Taipei
2008-2011 Recipient of the grant of “Outstanding Scholar Project” from the National Science Council, Taiwan
2011 Outstanding Research Award, National Science Council
2011 Distinguished Alumnus, Ming-Chi University of Technology
Literatures
1. H.-L. Chen and R. S. Porter*, “Phase and Crystallization Behavior of Solution-Blended Poly(ether ether ketone) and Poly(ether imide), Polym. Eng. Sci., 32, 1870 (1992).
2. H.-L. Chen and R. S. Porter,*”Melting behavior of Poly(ether ether ketone) in Its Blends with Poly(ether imide), J. Polym. Sci. Polym. Phys. Ed, 31, 1845 (1993).
3. H.-L. Chen and R. S. Porter*,”Observation of Two-Stage Crystallization of Poly(ether ether ketone) by Thermal Mechanical Analysis”, Polymer, 34, 4576 (1993).
4. H.-L. Chen and R. S. Porter*, “Composite of Polyethylene and Kenaf, a Natural Cellulose Fiber”, J. Appl. Polym. Sci , 54, 1781 (1994).
5. H.-L. Chen and R. S. Porter*, ”Uniaxial Draw of Poly(ether ether ketone)/Poly(ether imide) Blends by Solid-State Coextrusion”, Macromolecules, 29, 3918 (1995).
6. H.-L. Chen* ,”Miscibility and Crystallization Behavior of Poly(ethylene terephthalate)/ Poly(ether imide) Blends”, Macromolecules, 28, 2845 (1995).
7. H.-L. Chen* and J. C. Hwang,”Some Comments on the Degree of Crystallinity Defined by the Enthalpy of Melting”, Polymer, 36, 4355 (1995).
8. H.-L. Chen*, J. C. Hwang, and C.-C, Chen,”Multiple Melting and Crystal Annealing of Poly(ethylene terephthalate) in Its Blends with Poly(ether imide)”, Polymer, 37, 5461 (1996).
9. H.-L. Chen*, J.-W. You, and R.S. Porter, ”Intermolecular Interaction and Conformation in Poly (ether ether ketone)/Poly (ether imide) Blends--An Infrared Spectroscopic Investigation”, J. Polym. Res., 3, 151 (1996).
10. H.-L. Chen*, D.-J. Liaw, J.-S. Tsai, J.-S. Shyu, and J.-M. Yang, ”Miscible Blends of Polystyrene and Polycaprolactone with Phenylacetylene-Carbon Monoxide Alternating Copolymer”, Polymer J., 28, 976 (1996)
11. J.-M. Yang, J.-W. You, H.-L. Chen, and C.-H. Shih, ”Calorimetric Characterization of the Formation of Acrylic Type Bone Cements”, J. Biomed. Mat. Res. (Appl. Biomaterials), 33, 83 (1996).
12. H.-L. Chen*, J.C. Hwang, D.-M. Fang, C.-C. Chen, M.-J. Tsai, and R.-C. Wang, ”Phase Behavior of Amorphopus and Semicrystalline Blends of Poly (butylene terephthalate)and Poly (ether imide)”, Polymer, 38, 2747(1997).
13. J. C. Hwang, C.-C. Chen, H.-L. Chen*, and W.C. Ou-Yang, ”Analysis of Two-Stage Crystallization Kinetics for Poly (ethylene terephthanlate)/Poly (ether imide) Blends”, Polymer, 38, 4097(1997).
14. J.-M. Yang, H.-L. Chen*, and J.-W. You, ”Miscibility and Crystallization of Poly (L-lactide)/Poly (ethylene glycol) and Poly(L-lactide)/Polycaprolactone Blends”, Polymer J., 29, 657(1997).
15. J. -M. Yang, J.-S. Shyu, and H.-L. Chen, ”Polymerization of Acrylic Bone Cement Investigated by Differential Scanning Calorimetry: Effect of Heating Rate and TCP Content”, Polym. Eng. Sci., 37, 1182(1997).
16. W.-C. Ou-Yang, L.-J. Li, H.-L. Chen*, and J.C. Hwang, ”Bulk Crystallization Behavior of Polycaprolactone with a Wide Range of Molecular Weight”, Polymer J ., 29, 889(1997).
17. H.-L. Chen*, L.J. Li, W.C. Ou-Yang, J.C. Hwang and W.Y. Wong, “Spherulitic Crystallization of Poly(e-caprolactone) with a Wide Range of Molecular Weight”, Macromolecules, 30, 1718 (1997).
18. H.-L. Chen*, D.J. Liaw, B.Y. Liaw, C.L. Shih and J.S. Tsai, “Compatibility and Crystallization Studies of Poly(phenylene acetylene)/Polycaprolactone Blends, Polym. J ., 30, 874 (1998).
19 H.-L. Chen*, J.C. Hwang and R.C. Wang, “A New Binary System Exhibiting Simultaneous Liquid-Liquid Phase Separation and Crystallization-PEN/Poly(ehter imide) Blends”, Polymer, 39, 6067 (1998).
20. H.-L. Chen*, J.C. Hwang, J.M. Yang, and R.C. Wang, “Simultaneous Liquid-Liquid Phase Separation and Crystallization and Its Effect on the Spherulitic Growth Behavior of Poly (ethylene terephthalate)/Poly(ether imide) Blends”, Polymer, 39, 6983 (1998).