Research Topics - Nanoengineering
Molecular modeling provides nanoscale images at atomic and even electronic resolution, predicts the nanoscale interaction of yet unfamiliar combinations of biological and inorganic materials, and can evaluate strategies for redesigning biopolymers for nanotechnological uses. The methodology's value has been reviewed for three uses in bionanotechnology. The first involves the use of single-walled carbon nanotubes as biomedical sensors where a computationally efficient, yet accurate description of the influence of biomolecules on nanotube electronic properties and a description of nanotube - biomolecule interactions were developed; this development furnishes the ability to test nanotube electronic properties in realistic biological environments. The second case study involves the use of nanopores manufactured into electronic nanodevices based on silicon compounds for single molecule electrical recording, in particular, for DNA sequencing. Here, modeling combining classical molecular dynamics, material science, and device physics, describes the interaction of biopolymers, e.g., DNA, with silicon nitrate and silicon oxide pores, furnishes accurate dynamic images of pore translocation processes, and predicts signals. The third case involves the development of nanoscale lipid bilayers for the study of embedded membrane proteins and cholesterol. Molecular modeling tested scaffold proteins, redesigned lipoproteins found in mammalian plasma that hold the discoidal membranes in shape, and predicted the assembly as well as final structure of the nanodiscs. In entirely new technological areas like bionanotechnology qualitative concepts, pictures, and suggestions are sorely needed; the three exemplary applications document that molecular modeling can serve a critical role for the new bionanotechnology, even though it may still fall short on quantitative precision.
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High-density lipoproteins (HDL), often called "good cholesterol", are protein-lipid particles which circulate in the blood collecting cholesterol from peripheral tissues and transporting them to the liver for degradation. Native HDL are heterogeneous particles which exhibit a variety of shapes and sizes, thus making structural studies of the major protein component apolipoprotein A-I (apo A-I) difficult. However, nanodiscs which are reconstituted discoidal HDL mimics being developed as platforms in which to embed membrane proteins, can be assembled into homogeneous particles. Thus, we utilized the extensive characterization of nanodiscs in furthering our understanding of the structure of apo A-I as well as the assembly of lipoprotein particles. Whereas, the structure of lipoprotein particles can be studied using all-atom molecular dynamics, the long time scales needed for assembly simulations required the development of a coarse grained protein-lipid model.
Papers
The role of molecular modeling in bionanotechnology. Deyu Lu, Aleksei Aksimentiev, Amy Y. Shih, Eduardo Cruz-Chu, Peter L. Freddolino, Anton Arkhipov, and Klaus Schulten. Physical Biology, 3:S40-S53, 2006.
Beyond the gene chip. J. B. Heng, A. Aksimentiev, C. Ho, V. Dimitrov, T. Sorsch, J. Miner, W. Mansfield, K. Schulten, and G. Timp. Bell Labs Technical Journal, 10:5-22, 2005.
Simulation of the electric response of DNA translocation through a semiconductor nanopore-capacitor. Maria E. Gracheva, Anlin Xiong, Jean-Pierre Leburton, Aleksei Aksimentiev, Klaus Schulten, and Gregory Timp. Nanotechnology, 17:622-633, 2006.
Stretching DNA using an electric field in a synthetic nanopore. J. B Heng, A. Aksimentiev, C. Ho, P. Marks, Y. V. Grinkova, S. Sligar, K. Schulten, and G. Timp. Nano Letters, 5:1883-1888, 2005.
Microscopic kinetics of DNA translocation through synthetic nanopores. Aleksij Aksimentiev, Jiunn Benjamin Heng, Gregory Timp, and Klaus Schulten. Biophysical Journal, 87:2086-2097, 2004.
Sizing DNA using a nanometer-diameter pore. J. B. Heng, C. Ho, T. Kim, R. Timp, A. Aksimentiev, Y. V. Grinkova, S. Sligar, K. Schulten, and G. Timp. Biophysical Journal, 87:2905-2911, 2004.
Ion-nanotube terahertz oscillator. Deyu Lu, Yan Li, Umberto Ravaioli, and Klaus Schulten. Physical Review Letters, 95:246801, 2005.
Empirical nanotube model for biological applications. Deyu Lu, Yan Li, Umberto Ravaioli, and Klaus Schulten. Journal of Physical Chemistry B, 109:11461-11467, 2005.
Screening of water dipoles inside finite-length armchair carbon nanotubes. Yan Li, Deyu Lu, Slava V. Rotkin, Klaus Schulten, and Umberto Ravaioli. Journal of Computational Electronics, 4:161-165, 2005.
Coarse grained protein-lipid model with application to lipoprotein particles. Amy Y. Shih, Anton Arkhipov, Peter L. Freddolino, and Klaus Schulten. Journal of Physical Chemistry B, 110:3674-3684, 2006.
Finding gas diffusion pathways in proteins: Application to O2 and H2 transport in CpI [FeFe]-hydrogenase and the role of packing defects. Jordi Cohen, Kwiseon Kim, Paul King, Michael Seibert, and Klaus Schulten. Structure, 13:1321-1329, 2005.
Approaches to developing biological H2-photoproducing organisms and processes. Maria L. Ghirardi, Paul W. King, Matthew C. Posewitz, Pin Ching Maness, Alexander Fedorov, Kwiseon Kim, Jordi Cohen, Klaus Schulten, and Michael Seibert. Biochemical Society Transactions, 33:70-72, 2005.
Molecular dynamics and experimental investigation of H2 and O2 diffusion in [Fe]-hydrogenase. Jordi Cohen, Kwiseon Kim, Matthew Posewitz, Maria L. Ghirardi, Klaus Schulten, Michael Seibert, and Paul King. Biochemical Society Transactions, 33:80-82, 2005.
Genetically engineered gold-binding polypeptides: Structure prediction and molecular dynamics. Rosemary Braun, Mehmet Sarikaya, and Klaus Schulten. Journal of Biomaterials Science, 13:747-758, 2002.