BIOL 85 |
| The understanding and control of protein adsorption to material surfaces has been, and continues to be, a major subject of research in the field of biomaterials because of its governing role for cellular response to implants and substrates for tissue engineering and regenerative medicine. The simulation of protein adsorption behavior is unique in that it requires the representation of three phases simultaneously: solid phase, liquid phase, and their interface. Class-I force fields, such as CHARMM, AMBER, and OPLS, have been parameterized and validated over the past 30 years primarily to accurately represent protein behavior in solution; however, they are often not suitable for the simulation of solid-phase materials. On the other hand, Class II force fields, such as CFF (Consistent Force Field), PCFF (Polymer CFF), and COMPASS (Condensed-Phase Optimized Molecular Potentials for Atomistic Simulation Studies), use a more complex functional form and have been suitably developed for solid-phase behavior, but are generally not suitable for proteins in solution. This becomes problematic when both a protein solution and solid phase need to be represented in the same simulation. Thus, specially designed molecular simulation methods need to be developed to deal with multiphase systems. Here we present an extension of CHARMM so as to enable it to employ two different force fields (Class-I and Class-II) for a solid-liquid multiphase simulation. The interactions between the two force fields are calibrated at the solid-liquid interface with various sample systems and experimental data for peptide adsorption on self-assembled monolayer (SAM) surfaces with different functionality. We shall present the modifications in the CHARMM code and results exhibiting the usefulness of this dual force field approach for calculating the change in free energy when a peptide interacts with a functionalized solid surface. |
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Frontiers in Chemical Biology
5:00 PM-7:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Biological Chemistry |