Abstract:
The attachment complex of an adenovirus to the cellular receptor CD46 has been
studied by quantum chemical ab-initio methods. Here, the focus is on the
comparison of the types Ad11 and Ad7, which show considerable differences in
their binding capability towards CD46 in spite of great structural similarity.
Based on previous mutation experiments, the theoretical studies shown here
allow more detailed insights into the molecular properties of the protein
complex, thereby giving an independent confirmation of an explanation
originally motivated by experimental findings. The computational insights are
achieved by calculating single residue contributions to the binding energy of
the complex, which enable the reliable assessment of the impact of point
mutations. The decisive charge influences of the protein environment are
included by treating the entire complex in a combined quantum
chemical/molecular mechanical hybrid approach. Thereby, QM regions of more than
1000 atoms are treated using linear scaling quantum chemical methods.
Another focus is on the testing of novel SCF methods that allow for a linear
scaling with system size for all sub-steps by circumventing the conventional
diagonalisation step.