This preview shows page 1. Sign up to view the full content.
Unformatted text preview: To completely optimize the molecule required 79 cycles, or a total of 263 days of computing!
How good was the calculation? Figure 2, taken from the article, shows the heavy-atom framework from the
calculation and from the X-ray crystal structure. The agreement is remarkable considering that the calculation was
performed in the gas phase and was compared to the solid-state crystal structure. 2 Figure 2. Comparison of heavy atom framework from Hartree-Fock geometry optimization and Xray crystal structure of crambin [from C. Van Alsenoy, C.-H. Yu, A. Peeters, J. M. L. Martin, and L.
Schafer, J. Phys. Chem. A 1 998, 1 02, 2246.] Some examples of the agreement between the calculated and X-ray geometrical parameters are the RMS deviation in
N-C(α) bond lengths is 0.013 Å, while the RMS deviation in N-C(α)-C´ bond angles is 1.5º.
Active S ite M odels
While molecular orbital calculations of proteins like crambin can now be carried out, it is still prohibitively
expensive in terms of CPU time to d...
View Full Document
This document was uploaded on 03/04/2014 for the course CHEM 380.37 at Illinois State.
- Fall '13