ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The dynamics of activated rotations of a tyrosine ring inside the bovine pancreatic trypsin inhibitor have been studied by computer simulation. The simulation method consists of two parts. In the first part, typical transition-state configurations of the protein atoms are prepared. In the second part, the classical equations of motion for the protein atoms are solved to yield trajectories which pass through these transition-state configurations. Analysis of the trajectories shows that the ring is driven over the rotational potential barrier by nearly impulsive collisions with atoms of the surrounding protein matrix. The collisions are similar to those that occur while the ring oscillates about its equilibrium orientation. The frequency and strength of the collisions are such that transition-state theory is approximately valid for this simple reaction. The enthalpy of activation is substantially reduced by bond-angle deformations which occur rapidly on the time scale of the barrier crossing. Small, transient packing defects in the protein appear to play a role in initiating the ring rotation.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1980.360190712
