NTU Undergraduates' research April 2014 - Biosciences | 页面 23

The Effects of 2’,5’-ADP Binding on the Folding Stability in Wild Type
Cytochrome P450 Reductase- Temperature Dependence Studies

Omar Aziz
Interdisciplinary Biomedical Research Centre, School of Science and Technology, Clifton
Campus, Nottingham Trent University, Nottingham, NG11 8NS.
Summer 2014

ABSTRACT: The stabilising effects of the binding of ligand 2’,5’-ADP upon Cytochrome
P450 reductase (CPR) was studied through cytochrome C reduction assays undertaken at 3
different temperatures. In doing so, the rate of thermal inactivation (K) was determined for
thermal incubation of CPR both with and without the presence of the ligand at 37°C, 45°C
and 55°C. The main findings showed that the binding of 2’,5’-ADP to reduced-cytochrome
P450 reductase caused a conformational change in CPR structure shifting the equilibrium of
the protein towards its closed conformation. This was reflected in the K values which showed
a decrease in rate of thermal inactivation for each temperature condition when in the presence
of the ligand 2’,5’-ADP as opposed to wild-type CPR alone. So it can be stated that at higher
temperatures CPR shows a lower rate of thermal stability than when in the presence of 2’,5’ADP as observed for all conditions tested.