Theoretical study on gas-phase conformations and isomerization reaction mechanism of cyclic 3′,5′-adenosine monophosphate

The gas-phase conformations and isomerization reaction mechanism of cyclic 3', 5'-adenosine monophosphate (cAMP) have been theoretically investigated at the B3LYP/6-31G** level. It is found that cAMP has four conformations and the rotation isomerization reaction of the base relative to the sugar ring takes place easily. In addition, hydrogen transfer reaction has been investigated at the same level. The results show that the potential energy surface of the associative H shuttling reaction is lowest with the participation of a water molecule to act as a shuttle. So the participation of a water molecule facilitates hydrogen transfer reaction. Our present calculations have rationalized all the possible reaction channels. (C) 2004 Elsevier B.V. All rights reserved.