The ABCB1-dependent ATPase activity stimulated by nitensidine A was greatly reduced by substituting sulfur (S) or oxygen (0) for the imino nitrogen atom (N) in nitensidine A.
To gain more insight into which structural features of nitensidine A contribute to its ability to serve as a substrate for ABCB1, the role of the imino nitrogen atom was examined with a focus on its biological activities.
The role of the imino nitrogen atom was also examined with a focus on its chemical features to gain more insight into which structural features of nitensidine A contribute to its ability to behave as a substrate for ABCB1.
The substitution in the imino nitrogen atom has been shown to change the optimal conformation of each analog.
The number, binding site, and polymerization degree of the isoprenyl moiety and the imino nitrogen atom in the guanidine alkaloids cooperatively determine the levels required to stimulate ABCB1-dependent ATPase activity
In contrast, their conformations are quite different as shown by their optimal conformations calculated in the presence of the electron, indicating that the electrons on the imino nitrogen atom in nitensidine A play a crucial role in determining its conformation and its affinity for ABCB1.