Endogenous polyamines, represented by putrescine, spermidine, and spermine, are known to exert their physiological functions by interacting with polyanionic biomolecules such as DNA, RNA, adenosine triphosphate (ATP), and phospholipids. Very few examples of conformation analysis have been reported for these highly flexible polymethylene compounds, mainly due to the lack of appropriate methodologies. To understand the molecular basis of the weak interaction between polyamines and polyanions that underlies their physiological functions, we aimed to elucidate the solution conformation of spermidine by using diastereospecifically deuterated and (13)C-labeled derivatives (1-7), which were designed to diagnose the orientation of seven conformationally relevant bonds in spermidine. (1)H-(1)H and (13)C-(1)H NMR coupling constants ((3)J(H,H) and (3)J(C,H)) were successfully determined for a spermidine-ATP complex. The relevant coupling constants markedly decreased upon complexation. The results reveal that spermidine, when interacting with ATP, undergoes changes that make the conformation more bent and forms the complex with the triphosphate part of ATP in an orientation-sensitive manner.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.