Calcium negatively regulates an intramolecular interaction between the N-terminal recoverin homology and EF-hand motif domains and the C-terminal C1 and catalytic domains of diacylglycerol kinase α

► We revealed the intramolecular interaction of DGKα. ► The EF-hand-containing N-terminal region of DGKα binds to the C-terminal region. ► The intramolecular interaction was negatively regulated by Ca2+. ► Ca2+ induced a decrease in the α-helical content of the EF-hand-containing region.