MARCKS, A MAJOR PROTEIN-KINASE-C SUBSTRATE, ASSUMES NON-HELICAL CONFORMATIONS BOTH IN SOLUTION AND IN COMPLEX WITH CA2-CALMODULIN()

MARCKS, a major cellular substrate for protein kinase C, plays importa nt roles in various cellular functions and its functions are regulated by calmodulin, We have studied the conformational properties of recom binant human MARCKS in solution and in complex with calmodulin, Circul ar dichroism (CD) spectra showed a high content of random coil in phys iological solution, When MARCKS or MARCKS-derived calmodulin-binding p eptide was complexed with Ca2+-calmodulin, little change was observed in the CD spectra, suggesting that MARCKS binds with calmodulin in a n on-helical conformation, which is unique among the calmodulin-binding proteins. (C) 1998 Federation of European Biochemical Societies.