Binding selectivity of conformationally restricted analogues of (-)-indolactam-V to the C1 domains of protein kinase C isozymes

Two conformationally restricted analogues of (-)-indolactam-V (1) (cis and trans amides) were examined for their binding selectivity to the synthetic C1 peptides of all protein kinase C (PKC) isozymes. Although the binding constants of the cis amide-restricted analogue (2) were equal to those of 1, the trans amide-restricted analogue (3) bound significantly only to the novel PKC (delta, epsilon, eta, theta) isozymes.