Synthesis and phorbol ester-binding studies of the individual cysteine-rich motifs of protein kinase D

To investigate the phorbol ester-binding properties of the individual cyste ine rich motifs of protein kinase D (PKD), the (52)-mer peptides containing each cysteine-rich motif of PKD (PKD-C1A, PKD-C1B) have been synthesized. The [H-3]phorbol-12,13-dibutyrate (PDBu) binding to PKD-C1A was affected dr astically by incubation temperature while that to PKD-C1B was not. Scatchar d analysis of [H-3]PDBu binding to both PKD C1 peptides gave dissociation c onstants of 2.5 +/- 0.4 and 2.7 +/- 0.8 nM for PKD-C1A and PKD-C1B, respect ively, indicating that the two cysteine-rich motifs of PKD are functionally equivalent like those of PKC gamma. (C) 1999 Elsevier Science Ltd. All rig hts reserved.