SYNTHESIS AND CHARACTERIZATION OF THE FIRST CYSTEINE-RICH DOMAIN OF NOVEL PROTEIN-KINASE-C

The first cysteine-rich domains (CRD's) of mouse PKC eta and PKC delta (eta-CRD1 and delta-CRD1) were prepared by automated solid phase pept ide synthesis. In the presence of phosphatidylserine, zinc-folded eta- CRD1 did not bind [H-3]phorbol 12,13-dibutyrate (PDBu) at all while th e zinc-folded second CRD of mouse PKC eta (eta-CRD2) bound PDBu strong ly with a K-d of 0.91 nM. Moreover, delta-CRD1 showed very weak PDBu b inding affinity (K-d=ca.500 nM) while the K-d of the second CRD of mou se PKC delta was reported to be 1.9 nM. These results suggest that the second CRD's of PKC eta and PKC delta play an important role in the P DBu binding. (C) 1997, Elsevier Science Ltd.