Probing the Recognition Properties of the Antiparallel Coiled Coil Motif from PKN by Protein Grafting
2008-12-23T00:00:00Z (GMT) by
Coiled coils have long been recognized as the major constituent of many fibrous proteins and also serve as oligomerization domains in a wide variety of proteins. More recently, it has become clear that the surfaces of two-stranded coiled coils are also involved in macromolecular recognition. Indeed, the helical hairpin or intramolecular antiparallel coiled coil (ACC) can serve as a protein or nucleic acid recognition motif. Protein kinase N (PKN) interacts with the small GTPase RhoA through ACC motifs. The crystal structure of RhoA with the N-terminal ACC motif (PKN-ACC1) is unusual in that these proteins interact through two distinct surfaces. Using the ACC domain of seryl tRNA synthetase (SRS-ACC) as a scaffold for protein grafting experiments, we show that RhoA interacts with only one face of PKN-ACC1. This result highlights the potential of the SRS-ACC scaffold for protein engineering applications and provides insight into the mechanism of RhoA-mediated signal transduction through PKN.