Novel destabilization of nucleotide binding by the gamma phosphate of ATP in the yeast SR protein kinase Sky1p

Results suggest that the yeast SR protein kinase, Sky1p, strongly destabilizes the gamma phosphate of ATP as determined by the affinities of several nucleotides to Sky1p, thus differeing from the cAMP-dependent protein kinase. Data indicate that both protein kinases may facilitate rapid phosphoryl transfer by a novel mechanism.